Equine Flashcards
- Is believed to play a role in the pathogenesis of equine sarcoidosis
Papillomavirus
What is the most common skin tumor of the horse
Sarcoids /fibrosarcomas - fibroblastic wart like skin lesions, often locally invasive and recurrent but not malignant
What are the recurrence rates of sarcoids that are surgically removed
50% - no single effective treatment, small lesions treated with benign neglect
What is colic and what are common signs
Abdominal pain - frequent pawing, kicking at abdomen with hindlegs, stretching out like to urinate, laying down, rolling, anorexia, muscle fascinations, flehman response
What is the flehman response
Upper lip curl - exposing smells to vomeronasal organs
Which horses are most affected by lipomas causing si disease and colic
Horses older than 20 years - lipoma on a stalk will twist causing strangulation
What is si volvulus
Twist in si causing strangulation at root of twist
Define intussuception
Invagination of one segment of intestine and its mesentery into the lumen of another piece of intestine
When is intussusception causing si disease and colic in horses likely to occur which part is most common
Common in younger horses, with diet changes, due to parasites like tapeworms - ileocecal most common
What is a mesenteric defect casing colic and si disease
Piece of si entrapped through aren’t in the mesentery causing strangulation
What is the epiploic foreman and what is the risk
A space between the greater and lesser omentums - risk of si entrapment
What are clinical signs of si disease in horses
Severe pain (analgesics don’t help), elevated heart rate, systemic shock, gastric reflux, rare palpable loops of si bowel
What will si intestinal disease look like on ultrasound
Dilated/nonmobile loops of si on trans abdominal ultrasound
What is a top differential for serosanguinous fluid with elevated proteins /WBC
Small intestinal disease
What are differentials for small intestinal disease in horses
Lipoma, volvulus , intussuption, herniation, mesenteric defect , anterior or proximal enteritis
What length of dead bowel leads you to a poor progress with si disease
Over 15 feet
What is Li volvulus / torsion
Severe form of colic, colon this then becomes ischemic then necrotic - can be fatal
What is the difference in treatment between small intestinal disease and large intestinal volulus treatment
Si - surgical resection and anastomosis
Li. - surgical correction rapidly (impossible almost to reset the LI)
What is the risk of surgically correcting Li volvulus
Risk of endotoxic shock when corrected
Which horses are more at risk of large intestinal volvulus
Older broodmares, just before partuition Or after, larger horses
What is the difference in clinical signs with si disease and Li volvulus
No gastric reflux in Li because Lester is too caudal and in Li you can actually palpate gas distension
What is colonic impaction , why does it occur and how is it often treated
Backup of fecal matter, often due to decreased water intake - medical management usually successful
What is worse - Li volvulus or colon impaction
Li volumes - colon impact mild colic signs and analgesia often helps
How do you treat colon impaction
Oral fluids and laxatives with either intermittent or indwelling nasogastric tube, using mineral oil , psyllium, Epsom salts
What commonly causes colic tympany or gas colic
Diet change or grain overload - but can happen anytime and spontaneously resolve
What are signs of colonic tympany and how do you treat
Mild to severe to spasmodic pain - treat with analgesics, sedation , iv and oral fluids
What is right dorsal colon displacement
Colon between cecum and right body wall
What is left dorsal colon displacement
Nephrosplenic entrapment - colon between left kidney and spleen the distends with gas
What is the treatment for nephrosplenic entrapment caused by colon displacement
Give phenylephrine IV - a sympathominetic that causes vasoconstriction to shrink the spleen and hopefully dislodge the colon
What does feeding alfalfa hay increase the risk of
Enteroliths (intestinal stones) due to mineral composition
What are enteroliths
Precipitation of struvite salts - magnesium ammonium phosphate, can block the small colon or transverse colon often
How does sand colic occur
Sand doesn’t pass well in manure so it settles in the ventral aspect of the colon
How can uw diagnose a sand colic
Might auscultate a fluid wave of sand in the ventral abdomen, mild intermittent pain
How do you diagnose sand colics/enteroliths
Positive fecal sand float , might see radiopaque sand or stores on abdominal rads
How do you treat sand colics
Frequent nasogastric ting with water, mineral oil, psyllium laxatives
How do you treat enteroliths
Enterotomy
Why do gastric ulcers occur in horses and where do they occur
Nonobstructive colic due to stress or prolonged time with an empty stomach - occur at the non glandular dorsal stomach (the squamous region of the stomach)
What are clinical signs of GI ulcers
Con continue eating and passing manure, intermittently colicky - cranky, no GI bleeding, often responds well to first dose of banamine/ analgesics but repeated use will worsen ulcers
How do you diagnose gastric ulcers and what is important to note
Fasted gastroscopy - reoccurrence common if lifestyle not addressed
How do you treat / prevent gastric ulcers
Oneprazole for several weeks to months, sucralfate - prevent by feeding alfalfa to reduce stomach acid and maximize roughage and turnout tire, reducing stress
What is the cause of both types of parasite associated colic and which horses are most affected
Improper or infrequent deworming - young horses most affected
Describe ascaria impaction casing parasite associated colic - what is the causative agent
Roundworms ( parascaris equorum)- occurs in young horses never previously dewormed then dewormed with a large dose of anthelmintics that caused a massive parasite die off then physical intestine blockage
Describe verminous arteritis or thromboembolic colic - what is the causative agent
Strongylus vulgaris parasite - migrates to cranial mesenteric artery, damage and immune system can form thrombus that cuts Off blood supply to the bowel causing infarction, cecum commonly
What are common causes of acute colitis
Infectious (salmonella, C perfringens or difficile, PHF, etc), non ininfectious (diet change or right dorsal colitis secondary to NSAID use), intestinal neoplasia
What is the causative agent of Potomac horse fever and what is often used to treat it
Neorickettsia risticii - tetracycline often used to treat
Which horses are most at risk for urolithiasis mimicking colic
Stallions and geldings - mares can form stones but are rarely obstructed
What stones usually cause urolitiasis in stallions and geldings
Calcium carbonate stones
Which horses are most at risk for uterine torsion that mimics colic
Mares late in gestation (7 months or so)
What helps diagnose uterine torsion in pregnant mares
Palpation of tight band of broad ligament over uterus palpable on rectal exam
What is the treatment for uterine torsion in pregnant mares
Anesthetize and roll over abdomen to stabilize fetus - surgery if unsuccessful
What would you expect to see in a horse that ingest sorghum? What is the treatment
Myelomalacia of the lower spinal cord causing pelvic limb incoordination and urine dribbling -no treatment rare to recover
Atrial sibrilkhor is most often associated with
Exercise intolerance in horses
What happens if a horse eats slafamine often found in moldy red clover
Causes hyper salivation
What is the most common ovarian tumor of horses
Granular theca cell tumor
Describe the causative agent of strangles in horse,
Strep equi equi - gram positive cocci bacteria with a large capsule
What would you expect to see if youvaspirated a lymph node in a horse with strangles
Purulent inflammation and gram positive cocci with large capsules
What is the causative agent of shaker foal syndrome
Closhidium botulinum
Describe shaker foal syndrome
Foul ingest spores of C. Botulinum that grow and make toxins in its intestines, leading to flaccid paresis or paralysis , decreased muscle tone, dyspnea, flaccid tongue
Which animals are most susceptible to tetanus
Horses and pigs
What is the causative agent of tetanus
Closhidium petani
Describe the pathogenesis of tetanus - does it work actively to invade wounds
Found widespread in soil and is introduced to patient through puncture wounds, castration sites, banding and dehorning - does not actively invade wounds, incubates for 10-21 dans tres produces a potent nervous system toxin
Tetanus is a - toxin
CNS
Once exposed to tetanus, will horse develop signs immediately
No - incubation period for 10- 21 days
What ave clinical signs of tetanus
Sawhorse stance, lock jaw causing inappetence, stiff tail, prolapsed third eyelid, flared nostrils, sensitivity to noise and movement
How do you diagnose tetanus
Based on clinical signs - no post mortem lesions
How do you treat tetanus ? How do you prevent it?
Antibiotics penicillin, tranquilization, tetanus antitoxin and supportive care - prevent with vaccination and do clean surgeries
Which botulism toxin are horses most susceptible to
Type B toxin
What is the caussitie agent of botulism and which toxins does it produce
Clostridium botulinum - produces toxins A, B or C
Describe the causative agent and patrogenesis of shaker foal syndrome
Clostridium botulinum - toxoinfectious form where toxins form in the git
What is the pathogenesis of botulism
Bacteria introduced through contaminated feed (dead cat or rabbit in feed or hay) where organism has produced high levels of toxins in feed - wound botulism is rare
What clinical signs can you expect with botulism
Muscle tremors, fascinations , ascending paralysis leading to respiratory paralysis and death, mydrinsis and ptosis, weak tongue
How do you diagnose botulism
Detect toxins in serum , intestines or feed -no postmortem signs
How do you treat botulism
No effective treatment - botulism antitoxin sometimes works in horses
How can you prevent botulism
Type B vaccine - 3 doses 4 weeks apart, booster mares before foaling
How long will clostridium protect foals from botulism
8-12 weeks
Define sheared heels
Asymmetry of heels due to imbalance of foot resulting in one heel hitting the ground before the other
What does monensin toxicity result in in horses
Cardiomyopathy and myocardial necrosis
What is normal fractional shortening in a horse (measure with an echo) and what value indicates a poor prognosis
30- 40% - less than 20% poor prognosis
What causes equine motor neuron disease, what signs do you see and how do you treat
Acquired neurodegenerative disease if horse is without pasture for 18 months - will see elevated muscle enzymes and low serum vitamin E, muscle wasting and fasiculations - supplement high lever of vitamin E
What are the 4 main equine nerve blocks used in lameness exams
Palmar digital , abaxial sesamoid block, low 4 point palmar block and high 4 point palmar block
Where is the proximal interphalangeal joint
Pastern joint - joint between p1 and p2
What is the distal interphalangeal joint
Coffin joint
What is the meta carpophalangeal joint
Fetlock joints
Where is metacarpal 2
Medial to the cannon bone (MC3)
Where is metacarpal 2
Medial to the cannon bone (MC3)
Where is metacarpal 4
Lateral to cannon bone ( MC3)
Where is metacarpal 1
Does not exist in horses (neither does metacarpal 5)
Describe the placement of the tendons / ligaments in the equine distal limb
Common digital extensor tendon is on the front of the limb, supensory ligament is directly on the bones, men deep next tendon, then superficial flexor tendon
Where is the palmar digital nerve block performed
Small amount of lidocaine placed between the medial and lateral palmar digital nerves , proximal to the cartilages of the hoof and on either side of P2
What do plantar and palmar mean
Plantar - rear facing hind limbs
Palmar - rear-facing forelimbs
How much desensitization does the palmar digital block
50 -70% of palmar/plantar part of the foot including the coffin joint (distal interphalamgeal joint)
If the palmar digital block and the abaxial sesamoid block both desensitize the medial and lateral palmar digital nerves, what is the difference
The palmar digital block is done on either side of P2, the abaxial sesamoid block is done around and above the proximal sesamoid bones
What is desensitized by the abaxial sesamoid block
Skin over the palmar pattern and distal dorsal pastern along foot, some partial desensitization of palmar fetlock - basically blocks everything below the fetlock
What nerves are blocked by the low 4 point palmar / plantar block
Medial/lateral palmar nerves, medial and lateral palmar metacarpal nerves
Where is the low 4 point palmar/planter block performed
Dorsolateral and dorsomedial to digital flexor tendan between the suspensory ligament and deep digital flexor tendon at level of the distal metacarpal bone, proximal to fetlock joint above the sesamoids, distal to the ends of the splint bones to reach the metacarpal nerves
What is desensitized by the low 4 point palmar/plantar block
Entire fetlock joint (metacarpophalangeal) and everything distal to it
What does the high 4 point or subcarpal block
Medial and lateral palmar nerves, medial and lateral palmar metacarpal nerves distal to carpus
Where do you do the high 4 point subcarpal block
Between the suspensory ligament and the deep digital flexor distal to carpus - also placed axial to the splint bones and abaxial to the suspensory ligament then towards the third metacarpal bone
What is desensitized by the high 4 point subcarpal block
Metacarpal region, entire fetlock (metacarpophalangeal ), and structures of digit
A horse with right front lameness that resolves 85% after performing a low 4 point block. Which area has the lameness
Metacarpophalangeal fetlock joint or below
A horse who’s lameness resolves after performing a palmar digital block most likely has a lameness where
Coffin joint or hoof
A horse with a lameness that resolves after performing an abaxial sesamoid block most likely has a lameness where
Fetlock or below
A horse with a lameness that resolves with a high four point subcarpal block most likely has a lameness where
Fetlock or digit or metacarpal bone
What is the only way to diagnose equine degenerative myeloencephalopathy
Histopath exam - lesions in caudal brainstem nuclei and spinal cord
What is the name for pinworms
Oxyuris equi
What lesions would you expect to see with pinworm infections (oxyuris equi)
Aloepecia around perineal region , tail rubbing
How do pinworms cause disease
Female pinworms crawl nt of anus and cement eggs around a perineal region
What is a common sequela to strangles caused by strep equi equi
Purpura hermorhagica - causing urticaria, edema, petechia, ecchymoses and vasculitis
Define urticaria
Skin condition causing raised welts
How do you treat sacroiliac luxations in horses
Untreatable -usually resolve over time with supportive care and NSAIDs but horse usually has limited movement after
What is the croup and what indicates good balance
Topline of horses hindquarters from hip to tail dock - must be same height as the withers for horse to balanced
What is the sacroiliac joint
Joint between the ilium of the pelvis and the sacrum of the spine
What is your top suspicion if you see a bump above the horses croup
Sacroiliac luxation
What is the causative agent of ringworm in equine
Trychophyton equinum
Describe lesions caused by dermatophilus congolensis and why they occur
Matted hair, supportive crusts, purulent exudate - bacteria enters under skin when it rains
What is another name for wobblers in horses
Cervical vertebral malformation
What is the causative agent of equine protozoal myeloencephalitis and when does it occur
Can occur at any age or breed - sarcocystis neurona
Who is the definitive host for sarcocystis neurona causing EPM in horses? What kind of host is the horse
Opossum definitive, horses are the aberrant hosts
How do horses become infected with EPM
Ingest sporocysts from opossums - only causes disease in some horses
What are clinical signs of EPM - equine protozoal myeloencephalitis
Ataxia, asymmetric atrophy, weakness, limb spasticity , maybe cranial nerve involvement
How do you diagnose EPM
Western blot, IFA, PCR
How do you treat EPM
Ponazuril or TMS with pyrethamine
What is the causative agent of equine herpes myeloencephalopathy and what type of disease does it cause
EHV I - respiratory 1 abortion and neuro disease associated with viral induced vasculitis in the CNS
What are clinical signs of equine herpes myeloencephalopathy
Hind limb ataxia or paresis, urinary incontinence, weak tail and anal tone , CN deficits, lethargy, recumbency, febrile episodes
How do you treat EHM - equine herpes myeloencephalopathy
Supportive care (padded stall to protect), evacuate bladder and rectum if needed, antiviral like acyclovir (efficacy variable)
When are you likely to see cases of cervical vertebral malformation /wobbler syndrome/ central stenotic instability
Young horses - 6 months to 3 years
What is your top differential in a yearling horse showing symmetrical ataxia
Cervical vertebral malformation
How can you differentiate cervical stenotic myelopathy from EPM based on clinical signs
Wobblers - symmetrical ataxia
EPM -asymmetric ataxia
What areas experience compression with wobblers syndrome
C3 - C4 or C4 - C5 (dynamic)
C5-C6 and C6-C7 (static)
What are clinical signs of wobblers syndrome in young horses
Hindlimb symmetric ataxia, proprioceptive deficits, weakness - young horses!
How do you diagnose wobblers
Saggital ratios - compare diameter of spinal cord with widest part of vertebral body, myelogram
How do you treat wobblers
Support, surgical correction but therapy is limited for sure
What is the causative agent of guttural pouch mylosis
Aspergillus
What causes equine degenerative myeloeneephalopathy
Occurs in yang horses due to lack of antioxidants like vitamin E and selenium in the diet
What causes equine degenerative myeloeneephalopathy
Occurs in yang horses due to lack of antioxidants like vitamin E and selenium in the diet
What does yellow star thistle ingestion lead to in horses and how do you treat
Dysphasia and other neuro signs - offer die due to dehydration or starvation, euthanasia often recommended
What is the causative agent of sweet itch? Where are lesions usually located
Cullcoides hypersensitivity ,occurs in warm months and lesions are usually due to self mutilation on the poll, mane, tail
Describe the muscles of the equine esophagus
Cranial 2/3 is striated muscle und caudal 1/3 is smooth mite
What is cushings disease in equine
Pituitary pars intermedia dysfunction
What is the most common cause of a pansystolic heart murmur with the point of maximum intensity on the right side
Ventricular septal defect
Why would terbutaline sulfate help diagnose anhidrosis
Beta 2 advenergic agonist that is supposed to stimulate sweat production - anhidrotic Norses will not over after intradermal injection of this
Describe parascaris equroum
Roundworm /ascarid affecting goals and yearlings - produce many eggs that are resistant and remain in the environment for years
What are clinical signs of equine cushings (ppid)
Lethargy, delayed shedding, abnormal sweating, laminitis
What is a common comorbidity of equine cushings that is associated with insulin dysregulation and can affect horses of any age
EMS - equine metabolic syndrome
What is a common comorbidity of equine cushings that is associated with insulin dysregulation and can affect horses of any age
EMS - equine metabolic syndrome
Why are horses with EMS at a greater risk for laminitis
Associated hyperglycemia (due to insulin disregulation)
Define poll evil - what is the causative agent
Brucella abortus - inflammation of the bursa adjacent to the nuchal ligament
Define fistulous withers - what is the causative agent
Brucella abortus - development of an open draining lesions over the supraspinous bursa
What does black walnut toxicity cause in horses
Laminitis
What is the causative agent of equine infectious anemia
Retrovirus
What is the causative agent of bacterial keratitis in horses
Pseudomonas
What happens with red maple leaf ingestion in horses
Hemolysis causing icteric mucus membranes , anorexia and mild intermittent colic
How does oak leaf ingestion affect horses
Causes diarrhea and abdominal pain
How is black walnut toxic to horses
Associated with laminitis
What heart arrhythmias are considered normal in horses
First and second degree AV block
What heart arrhythmias are considered normal in horses
First and second degree AV block
What is neonatal isoerythrolysis (Ni)
Destruction of a foals ABCs by all antibodies from the mare ingested through colostrum
What is neonatal isoerythrolysis (Ni)
Destruction of a foals ABCs by all antibodies from the mare ingested through colostrum
When are you most likely to see cases of neonatal isoerythrolysis
Foals less than 7 days old born to mares that have foaled once before
What type of immune reaction is Ni - neonatal isoerythrolysis
Type 2 hypersensitivity reaction between RBC antigens from foal and antigen specific antibodies from the mare ingested through colostrum
What antigens are most likely the cause of NI and where do they came from
Aa and Qa - foal antigens inherited from sire
How could a mare develop antibodies against RBC antigens
Must be exposed either through prior blood transfusions , exposure to fetal blood from placental abnormalities or exposure to fetal blood during partition
Which equid foal has a higher Chance of NI
Donkeys - unique donkey factor RBC antigen (mule foals)
What 3 things must happen for a foal to develop Ni (neonatal isoerythrolysis)
- Neonate RBC antigen not expressed by mare is inherited from the sire
- Mare has developed antibodies to specific manage RBC antigen
- Neonate ingests colostrum with antibodies
What are clinical signs of NI in foals
Indicate poor oxygen content in blood - icterus, hyperbilinbiremia, anemia, tachycardia, tachynpnea
What are clinical signs of NI in foals
Indicate poor oxygen content in blood - icterus, hyperbilinbiremia, anemia, tachycardia, tachynpnea
How do you diagnose Ni in foals
Clinical signs, cross match foal RBC with mare serum - jaundice foal agglutinates test between foal ABC, and mare colostrum
How do you treat NI in foals
Withhold colostrum, monitor PCV and perform blood transfuion if below 16%
What is the prognosis of foal Ni
Good if treated quick with blood transfusions - if anemic (PCV less than 10% ) more guarded
Define a malunion
Healed fracture where bone alignment was not achieved or maintained
What results if there is malunion of the appendicular skeleton after a fracture
Angular deformity
How can you differentiate between a minor and major angular deformity
Minor is a less than 10% difference in anyplane or 10% or less of the original length (everything else is major)
What is a common site for fracture malunion and what does it lead to
Pelvis - leads to barrowing of pelvic canal
Define physeal fractures
Growth plate fracture in long bones
Define Varus
Deviation of axis toward median plane
Define valgus
Deviation of axis away from median (latral)
Define procurvatus angular deformity
Cranial bowing
Define procurvatus angular deformity
Cranial bowing
Define recurvatus angular deformity
Caudal bowing
Define pronatus angular deformity
Internal rotation of axial plane
Define supinatus angular deformity
External rotation of axial plane
How do you fix a fracture malunion
Corrective osteotomy
What is the most common cause of acute hepatitis and hepatic failure in horses
Acute serum hepatitis / theilers disease
What causative agent is associated with theilers disease / acute serum hepatitis
Admin of the tetanus antitoxin possible - otherwise idiopathic (unidentified virus or plant toxin )
What causative agent is associated with theilers disease / acute serum hepatitis
Admin of the tetanus antitoxin possible - otherwise idiopathic (unidentified virus or plant toxin )
How do you definitively diagnose pyrrolizidine alkaloid toxicity
Based on observing fibrosis, megalocytosis and bile duct proliferation
What clinical signs would you expect with theilers disease
Acute depression , anorexia, severe icterus , photosensitization, hepatoencephalopathy, pica
How do you diagnose theilers disease/ acute serum hepatitis
Hepatic necrosis , informative cells with mononuclear cells and metrophil, in portal areas I proliferation of bile ducts
Define hepatoencephalopathy - if you see this with photosensitization Ina horse what is your top differential
Brain dysfunction due to liver dysfunction - theilers disease
What might you find on necropsy of a horse with theilers disease
Decrease in liver size, severe icterus
What clinical signs would you see with chronic active hepatitis
Progressive weight loss, intermittent fever , icterus, inappetence, photosensitization
How does hepatic disease cause photo sensitization
Hepatic disease allows pylloerythyn (produced in the stomach ) to re-enter circulation which causes a phototoxic reaction to occur under the skin
What are differentials for chronic active hepatitis
Plant or chemical toxins, environmental chemicals, ascending bacterial infections from billiary tract or immune mediated disease - basically anything causing a chronic inflammatory response
What would you see that could help diagnose chronic active hepatitis - what will the hepatocytes look like
Fibrosis in portal areas, cellular infiltrate and biliary hyperplasia - hepatocytes may be normal
How do you treat chronic active hepatitis and why
Corticosteroids because it is a chronic information response in the liver - treat the inflammation - but if it is due to bacterial cholongiohepatitis you would use antibiotics
What is the cause of pyrrolizidine alkaloid toxicity in horses
Chronic progressive intoxication from consuming plants with PAs - senecio crotalaria and heliotropium
Describe Tre pathophys of PA toxicity - pyrrolizidine alkaloid toxicity
Toxin absorbed by git then liver where it is metabolized to pyrroles which have an antibiotic effect (hepatocytes can’t divide) I leading to megalocyte formation - these cells will tra die and be replaced by connective and fibrous tissue - makes live unusable pretty much
What clinical signs would you see with PA toxicity - pyrrolizidine alkaloid
Weight loss, icterus, photosensitization
If u are presented with a horse with icteric muss membranes and sclera , a history of weight loss, And photosensitization - what are your top 3 differentials
Theilers disease (acute serum hepatitis), chronic active hepatitis, pyrrolizidine alkaloid toxicity
What family does west nile virus belong to
Flavovirus
What family of viruses does eee, wee and vee belong to
Alphavirus genus , togavirus family
Since its out break in 1999,- has been a leading cause of human and viral encephalitis
West Nile virus
How is West Nile virus transmitted
WNV infected mosquito bites a horse - mosquitos became infected by birds and vice versa
What results from a horse infected with WNV? What clinical signs might you see
Low grade viremia (short duration) - depressed mentation, fever, ataxia, weakness, made fascinations, recumbency
Will all horses infected with WNV develop clinical signs
No - not all will develop clinical signs , if horse is vaccinated signs are vocally Vera mild
What will CSF look like in a horse infected with WNV
High protein concentration and mononuclear pleocytosis
How can you confirm a diagnosis of WNV
Igm antigen capture ELISA / virus isolation and plaque reduction neutralization
What is the prognosis of WNV
Mortality of 33% - many recover
Who are vectors for togavirus encephalitis (EEE, WEE, VEE)
Mosquitos - bite Asymptomatic birds, small mammals then bite horses
What are clinical signs of the togavirus encephalitis
Fever, depression, sleeping sickness, anorexia, proprioceptive deficits, hyperesthesia, cerebral/CN deficits, propulsive walking, head tilt
How do you diagnose EEE, VEE, WEE
Abnormal CSF (high protein, pleocytosis), serology
Describe the prognosis for togavirus encephalitis
EEE has high mortality (75%), WEE and VEE are lower(20-80%)- horse may have residual neuro deficits
Describe the prognosis for togavirus encephalitis
EEE has high mortality (75%), WEE and VEE are lower(20-80%)- horse may have residual neuro deficits
How is strangles (strep equi equi ) spread - bacterial!
Respiratory secretions that are then inhaled or ingested
What clinical signs do you expect with strangles in horses
Fever, mucopurelent nasal discharge, enlarged lymph nodes (particularly submandibular), pupura hemorrhagica (severe edema, petechiae, septicemia), chondroids
What is guttural pouch empyema
Usually secondary to strangles - bacterial infection causes the thin lining of the guttural pouch to be inflammed and the pouch to then fill with thick pus
What is bastard strangles
Strangles infection that spreads to internal organs causing abscesses
What is pupura hemorrhagica
Hemorrhage or edema due to an allergic reaction - causes aseptic vasculitis and swelling of blood vessels leading to petechia, septicemia, etc
why would a horse with strangles develop a secondary pupura hemorrhagica
Either repeated exposures to natural infections or vaccination
What are chondroids and why do they offer occur
Can be caused by a strangles infection - solidified caseous material /stones in guttural pouches that persist for years if not removed and can cause bacterial shedding
How can you diagnose strangles
PCR from nasal swab , guttural pouch lavage - if acute
Serology for liters - if chronic
What do high antibody titers for strangles on serology indicate
Chronic infection - either pupura hemorrhagic or bastard strangles
What is contraindicated when treating strangles and why
Antibiotics like penicillin or ceftiofur - they allow bacteria to hide which prolong, clearance and recovery, onlynuse in severe cases
How should you treat Strangles
Most infections clear on their own - savage guttural pouches, instill penicillin, antiinflammatories, and supportive care
How can horses become carriers for strangles infection and how can they her it
Can be persistent carriers if abscesses or chondroids remain, can also shed without showing any signs - should have 3 negative nasal PCRs before cleared
How can you prevent spread of strangles
Isolate + biosecurity measures - vaccine with mlv intranasal or killed IM
There is an outbreak of strangles on a farm - do you recommend vaccinating the healthy horses
No- vaccines + natural exposure increases the risk for pupura hemorrhagica which can be fatal
There is an outbreak of strangles on a farm - do you recommend vaccinating the healthy horses
No- vaccines + natural exposure increases the risk for pupura hemorrhagica which can be fatal
What can occur if EHV 1 mutates
It can mutate to the wild type /neurogenic type causing neurologic disease (equine herpes myeloencephalopathy)
What can occur if EHV 1 mutates
It can mutate to the wild type /neurogenic type causing neurologic disease (equine herpes myeloencephalopathy)
What are clinical signs of EHV 1 and 4
Fever, cough, mucopurelent nasal discharge , abortions in pregnant mares, secondary pneumonia
What can be a source of subclinical spread for EHV
Vaccinated horses with a more mild infection
How do you diagnose EHV
PCR of nasal discharge
How should you vaccinate horses for ehv
MLV intranasal or IM killed - give biannual vaccines to mares during pregnancy to prevent abortions
What is another name for equine rhinopneumonitis
EHV I or 4
What is the causative agent of equine herpes myeloencephalopathy
EHV 1 or 4
What viral infection looks just like EHV except it does not cause abortions in pregnant mares usually ( spread through respiratory secretions, same vaccine protocol, same treatment, nasal swab pcr to diagnose)
Require influenza A
What is thought to be the cause of EIPH and what predisposes horses
Likely in high speed event horses with lung damage or chronic infections - high pressure and high cardiac output cause capillary wall collapse and hemorrhage
How can you treat EIPH
Give furosemide a few hours before an event to decrease interstate pressure and hemorrhage
What risk factors predispose to recurrent airway obstruction / heaves
Warm dry environment, barn with pour ventilation, little turnout
How does RAO / heaves cause disease
Causes inflammation of lower airways leading to bronchospasm, excess mucus production and airway remodeling that on lead to obstructin
What are clinical signs of heaves / RAO
Tachypnea or dyspnea, respiratory noise, flared nostrils , cough, wheeling noise on end exhalation, have line on abdomen - otherwise fne asymptomatic between flare ups usually
How can you diagnose rao / heaves
BAL cytology (increased neutrophils), clinical signs
How can you diagnose rao / heaves
BAL cytology (increased neutrophils), clinical signs
How do you treat rao/heaves
Environmental modification mostly 1 corticosteroids to decrease inflammation, bronchodilators
What is almost always the cause of sinusitis
Usually secondary to a dental problem
Which teeth are usually involved in sinusitis? which sinus
08-11 but 09 is most common - sinus affected depends on tooth affected
What are clinical signs of sinusitis
Chronic unilateral mucopurelent nasal discharge that is foul smelling that goes away with antibiotics but then came back when you stop
How do you diagnose sinusitis
Rule out other causes with nasal PCR and nasal endoscopy - then head and dental rads and CT
Which nerve is affected during laryngeal paralysis and why
Left recurrent laryngeal nerve because it is the longest equine nerve
What is the pathophysiology of laryngeal hemiparesis /recurrent laryngeal nerve paralysis/ roarer
Idiopathic neuropathy of left recurrent laryngeal nerve causing the left arytenoid cartilage to fail to abduct during inspiration leading to partial or full obstruction
What are clinical signs of laryngeal hemiparesis
Upper respiratory noise on inspiration during exercise, exercise intolerance, poor performance
How do you diagnose laryngeal hemi paresis
Upper endoscocopy while horse is exercising and in sedated
When are you likely to see R. Equi infections
Foals 1-3 months old - gradual unset but often have significant disease before clinical signs develop
How easy is R. Equi to get rid of
Not easy -lives in soil and can be endemic for years on farms
What are clinical signs seen with R. Equi infections in foals
Pyogranulomatous bronchopneumonia, fever , lethargy, anorexia, poor weight gain -if disseminated it can cause septic arthritis / uveitis, etc
How can you diagnose R. Equi infection in foals
Transtacheal wash and cytology - will see intracellular rods , abscesses on thoracic rads
How do you treat R. Equi infection
Rifampin and azithromycin for 4-10 weeks
How can farms help prevent R. Equi infections
Endemic farms can treat foals with R. Equi hyper immune plasma at birth then again 1 month of age
What are predisposing factors for pleuropneumonia / shipping fever in horses
Thing a horses head up during transport which decreases ability to clear airways, extended duration of transport - maybe infectious respiratory disease
What are predisposing factors for pleuropneumonia / shipping fever in horses
Thing a horses head up during transport which decreases ability to clear airways, extended duration of transport - maybe infectious respiratory disease
What are clinical signs of pleuropneumonia /shipping fever in horses
Severe fever, dyspnea, decreased lung sounds ventrally, nasal discharge, reluctance to move due to pleural pain from fluid accumulation
How can you diagnose pleuropneumonia
Thoracic rads to check for pleural effusion / clinical signs
How can choke ( gastro esophageal obstruction) present as a respiratory disease
May begin as bilateral green nasal discharge or coughing, gagging,
What happens if choke is not treated within 6 - 12 hours
Aspiration pneumonia risk a lot higher
How can youdiagnose choke
Inability to pas a nasogastric tube and clinical signs
How can youdiagnose choke
Inability to pas a nasogastric tube and clinical signs
How do you treat choke
Sedation to lower head and decrease risk of aspiration pneumonica ,gentle lavage via a nasogastric tube
How do you treat choke
Sedation to lower head and decrease risk of aspiration pneumonica ,gentle lavage via a nasogastric tube
What is founder? Describe its pathophysiology
Laminitis - inflammation causing laminar projections /lamellae in the hoof capsule to be inflamed and weak - when laminate are weak, the deep digital flexor tendon will pull the coffin bore to rotate toward the palmar aspect (tippy toe) - coffin bone en sink lower in the hoof
What often predisposes to laminitis /founder
Metabolic disease, obesity, equine cushings disease, excess grain intake, endotoxemic diseases ( colitis, grain overload, inorganic steroid induced)
Which limbs are usually affected by laminitis
Front limbs
What clinical signs would you see with founder/ laminitis
Increased digital pulses, rocked back stance, walking on eggshells, positive to pressure at the toe, difficulty picking up hoof due to pain
What might you see on radiographs of a laminitis case
Coffin bore rotated at a palmar angle, decreased sole depth at point of the coffin bone , osteophyte ski tip at point of coffin bone
What might you see on radiographs of a laminitis case
Coffin bore rotated at a palmar angle, decreased sole depth at point of the coffin bone , osteophyte ski tip at point of coffin bone
What diagnostic tool is contraindicated in cases of laminitis
Nerve blocks -lead to increased temporary weight bearing which can make it worse
What diagnostic tool is contraindicated in cases of laminitis
Nerve blocks -lead to increased temporary weight bearing which can make it worse
How do you treat laminitis / founder
Ice/cool the feet , antiinflammatories, fashioned boots and a deeply bedded stall, trimming to derogate the toe and decrease heel angle. - tenotomy for chronic cases , weight loss plan to keep low sugar, low starch hay and grain
Which breeds are over represented for navicular syndrome and why
Paints, quarter horses - small feet
What is navicular syndrome
Any source of pain from the navicular bone or attached ligaments - osteophytes on the mericular bore will care pain on the deep digital flexor tendon where it attaches to bottom of coffin bone
What is navicular syndrome
Any source of pain from the navicular bone or attached ligaments - osteophytes on the mericular bore will care pain on the deep digital flexor tendon where it attaches to bottom of coffin bone
Which feet are usually affected by navicular syndrome
Front feet bikteally usually - but one foot will be worse ( and lameness will be worse when initial is blocked)
You perform a palmar digital nerve block on a horse with a lower limb lameness that then shifts to the other limb. what is your top differential
Navicular syndrome
What diagnostics indicate navicular syndrome
Positive pressure at heels, palmar digital nerve block causing shifting leg lameness
What will navicular syndrome look like on radiographs
Normally looks like a Reverse Oreo (central medulla is darker and less dense) - with navicular disease, the navicular bone will be enlarged and have increased nutrient dense former, medulla has increased density - in severe cases the medulla and cortex are indistinguishable - will tho see osteophytes
What is breakover in horses
The point where the horse pivots from when pushing heels
How can you treat navicular syndrome and what is the goal
Trim to improve breakover, increase heel angle to take pressure off tendons, wedge or heel pad/ biphosphonate injection to decrease osteoclast action labor for osteoblast action)
What tendons are most likely affected by tendinitis or desmitis
Suspensory ligament, deep digital flexor tendon and superficial digital flexor tendon
Define desmitis
Inflammation of a ligament
Define desmitis
Inflammation of a ligament
Describe DSLD - degenerative suspensory ligament desmitis/ disease pathophysiology
Progressive failure of collagen fiber repair in the suspensory ligament apparatus, causing a gradual enlargement but weakening of the suspensory ligament, leading to a fetlock drop (bilaterally)
What clinical signs might you see with desmitis or tendonitis
Swollen tendon or tendon sheath , painful on palpation, lameness at a trot but almost always weight bearing
How do you diagnose tendonitis or desmitis and what will you see
Ultrasound - focal anechoic lesions or abnormal fiber pattern if chronic
How do you treat tendonitis or desmitis
Neurectomy, PRP, shockwave therapy
How do you treat tendonitis or desmitis
Neurectomy, PRP, shockwave therapy
What does a positive to flexion test mean
Obvious lameness for 3-5 strides while horse trots a straight line after flexing the limb
What is the pathogenesis of osteoarthritis
Degeneration of articular cartilage due to trauma/synovitis - joint fluid loses viscosity which increases shock leading to remodeling and osteophyte formation - can fracture and form fragments leading to joint stress
What is high ringbone
Pastern joint OA
What is low ringbone
Coffin joint OA
Differentiate between bone spavin and bog spavin
Bone spavin - hock joint OA (intertarsal)
Bog spavin - tibiotarsal joint effusion
What predisposes a horse to subsolar / hoof abscesses
Week hoof, moist environment , poor hoof hygiene - all allow bacteria to travel intofoot and proliferate deep in hoof
What predisposes a horse to subsolar / hoof abscesses
Week hoof, moist environment , poor hoof hygiene - all allow bacteria to travel intofoot and proliferate deep in hoof
What clinical signs would you expect to see with a subsolar abscess
Almost non weight bearing lameness, positive to hoof testers , heat in hoof, gray purulent drainage
What will a sub solar abscess look like on rads
Big gas pocket on rads
What is contraindicted for treating subsolar abscesses and why
Systemic antibiotics not used because limited blood supply to superficial hoof means poor antimicrobial penetration
How does a laceration leading to a septic joint or tendon cause lameness
Initially due to pain of the joint capsule - then continues due to distention and pressure on the joint capsule as WBC and inflammatory markers increase effusion
