EQUINE Flashcards
I love donkeys
Which of these parasites causes granulomatous skin lesions that often contain small calcified dead larvae inside?
a. Onchocerca
b. Haematobia
c. Culicoides
d. Habronema
d. Habronema
Habronemiasis is a condition where the larvae of the stomach worm migrate and emerge, creating granulomatous lesions, usually around the eyett, male genitalia, or lower extremities. Inside the granulomas, you can find dead larvae. Culicoides hypersensitivity, also referred as sweet itch, occurs due to allergy to the saliva of the gnat. It recurs seasonally in the warmer months and tends to worsen with age. Typically, horses are pruritic and develop lesions on the poll, mane, and tail from self trauma, although ventral midline dermatits can occur as well. More chronically, scarring can occur. Treatment is to decrease exposure to the gnat and to treat with steroids. Haematobia irritants is a bigger problem in cattle than horses (they reproduce in cow feces) but can affect horses, especially ones that are near cattle. It typically causes ventral midline dermatitis with wheals with a central crust that progress to alopecia and ulceration with fairly focal lesions. Onchocerca can cause dermatitis in the horse due to hypersensitivity to dying microfilariae. Lesions include alopecia and scaling of the ventral midline, face, and pectoral region. Often lesions are diamond shaped, and there may be a “bull’s eye” lesion on top of the head
You are visiting a horse farm to evaluate a horse with seborrheic lesions of the oatern and mild lameness. The owner notes that his horses have had problems with “Scrathces” in the past. Which of the following management recommendations would be helpful in preventing this problem?
a. Keep the horses in an insect-free environment
b. Keep the horses away from the sun during the hottest hours of the day
c. Keep the horses in a dry and clean environment
d. Keep the horses on a regular deworming regimen
c. Keep the horses in a dry and clean environment
Scartches is a condition of chronic seborrheic dermatitis of the palmar/plantar aspect of the pastern. The condition is sometimes referred to by several other names including “grease heel”, “dermatitis verrucosa”. “dew poisoning” and “mud fever”. It is not specific to the underlying infectious cause but the condition is generally associated with horse kept in wet or muddy environment.
Treatment involves removing the horse from the wet environment, clipping the surrounding hair, and gently washing and cleaning the area with a disinfectant followed by careful drying. Topical ointments or astringent dressings may sometimes be used. The best prevention is to keep horses in a dry and clean environment and maintain good hygiene practices
A 2-month-old Thoroughbred foal presents with the onset of profuse watery diarrhea and you suspect salmonellosis (image). There are three specific diagnostic parameters that you, as the clinician. must assess to determine whetehr or not this patient should be confined to isolation. What are the three diagnostic parameters?
a. Diarrhea, fever, and neutrophilia. All 3 of the diagnostic parameters must be present to qualify for isolation
b. Diarrhea, fever, and neutrophilia. All 3 of the diagnostic parameters must be present to qualify for isolation
c. Diarrhea, fever, and neutropenia. Any 2 of the 3 diagnostic parameters qualify for isolation
d. Diarrhea, fever, and neutrophilia. Any 2 of the 3 diatnostic parameters qualify for isolation
c. Diarrhea, fever, and neutropenia. Any 2 of the 3 diagnostic parameters qualify for isolation
Any 2 of these 3 parameters meet the criteria to admit any equine patient into isolation. The most likely cause of the neutropenia is bacteria septicemia and endotoxemia due to gastrointestinal disease. Other common disease that can cause a neutropenia are metritis and coliform mastitis
What is the most common cause of colic in a newborn foal?
a. Salmonella
b. Nephrosplenic entrapment
c. Strongylus vulgaris
d. Meconium impaction
e. Parascaris equorum
d. Meconium impaction
Meconium impaction occurs in the rectum or small colon. Clinical signs include straining, swishing of the tail, and restlessness. Rectal examination reveals numerous hard fecal balls. Treatment consists of an enema with water and a mild soap. Meconium is the first intestinal discharges of the newborn foal, consisting of epithelial cells, mucus, and bile
What is the most common gastric neoplasia in the horse?
a. Lymphosarcoma
b. Adenocarcinoma
c. Squamous cell carcinoma
d. Mesothelioma
c. Squamous cell carcinoma
Squamous cell carcinoma is the most common reported gastric neoplasia in the horse; the other answers have been rarely observed. Presenting signs include weight loss and colic. Unfortunately, there is no effective treatment at this time
A 13-year old Hanoverian brood mare presents for an acute onset of lethargy, anorexia, and explosive, watery, diarrhea. The diarrhea began approximately 14 hours after the initial signs of anorexia and lethargy. Clinicopathologic findings include neutropenia 2300/ul (normal 2,900-8,500/ul) with toxic neutrophils along with the typical electrolyte abnormalities seen with diarrhea Sodium 115 mEq/L (128-142 mEq/L) and Chloride 83 mEq/L (98-109 mEq/L). Which of the following pathogens is most commonly known for being able to cause a presentation such as the one described in this horse?
a. Parascaris equorum
b. Ehrlichial equi (Anaplasma phagocytophilia)
c. Strongyloides westeri
d. Salmonella
d. Salmonella
Salmonella can cause several different clinical presentations including subclinical infection, self limiting diarrhea, and acute diarrhea with endotoxemia.
Parascaris equorum and Strongyloides westeri are both parasites that may cause diarrhea. Parascaris equorum infestations may result in lethargy, depression, and respiratory signs. Occasionally, they result in intestinal obstruction and subsequent perforation. Strongyloides westeri is associated with diarrhea in foals and not in adult horses. Mares usually harbor this organism in their tissues and then transmit the parasite in the milk, thus infecting foals. Ivermectin administered to the mare will usually kill any Strongyloides westeri harbored by the mare.
Clinical signs of Ehrlichia equi include lethargy, anorexia, fever, limb edema and hematology changes such as neutropenia and thrombocytopenia. One might confuse Ehrlichia equi with Ehrlichia risticii (Neorickettsia risticii), the later causing lethargy, anorexia, fever, diarrhea, and laminitis. However, keep in mind that less than 60% of horses with Potomac Horse Fever develop diarrhea.
Diagnosis of E. risticii requires measurement of paired serum titer via immuno-fluorescent antibodies or detection of the organism via PCR in the blood or feces. Diagnosis of Salmonella requires serial cultures of feces for 3-5 days. Diagnosis of Strongyloides westeri and Parascaris equorum is by demonstration of eggs in the feces.
A valuable horse suddenly developed severe intractable diarrhea and fever 5 days ago. The owner has been giving it oral electrolytes free choice in the water, and offering it hay, grain, and green grass. It is brought to your clinic on a normal warm summer day looking thin, dehydrated, weak, and anorectic (see photo). You do a physical exam and find T=102F (38.9 C), HR=56, RR=24, with somewhat purplish oral mucous membranes. The urine is normal but has a small volume and looks concentrated. You run a PCV (45%), WBC count (normal at 7000/microliter) and total protein (TP). The TP is low at 3.5 gm/dL and the albumin is 1.4 gm/dL indicating a protein-losing enteropathy. Of the following, what is the best treatment for the low plasma proteins in this horse?
a. IV plasma
b. Whole blood IV
c. Oral albumin
d. IV amino acids
a. IV plasma
The damaged bowel is leaking albumin out into the gut lumen, and the horse may develop other problems such as edema and poor healing ability if the protein levels are not boosted. The best way to do that in an animal with GI disease is by the IV route. Whole blood may raise the PCV to a level where sludging and circulatory problems develop in an already dehydrated horse. Another option to consider if plasma is not readily available is the use of synthetic colloidal solutions such as hetastarch.
You are treating a colicky 8-year old horse and pass a stomach tube to assess gastric reflux. The 20 liters of reflux is hemorrhagic, orange-brown in color, and foul-smelling. On physical exam, you find T=101.5F (38.6 C), HR=70, and RR=35 and overall depressed attitude. There are few auscultable gut sounds. Oral mucous membranes are injected. On rectal exam, there are multiple dilated fluid-filled loops of bowel palpated. Peritoneal fluid is serosanguinous with a 3.5 gm/dl protein and a WBC count of 7000. After decompressing the stomach, the horse appears less painful, but remains depressed. Based on these findings, what is the best tentative diagnosis?
a. Impaction colic (large bowel impaction)
b. Verminous arteritis cuased by strongylus vulgaris
c. Duodenitis-proximal jejunitis
d. Large bowel torsion
e. Acute small intestinal obstruction
c. Duodenitis proximal jejunitis
Duodenitis-proximal jejunitis, also known as either anterior enteritis, or proximal enteritis best fits this case because of the characteristic reflux, fever, peritoneal fluid characteristics, rectal findings, the depression and relatively less pain than would be expected with an obstruction. The cause is still uncertain, but a relationship of this disease to positive cultures of reflux for Clostridium difficile has been found. Typically these cases are treated medically, which would include repeated decompression of the stomach, IV fluids, replacement of electrolyte deficiencies, analgesics and correction of any acid-base abnormalities.
Consumption of yellow star thistle results in this lesion.
a. Leukoencephalomalacia of the reticular system
b. Destruction of the lateral and medial geniculate nucleus
c. Destruction of the pons
d. Nigropallidal encephalomalacia
d. Nigropallidal encephalomalacia
Consumption of yellow star thistle destroys the globus pallidus and the substantia nigra. These lesions will result in a characteristic dysphagia.
A 12-year old mare presents for a sudden onset of ptyalism and an inability to prehend food. Where is the lesion?
a. Substantia nigra and globus pallidus
b. Carpus callosum and amyglada
c. Caudal cerebellar peduncle and medial longitudinal fasciculus
d. Lateral lemniscus and rostral olivary nucleus
a. Substantia nigra and globus pallidus
A lesion to these basal ganglia will result in movement disorders. Particularly, yellow star thistle poisoning will lead to an inability to prehend food in horses. The corpus callosum connects the two cerebral hemispheres together, and the amygdala is involved with fear and memory. The caudal cerebellar peduncle connects the medulla to the cerebellum and is involved in transmission of signals pertaining to movement. The medial longitudinal fasciculus is involved in conjugate gaze. The rostral olivary nucleus and lateral lemniscus are both involved in auditory pathways.
The owner of a horse farm in the Southeastern United States calls you to come to his place two days after a huge wind storm that knocked down trees and power poles. There are seven ill horses. Upon examination you note lethargy, anorexia, dyspnea, coffee-colored urine, and icterus. Which of the following is the most likely cause?
a. Rattlesnake bite
b. Equine infectious anemia
c. Red maple (Acer rubrum) poisoning
d. Babesiosis
e. Copper poisoning
c. Red maple (Acer rubrum) poisoning
Horses seem to eat the leaves when branches are available, and the plant contains an unidentified hemolysin in wilted leaves. Ingestion can be fatal.
You are examining a 5-year old pony for lethargy, anorexia, and mild intermittent colic. Upon physical examination, you notice the abnormal finding in the image. Consumption of which of the following can produce these clinical signs and physical examination findings?
a. Oak leaves and acorns (Quercus sp)
b. Red maple leaves (Acer rubrum)
c. Black walnut (Juglans nigra)
d. Yellow star thistle (Centaurea solstitialis)
b. Red maple leaves (Acer rubrum)
The sclera appears icteric. In combination with the clinical signs, ingestion of Red maple leaves would result in these signs due to hemolysis and low oxygen content of the blood. Oak is toxic but causes diarrhea and abdominal pain, whereas Black walnut is associated with laminitis. Yellow star thistle causes nigropallidal encephalomalacia resulting in CNS signs.
Which of the following causes liver failure when ingested by horses?
a. Oleander
b. Fiddleneck
c. Bracken fern
d. Astragalus
b. Fiddleneck
Fiddlenecks contain pyrrolizidine alkaloids as does groundsel, ragwort, and senecios. Pyrrolizidine alkaloids cause secondary photosensitization as well as hepatic damage that are cumulative and progressive. Treatment consists of supportive care for liver failure and prognosis is poor.
What are the two most common NSAID toxicoses seen in the horse?
a. Right ventral colitis and pulmonary edema
b. Renal papillary necrosis and right dorsal colitis
c. Hepatic necrosis and renal papillary necrosis
d. Bone marrow suppression and hepatic necrosis
e. Right dorsal colitis and splenic infarcts
b. Renal papillary necrosis and right dorsal colitis
The exact reason why the right dorsal colon is susceptible to ulceration as a result of NSAID use is not entirely known. Interestingly, some horses may develop right dorsal colitis even on appropriate doses of NSAIDS. Consistent findings of right dorsal colitis include colic and hypoproteinemia. The lesion in the kidney is classic and is due to the limited blood flow normally supplied to the corticomedullary region of the kidney. This part of the kidney relies on prostaglandins for adequate blood flow; with inappropriate NSAID use, blood flow to this area of the kidney is compromised, resulting in this classic lesion. Don’t forget, NSAIDs are also associated with gastric ulcers.
If a horse is in seasonal anestrus, which of these is the most effective means of hastening the start of the breeding season?
a. Provide artificial light for 16 hours per day 30 days prior to the start of breeding
b. Provide artificial light for 12 hours per day 60 days prior to the start of breeding
c. Provide artificial light for 16 hours per day 60 days prior to the start of breeding
d. Provide artificial light for 12 hours per day 30 days prior to the start of breeding
c. Provide artificial light for 16 hours per day 60 days prior to the start of breeding
To get a horse to transition out of seasonal anestrus, you can gradually increase the amount of light to 15-16 hours per day to initiate ovarian activity. It usually takes at least 60 days until physiologic breeding will occur. There are hormonal methods to promote cycling, but they are less consistent than altering light.
You suspect equine infectious anemia is a cause of abortion in a mare. What test would confirm this diagnosis?
a. Direct Coomb’s test
b. Coggin’s test
c. Indirect Coomb’s test
d. Live biopsy with immunofluorescent antibody
e. Blood smear
b. Coggin’s test
This test is an agar immunodiffusion to detect serum antibodies against the retrovirus causing equine infectious anemia. Coomb’s tests are done to diagnose immune mediated hemolytic anemias. The blood smear and liver biopsy would not show anything specific for equine infectious anemia.
A uterine biopsy is most useful for which of the following in a mare?
a. Predicting if a mare can carry a foal to term
b. Predicting where a mare is in the estrus cycle
c. Predicting if a mare can undergo parturition without dystocia
d. Predicting if a mare can become pregnant
a. Predicting if a mare can carry a foal to term
Uterine biopsies in horses are most useful to determine the amount of fibrosis present in an older mare’s uterus, which indicates how able she is to carry a foal to term. Biopsies can be categorized into Kenney categories, which is a scoring system from 1-3 where a “1” means there are minimal changes and a “3” indicates marked changes. A mare with a score of “3” has approximately a 5% chance of carrying a pregnancy to term. However, she may still be able to get pregnant. Biopsy will show some changes that reflect the phase of the cycle but is not an accurate way to predict where you are in the cycle.
A mare has aborted due to an equine herpesvirus-1 infection. What would you tell the owner about her future as a breeding horse?
a. She should be treated with oral acyclovir for at least 3 weeks to avoid future abortions
b. Future breeding are still possible, and the mare can still prodcue healthy foals in the future
c. She will be latently infected and should not breed this mare again
d. The mare can maintain a future pregnancy, but the fetus is likely to be born with equine herpesvirus with a low chance of survival
b. Future breeding are still possible, and the mare can still prodcue healthy foals in the future
Vaccination of the mare during her next pregnancy against EHV (gestational months 5, 7 and 9) may help lessen the chance of abortion in the future. Acyclovir, while active against herpesvirus is not indicated (and is not well absorbed orally anyway).
You examine a 2 year old horse with the complaint of bilateral nasal discharge and lethargy for about a week. The horse has a temperature of 102F (38.9 C), HR 40, and RR 25. The nasal discharge is non-odorous and contains multiple bacteria and neutrophils. The lateral throat area is swollen and tender on palpation. Lateral radiographs reveal fluid lines in the area of the guttural pouches. You submit some of the liquid pus for culture. What treatment is now most indicated?
a. Dialy catheterization and lavage of the pouches
b. IM tetracycline daily for 2 weeks
c. Systemic erythromycin for one month
d. Systemic treatment with antifungal drugs for 4 weeks
e. Immediate surgical drainage
a. Dialy catheterization and lavage of the pouches
Irrigation should use saline or saline plus an appropriate and non-irritating antimicrobial drug. Systemic antimicrobial drugs are also used, but the hallmark of successful therapy is lavage and drainage. For inspissated pus or refractory cases, surgical drainage may be necessary.
Which of the following treatments is the least effective in the management of Recurrent Airway Obstruction (RAO; also known as chronic obstructive pulmonary disease) in a horse?
a. Corticosteroids
b. Flunixin meglumine
c. Environmental changes
d. Clenbuterol
b. Flunixin meglumine
While flunixin (Banamine) is a common non-steroidal anti-inflammatory drug used in horses, it does not impart great therapeutic benefits in the horse with RAO. RAO is characterized by bronchoconstriction and accumulation of mucus/neutrophils. Clenbuterol is a Beta agonist that causes bronchodilation, while corticosteroids are potent anti-inflammatory medications that can reduce mucus and neutrophil accumulation. Environmental changes, such as placing the horse at pasture, feeding hay that has been soaked in water, and trying to reduce exposure to inhaled allergens are also part of the treatment protocol for a horse with RAO.
Equine viral arteritis can be transmitted by which of these routes?
a. Blood-sucking arthropods
b. Venereally
c. Fecal-oral
d. Through open wounds
b. Venereally
Carrier stallions can infect mares. It can also be spread by aerosol. Equine viral arteritis (EVA) is in the genus Arterivirus, family Arteriviridae and causes vasculitis leading to edema, conjunctivitis, rhinitis, and abortion.
You are evaluating a 4 year old Thoroughbred for intermittent epistaxis. Upon examination of skull radiographs (see image), what is the most likely diagnosis for the epistaxis?
a. Exercise induced pulmonary hemorrhage
b. Nasal adenocarcinoma
c. Guttural pouch mycosis
d. Ethmoid hematoma
d. Ethmoid hematoma
The most likely cause of the epistaxis based on the radiographs is ethmoid hematoma. These lesions are angiomatous masses that originate from the mucosal lining of the ethmoid conchae or walls of the maxillary or frontal sinus. Guttural pouch mycosis also can result in epistaxis but typically has no radiographic changes. Although horses can get tumors in the nasal passages, this is relatively rare. Exercise-induced pulmonary hemorrhage also can result in epistaxis, but the blood originates from the lungs. In the radiograph provided, notice the smooth, well-defined soft tissue mass in the sinus region of this horse. No osseous changes or fluid lines are apparent in this radiograph. In this particular case (ethmoid hematoma), the soft tissue mass is actually dorsal to the ethmoid turbinates (ethmoids are normal appearance in this case). Upon surgical removal, a definitive diagnosis of ethmoid hematoma was confirmed
What is the treatment of choice for a Rhodococcus equi infection in a foal?
a. Penicillin and metronidazole
b. Enrofloxacin and ampicillin
c. Trimethoprim-sulfa and metronidazole
d. Erythromycin (or other macolide antimicrobial such as clarithromycin and rifampin
d. Erythromycin (or other macolide antimicrobial such as clarithromycin and rifampin
This is a must-know fact, as this disease is very commonly encountered. Treatment is usually for about 2 months but should be based on resolution of clinical signs, radiographic signs, and bloodwork. More recently, newer macrolide antimicrobials such as Clarithromycin and Azithromycin have been used in foals with R. equi pneumonia. One clinical study demonstrated better outcome with Clarithromycin and rifampin; additionally, Clarithromycin is typically administered twice daily, whereas erythromycin may have to be administered four times a day.
A 4 year old horse presents to you with a mucopurulent nasal discharge, lethargy, and depression. On physical exam, the horse has a temperature of 103.7F (39.8 C) and has markedly enlarged mandibular and retropharyngeal lymph nodes. You suspect that the horse has strangles. What would you expect to see if you aspirated one of the enlarged lymph nodes?
a. Purulent inflammation and gram positove cocci with large capsules
b. Reactive lymphocytes and macrophages with no bacteria
c. Purulent inflammation and gram negative rods with large capsules
d. Granulomatous inflammation and gram negative cocci
e. Fungal hyphae and granulomatous inflammation
a. Purulent inflammation and gram positove cocci with large capsules
The causative agent of strangles is streptococcus equi ssp. equi which is a gram positive cocci with a large capsule. It causes suppurative abscessation and enlargement of the mandibular and retropharyngeal lymph nodes.
7 year old male Clydesdale horse presents for exercise intolerance and noisy breathing. On your exam, you note mild inspiratory dyspnea with an audible whistling sound on inspiration. What is the most likely diagnosis?
a. Laryngeal hemiplegia
b. Sinusitis
c. Asthma
d. Intrathoracic large airway obstruction
a. Laryngeal hemiplegia
In this condition, the recurrent laryngeal nerve is damaged. Interestingly, the left side is almost always the side that is affected. An actual cause is usually not found, although direct trauma and certain toxins can cause laryngeal hemiplegia. It is thought to be a hereditary disorder. An intrathoracic large airway obstruction and asthma would both cause more expiratory dyspnea. Sinusitis may cause nasal discharge but is not likely to cause the signs this horse is showing.
In the horse, what is the most important muscle or muscle group required for the inspiratory phase of the respiratory cycle?
a. External intercostals
b. Abdominal muscles
c. Diaphragm
d. Internal intercostals
c. Diaphragm
Contraction of the diaphragm pushes the abdominal contents back, increasing the length of the thoracic cavity, and pulls the ribs abaxially. The external intercostal muscles assist in pulling the ribs abaxially. This ends up producing subatmospheric intrathoracic pressures and allows inspiration to occur. Contraction of the internal intercostal muscles and the muscles of the abdominal wall decrease lung volume and compress the chest wall. The diaphragm is important in this process because diseases altering innervation or strength of the diaphragm (such as botulism or phrenic nerve damage) or diseases preventing expansion of the diaphragm into the abdomen (such as large colon torsion) are important causes of respiratory distress and potentially hypoxemia and death.
Cervical vertebral stenotic myelopathy in horses is best treated with _______.
a. Surgery
b. Steroids
c. Non-steroidal anti-inflammatories
d. Stall rest
a. Surgery
Surgery is required so that you may stabilize the cervical vertebrae and decompress the spinal cord. There are two forms of cervical vertebral stenotic myelopathy (aka wobbler syndrome). One form is called cervical vertebral instability. In this case, ventroflexion of the neck results in spinal cord compression. Most commonly affected sites are C3-4 and C4-5. The other form is known as cervical static stenosis. In this case, the compression is continuous regardless of the neck position. Clinical signs are usually in the form of a wide-based stance, conscious proprioceptive deficits, ataxia, paresis, and spasticity which is worse in the hindlimbs. Anti-inflammatories and stall rest may temporarily decrease clinical signs but are typically not a long-term therapy.
A 6-year old Morgan horse presents for an ocular evaluation. The owner is concerned that the horse has a corneal ulcer. You notice that the horse has marked blepharospasm. Which of the following best describes the effects of an auriculopalpebral nerve block in this horse?
a. Blocks sensory innervation of the upper two-thirds of the eyelids
b. Blocks sensory innervation of the cornea
c. Disrupts motor innervation to the levator palpebrae superioris
d. Disrupts motor and sensory innervation to the eyelids
e. Disrupts motor innervation to the orbicularis oculi
e. Disrupts motor innervation to the orbicularis oculi
The auriculopalpebral nerve is a branch of the facial nerve and is therefore motor only. The auriculopalpebral block is useful in providing eyelid akinesis by blocking motor innervation primarily to the orbicularis oculi, thereby allowing manipulation of the eyelids without putting pressure on an already painful eye. This block is motor only and does not provide any desensitization.
The supraorbital/frontal nerve block can be used to block a branch of the ophthalmic division of the trigeminal nerve, desensitizing the middle two-thirds of the upper eyelid and forehead skin. It may also provide some motor block of the levator palpebrae superioris due to a branch of the oculomotor nerve which runs adjacent.
A 3-month-old paint colt presents to you after flipping over backward while being led by the owner the previous day. Clinical signs at the time of presentation are shown in the image (head tilt, flaccid ear, muzzle deviation). Based on the history and clinical signs, what cranial nerves are damaged and what is the most likely diagnosis?
a. Cranial nerves V and VII (left side); atlanto-occipital malformation
b. Cranial VII and VIII (left side); fracture of the basisphenoid bone
c. Cranial nerves V and VIII (left side); fracture of the sphenoid bone
d. Cranial nerves V and VII (left side); atlanto-occipital malformation
e. Cranial nerves VII and VIII (rightside); fracture of the basisphenoid bone
b. Cranial VII and VIII (left side); fracture of the basisphenoid bone
The correct answer is damage to cranial nerves VII (facial nerve) and VIII (vestibular nerve) on the left side caused by fracture of the basisphenoid bone. This is a common injury when a fractious young foal rears up and falls backward on the poll. The basisphenoid bone becomes injured resulting in injury to cranial nerves VII and VIII. Damage to the facial nerve results in the muzzle deviation (opposite direction of the side of injury, in this case deviated to the right), ptosis of the left eye and drooping of the left ear. Damage to the vestibular nerve results in the head tilt.
What structure is not likely to be affected with a guttural pouch infection of a horse?
a. CN VIII
b. CN VI
c. CN IX
d. Carotid artery
e. Cranial sympathetic trunk
b. CN VI
This nerve does not run along the guttural pouch in contrast to the others listed. Both the internal and external carotids may be affected during a guttural pouch infection. In case you don’t remember, the guttural pouch in a horse is the air-filled diverticula of the auditory tube which communicates between the middle ear and the pharynx. Sometimes foreign material will get trapped there and result in infection.
How long after receiving a puncture wound would you expect to see clinical signs of tetanus if a horse was infected?
a. 3-4 weeks
b. 3-5 days
c. 1-2 hours
d. 10-14 days
e. 12-24 days
d. 10-14 days
Typically, the incubation period for tetanus is about 2 weeks, because it takes time for the spores to grow in an anaerobic environment before they produce toxin that can then be picked up by the nerves.
The owner of a weanling colt has asked for a pre-purchase examination to be performed on her 4 month old colt. The colt appears in good health based on physical examination with the only abnormality noted being a holosystolic murmur heard best on the right side of the thorax. What is your diagnosis based on auscultation and echocardiographic findings (see image; long-axis view from left side)?
a. Atrial septal defect (ASD)
b. Ventricular septal defect (VSD)
c. Truncus arteriosus
d. Patent ductus arteriosus (PDA)
b. Ventricular septal defect (VSD)
The image demonstrates a VSD or a hole in the intraventricular septum (identified by two markers). This is one of the more common congenital defects of the heart in horses.
The murmur occurs as blood is shunted from the left side of the heart to the right during systole. Some horses can perform normally with a VSD while others, with large defects, can demonstrate heart failure. In this case, it was an incidental finding, as the horse was bright and alert at the time of exam. The remainder of the answers (ASD, PDA, and truncus arteriosus) can occur but are less common and would appear differently on echocardiography.
It is unlikely but possible that you will be asked to interpret an echocardiogram on your board exam. If you are, this is likely to be one of the diseases you could be shown.
What is the treatment of choice for atrial fibrillation in the horse?
a. Electrical defibrillation
b. Digoxin
c. Precordial thump
d. Do nothing; this is a benign arrhythmia in the horse
e. Quinidine
e. Quinidine
Ideally, you would begin oral dosing of quinidine via a nasogastric tube at 2 hour intervals until there is conversion or toxicosis. An increase in the QRS duration of greater than 25% as compared to before initiation of treatment is considered a sign of toxicity. Clinical signs of toxicosis include colic, ataxia, hypotension, diarrhea, and edema. Digoxin will not convert an atrial fibrillation to a normal rhythm. However, it is indicated as adjunctive therapy when the vagolytic effect of quinidine causes a significant acceleration in ventricular response rate, the resting heart rate in excess of 90 beats per minute, if the horse is exhibiting a low vagal tone, or if conversion has not been achieved within 24 hours of initiating quinidine therapy. A precordial thump is ineffective, and defibrillation is only indicated during ventricular fibrillation, not atrial. Usually, there is an excellent prognosis for conversion if the horse has a heart rate of less than 60 beats per minute, atrial fibrillation of less than four months duration, and if there is a murmur less than or equal to a grade 3/6.
What is the most frequently observed side effect associated with acepromazine use in horses?
a. Arrythmias
b. Paraphimosis
c. Hypotension
d. Seizures
c. Hypotension
Acepromazine will reliably cause hypotension. Acepromazine may cause paraphimosis in male horses, but this is not very common. However, because of this, many veterinarians will not use acepromazine on stallions. Acepromazine actually has anti-arrhythmogenic properties. Acepromazine does reduce the seizure threshold, but seizures are not as common as hypotension.
A 28 year old Paint stallion presents with an acute onset of colic. On presentation he has a rectal temperature of 99.8F (37.7 C), heart rate of 75 beats/min, respiratory rate of 24 breaths/min, and is pawing and trying to lie down. CRT is approximately 3.0 seconds, and mucous membranes are purple-red. Gastrointestinal sounds are completely absent, and gastric reflux yielded 18L of brown- to yellow-colored fluid. Peritoneal fluid analysis yielded a cloudy yellow fluid with a protein of 3.2 gm/dl and white blood cell count of 11,000/ul. Which of the following is a possible diagnosis?
a. Cecal volvulus
b. Left dorsal colon displacement
c. Strangulating lipoma
d. Strongylus vulgaris infestation
e. Right dorsal colon displacement
c. Strangulating lipoma
Lipomas are a common cause of small intestinal obstruction in older horses. Typically, a section of the small intestine becomes intertwined with a pedunculated lipoma, resulting in obstruction and possible devitalization of the small intestine. Surgical correction is necessary to correct this problem. None of the other answer choices typically result in the clinical signs described, particularly gastric reflux. Left dorsal colon displacement typically have milder clinical signs, and the diagnosis can be made by rectal palpation and ultrasonography.
A Paint horse is found to be approximately 7% dehydrated after a several day trail ride. Assuming there are no other ongoing losses and the horse weights 500kg how many liters of fluid will you need to give this horse over a 24 hou period to correct the deficit and account for maintenance requirements?
a. 40L
b. 65L
c. 35L
d. 75L
e. 125L
b. 65L
To determine this answer you must figure out the deficit and calculate the horse’s maintenance needs. The deficit is 35L (deficit x BW). Maintenance needs for a horse is approximately 60mL/kg/day. In this case, 30L. Adding the deficit and maintenance fluids together yields a total of 65 liters.
A 36 hour foal born from a multiparous mare presents for weakness, decreased appetitie, and tachycardia. On physical exam, you examine the sclera as seen in the photo. Based on the signalment and findings, what is a likely cause?
a. Congenital iron toxicity
b. Neonatal Isoerythrolysis
c. Immune mediated thrombocytopenia
d. Failure of passive transfer
b. Neonatal Isoerythrolysis
Neonatal Isoerythrolysis (NI) would be a possible cause of the icterus noted in the sclera. NI is common in multiparous mares and usually affects foals between 24-72 hours of age. NI results in hemolysis, hyperbilirubinemia, and icterus. A low packed cell volume would further support NI.
NI develops because the newborn foal expresses alloantigens on its red blood cells inherited from the sire that the mare does not have. If the mare becomes sensitized to the sire’s specific antigen, maternal antibodies are produced and absorbed by the foal soon after birth. This subsequently results in lysis of the red blood cells
Which of the following can cause aggression in mares?
a. Melanoma
b. Luteal cyst
c. Granulosa cell tumor
d. Sertoli Cell tumor
c. Granulosa cell tumor
Granulosa=theca cell tumors are the most comon ovarian tumor in horses and can cause increased levels of testosterone, sometimes causing aggressive behavior towards people. Another cause of aggression in horses is hypothyroidism.
During your examination of an 19-year old horse, you observe what
Two pet horses on a ranch are presented for extreme pruritus at their ventrum. The owners report the pruritus has gotten worse during the summer, and they notice increased numbers of small flying insects around at dusk and dawn. Examination of the horses reveals excoriations, alopecia, and thickening of the skin at the ventrum. One of the flies collected in the field by the owner is a small fly with mottled wings. What is your most likely diagnosis?
a. Onchocerciasis
b. Tabanus fly bites
c. Culicoides hypersensitivity
d. Mosquito hypersensitivity
e. Chrysops fly bites
c. Culicoides hypersensitivity
Culicoides hypersensitivity is extremely pruritic and is also known as “sweet itch”. Horses can be affected on their ventrum or dorsum, depending on the species of the fly. The horse develops a type 1 hypersensitivity to the flies’ salivary antigens and develops excoriations, alopecia, and thickened skin as a result of scratching. The flies are more prevalent during the warmer seasons and are most active during dusk and dawn. Treatment includes controlling the fly population. Stabling the horses at dusk is often helpful because the flies rarely enter barns. Insecticides, stable blankets, and fans for circulating air in the stables may also be useful. The extreme pruritus and seasonality of the clinical signs is often enough to differentiate the Culicoides hypersensitivity from other skin diseases. Onchocerciasis is vectored by Culicoides, but is not seasonal and is not nearly as pruritic. Mosquitoes can be an annoyance and, more importantly, are vectors for more serious diseases such as the equine encephalitides. Tabanus flies and Chrysops flies cause pain to horses by lacerating them with their mouth parts to feed on their oozing blood. They do not cause pruritus and can be differentiated by their large, robust size.
Which of the following is not known to classically cause crusting dermal lesions on horses?
a. Dermatophytosis
b. Dermatophilosis
c. Generalized granulomatous disease
d. Corynebacterium psuedotuberculosis
e. Pemphigus foliaceus
d. Corynebacterium psuedotuberculosis
Corynebacterium pseudotuberculosis is also known as pigeon fever. It causes an ulcerative lymphangitis and abscesses in the pectoral region of horses. Treatment is aimed at hot packing the swellings and draining the abscesses. Antibiotics can be administered but have been known to prolong the disease by delaying abscess formation. The other four answer choices classically present as crusting dermal lesions on horses.
A 6-year old Quarter Horse presents with the lesion seen in the photograph. Which of the following is true regarding equine sarcoids?
a. Papiloomavirus is believed to play a role in the pathogenesis
b. They usually regress spontaneously without treatment
c. Surgical excision is nearly always curative
d. Metastasis is common with advanced lesions
a. Papiloomavirus is believed to play a role in the pathogenesis
Sarcoids are one of the most common tumors in horses. They are considered non-metastatic tumors in virtually all cases. For this reason, small lesions are sometimes treated with benign neglect, but they are not expected to regress. More advanced lesions or tumors in certain sites do need to be treated more aggressively. Unfortunately, no single treatment is universally effective. Recurrence rates after surgical excision are approximately 50%. Although there is still controversy surrounding this issue, either bovine papillomavirus or an equine variant is thought by many to play a role in development of these tumors.
A Thoroughbred race horse has been moved from California to Florida in July and is experiencing poor performance, exercise intolerance and tachypnea. You observe the horse working out one hot afternoon and see these signs, but you also note that the horse is not sweating. You check the rectal temperature and note that it is 104F (40 C). What is the diagnosis?
a. Anhidrosis
b. Hypothyroidism
c. Diabetes insipidus
d. Equine Cushing’s
e. Influenza
a. Anhidrosis
Anhidrosis is the inability to sweat, which can be fatal if not addressed. The cause is unknown. It tends to occur in hot humid climates, and may occur in horses raised in the climate, or more commonly, horses brought into the climate. The most successful treatment is to move the horse back to a more favorable climate.
What stimulates antidiuretic hormone (ADH) secretion in the horse?
a. Hyperosmolality and increased circulating blood volume
b. Hypoosmolality and decreased circulating volume
c. Hypoosmolality and increased circulating volume
d. Hyperosmolality and decreased circulating blood volume
d. Hyperosmolality and decreased circulating blood volume
In the horse, as in other species, ADH increases renal water reabsorption and urine osmolality by increasing permeability of the collecting tubules. Osmoreceptors in the hypothalamus detect subtle changes in plasma osmolality. If osmolality rises, you will hope to see ADH secretion so that the urine excreted would be more concentrated. The same is true if circulating volume decreases; thus, a lesser volume of water would be lost. When ADH secretion does not occur or if the kidneys are unable to respond to ADH, this is likely diabetes insipidus, and animals will be very polyuric, polydipsic and have extremely dilute urine.
A 23-year old Morgan horse presents to you for evaluation due to several changes that the owner has noticed in recent months. He reports that the horse has been drinking and urinating more frequently and seems to have lost muscle mass. He also reports excessive sweating and hair coat changes. Specifically he reports that the horse has developed a long curly hair coat that does not shed properly (see image). You recognize this array of clinical signs as being very consistent with a common clinical syndrome in older horses. Which of the following is the most appropriate treatment for this condition?
a. Pergolide
b. Levothyroxine
c. Quinidine
d. Glargine
e. Dexamethasone
a. Pergolide
This case describes the typical presentation of equine pituitary pars intermedia dysfunction (PPID), sometimes referred to as equine Cushing’s disease. The disease is a progressive disorder of pituitary pars intermedia enlargement (adenoma). The condition usually affects horses greater than 15 years of age and may affect any breed but ponies and Morgan horses have increased incidence. The classic symptom which is highly suggestive of this condition is hirsutism which is the symptom of a long curly hair coat that does not shed properly. Other symptoms include polyuria, polydipsia, laminitis, lethargy, excessive sweating or lactation, decreased muscle mass, infertility, and susceptibility to infections such as tooth root abscesses.
Hirsutism as a clinical sign is the most sensitive indicator of PPID. Diagnosis of PPID by laboratory testing in horses with subtle signs can be challenging since no single test is absolutely sensitive and specific. Measurement of plasma ACTH concentrations is a simple and acceptable test, but must be compared to seasonal reference intervals as the concentration of ACTH fluctuates during the year (highest in the September, lower in January). Of practical note, the sample must be chilled or frozen until processing. Others have suggested the use of the thyrotropin-releasing hormone (TRH) stimulation test, which causes a significantly higher concentration of ACTH in PPID horses. However, TRH is may not be readily available. Finally, the dexamethasone suppression test has historically been used to diagnose PPID, but concerns in regard to steroid administration and the development of laminitis (or worsening of existing laminitis) has resulted in the test being used less frequently.
Treatment aims to decrease clinical signs and does not typically result in a cure or complete remission of all signs. Pergolide is generally considered the treatment of choice. Pergolide is a dopamine agonist that is used to treat Parkinson’s disease in humans. The drug acts to suppress pituitary hormone secretion. Older references will refer to the use of cyproheptadine which is a serotonin antagonist as a preferred treatment for PPID. There is also investigation that trilostane, a 3-beta hydroxysteroid dehydrogenase inhibitor may be useful in the management of PPID.
Quinidine is used to treat atrial fibrillation in horses. Glargine is a long acting insulin analogue used in the treatment of diabetes mellitus. Levothyroxine is a synthetic thyroid hormone used to treat hypothyroidism. Dexamethasone is a corticosteroid and can be used to help establish a diagnosis of PPID but is not a treatment.
A 2-month-old Thoroughbred foal presents with the onset of profuse watery diarrhea and you suspect salmonellosis (see image). There are three specific diagnostic parameters that you, as the clinician, must assess to determine whether or not this patient should be confined to isolation. What are the three diagnostic parameters?
a. Diarrhea, fever, and neutropenia. All 3 of the diagnostic parameters must be present to qualify for isolation
b. Diarrhea, fever, and neutrophilia. All 3 the diagnostic parameters must be present to qualify for isolation
c. Diarrhea, fever, and neutropenia. Any 2 of the 3 diagnostic parameters qualify for isolation
d. There are no specific diagnostic parameters for isolation qualification. Any foal or horse with diarrhea should be admitted to isolation.
e. Diarrhea, fever, and neutrophilia. Any 2 of the 3 diagnostic parameters qualify for isolation
c. Diarrhea, fever, and neutropenia. Any 2 of the 3 diagnostic parameters qualify for isolation
The most likely cause of the neutropenia is bacterial septicemia and endotoxemia due to gastrointestinal disease. Other common diseases that can cause a neutropenia are metritis and coliform mastitis.
You are treating a colicky 8-year old horse and pass a stomach tube to assess gastric reflux. The 20 liters of reflux is hemorrhagic, orange-brown in color, and foul-smelling. On physical exam, you find T=101.5F (38.6 C), HR=70, and RR=35 and overall depressed attitude. There are few auscultable gut sounds. Oral mucous membranes are injected. On rectal exam, there are multiple dilated fluid-filled loops of bowel palpated. Peritoneal fluid is serosanguinous with a 3.5 gm/dl protein and a WBC count of 7000. After decompressing the stomach, the horse appears less painful, but remains depressed. Based on these findings, what is the best tentative diagnosis?
a. Impaction colic (large bowel impaction)
b. Verminous arteritis caused by strongylus vulgaris
c. Doudenitis-proximal jejunitis
d. Large bowel torsion
e. Acute small intestinal obstruction
c. Doudenitis-proximal jejunitis
Duodenitis-proximal jejunitis, also known as either anterior enteritis, or proximal enteritis best fits this case because of the characteristic reflux, fever, peritoneal fluid characteristics, rectal findings, the depression and relatively less pain than would be expected with an obstruction. The cause is still uncertain, but a relationship of this disease to positive cultures of reflux for Clostridium difficile has been found. Typically these cases are treated medically, which would include repeated decompression of the stomach, IV fluids, replacement of electrolyte deficiencies, analgesics and correction of any acid-base abnormalities.
Horses living in a sandy region such as California and Florida tend to be predisposed to developing sand enteropathies. If one is suspected, which of the following treatments will be most effective?
a. Mineral oil
b. Charcoal
c. Psyllium
d. Bismuth subsalicylate
c. Psyllium
Psyllium is a hemicellulose laxative that has the ability to bind with sand and help remove it from the gastrointestinal tract. Feeding the horse in a stall and/or utilizing hay racks will also help the inadvertent consumption of sand that may be ingested if a horse is eating on sandy ground. None of the other answer choices are as effective as psyllium.
A 7-year old male Thoroughbred presents with a history of colic, increased heart rate, and increased respiratory rate. On physical exam, there is no reflux; on rectal exam, the colon is palpable between the cecum and body wall. What is the diagnosis?
a. Cecal volvulus
b. Left dorsal colon displacement
c. Right dorsal colon displacement
d. Strandulating lipoma
c. Right dorsal colon displacement
The rectal exam findings are characteristic for a right dorsal colon displacement. You can sort of figure out the answer even if you know nothing about horses, just think anatomy. The cecum is on the right side… so there is probably something going on in the right side. A left dorsal displacement is the same thing as a nephrosplenic entrapment. In this case, the colon becomes trapped in the renosplenic space. A primary cecal volvulus is rare in horses and are usually seen secondary to a large colon volvulus. These horses will ping similarly to a cow and usually present with acute colic. A strangulating lipoma is highly unlikely, given the age of the horse and lack of gastric reflux. Additionally, these tend to strangulate small intestines, not the colon.
A horse presents to you with a corneal ulcer. You are concerned because it appears to be infected, as shown in this image. You perform cytology and find gram negative rods. What is the most likely organism infecting the corneal ulcer in this horse?
a. E. coli
b. Pasturella multocida
c. Pseudomonas
d. Staphylococcus spp
c. Pseudomonas
Pseudomonas is the most common agent causing bacterial keratitis in the horse. The gram negative cytology provides further evidence that it is the likely culprit. Staphylococcus can cause keratitis in horses but is gram positive. E. coli and Pasteurella are not agents that are commonly involved with keratitis in the horse.
Which of the following toxins causes reproductive failure in mares?
a. Fescue
b. Cantharidin
c. Pyrrolizidine alkaloids
d. Red maple
e. St. John’s wort
a. Fescue
Fescue ingestion leads to prolactin suppression and can result in thickened placenta, dystocia, or agalactia. Red maple causes Heinz body anemia. St John’s wort causes photosensitization and hepatotoxicity. Pyrrolizidine alkaloids cause photosensitization and hepatotoxicity. Cantharidin causes colic.
An 11-year old Peruvian Paso presents with a history of progressive weight loss. Serum chemistry shows elevation in sorbitol dehydrogenase, lactate, alkaline phosphatase, and a decrease in albumin. A vast amount of Crotalaria spp. is seen in the pasture. What type of toxin does Crotalaria spp. possess?
a. Nitrate
b. Pyrrolizidine alkaloid
c. Cyanide
d. Organophosphate
b. Pyrrolizidine alkaloid
The clinical signs described are typical for pyrrolizidine alkaloid toxicity. Consumption of this plant typically results in abnormalities in hepatic cell division; thus resulting in large hepatocytes known as megalocytosis.
In the Spring of 2001, a syndrome later termed Mare Reproductive Loss Syndrome, also known as MRLS, occurred in central Kentucky. This resulted in the abortion of 20-30% pregnant mares. Which of the following was NOT a manifestation of MRLS?
a. Fetal or neonatal hemoabdomen
b. Early fetal loss
c. Neonatal foal death
d. Late-term abortion
e. Fibrionous pericarditis
a. Fetal or neonatal hemoabdomen
The correct answer is fetal or neonatal hemoabdomen. All other choices listed were potential disease manifestations of MRLS. The exact pathogenesis of MRLS is still unknown, but the presence of eastern tent caterpillars was strongly associated with the disease. Later, experimental studies in which pregnant mares were exposed to or fed, via NG tube, eastern tent caterpillars resulted in early and late fetal loss.
You are called one hot summer day to see a group of horses in New Mexico which are slobbering and not eating their hay. Three out of 20 horses seem to be visibly affected. On physical exam of the first one, you find fever of 104 F (40 C) and obvious oral ulcers as shown in the image, mainly on the tongue. What is your tentative diagnosis?
a. Glanders
b. Bovine papular stomatitis
c. Foot-and-mouth disease (FMD)
d. Vesicular stomatitis
e. African Horse Sickness
d. Vesicular stomatitis
VS affects horses, cattle and pigs with similar clinical signs. It is a viral disease of high morbidity and low mortality that appears about every 7 to 10 years in the Southwestern United States. Yearly outbreaks occur in southern Mexico and northern South America. Black flies and midges appear to be the vectors. Affected premises should be quarantined.
Which of the following is not a cause of dysphagia in the horse?
a. Foxglove
b. Guttural pouch mycosis
c. Tetanus
d. Rabies
a. Foxglove
This is a cardiotoxic plant
Consumption of fescue grass infected with Neotyphodium coenophialum by a pregnant mare may typically result in which of the following clinical signs?
a. Shortened gestational length and fetal skeletal malformation of the cuboidal bones
b. Prolonged gestation and decreased milk production
c. Shortened gestational length and fetal joint laxity
d. Prolonged gestation and fetal mummification
b. Prolonged gestation and decreased milk production
Common clinical signs associated with fescue toxicosis include prolonged gestation and/or decreased milk production (agalactia). Ergopeptine alkaloids are ingested by the mare, which act as dopamine agonists. Dopamine serves to inhibit prolactin, thus inhibiting lactation. Placental thickening and weak or stillborn foals may also occur.
Which of these is normally found in the guttural pouch of a healthy horse?
a. Aspergillus nidulans
b. Streptococcus equi ssp. zooepidemicus
c. Streptococcus equi ssp. equi
d. Salmonella
b. Streptococcus equi ssp. zooepidemicus
This is a normal inhabitant of the guttural pouch. Streptococcus equi ssp. equi can be present when there is guttural pouch empyema. Aspergillus nidulans can be present in cases of guttural pouch mycosis. Salmonella should not be present in the guttural pouch.
What age of horse is at highest risk for development of recurrent airway obstruction or heaves?
a. 2-6 months
b. 0-2 months
c. > 6 years of age
d. 1-5 years
e. 6 months to 1 year
c. > 6 years of age
RAO is a disease of mature horses older than 6 years of age. The direct cause is debatable but it has a progressive onset and is thought to be related to hypersensitivity to environmental factors. It is seen most commonly in the winter in stabled horses.
A 1.5-year old Quarter Horse gelding is presented to you for symmetric ataxia, weakness, and spasticity of all limbs, but worse in the hind limbs. When walking, the horse frequently drags his toes and the hind limbs frequently interfere with one another. Based on the signalment, history and physical examination findings, which of the following is the most likely cause of these clinical signs?
a. Equine Protozoal Myeloencephalitis (EPM)
b. Botulism
c. Equine Motor Neuron Disease (EMND)
d. Cauda Equina Syndrome
e. Equine Degenerative Myeloencephalopathy (EDM)
e. Equine Degenerative Myeloencephalopathy (EDM)
The horse in this question has clinical signs most consistent with EDM; cervical vertebral malformation (wobblers) is also a possibility, but was not provided as an answer. The cause of EDM is unknown, but this disease typically affects young horses (< 2-3 years of age; but older horses can develop disease). Clinical signs are a result of diffuse neuronal fiber degeneration of various portions of the central nervous system. This disease has been associated with low serum vitamin E concentrations, suggesting that oxidative damage may play a role in the development of disease.
EMND is typically associated with muscle tremors, shifting of weight while standing, muscle atrophy and recumbency. Botulism is associated with generalized muscle weakness. Cauda equina syndrome causes analgesia of the perineum. EPM can cause a range of clinical signs, but is typically with asymmetric neurologic deficits.
A 2-year-old Quarter horse filly presents with a history of intense pruritis and alopecia in the perineal area (see image). The owners indicated that they noticed the filly rubbing her tail head and perineal area along fences for a period of one week. What diagnostic test will you use to confirm your top differential?
a. A fecal flotation to confirm Oxyruis equi
b. A scotch tape test to confirm Oxyuris equi
c. A scotch tape test to confirm Strongyloides vulgaris
d. A superficial skin scrape to confirm Chorioptes spp.
e. A fecal flotation to confirm Cyathostomiasis
b. A scotch tape test to confirm Oxyuris equi
While all of these diagnostic tests are important when you suspect parasitism, the scotch tape test will enable you to observe the eggs stuck to the hair. The egg laying activity by the female worm is what causes the intense pruritis. Occasionally, eggs can be found in a flotation, which may give you a false negative interpretation if not found. A superficial skin scrape is a great alternative for this case; however, Chorioptes spp. tend to infest breeds with feathered legs. An infestation of Strongyloides vulgaris or Cyathostomes will likely cause colic, diarrhea, and lethargy.
A horse presents to you with a laceration across the caudal aspect of the hock; the horse is not weight-bearing, and the hock completely dropped to the ground. What structure has likely been ruptured to cause these clinical signs?
a. Suspensory ligament
b. Superficial digital flexor
c. Proximal check ligament
d. Achilles tendon
e. Gastrocnemius
d. Achilles tendon
A complete laceration of the Achilles tendon involves rupture of the gastrocnemius and superficial flexor tendons. A gastrocnemius rupture alone may cause a dropped hock, but horses with this injury will still bear weight on the affected limb. Prognosis for this injury is grave.
A 9-month old foal presents with difficulty walking. You immediately note that the foal appears to have a flexural deformity of the right forelimb consisting of an increased dorsal hoof wall angle of 80 degrees such that the heel does not contact the ground. The coronary band is prominent. You take radiographs which confirm a broken forward hoof-pastern angle. What is the most appropriate treatment for this type of flexural limb deformity?
a. Superior check ligament desmotomy
b. Transection of the insertion of the semitendinosus
c. Lateral digital extensor tenectomy
d. Desmotomy of the accessory ligament of the deep digital flexor tendon
d. Desmotomy of the accessory ligament of the deep digital flex
This case describes a severe flexural deformity of the distal interphalangeal joint, also known as “clubfoot”. This is typically a congenital condition in young horses although it can be acquired. A genetic component is suspected. Mild cases can sometimes be managed conservatively with NSAIDs, farriery, exercise and nutritional changes. Severe cases often require surgery; the surgical procedure of choice is desmotomy of the accessory ligament of the deep digital flexor tendon (also known as inferior check ligament desmotomy). The accessory ligament of the deep digital flexor tendon (inferior check ligament) runs from the palmar surface of the proximal metacarpus to the deep flexor tendon in the mid-metacarpal region.
The superior check ligament originates above the knee and attaches to the superficial flexor tendon, and its primary purpose is to support the tendon. Superior check ligament surgery is used to treat a bowed tendon.
Lateral digital extensor tenectomy is a procedure used to treat stringhalt. Transection of the insertion of the semitendinosus is used to treat fibrotic myopathy.
A 24-year old Appaloosa has an increased heart rate, increased respiratory rate, and is pacing while staring at her abdomen. During initial colic work up there was no gastric reflux. On rectal exam, a distended large colon could be palpated. On abdominal ultrasound, large colon was the predominant structure visualized on the left side while the left kidney could not be visualized via ultrasonography. What is the most likely diagnosis?
a. Right dorsal displacement
b. Strangulating lipoma
c. Nephrosplenic entrapment
d. Sand impaction
c. Nephrosplenic entrapment
The kidney is obscured as a result of a left dorsal displacement of the large colon over the nephrosplenic ligament. Additionally, the spleen is pushed away from the body wall, making it difficult to see on ultrasound. Large horses may be predisposed to this. Besides surgical correction, one may try to roll the horse 360 degrees. Pain associated with these types of displacements are usually mild to moderate.
What is the most common form of neoplasia seen in the intestines of a horse?
a. Lipoma
b. Squamous cell carcinoma
c. Lymphosarcoma
d. Leiomyosarcoma
c. Lymphosarcoma
Squamous cell carcinoma is the most common tumor of the equine stomach. Lipomas are seen commonly, but these do not involve the intestinal tract directly. Leiomyosarcomas are simply not as common as lymphosarcoma. Unfortunately, the prognosis in horses with lymphosarcoma is extremely poor.
You are examining a 13-year old Standardbred brood mare 5 hours after parturition. You note that the placenta is still present in the reproductive tract of the mare (see image). What is the most appropriate therapy?
a. Administer penicillin (IM) until the placenta is expelled on its own
b. Do nothing; the placenta is not considered retained until 12 hours post-parturition and it will likely be expelled by this time
c. Place physical traction on the placenta and remove it manually
d. Administer oxytocin (IM or IV) and lavage the uterus to facilitate removal
d. Administer oxytocin (IM or IV) and lavage the uterus to facilitate removal
Most texts state that the placenta in a mare is retained after greater than 3 hours post-parturition; therefore, this would be considered a retained placenta. Oxytocin, along with uterine lavage, will cause the uterus to contract and facilitate expulsion of the placenta. Strong physical traction on the retained placenta is generally considered contraindicated, as you may tear the placenta and leave remnants of it within the uterus, resulting in possible complications. Broad-spectrum antimicrobials are often administered to decrease the incidence of metritis but alone would not be appropriate.
Equine infectious anemia is caused by what type of organism?
a. Bacteria
b. Rickettsia
c. Virus
d. Fungus
e. Protozoan
c. Virus
Equine infectious anemia is caused by a retrovirus that establishes a lifelong infection and causes cyclic anemia and abortions.
Which of the following answer choices results in encephalomyelitis?
a. Influenza
b. Strangles
c. Eastern equine encephalomyelitis
d. Tetanus
c. Eastern equine encephalomyelitis
This question was not meant to be hard. Another cause of a viral encephalomyelitis which we also vaccinate for is western equine encephalomyelitis. The other diseases do not result in encephalomyelitis. Tetanus will cause a rigid paralysis due to binding of tetanus toxin to inhibitory receptors. Influenza will usually cause respiratory disease. Strangles will usually result in a raging lymphadenopathy with subsequent abscessation.
A 12-year old Quarter Horse gelding presented to you for acute diarrhea, mild colic signs and moderate neurologic signs. Upon initial examination, neurologic signs consisted of head pressing, ataxia, recumbency and general lethargy. The vital parameters included a heart rate of 60 beats/min, respiratory rate of 16 breaths/min and rectal temperature of 102.8F (39.3 C). You decide to perform a biochemistry profile with the following abnormalities observed:
Lactate: 6.5 mmol/L; (RR 0-2.5 mmol/L)
Glucose: 180 mg/dL; (RR 80-115 mg/dL)
Ammonia: 608 micromol/L; (RR 12-61 micromol/L)
Sodium: 124 mEq/L; (RR 137-145 mEq/L)
Chloride: 86 mEq/L; (RR 95-105 mEq/L)
Creatinine: 3.4 mg/dL; (RR 1-2.1 mg/dL)
BUN: 30 mg/dL; (RR 14-21 mg/dL)
Based on the clinical signs and clinicopathologic data, you suspect the horse has colitis; how would you best explain the neurologic deficits in this case?
a. Neurologic signs associated with hyponatremia and osmotic fluid shifts in the brain
b. Neurologic signs associated with acute renal failure and azotemia
c. Neurologic signs associated with extreme hyperglycemia
d. Neurologic signs associated with hyperammonemia and intestinal disease
e. Neurologic signs associated with hepatic encephalopathy
d. Neurologic signs associated with hyperammonemia and intestinal disease
Ok, admittedly this is a tough question, but we do not want to make them too easy. Hyperammonemia has been associated with intestinal disease in horses. The exact cause of the neurologic signs and disease process is unknown, but it is presumed to result from excessive ammonia production within the intestinal tract. This overwhelms the ability of the liver to metabolize ammonia, and subsequently causes the development of encephalopathic signs, such as those reported in this question.
Diarrhea is a common concurrent problem suggesting a possibility that overgrowth of ammonia producing bacteria causes an elevated blood ammonia. In regards to the other possible answers, hyponatremia can cause neurologic deficits if the sodium is very low (100-105 mEq/L), so the sodium of 124 mEq/L in this question rules that option out. The mild azotemia and hyperglycemia are unlikely to cause neurologic deficits and there is no other evidence to support hepatic disease.
What is the most commonly reported tumor in the bladder of a horse?
a. Squamous cell carcinoma
b. Lymphosarcoma
c. Prostatic carcinoma
d. Transitional cell carcinoma
a. Squamous cell carcinoma
he most common tumor of the kidney in a horse is renal carcinoma.
A horse presents with urticaria, edema of the extremities, petechiation of the mucous membranes, and a stiff gait. On physical exam, you suspect the horse to have purpura hemorrhagica. Which of these abnormalities is associated with purpura hemorrhagica?
a. Thrombocytopenia
b. Anemia
c. Prolonged PT and PTT
d. Hypoproteinemia
b. Anemia
Purpura hemorrhagica is a possible sequela of streptococcus equi infection exposure or vaccination. It develops from a Type III hypersensitivity resulting in immune complex deposition in blood vessel walls and vasculitis. Common clinical signs are as described in the question. This is a nonthrombocytopenic purpura (most horses will have a normal platelet count). Common findings include anemia, hyperproteinemia, hyperfibrinogenemia, hyperglobulinemia, and neutrophilia.
You diagnose a horse with vesicular stomatitis. What should you do next?
a. Euthanize the horse immediately
b. Notify the state and federal authorities
c. Vaccinate the horse
d. Start the horse on anti-viral medications
b. Notify the state and federal authorities
The correct answer is notify the state and federal authorities. Vesicular stomatitis is a disease that must be reported to state and federal authorities. There is no specific treatment for the disease. Secondary infections should be treated symptomatically.
What is the main disadvantage of giving xylazine to a horse with acute colic?
a. Inhibition of intestinal motility
b. Laminitis
c. Cardiac arrhythmias
d. Masking of clinical signs and the need for surgical intervention
a. Inhibition of intestinal motility
The correct answer is inhibition of intestinal motility. When xylazine is given at 1.1 mg/kg it decreases the motility of the distal jejunum, cecum, and pelvic flexure for over 2 hours. Xylazine can also transiently decrease cardiac output in a potentially hypovolemic horse with colic. Conversely, xylazine is a potent analgesic and can provide immediate relief to a horse with abdominal pain.
You are visiting Egypt with a friend and go to a horse farm where you see several horses with swelling in the indentation above the eyes. You recall from your classes in veterinary school that swelling of the supraorbital fossa is a characteristic sign of which of the following exotic diseases?
a. Glanders
b. Surra
c. African Horse Sickness
d. Rift Valley Fever
c. African Horse Sickness
African horse sickness (AHS) is a viral disease of equids that is transmitted by insects, primarily Culicoides. Clinical signs of AHS typically develop 5-7 days after infection and begin with fever and conjunctivitis. Some animals may recover but many go on to develop the pulmonary and/or cardiac form of AHS. The pulmonary form consists of acute respiratory distress, coughing, sweating, and foaming from the nostrils; this form is usually fatal. The cardiac form consists of edema of the head and neck as well as abdominal pain and depression. A characteristic sign is swelling in the indentation above the eyes (also referred to as swelling of the supraorbital fossa). About 50% of animals with the cardiac form die from heart failure while the rest gradually recover after about one week.
Glanders is a bacterial disease caused by Burkholderia mallei (previously known as Pseudomonas mallei). Burkholderia mallei causes 3 different forms of disease; nasal glanders, pulmonary glanders, and cutaneous glanders. The nasal form presents with high fever, loss of appetite and labored breathing with cough. The pulmonary form often develops over several months, beginning as a fever with dyspnea and cough. The cutaneous form develops over several months as nodules develop in subcutaneous tissue along the course of the lymphatics of the legs, costal areas, and ventrum.
Surra is a trypanosomal disease causing primarily fever, weakness, and lethargy.
Rift Valley Fever is a viral disease primarily of ruminants causing influenza-like signs and hepatic lesions.
An 8-year old Thoroughbred gelding was presented for acute onset of trembling, excessive recumbency, constant shifting of body weight while standing, and muscle atrophy. The horse is housed in a dry lot with no pasture availability. Diet consists of moderate quality grass hay and sweet feed. The CBC is normal with abnormalities on biochemistry analysis including mild elevation in creatine kinase (CK) and aspartate aminotransferase (AST). Cerebrospinal fluid (CSF) analysis shows no remarkable findings. Based on this information, what disease process do you suspect?
a. Equine Protozoal Myeloencephalitis (EPM, Sarcocystis neurona)
b. Cervical Vertebral Malformation (Wobbler Syndrome)
c. Verminous encephalomyelitis (Halicephalobus deletrix)
d. Equine Herpes Myeloencephalopathy (EHV-1)
e. Equine Motor Neuron Disease (EMND)
e. Equine Motor Neuron Disease (EMND)
The correct answer is EMND. This is a neurologic disease associated with dietary vitamin E deficiency which is believed to contribute to oxidative damage to the CNS. However, the precise pathophysiology is unknown. Retrospective studies have noted that horses with EMND are commonly housed on dry lots with little to no availability to pasture or good quality hay (perhaps contributing to low blood vitamin E concentrations). The clinical signs in this question are classic for EMND whereas horses afflicted with the other options do not typically demonstrate trembling or shifting of body weight.
An 11 year old Quarter Horse mare presents to you for progressive neurologic signs over 4 days. The horse has been vaccinated for rabies only.
Signs began with anorexia and depression but moved on to hyperesthesia, propulsive walking and a head tilt. Cerebrospinal fluid analysis shows CSF protein of 75 mg/dl with a mononuclear pleocytosis. Which of these is the most likely diagnosis?
a. Equine protozoal myeloencephalitis
b. Wobbler Syndrome
c. Equine degenerative myelopathy
d. Thiamine deficiency
e. Western Equine Encephalitis
e. Western Equine Encephalitis
The keys to this question are that the horse is unvaccinated for WEE, has a progression of central nervous system signs over several days and characteristic CSF changes.
Another reasonable differential would be rabies, particularly if the horse had not been vaccinated for it.
Equine protozoal myeloencephalitis (or myelitis) can be seen at any age and is caused by Sarcocystis neurona. It should be suspected when a horse has asymmetric neurological signs as it is a multifocal disease of the central nervous system.
Cervical vertebral malformations (Wobbler Syndrome) and degenerative myeloencephalopathy are diseases seen primarily in horses under a year of age. Degenerative myelopathy causes a symmetrical ataxia.
Cerebellar abiotrophy is usually observed in foals which are less than one year of age, particularly 1-6 months of age. It is mostly seen in Arabian, Oldenburg, and Gotland breeds. There is no treatment and signs may be progressive. Diagnosis is based on a good history and clinical signs such as intention tremors, lack of a menace, hypermetria, and ataxia.
Thiamine deficiency in horses usually occurs from ingestion of thiaminase-containing plants (bracken fern) and results in loss of condition and slight uncoordinated movements. If not treated, the disease may progress to cause twitching, tremors and seizures.
What is the definitive host for the causative agent of equine protozoal myelitis/myeloencephalitis?
a. Opossum
b. Donkey
c. Horse
d. Wildebeest
e. Raccoon
a. Opossum
The correct answer is opossum. This is a must-know fact. The opossum is the definitive host for Sarcocystis, the causative agent of equine protozoal myelitis.
Nine out of 100 adult cattle are found weak, depressed, and staring into space. On physical exam, they are found to be pale, icteric, and febrile. None of them have hemoglobinuria. The nine cattle all arrived at the ranch approximately one month ago. What is your most likely diagnosis?
a. Anaplasmosis
b. Leptospirosis
c. Bacillary hemoglobinuria
d. Anthrax
a. Anaplasmosis
The correct answer is Anaplasmosis. The causative agent is Anaplasma marginale. The clinical signs are fairly straight forward, and you need to pick up on a couple key features. The fact that new adults are sick is one feature because cattle are resistant to clinical Anaplasmosis as calves. Also, it should be remembered that hemoglobinuria with Anaplasmosis is never seen because it is all extravascular hemolysis. Since there is no hemoglobinuria, leptospirosis, bacillary hemoglobinuria, and anthrax can be ruled out. Additionally, icterus with anthrax is not seen.
What is the treatment for a horse with a Streptococcus equi abscess?
a. Lance and drain the abscess
b. Non-steroidal anti-inflammatory drug administration
c. Corticosteroid administration
d. Systemic antibiotic administration
a. Lance and drain the abscess
Antibiotics should only be used early on in the infection before abscessation or in cases where the abscess has become internal (bastard strangles).
You are visiting a horse farm to evaluate a horse with seborrheic lesions of the pastern and mild lameness. The owner notes that his horses have had problems with “Scratches” in the past. Which of the following management recommendations would be helpful in preventing this problem?
a. Keep the horses in a dry and clean environment
b. Keep the horses in an insect-free environment
c. Keep the horses on a regular deworming regimen
d. Keep the horses away from the sun during the hottest hours of the day
a. Keep the horses in a dry and clean environment
Scratches is a condition of chronic seborrheic dermatitis of the palmar/plantar aspect of the pastern. The condition is sometimes referred to by several other names including “grease heel”, “dermatitis verrucosa”, “dew poisoning” and “mud fever”. It is not specific to the underlying infectious cause but the condition is generally associated with horses kept in wet or muddy environments.
Treatment involves removing the horse from the wet environment, clipping the surrounding hair, and gently washing and cleaning the area with a disinfectant followed by careful drying. Topical ointments or astringent dressings may sometimes be used. The best prevention is to keep horses in a dry and clean environment and maintain good hygiene practices.
You are examining a 6-year old Thoroughbred gelding for acute onset of diarrhea on a warm summer day. Upon physical examination, tachycardia and fever are present along with severe diarrhea. You also notice signs of lameness in the front feet suggestive of laminitis. What is a cause of diarrhea that is seasonal and is associated commonly with laminitis?
a. Corynebacterium pseudotuberculosis
b. Neorickettsia risticii (Potomac Horse Fever)
c. Clostridium sordellii
d. Salmonella typhimurium
b. Neorickettsia risticii (Potomac Horse Fever)
Neorickettsia risticii commonly causes diarrhea in the warmer summer months and is observed in horses stabled near bodies of water. Although a trematode vector is suspected, the exact pathogenesis remains an area of study. The treatment is oxytetracycline. While many causes of diarrhea can result in laminitis, PHF has been associated with laminitis frequently. Salmonella can also result in the clinical signs noted but is not restricted by season.
How is equine influenza transmitted?
a. Venereally
b. Blood-sucking arthropods
c. Aerosol
d. Through bite wounds
c. Aerosol
Equine influenza is an orthomyxovirus and is spread in respiratory secretions of infected animals. It can be endemic in areas or spread as an epidemic because it is highly contagious.
A 4-year old Standardbred stallion presents to you in the afternoon with a recent onset of lameness. The owner reports that in the early morning, feed was delivered and the horse apparently got into a bag of grain. On exam, you note heat over the hoof wall and coronary band in the front feet and a very strong digital pulse. The horse is tremoring and sweating. A hoof tester reveals pain over the sole at the toe and the horse is sensitive to tapping on the hoof wall. What treatment is most appropriate?
a. Induce vomiting with xylazine and the administer activated charcoal by stomach tube
b. Administer 1 gallon of saline by stomach tube and give an injection of dexamethasone
c. Administer intravenous fluids, penicillin, and gentamycin
d. Attempt to empty any grain out of the stomach via NG lavage of stomach, administer NSAIDs and start IV fluids
e. Administer neomycin and lactulose by stomach tube and cold pack the feet
d. Attempt to empty any grain out of the stomach via NG lavage of stomach, administer NSAIDs and start IV fluids
The clinical presentation is consistent with a case of acute laminitis secondary to grain overload. Acute laminitis is frequently associated with excessive ingestion of carbohydrates, grazing of lush pastures, and/or excessive exercise.
Acute laminitis more commonly affects the front feet but can affect all four. Local heat and pain are usually detected as well as bounding digital pulses. Pain may also manifest as tachycardia, muscle tremors, or sweating.
The goals of treatment are to prevent further development of laminitis, reduce pain, and reduce other complications from laminitis. Acute laminitis is considered a medical emergency and treatment should be initiated as soon as possible. When a horse is suspected of grain overload, administration of mineral oil by stomach tube acts as a laxative and decreases absorption of toxic material from the gastrointestinal tract. Other recommended treatments include intravenous fluids, parenteral antimicrobials, anti-inflammatory drugs (such as flunixin meglumine or phenylbutazone), and hyperimmune serum or plasma. It is also recommended to place the horse in a stall with soft flooring. Other treatment considerations include heparin, phenoxybenzamine, and heart-bar shoeing. There are some practitioners who recommend cold packs but there is conflicting evidence that hot packs may be more beneficial. Corticosteroids are contraindicated.
Newly formed type III collagen is eventually replaced by what permanent type of collagen?
a. Type I
b. Type II
c. Type III collagen is never placed
d. Type IV
a. Type I
The newly formed type III collagen is eventually replaced by type I collagen; however, the replacement is never complete. This process takes between 8-11 months.
What is the most common slab fracture in the horse?
a. Accessory carpal bone
b. Central tarsal bone
c. Radial carpal bone
d. Intermediate tarsal bone
e. Third carpal bone
e. Third carpal bone
Chip fractures of the radial carpal bone and radius are common and slab fractures are most common in the third carpal bone. Slab fractures of the central tarsal bone and third tarsal bone do occur but less frequently than in the carpus.
What is the average percent of gross production paid to an equine practitioner that is paid exclusively on a percent production basis?
a. 40
b. 35
c. 12
d. 18
e. 25
e. 25
Most equine practitioners should earn 25-30% of their gross intake; the average is about 26%. The national board examination will ask a few basic practice management questions that you should be prepared for.
An 18-year old Miniature Horse mare is presented with signs of lethargy, anorexia and mild diarrhea of 5 days duration. Upon physical examination, the mare is quiet and lethargic with a heart rate of 56 beats/min, respiratory rate of 16 breaths/min and rectal temperature of 102.8F (39.3 C). The mare postures to urinate but only produces a small volume of urine. In addition, intestinal borborygmi are slightly increased and loose feces is noted staining the tail. You suspect the mare has colitis, thus prompting collection of blood for a CBC and chemistry profile. After leaving the blood on the counter top for a few minutes prior to submission to the laboratory, you note the unusual appearance of the sample (see image). Based on the history and clinical examination, what would be the most likely abnormal clinicopathologic data measured from your blood samples?
a. Hyponatremia, hypochloremia and hypokalemia suggestive of acute kidney injury
b. Elevations in serum triglycerides, gamma glutamyl transpeptidase (GGT), and sorbital dehydrogenase (SDH) suggestive of hyperlipemia and hepatic lipidosis
c. Elevations in serum fatty acids and cortisol along with hypoglycemia suggestive of pituitary pars intermedia dysfunction (equine Cushing’s syndrome) with secondary colitis
d. Neutropenia, hyponatremia and metabolic alkalosis suggestive of colitis and pre-renal azotemia
b. Elevations in serum triglycerides, gamma glutamyl transpeptidase (GGT), and sorbital dehydrogenase (SDH) suggestive of hyperlipemia and hepatic lipidosis
The most likely clinicopathologic changes that you would observe are elevations in serum triglycerides, GGT, and SDH. Unlike other larger sized horses, Miniature horses are susceptible to the development of hyperlipemia and hepatic lipidosis as a result of anorexia; the anorexia typically results from a primary disease, in this case mild colitis. Because of the negative energy balance, fats are mobilized in excess resulting in the opaque appearance of the serum.
The other answers have one incorrect variable within the response: colitis is associated with metabolic acidemia, acute kidney injury is associated with hyperkalemia, and equine Cushing’s syndrome is associated with hyperglycemia.
You are treating a colicky 8-year old horse and pass a stomach tube to assess gastric reflux. The 20 liters of reflux is hemorrhagic, orange-brown in color, and foul-smelling. On physical exam, you find T=101.5F (38.6 C), HR=70, and RR=35 and overall depressed attitude. There are few auscultable gut sounds. Oral mucous membranes are injected. On rectal exam, there are multiple dilated fluid-filled loops of bowel palpated. Peritoneal fluid is serosanguinous with a 3.5 gm/dl protein and a WBC count of 7000. After decompressing the stomach, the horse appears less painful, but remains depressed. Based on these findings, what is the best tentative diagnosis?
a. Impaction colic (large bowel impaction)
b. Duodenitis-proximal jejunitis
c. Verminous arteritis caused by strongylus vulgaris
d. Large bowel torsion
e. Acute small intestinal obstruction
b. Duodenitis-proximal jejunitis
Duodenitis-proximal jejunitis, also known as either anterior enteritis, or proximal enteritis best fits this case because of the characteristic reflux, fever, peritoneal fluid characteristics, rectal findings, the depression and relatively less pain than would be expected with an obstruction. The cause is still uncertain, but a relationship of this disease to positive cultures of reflux for Clostridium difficile has been found. Typically these cases are treated medically, which would include repeated decompression of the stomach, IV fluids, replacement of electrolyte deficiencies, analgesics and correction of any acid-base abnormalities.
A one-month old foal is suffering from diarrhea. The foal is depressed, anorectic, and has a watery diarrhea. Bloodwork abnormalities are consistent with electrolyte loss from diarrhea, dehydration, and a stress leukogram. Which of the following viruses is most likely to result in this clinical presentation?
a. Flavivirus
b. Rotavirus
c. Calicivirus
d. Coronavirus
b. Rotavirus
The correct answer is rotavirus. Rotaviruses are the most common viral cause of diarrhea in foals. Rotavirus will destroy absorptive intestinal cells in the small intestine thus causing a malabsorptive diarrhea. As with almost all viral diseases, treatment is supportive.
You are presented with a 7-year old Thoroughbred gelding with persistent epistaxis (see image). Which medication would be appropriate to administer to promote hemostasis?
a. Aminocaproic Acid
b. Aspirin
c. Low-Molecular Weight Hepatin (LMWH)
d. Tissue Plasminogen Activator (tPA)
a. Aminocaproic Acid
Aminocaproic acid is the only anti-fibrinolytic medication listed that may promote hemostasis. Aminocaproic acid binds and inhibits plasminogen activation thereby promoting clot maintenance and stabilization. The other medications would be considered fibrinolytics (tPA) or anti-coagulants (LMWH, aspirin).
Which of these combinations should not be used in horses?
a. Flunixin meglumine and medetomidine
b. Prednision and omeprazole
c. Flunixin meglumine and phenylbutazone
d. Phenylbutazone and trimethoprim sulfa
c. Flunixin meglumine and phenylbutazone
The correct answer is flunixin meglumine and phenylbutazone. Simultaneous administration of two NSAIDS increases the likelihood of gastric ulceration.
An 18 year old mare presents with a head tilt, circling, and nystagmus with the fast phase to the left. Where is the lesion most likely located?
a. Not enough information
b. Left side
c. Bilateral involvement
d. Right side
d. Right side
The correct answer is right side. Although this is not right 100% of the time, the fast phase of nystagmus tends to go away from the lesion. The direction of nystagmus is named after the fast phase. So be careful, this can get a little confusing. In addition, if this question had provided information as to which direction the head tilt and circling were occurring, you would be that much more confident in localizing your lesion (ex. right-side head tilt or circling would be a right-sided lesion). Sometimes you may have paradoxical vestibular disease, in which the lesion does not follow the rules, and the lesion is on the opposite side of what is expected; however, this is rare. This is usually caused by destruction of the cerebellopontine angle or flocculonodular lobe.
A 15-year old Quarter Horse gelding is presented for a chronic history of right forelimb lameness. Upon examination of the radiograph (see image), what is the most distal diagnostic nerve block necessary to desensitize the source of lameness?
a. Abaxial Sesamoid Nerve Block
b. Palmar Digital Nerve Block
c. Palmar Metacarpal Nerve Block (low four points)
d. Subcarpal Nerve BLock (high four point)
a. Abaxial Sesamoid Nerve Block
First, you must determine that there is osteoarthritis of the pastern joint (proximal interphalangeal joint). Observe the periosteal bone proliferation and sclerosis along the medial side of the joint along with collapse of the medial joint space.
Next, it is important to know what locations are blocked by the various perineural injections. You are likely to see at least one question on the board exam in regard to nerve blocks.
The palmar digital nerve block typically blocks the palmar part of the foot; the abaxial block desensitizes the foot and proximal interphalangeal (pastern) joint; the low four point block desensitizes the foot, pastern and fetlock joint; and the subcarpal block desensitizes the metacarpal region and below. Thus, the lowest block that would likely desensitize the area in question is the abaxial sesamoid block.
A horse presenting for discharge around the ear should be assessed for this condition.
a. Demodex
b. Sarcoptes
c. Tooth root abscess
d. Dentigerous cyst
d. Dentigerous cyst
The correct answer is dentigerous cyst. This occurs as a result of having tooth germ tissue in the ear. Usually, a swelling at the base of the ear and observe a seromucoid discharge can be identified. Treatment is surgical removal of the tissue.
Salmonella typhimurium is a _________________
a. Gram positive obligate aerobe
b. Gram negative facultative anaerobe
c. Gram negative obligate anaerobe
d. Gram negative obligate aerobe
b. Gram negative facultative anaerobe
The correct answer is gram negative facultative anaerobe. In horses, it primarily infects the cecum and proximal colon.
A client presents a horse that was found dead in the pasture. The horse was normal yesterday. On examination, you note cherry red mucous membranes and an almond smell to the horse. What is the most likely diagnosis?
a. Black walnut toxicity
b. Rhododendron toxicity
c. Cyanide toxicity
d. Carbon monoxide toxicity
c. Cyanide toxicity
The correct answer is cyanide toxicity. Cyanide does not allow hemoglobin to release oxygen, thus causing the cherry red lips. It is found in cherries, chokecherries, arrow grass, and Sudan grass. Large amounts must be consumed. There is a bitter odor of almonds to the GI tract with this toxicity. Treatment is sodium nitrate and sodium thiosulfate. Prognosis is poor due to the rapid onset. Carbon monoxide can cause cherry red mucous membranes but would not cause the almond smell.
A horse presents to you with a corneal ulcer. You are concerned because it appears to be infected ,as shown in this image. You perform cytology and find gram negative rods. What is the most likely organism infecting the corneal ulcer in this horse?
a. Staphylococcus spp.
b. Pasteurella multocida
c. Pseudomonas
d. E. coli
c. Pseudomonas
The correct answer is Pseudomonas. Pseudomonas is the most common agent causing bacterial keratitis in the horse. The gram negative cytology provides further evidence that it is the likely culprit. Staphylococcus can cause keratitis in horses but is gram positive. E. coli and Pasteurella are not agents that are commonly involved with keratitis in the horse.
A 6-year old Quarter Horse presents with the lesion seen in the photograph. Which of the following is true regarding equine sarcoids?
a. They usually regress spontaneously without treatment
b. Metastasis is common with advanced lesions
c. Surgical excision is nearly always curative
d. Papillomavirus is believed to play a role in the pathogenesis
d. Papillomavirus is believed to play a role in the pathogenesis
Sarcoids are one of the most common tumors in horses. They are considered non-metastatic tumors in virtually all cases. For this reason, small lesions are sometimes treated with benign neglect, but they are not expected to regress. More advanced lesions or tumors in certain sites do need to be treated more aggressively. Unfortunately, no single treatment is universally effective. Recurrence rates after surgical excision are approximately 50%. Although there is still controversy surrounding this issue, either bovine papillomavirus or an equine variant is thought by many to play a role in development of these tumors.
You are examining a 5-year old pony for lethargy, anorexia, and mild intermittent colic. Upon physical examination, you notice the abnormal finding in the image. Consumption of which of the following can produce these clinical signs and physical examination findings?
a. Red maple leaves (Acer rubrum)
b. Yellow star thistle (Centaurea solstitialis)
c. Oak leaves and acorns (Quercus sp)
d. Black walnut (Juglans nigra)
a. Red maple leaves (Acer rubrum)
The sclera appears icteric. In combination with the clinical signs, ingestion of Red maple leaves would result in these signs due to hemolysis and low oxygen content of the blood. Oak is toxic but causes diarrhea and abdominal pain, whereas Black walnut is associated with laminitis. Yellow star thistle causes nigropallidal encephalomalacia resulting in CNS signs.
A yearling horse has fever of 103F (39.4 C), depressed attitude, and a ruptured submandibular abscess draining thick white non-odorous pus (see image). What is the most likely cause of these signs?
a. Rhodococcus equi
b. Rhinopneumonitis
c. Strangles
d. Guttural pouch empyema
e. Histoplasma capsulatum
c. Strangles
Strangles is caused by Streptococcus equi. It is a highly contagious disease, especially to naive young animals.
A 3-month-old paint colt presents to you after flipping over backward while being led by the owner the previous day. Clinical signs at the time of presentation are shown in the image (head tilt, flaccid ear, muzzle deviation). Based on the history and clinical signs, what cranial nerves are damaged and what is the most likely diagnosis?
a. Cranial nerves VII and VIII (left side); fracture of the basiphenoid bone
b. Cranial nerves V and VIII (left side); fracture of the sphenoid bone
c. Cranial nerves VII and VIII (right side); fracture of the basisphenoid bone
d. Cranial nerves V and VII (right side); atlanto-occipital malformation
e. Cranial nerves V and VII (left side); atlanto-occipital malformation
a. Cranial nerves VII and VIII (left side); fracture of the basiphenoid bone
The correct answer is damage to cranial nerves VII (facial nerve) and VIII (vestibular nerve) on the left side caused by fracture of the basisphenoid bone. This is a common injury when a fractious young foal rears up and falls backward on the poll. The basisphenoid bone becomes injured resulting in injury to cranial nerves VII and VIII. Damage to the facial nerve results in the muzzle deviation (opposite direction of the side of injury, in this case deviated to the right), ptosis of the left eye and drooping of the left ear. Damage to the vestibular nerve results in the head tilt.
You are asked to perform a necropsy on a 17-year old Standardbred mare on a large horse ranch. Although not related to the cause of death, you notice the parasite shown in the image within the stomach. You tell the owner that this parasite is also responsible for the eggs that he sees seasonally on the hair of the front legs of his horses. The owner asks what should be done about this. You discuss the importance of promptly cleaning up feces and transporting feces away. In addition, which of the following is the most appropriate recommendation for ongoing control of this parasite?
a. Administer fenbendazole twice annually, once in the early summer and again in later summer
b. Administer ivermectin twice annually, once in the early spring and again in the winter
c. Administer fenbendazole twice annually, once in the early sping and again in the fall
d. There is no need to treat these parasites because they are not associated with disease in horses
e. Administer ivermectin twice annually, once in the early summer and again in the fall
e. Administer ivermectin twice annually, once in the early summer and again in the fall
This case describes the appearance of the horse bot fly, Gasterophilus spp. Gasterophilus is frequently asymptomatic but treatment is recommended because bots can cause gastritis and frequently are a source of annoyance and stress to horses. In addition, the larval instars can cause stomatitis, and colic.
The key to answering this question regarding optimal treatment and management is an understanding of the Gasterophilus life cycle. Gasterophilus undergoes complete metamorphosis, including three larval instars and only one generation is produced per year. The general cycle typically begins with the female ovipositing 150-1,000 eggs on a horse during the early summer months directly on single hairs of the horse’s front legs (especially around the cannon bone area) as well as the abdomen, flanks, and shoulders. The eggs are approximately 1-2mm long and are pale to grayish yellow attached near the tip of the hair.
The eggs develop into first instar larvae within five days and they are stimulated to emerge by the horse licking or biting at the fully developed eggs. The larvae then crawl to the mouth or are ingested and subsequently bury themselves in the tongue or gingiva and remain for approximately 28 days. The larvae molt to the second stage and move into the stomach. The second and later third stage larvae typically attach to the lining of the stomach in the non-glandular portion near the junction of the esophageal and cardiac regions where they remain immobile for the following 9 to 12 months.
The third instar larvae are relatively large, between 1-2cm long with a rounded body, narrow, hooked mouthparts, and spines. The hooked mouthparts enable the larvae to securely attach to the lining of the stomach and intestinal tract. After the third instar larvae have matured, they detach from the gastrointestinal tract and pass from the horse’s body in the feces. The larvae burrow into the soil or dried manure where they pupate and remain for the next one to two months. This stage of the life cycle occurs between late winter and early spring.
Based on this life cycle, the recommended management protocol is typically to treat with an avermectin to control adults and all larval stages by administering in the early summer, shortly after any eggs are seen and again in the fall at the end of the botfly season. Such a control program will substantially reduce fly numbers.
The image shows a 2 month old Thoroughbred foal with a limb abnormality. What is the name of this abnormality?
a. Osteoarthritis
b. Septic arthritis
c. Carpus valgus
d. Carpus varus
e. Subchondral bone cyst
c. Carpus valgus
This is one of the most common angular limb deformities that occurs in foals, usually as the result of asynchronous growth of the metaphyseal and epiphyseal growth plates.
A 3-year-old Standardbred gelding presents with epiphora, blepharospasm, and severe pain of the right eye (see image). There are numerous treatment options. Which medication would be contraindicated for this case?
a. Tropicamide
b. Neomycin and polymyxin B and dexamethasone (Neo-Poly-Dex)
c. Tobramycin
d. Banamine
e. Serum
f. EDTA
b. Neomycin and polymyxin B and dexamethasone (Neo-Poly-Dex)
The correct answer is Neo-Poly-Dex. This is an illustration of a melting ulcer. Any corneal ulcer, whether it is superficial or deep, can be perpetuated by steroid use. Steroids increase the protease activity causing the “melting”; therefore, one of the primary goals in managing corneal ulcers is to decrease protease activity by using EDTA and serum. Further, aggressive topical antibiotic use is essential. Tobramycin, gentamicin, neomycin-polymyxin B-bacitracin, among others are appropriate. Intravenous banamine is the drug of choice for ocular pain and inflammation in horses. Tropicamide is used for its mydriatic and cycloplegic effect because all animals with corneal ulcers have uveitis. Atropine is an alternative to tropicamide. It is important to note that, even though atropine has a longer duration of action than tropicamide, atropine must be used with extreme caution in horses as it may potentiate colic
A 48-hour Paint colt is presented to you for lethargy, irregular facial twitching and prolonged recumbency (see image). The owner reports that the gestation was 343 days and parturition was normal. Upon physical examination, the foal heart rate is 88 beats/min, respiratory rate is 10 breaths/min, and the rectal temperature is 101.2F (38.4 C). The foal is difficult to arouse and appears to have mild intermittent seizure-like activity. The foal can stand briefly but has no suckle response. The CBC and biochemistry analysis are within normal limits for a foal of this age; the arterial blood gas (collected while foal was in lateral recumbency) demonstrates the following results:
pH 7.19 (7.35-7.5)
PO2 78 mmHg (~94 mmHg)
PCO2 80 mmHg (36-46 mmHg)
HCO3 42 mEq/L(24-30 mEq/L)
Ionized Ca++ 1.7 mmol/L (1.4-1.8 mmol/L)
What is your interpretation of this arterial blood gas analysis and what is the most likely cause?
a. Respiratory alkalosis with metabolic compensation caused by bacterial meningitis
b. Respiratory acidosis with metabolic compensation caused by atlantoaxial malformation (OAAM)
c. Respiratory acidosis without metabolic compensation caused by neonatal septicemia
d. Respiratory acidosis with metabolic compensation caused by neonatal encephalopathy (hypoxic-ischemic encephalopathy)
d. Respiratory acidosis with metabolic compensation caused by neonatal encephalopathy (hypoxic-ischemic encephalopathy)
This is a more complicated question that requires evaluation of the entire case. First, recognize the foal’s problem list includes: lethargy, hypoventilation, intermittent seizures as well as no suckle response. Next recognize that the arterial blood gas reveals a normal PO2 in a recumbent foal but hypercarbia (respiratory acidosis) with metabolic compensation. Based on these findings, the most likely cause in neonatal encephalopathy.
This disease can arise from hypoxic conditions in utero or during parturition (dystocia, premature placental separation) resulting in a cascade of biochemical derangements within the body. Clinical signs include lethargy, failure to find and nurse from the udder, seizure activity, and in more severe cases damage to the gastrointestinal system and/or kidneys from hypoxia. Many foals are hypercapnic because the respiratory center within the CNS is not operating normal. There can be evidence of infection that complicates the presentation of some foals with neonatal encephalopathy, but in this case the CBC and rectal temperature are normal, making infectious diseases (bacterial meningitis, septicemia) less likely.
You should have some knowledge of what normal arterial blood gas reference intervals are: pH 7.35-7.5; PO2 variable in venous blood; PCO2 around 40 mmHg, HCO3 24-30 mEq/L, iCa++ 1.4-1.8 mmol/L. This is a general range, with each species having slight changes to this range.
You are examining a 13-year old Standardbred brood mare 5 hours after parturition. You note that the placenta is still present in the reproductive tract of the mare (see image). What is the most appropriate therapy?
a. Administer oxytocin (IM or IV) and lavage the uterus to facilitate removal
b. Place physical traction on the placenta and remove it manually
c. Administer penicillin (IM) until the placenta is expelled on its own
d. Do nothing; the placenta is not considered retained until 12 hours post-parturition and it will likely be expelled by this time
a. Administer oxytocin (IM or IV) and lavage the uterus to facilitate removal
You examine a 2 year old horse with the complaint of bilateral nasal discharge and lethargy for about a week. The horse has a temperature of 102F (38.9 C), HR 40, and RR 25. The nasal discharge is non-odorous and contains multiple bacteria and neutrophils. The lateral throat area is swollen and tender on palpation. Lateral radiographs reveal fluid lines in the area of the guttural pouches. You submit some of the liquid pus for culture. What treatment is now most indicated?
a. IM tetracycline daily for 2 weeks
b. Systemic erythromycin for one month
c. Systemic treatment with antifungal drugs for 4 weeks
d. Daily catheterization and lavage of the pouches
e. Immediate surgical drainage
d. Daily catheterization and lavage of the pouches
Irrigation should use saline or saline plus an appropriate and non-irritating antimicrobial drug. Systemic antimicrobial drugs are also used, but the hallmark of successful therapy is lavage and drainage. For inspissated pus or refractory cases, surgical drainage may be necessary.
Below is a lateral thoracic radiograph of the caudodorsal lung field of a 4-month old foal with clinical evidence of weight loss, fever, and tachypnea. What is the best diagnosis based on the clinical signs and radiograph?
a. Congestive heart failure
b. Pulmonary abscesses
c. Pulmonary carcinoma
d. Phinopneumonitis pneumonia
e. Pulmonary aneurism
b. Pulmonary abscesses
The two horizontal lines represent fluid or pus capped by gas within cavitary lesions. In foals, this occurs most frequently with Rhodococcus equi pneumonia.
An 8 year-old, 1223 lb, Quarter Horse gelding is presented to you with a 4-day history of lethargy, inappetance, intermittent fever (ranging from 101.2-104.5F, 38.4-40.3 C), and peripheral limb edema. Upon physical examination, you note the following abnormalities: lethargy, tachycardia (60 beats/min), limb edema and fever (103.2F, 39.6 C). The serum biochemistry analysis is within relatively normal reference intervals but the CBC yields the following abnormalities:
WBC: 1.50 x 10,000/mcL (reference 5.0-11 x 10,000/mcL)
HCT: 32% (reference 34-45%)
Platelet: 71 x 10,000/mcL (reference 130-300 x 10,000/mcL)
Neutrophil: 1.20 x 10,000/mcL (reference 2.2-6.5 x 10,000/mcL)
Lymphocyte: 0.23 x 10,000/mcL (reference 1.3-4.5 x 10,000/mcL)
Fibrinogen: 500 mg/dL (reference 100-400 mg/dL)
In addition, the following was observed on microscopic examination of the blood smear (see image). The most likely diagnosis, based on the history, clinical findings, and CBC results in this case, is which of the following?
a. Streptococcus equi infection
b. Heinz body anemia
c. Endotoxemia/septicemia (toxic changes within cell)
d. Anaplasma phagocytophilum infection
e. Equine infectious anemia (EIA) infection
d. Anaplasma phagocytophilum infection
Based on the clinical signs (fever, lethargy, tachycardia and limb edema), CBC results (leukopenia, neutropenia, thrombocytopenia) and microscopic observation of a morula within the neutrophil, the correct answer and diagnosis is Anaplasma phagocytophilum infection. Diagnosis can be supported via PCR assays.
Anaplasmosis (formerly Ehrlichi equi) infects primarily neutrophils and form inclusion bodies which consists of one or more coccobacillary organisms within these cells, known as morula. The complete pathogenesis of this disease is not fully elucidated but the organism is spread via tick bites. Other clinical signs that may be associated with this disease include petechiation, icterus and ataxia. The drug of choice for this disease is…(think about it for a second)…you got it…oxytetracycline.
You are examining a 13-year old Standardbred brood mare 5 hours after parturition. You note that the placenta is still present in the reproductive tract of the mare (see image). What is the most appropriate therapy?
a. Administer oxytocin (IM or IV) and lavage the uterus to facilitate removal
b. Place physical traction on the placenta and remove it manually
c. Administer penicillin (IM) until the placenta is expelled on its own
d. Do nothing; the placenta is not considered retained until 12 hours post-parturition and it will likely be expelled by this time
a. Administer oxytocin (IM or IV) and lavage the uterus to facilitate removal
Most texts state that the placenta in a mare is retained after greater than 3 hours post-parturition; therefore, this would be considered a retained placenta. Oxytocin, along with uterine lavage, will cause the uterus to contract and facilitate expulsion of the placenta. Strong physical traction on the retained placenta is generally considered contraindicated, as you may tear the placenta and leave remnants of it within the uterus, resulting in possible complications. Broad-spectrum antimicrobials are often administered to decrease the incidence of metritis but alone would not be appropriate.
You diagnose this 15-year old mare in the picture with a mild, acute laminitis. Which of the following can be used as treatment for this horse?
a. Prednisone
b. Application of horse shoes
c. Phenoxybenzamine
d. Trimethoprim sulfa
c. Phenoxybenzamine
The correct answer is phenoxybenzamine. Phenoxybenzamine is an alpha-adrenergic antagonist promoting vasodilation and restoration of blood flow to the digits. Prednisone is contraindicated in laminitis because corticosteroids are believed to induce the condition. Antibiotics are not indicated unless a secondary bacterial infection develops. Application of a horse shoe would not help and would be very painful in an already sensitive and painful condition. Other medications used to restore blood flow to the digits include acepromazine, isoxsuprine hydrochloride, dimethylsulfoxide (DMSO), heparin, and nitroglycerine.
A valuable horse suddenly developed severe intractable diarrhea and fever 5 days ago. The owner has been giving it oral electrolytes free choice in the water, and offering it hay, grain, and green grass. It is brought to your clinic on a normal warm summer day looking thin, dehydrated, weak, and anorectic (see photo). You do a physical exam and find T=102F (38.9 C), HR=56, RR=24, with somewhat purplish oral mucous membranes. The urine is normal but has a small volume and looks concentrated. You run a PCV (45%), WBC count (normal at 7000/microliter) and total protein (TP). The TP is low at 3.5 gm/dL and the albumin is 1.4 gm/dL indicating a protein-losing enteropathy. Of the following, what is the best treatment for the low plasma proteins in this horse?
a. IV plasma
b. Oral albumin
c. Whole blood IV
d. Feed very high protein diet with added amino acids
e. IV amino acids
a. IV plasma
The damaged bowel is leaking albumin out into the gut lumen, and the horse may develop other problems such as edema and poor healing ability if the protein levels are not boosted. The best way to do that in an animal with GI disease is by the IV route. Whole blood may raise the PCV to a level where sludging and circulatory problems develop in an already dehydrated horse. Another option to consider if plasma is not readily available is the use of synthetic colloidal solutions such as hetastarch.
Black walnut toxicity causes what condition in horses?
a. Pulmonary edema
b. Hypersalivation
c. Colic
d. Laminitis
d. Laminitis
The correct answer is laminitis. Black walnuts contain Juglone (naphthoquinone) which results in laminitis. Do not use black walnuts for horse bedding.
Black walnut shavings, photo courtesy of Krishona Martinson, University of Minnesota
An 8-year old Thoroughbred horse presents to you for evaluation of skin lesions. On exam, you see the lesions shown in the photo. Which of the following toxins is most likely responsible for these lesions?
a. Slaframine
b. Blue-green alga
c. St. John’s wort
d. Cantharidin
c. St. John’s wort
This image shows a horse with skin sloughing due to cutaneous photosensitization. St. John’s wort acts as a primary photosensitizer and can lead to photophobia, conjunctivitis, sloughed skin, and icterus. Blue-green algae cause sudden death. Slaframine causes hypersalivation and cantharidin causes colic.
You are examining a 3 year old Thoroughbred gelding that just completed a race and notice discharge from the nostrils (see image). What would be an appropriate treatment for this horse prior to the next race?
a. Furosemide
b. VItamin K
c. Plasma transfusion to replace clotting factors
d. Vasopressin
e. Whole blood transfusion
a. Furosemide
In this instance, the discharge is blood, with the most likely diagnosis being exercise-induced pulmonary hemorrhage (EIPH). One of the most commonly administered medications for EIPH is furosemide, which seems to decrease the incidence or lessen the severity of bleeding. The exact mechanism by which this occurs is not completely known but may be associated with reduced pulmonary capillary pressure.
You examine a horse for lameness and find that the 8-year old gelding is lame on both forelimbs. The stride is short and choppy, and the horse is reluctant to move. There is an increased digital pulse in both forelimbs, and the horse is sensitive to tapping on the hoof wall. At rest he leans back and puts more weight on his rear limbs. The horse appears improved and moves much better following a nerve block of the foot using local anesthesia. You take radiographs (see image). What is the diagnosis?
a. Fracture of the third phalanx
b. Navicular disease
c. Sole abscesses
d. Laminitis with rotation of the third phalanx
e. Coffin joint sepsis
d. Laminitis with rotation of the third phalanx
Laminitis, or founder, is severe and has progressed to the point of rotation of the third phalanx. The angle of the hoof wall surface and the dorsal third phalanx are no longer parallel. These radiographic findings along with the clinical signs are diagnostic for laminitis.
A 3-month-old paint colt presents to you after flipping over backward while being led by the owner the previous day. Clinical signs at the time of presentation are shown in the image (head tilt, flaccid ear, muzzle deviation). Based on the history and clinical signs, what cranial nerves are damaged and what is the most likely diagnosis?
a. Cranial nerves VII and VIII (left side); fracture of the basisphenoid bone
b. Cranial nerves V and VII (right side); atlanto-occipital malformation
c. Cranial nerves VII and VIII (right side); fracture of the basisphenoid bone
d. Cranial nerves V and VII (left side); atlanto-occipital malformation
e. Cranial nerves V and VIII (left side); fracture of the sphenoid bone
a. Cranial nerves VII and VIII (left side); fracture of the basisphenoid bone
The correct answer is damage to cranial nerves VII (facial nerve) and VIII (vestibular nerve) on the left side caused by fracture of the basisphenoid bone. This is a common injury when a fractious young foal rears up and falls backward on the poll. The basisphenoid bone becomes injured resulting in injury to cranial nerves VII and VIII. Damage to the facial nerve results in the muzzle deviation (opposite direction of the side of injury, in this case deviated to the right), ptosis of the left eye and drooping of the left ear. Damage to the vestibular nerve results in the head tilt.
A 2-year old Standardbred gelding presents for a prepurchase exam. On auscultation you hear a loud grade IV/VI systolic murmur on the right thorax. An echocardiogram is performed, which is shown below. The cardiac chambers are labeled LV (left ventricle), RV (right ventricle), Ao (Aorta). What is your diagnosis?
a. Unremarkable echocardiogram
b. Tricuspid valve endocarditis
c. Ventricular septal defect
d. Patent ductus arteriosus
e. Subaortic stenosis
c. Ventricular septal defect
The correct answer is ventricular septal defect. There is echo dropout immediately below the aortic valve and extending into the right ventricle. The auscultatory findings also fit with a VSD as the murmur is typically louder on the right. A PDA would cause a continuous heart murmur. There is no narrowing in the LV outflow tract so subaortic stenosis is not evident. There is no evidence of a vegetation or mass on the tricuspid valve so endocarditis is not correct.
A 5-year old cow presents with skin lesions confined to the nonpigmented areas (see image). The affected skin is dry and raised at the periphery. The skin of the teats appears dry. Which of the following could result in this presentation?
a. Ingestion of moldy feed containing aflatoxins
b. Ingestion of Quercus spp.
c. Ingestion of lupine
d. Ingestion of preridum aquilinum (bracken fern)
a. Ingestion of moldy feed containing aflatoxins
This is a case of photosensitization based on the skin lesions confined to the nonpigmented areas. Primary photosensitization can occur when photodynamic agents are absorbed from the G.I. tract such as Hypericum perforatum (St. John’s wort), Fagopyrum esculentum (buckwheat), Ammi majus (bishop’s weed), and Cymopterus watsonii (spring parsley). Secondary (hepatogenous) photosensitization occurs when the liver’s excretion of phylloerythrin is impaired due to liver damage. Phylloerythrin is derived from the breakdown of chlorophyll by rumen microbes. The best answer in this question is aflatoxins because they are known to cause liver damage.
Bracken fern toxicity causes acute hemorrhagic syndrome in cattle. Lupine toxicity primarily causes birth defects. Quercus (oak) toxicity causes GI and renal dysfunction.
