Small Mammals Flashcards
A female ferret of unknown age presented for acute onset of severe lethargy (see image). The owners obtained the pet 2 weeks ago from an elementary school class which had owned the ferret for 6 years. It is not known if the ferret was spayed. Physical exam reveals depression and thin body condition. Heart rate is 200 bpm. The spleen feels enlarged but no masses are palpable. Blood glucose measures “Lo” on a glucometer. Which of the following treatments are most useful long term for the likely condition?
- Ovariohysterectomy and intravenous fluids
- Meloxicam and amoxicillin
- Insulin and potassium supplementation
- Adrenalectomy and trilostane
- Prednisone and diazoxide
Answer: Prednisone and diazoxide
Explanation
This ferret’s clinical signs and blood glucose are most consistent with insulinoma. Medical management consists of prednisone and diazoxide alone or in combination. Dietary management with a high protein and low carbohydrate diet is also important. Surgical removal of the tumor is also an option in otherwise healthy ferrets.
***PowerPage: Ferret Neoplastic Diseases
The ferret’s symptoms and low blood glucose suggest insulinoma. Long-term treatment includes prednisone and diazoxide, which help manage the condition. Additionally, a high protein, low carbohydrate diet is recommended. Surgical removal of the tumor is another option for otherwise healthy ferrets.
Comprehensive Veterinary Information on Insulinomas in Ferrets
Definitions & Causative Agents:
• Insulinomas: Functional tumors of pancreatic beta cells causing excessive insulin secretion, leading to hypoglycemia. • Age of Onset: Common in ferrets >2–3 years old.
Pathophysiology:
• Excess insulin production leads to persistent hypoglycemia. • Tumors are typically small (0.5–2 mm).
Clinical Signs:
• Lethargy, weakness (especially in hind limbs), stargazing, seizures, coma, ptyalism, pawing at the mouth, nausea, and episodic resolution of symptoms after food intake.
Diagnosis:
• Based on clinical signs and low blood glucose (<60 mg/dL) after a fasting period of 4 hours. • Plasma insulin concentrations are often elevated (>108 mIU/L). • Fructosamine concentrations generally normal. • Imaging studies (ultrasound, CT) may be used for tumor localization.
Treatment Options:
1. Surgical Treatment: • Nodulectomy or partial pancreatectomy depending on tumor location. • Goal: Eliminate the source of insulin production. 2. Medical Treatment: • Prednisone (0.5–2 mg/kg, PO, twice a day): Stimulates gluconeogenesis. Side effects may include weight gain and impaired hair growth. • Diazoxide (5–30 mg/kg, PO, twice a day): Inhibits insulin release, stimulates hepatic gluconeogenesis, and glycogenolysis, and inhibits glucose uptake. Can be used alone or synergistically with prednisone.
Monitoring & Long-Term Management:
• Regular monitoring of blood glucose and clinical signs. • Post-treatment, ferrets should have free access to food to prevent hypoglycemic episodes.
(https://www.merckvetmanual.com/exotic-and-laboratory-animals/ferrets/endocrine-disorders-of-ferrets?query=Insulinoma ferrets)
Insulinomas in Ferrets
• Definition: Insulinomas are pancreatic islet beta-cell tumors that produce insulin excessively, leading to hypoglycemia. • Causative Agents: Insulinomas are generally associated with a genetic predisposition. Excessive carbohydrate intake is also suspected to contribute.
Pathophysiology:
- These tumors cause continuous insulin secretion, regardless of blood glucose levels. This can lead to severe hypoglycemia, neuronal glucose deprivation, and cerebral hypoxia.
• Clinical Signs: Common signs include mental dullness, irritability, hindlimb weakness, ataxia, ptyalism, and seizures. These signs are often episodic but worsen over time. • Diagnostics: Diagnosis is based on fasting blood glucose levels below 70 mg/dL accompanied by neurological symptoms that improve after feeding. Imaging may not be helpful due to the small size of the tumors. • Management: • Acute Hypoglycemia: Managed with intravenous dextrose and continuous-rate infusion with 5% dextrose. • Palliative Therapy: • Glucocorticoids (Prednisone/Prednisolone): Increases blood glucose by promoting hepatic gluconeogenesis and inhibiting peripheral glucose uptake. • Diazoxide: Inhibits insulin secretion by decreasing intracellular calcium. • Octreotide: A somatostatin analog that inhibits insulin secretion; however, effectiveness varies. • Diet Modification: High-protein, low-carbohydrate diets help manage blood glucose levels. • Surgical Excision: Considered the treatment of choice for longer survival times, though not curative.
What is the most effective treatment for adrenal gland disease in ferrets?
- Prednisone
- Surgery（adrenalectomy）
- Ketoconazole
- Trilostane
- Mitotane (Lysodren)
Answer: Surgery（adrenalectomy)
Explanation
The correct answer is surgery (adrenalectomy). Adrenalectomy is the treatment of choice for adrenal disease in ferrets. If both adrenals are affected, you can perform a unilateral adrenalectomy and a subtotal adrenalectomy on the contralateral side. Mitotane is rarely successful in reducing clinical signs in these patients. The same is true for ketoconazole.
Trilostane, is a medicine used in dogs with hyperadrenocorticism. Unfortunately it increases 17-hydroxyprogesterone which is one of the hormones that is frequently elevated in ferrets with adrenal gland disease. It will likely raise this hormone in ferrets, too, and make the adrenal problem even worse.
***PowerPage: Ferret Neoplastic Diseases
The most effective treatment for adrenal gland disease in ferrets is surgery (adrenalectomy). This procedure is preferred, especially if both adrenals are involved. Medications like Mitotane, Ketoconazole, and Trilostane are generally ineffective, with Trilostane potentially worsening the condition by increasing 17-hydroxyprogesterone levels.
Adrenocortical Disease in Ferrets
• Definition: Adrenocortical disease in ferrets is a hyperadrenocorticism syndrome primarily due to neoplasms in the adrenal cortex that overproduce sex hormones like estradiol, androstenedione, or 17a-hydroxyprogesterone. • Causative Agents: The disease is often linked to early sterilization, prolonged photoperiods, and potentially a genetic predisposition due to a limited gene pool. • Pathophysiology: Increased levels of gonadotropins after gonadectomy stimulate adrenal cells, leading to hyperplasia and tumor formation in the adrenal cortex. This condition mimics the effects of prolonged estrus in ferrets. • Clinical Signs: The most common sign is varying degrees of alopecia, which may be accompanied by pruritus, vulvar swelling in females, and prostatic enlargement in males, leading to urinary obstruction. Bone marrow toxicity from hyperestrogenism may result in anemia and thrombocytopenia. • Diagnostics: Ultrasonography is essential for evaluating adrenal gland abnormalities, including size and echogenicity. Hormone assays measuring estradiol, androstenedione, and 17a-hydroxyprogesterone are useful in diagnosing the disease. • Management: • Medical Therapy: • Leuprolide Acetate: A GnRH agonist that downregulates gonadotropin release, reducing clinical signs. • Deslorelin Acetate: Another GnRH agonist with a longer duration of effect, reducing hormone levels for up to 20 months. • Melatonin: Used to supplement the hormone to reduce gonadotropin production. • Antiandrogens and Estrogen Inhibitors: Used anecdotally to manage prostate enlargement and estrogen-related signs. • Surgical Excision: Adrenalectomy is the treatment of choice, especially for long-term resolution of clinical signs. Recurrence is possible, and survival rates are generally high post-surgery.
Summary
The document thoroughly details the diagnostics and treatments of insulinomas and adrenocortical disease in ferrets, with emphasis on clinical signs, palliative care, and surgical management. Understanding the pathophysiology, clinical manifestations, and treatment options for these conditions is crucial for effective veterinary care and NAVLE preparation.
Adrenal Gland Disease in Ferrets: Key Information for NAVLE Preparation:
Anatomy and Physiology:
• The adrenal glands in ferrets are located adjacent to the cranial borders of the kidneys, often embedded in fat. The adrenal cortex has multiple layers, including the zona glomerulosa, fasciculata, reticularis, intermedia, and juxtamedullaris. The right adrenal gland is typically larger and more elongated than the left.
Proposed Etiology:
• The exact cause is unknown, but several factors are implicated: • Early Sterilization: Early neutering (4-6 weeks of age) is thought to contribute to adrenal gland disease by disrupting normal hormonal feedback mechanisms, leading to continuous gonadotropin-releasing hormone (GnRH) stimulation and subsequent adrenal hyperplasia or neoplasia. • Prolonged Photoperiods: Ferrets exposed to unnatural, prolonged light cycles (>8 hours) may experience melatonin deficiency, contributing to increased GnRH and luteinizing hormone (LH) production. • Genetic Component: Adrenal gland neoplasia in ferrets may have a genetic basis, with mutations in tumor suppressor genes playing a role.
Pathophysiology:
• Adrenal gland disease in ferrets is primarily caused by adrenocortical adenomas, hyperplasia, or adenocarcinomas. These tumors lead to excess secretion of sex hormones, particularly estradiol, androstenedione, and 17-hydroxyprogesterone. • The disease can result in various clinical signs, including vulvar enlargement, squamous metaplasia of prostatic ducts, cystic prostatic disease, progressive alopecia, and pruritus. • The left adrenal gland is more commonly affected, and grossly affected glands may appear cystic, discolored, and enlarged.
Clinical Signs:
• Alopecia: Progressive hair loss, often starting from the tail and progressing to the dorsum and ventrum. • Vulvar Swelling: Occurs in over 70% of female ferrets with adrenal gland disease. • Prostatic Enlargement: In males, this can cause urethral obstruction, resulting in dysuria, strangury, or complete blockage. • Other Signs: Lethargy, muscle atrophy, pruritus, and a strong odor.
Diagnosis:
• Diagnosis is based on history, clinical signs, and hormone testing (estradiol, androstenedione, and 17-hydroxyprogesterone levels). • Ultrasound: Useful for assessing gland size, architecture, and the presence of concurrent diseases. • Differential Diagnosis: Includes ovarian remnants in spayed females and estrus in intact females.
Treatment:
• Surgical Management: Surgical excision of the affected adrenal gland is preferred for suitable candidates. Left adrenalectomy is generally simpler, while right adrenalectomy is more challenging due to proximity to the vena cava. • Medical Management: • GnRH Agonists (Leuprolide Acetate): Down-regulates gonadotropin receptors, reducing clinical signs within 6-8 weeks. • Deslorelin Acetate: A slow-release implant providing symptom relief for 8-20 months. • Aromatase Inhibitors (Anastrozole): Useful for ferrets with prostatic disease and elevated estradiol levels. • Androgen Blockers: Bicalutamide is used in male ferrets with prostatic disease. • Melatonin: Short-term suppression of sex hormones and clinical signs; oral and implant formulations are available. • Mitotane: Used for cytotoxic debulking with variable results; careful monitoring is necessary.
Postoperative Care:
• Ferrets should receive supportive care and analgesia post-surgery. Monitoring of packed cell volume, blood glucose, and blood pressure is recommended.
A 3 1/2 year old castrated male ferret presents for episodes of lethargy. He has also been intermittently dragging the pelvic limbs. Which of these choices is a likely cause of these signs in this ferret?
- Insulinoma
- Adrenal tumor
- Renal carcinoma
- Diabetes mellitus
Answer: Insulinoma
Explanation
The correct answer is insulinoma. This condition is common in ferrets and would cause bouts of lethargy.
Intermittent pelvic limb weakness is another manifestation of systemic weakness secondary to hypoglycemia.
Renal carcinoma is not common in ferrets. Adrenal tumors and diabetes mellitus usually are accompanied by different clinical signs.
***PowerPage: Ferret Infectious and Metabolic Diseases
The likely cause of lethargy and intermittent pelvic limb dragging in this ferret is insulinoma. This condition commonly causes hypoglycemia, leading to systemic weakness and the observed signs. Renal carcinoma is rare in ferrets, and adrenal tumors or diabetes mellitus typically present with different symptoms.
A middle-aged spayed female ferret presents with progressive bilaterally symmetric alopecia. You are suspicious of adrenal gland disease and run sex steroid hormone blood levels. Which of the following hormones is not usually elevated in ferrets with adrenal disease?
- Estradiol
- 17a-hydroxyprogesterone
- Androstenedione
- Cortisol
Answer: Cortisol
Explanation
Cortisol levels are usually within normal limits. Therefore, many of the tests that are used in small animals to diagnose Cushing’s disease (corticotropin stimulation test, dexamethasone suppression test) are not useful for ferrets.
Adrenocortical hyperplasia/neoplasia should be considered in any ferret that presents with a non-inflammatory alopecia. The prevalence of this disease in the United States is estimated at 70%. Genetic factors, early sterilization, and prolonged photoperiod from indoor housing likely contribute to the high incidence. In ferrets, adrenal gland disease is most often due to hyperplasia followed by adenocarcinoma and then adenomas. Other clinical signs include pruritus, lethargy, sexual aggression, vulvar swelling, dysuria/stranguria, tenesmus, and mammary gland enlargement.
Treatment of choice is adrenelectomy. Other treatment options include leuprolide acetate (long acting gonadotropin releasing hormone agonist) and deslorelin acetate (GnRH analog).
In ferrets with adrenal gland disease, cortisol levels are typically normal. Tests like the corticotropin stimulation test and dexamethasone suppression test used for diagnosing Cushing’s disease in small animals are not useful for ferrets. Adrenal gland disease in ferrets is often due to hyperplasia and can lead to alopecia, pruritus, and other symptoms. Treatment options include adrenalectomy, leuprolide acetate, and deslorelin acetate.
A 4-year old female ferret presents with a history of an enlarged vulva and truncal alopecia. What is the most likely diagnosis?
- Insulinoma
- Adrenal tumor
- Hypothyroidism
- Sertoli cell tumor
Answer: Adrenal tumor
Explanation
The correct answer is adrenal tumor. These tumors are very common in middle-aged ferrets and usually secrete estradiol. Common clinical signs are hair loss, enlarged vulva, pruritus, and behavior changes. Diagnosis is made by clinical signs, ultrasound, and measurement of serum estradiol levels. Treatment is adrenalectomy.
***PowerPage: Ferret Neoplastic Diseases
The most likely diagnosis for a 4-year-old female ferret with an enlarged vulva and truncal alopecia is an adrenal tumor. These tumors often secrete estradiol and are common in middle-aged ferrets. Typical signs include hair loss, pruritus, and behavior changes. Diagnosis is confirmed by clinical signs, ultrasound, and serum estradiol levels. Treatment involves adrenalectomy.
An adult ferret presents for acute onset of ataxia, salivation, and lethargy. Which of these diagnostic tests would you perform first?
- Sex steroid levels
- Radiographs
- Blood glucose
- lonized calcium
Answer: Blood glucose
Explanation
The correct answer is blood glucose. The first rule out for a ferret with these signs is hypoglycemia. If hypoglycemia is confirmed, an insulin level should be submitted as a diagnostic test for insulinoma.
***PowerPage: Ferret Neoplastic Diseases
For an adult ferret presenting with acute ataxia, salivation, and lethargy, the first diagnostic test should be blood glucose. Hypoglycemia is the primary concern, and if confirmed, insulin levels should be tested to diagnose insulinoma.
Which of these is the most common cause of seizures in the adult ferret?
- Hypocalcemia
- Intracranial neoplasia
- Hepatic encephalopathy
- Hypoglycemia
- Idiopathic epilepsy
Answer: Hypoglycemia
Explanation
The correct answer is hypoglycemia. Hypoglycemia secondary to insulinoma is the most common cause of seizures in the adult ferret. Keep in mind, a prolonged seizure can actually cause hypoglycemia, so the finding of low blood glucose in a seizuring ferret does not necessarily confirm a diagnosis of insulinoma. Idiopathic epilepsy has not been reported in ferrets. Hypocalcemia and hepatic encephalopathy can cause seizures, but are not as commonly reported as hypoglycemia.
The most common cause of seizures in adult ferrets is hypoglycemia, typically due to insulinoma. While prolonged seizures can also lead to hypoglycemia, this doesn’t always indicate insulinoma. Other causes like hypocalcemia and hepatic encephalopathy can cause seizures but are less common. Idiopathic epilepsy hasn’t been reported in ferrets.
Which of these products would be safe and effective against Psoroptes cuniculi in a rabbit?
- Fipronil
- Penicillin G
- Enrofloxacin
- Lufenuron
- Ivermectin/selamectin
Answer: Ivermectin / selamectin
Explanation
The correct answer is ivermectin/selemectin. Psoroptes is the ear mite of rabbits and is treated with ivermectin. Fipronil (trade name Frontline) is a product against fleas and ticks and is very toxic to rabbits.
What is the treatment for proliferative bowel disease in ferrets?
- Nonsteroidal anti-inflammatory drugs
- Anthelmintics
- Corticosteroids
- Antibiotics
- Antiprotozoals
Answer: Antibiotics
Explanation
The correct answer is antibiotics. Proliferative bowel disease in ferrets is caused by Lawsonia, an intracellular bacterium. The organism is very susceptible to chloramphenicol and has a variable susceptibility to other antibiotics.
This 2-year old FS Dwarf domestic rabbit presents on emergency for a 2-day history of lethargy and inappetance. On further questioning, the owners state that she has been grinding her teeth on occasion. Her normal diet consists of a pellet seed mix from the local pet store and occasional lettuce. On physical exam, she has absent gastrointestinal sounds on auscultation and is painful in her abdomen with no formed feces. She is otherwise normal. Based on the radiographs below, what is the most likely cause for her clinical signs, and what husbandry changes would be recommended?
- Premolar/molar/incisor malocclusion; increasing hay and leafy greens, reducing pellets/seeds
- Incisor malocclusion; adding wooden chews
- Mandibular abscessation; reducing the amount of seed in the diet
- Normal dental radiographs; no changes recommended
Answer: Premolar/molar/incisor malocclusion; increasing hay and leafy greens, reducing pellets/seeds
Explanation
There is evidence of malocclusion of her premolar and molars based on the uneven occlusal surface. There is also root elongation of the mandibular and maxillary premolars and molars. Additionally, the incisors have an improper occlusal angle. Most commonly, genetics and diet are significant contributors to dental malocclusion in rabbits. Dietary changes should include increasing the amount of leafy greens and hay as well as eliminating or significantly reducing pellets.
During a new pet exam on a guinea pig, you discuss with the owner, Ms. Washington and her daughter, how to appropriately care for their new guinea pigs. As the exam progresses, you notice that one guinea pig is smaller than the other, even though they are both sows and are from the same litter. You ask the owners if they have noticed the difference in sizes and they stated that even though both guinea pigs were of the same size when they were purchased, they just figured that one will be naturally smaller than the other. They also state that they always keep the guinea pigs together for companionship. What recommendation could you give the owners?
- You recommend that they put twice as much food in the cage to ensure that both sows can get enough food.
- You recommend that the owners permanently separate the animals so that the smaller one can get
enough food. - You recommend that the animals be given opportunities to eat apart. The smaller animal may need vitamin C supplementation.
- You recommend that the owners procure a third guinea pig since more animals will provide the animals with additional companionship.
- No recommendation is needed as the owners are correct, one sibling will naturally be smaller than the other.
Answer: You recommend that the animals be given opportunities to eat apart. The smaller animal may need vitamin C supplementation.
Explanation
Just like in other species, separate controlled feedings are the best way to ensure proper nutrition for multiple individuals.
A 4-year old male castrated ferret presents for stranguria. On physical exam there is alopecia over the base of the tail and the ferret is pruritic. What is the most likely diagnosis?
- Adrenal disease
- Dermatophytosis
- Insulinoma
- Cutaneous lymphoma
- Cystic calculi
Answer: Adrenal disease
Explanation
This ferret is exhibiting signs of prostatitis/paraprostatic cysts, secondary to adrenal disease. Common signs of adrenal disease include bilaterally symmetric alopecia, pruritus, vulvar enlargement in females, and prostatitis/cystitis in males. Cystic calculi occur uncommonly in ferrets but would not cause alopecia and pruritus. Dermatophytosis and cutaneous lymphoma could cause alopecia and pruritus but would not cause stranguria. Insulinoma is common in ferrets, but the clinical signs are related to hypoglycemia and would not include stranguria, alopecia or pruritus.
***PowerPage: Ferret Neoplastic Diseases
Most bladder stones in rabbits are primarily composed of
- Magnesium
- Calcium carbonate
- Urate
- Cysteine
- Phosphorus
Answer: Calcium carbonate
Explanation
The correct answer is calcium carbonate, although there seem to be multiple causes of formation of cystic calculi. One major component is that rabbits will absorb calcium through their Gl tract at a rate directly proportional to the amount of calcium in their diet regardless if they need it or not. Excess calcium is then excreted through the kidneys.
You are examining a rabbit on annual exam and note shedding, scaling, and dandruff along the dorsum. You collect a sample on clear tape for cytology and identify a mite. What mite of rabbits commonly causes the clinical signs described?
- Cheyletiella
- Chorioptes
- Demodex
- Psoroptes cuniculi
Answer: Cheyletiella
Explanation
The correct answer is Cheyletiella. This is the fur mite seen in rabbits. Psoroptes cuniculi is the ear mite of rabbits. Chorioptes is a mite that infests livestock. Cheyletiella can infest dogs, cats, and humans.
You are using a Bain circuit to anesthetize a ferret. Which of the following measures is the most important thing to do to prevent re-breathing of carbon dioxide by the ferret?
- Maintain high flow rates of oxygen in the circuit
- Make sure that the endotracheal tube extension is longer than the ferret
- Make sure the soda-lime canister is fresh
- Make sure the pop-off and one-way valves are opening correctly
Answer: Maintain high flow rates of oxygen in the circuit
Explanation
A Bain circuit is a non-rebreathing system (in contrast to circle systems used more commonly in larger animals).
Therefore, there is no carbon dioxide absorber such as soda lime. Instead, you must use sufficient oxygen flow rates to constantly flush the system (typically at least 100 ml/kg/min). The system is not dependent on valves as a circle system is. A long endotracheal tube will increase re-breathing and should not be used.
A black mouse is presented for progressive, partial alopecia that started at the face and head and progressed to the trunk. The other mouse that it is housed with appears completely normal. The underlying skin is normal. What is the most likely cause for the alopecia?
- Dermatophytosis
- Pattern alopecia
- Ectromelia
- Mite infestation
- Barbering or chewing of the hair by its cagemate
Answer: Barbering or chewing of the hair by its cagemate
Explanation
The correct answer is barbering or chewing of the hair by its cagemate. The key to this question is that the underlying skin is normal and the cagemate is normal. Barbering commonly occurs with pigmented mice and is a behavioral occurrence.
Dermatophytosis or a mite infestation would cause crusting and scaling of the underlying skin, and the cagemate would most likely be affected as well. Ectromelia virus is a member of the family Poxviridae, and causes mousepox. Clinical signs include skin lesions and generalized disease.
A 4-year old female ferret presents with a history of an enlarged vulva and truncal alopecia. What is the most likely diagnosis?
- Insulinoma
- Sertoli cell tumor
- Hypothyroidism
- Adrenal tumor
Answer: Adrenal tumor
Explanation
The correct answer is adrenal tumor. These tumors are very common in middle-aged ferrets and usually secrete estradiol. Common clinical signs are hair loss, enlarged vulva, pruritus, and behavior changes. Diagnosis is made by clinical signs, ultrasound, and measurement of serum estradiol levels. Treatment is adrenalectomy.
***PowerPage: Ferret Neoplastic Diseases
Which of the following statements about rabbit teeth is correct?
- Only the rabbit’s incisors are open-rooted and continuously growing
- All of the rabbit’s teeth are open-rooted and continuously growing
- Only the rabbit’s canine teeth are open-rooted and continuously growing
- All of the rabbit’s teeth are open-rooted but only the incisors are continuously growing
Answer: All of the rabbit’s teeth are open-rooted and continuously growing
Explanation
The correct answer is all of the rabbit’s teeth are open-rooted and continuously growing. Rabbits do not have canine teeth but have a diastema between the incisors and premolars. Because their teeth continually grow, dental malocclusion necessitates teeth trimming since the teeth do not wear down and grow continuously.
A rat is presented for bleeding from its eyes. On physical exam, the rat is exophthalmic, squinting, and has a swollen face and neck. There is a red discharge from both eyes. What is your most likely diagnosis?
- Coronavirus infection
- Carcinoma at the thoracic inlet
- Rotaviral infection
- Head trauma
- Glaucoma
Answer: Coronavirus infection
Explanation
The correct answer is coronavirus infection. Coronavirus in rats causes sialodacryoadenitis which causes inflammation and necrosis of the salivary and lacrimal glands, as well as the nasolacrimal duct. The disease is self-limiting and usually resolves within 2 weeks; however, corneal drying can lead to secondary lesions such as corneal ulcers. Transmission is by respiratory aerosol. The red discharge from the eyes is a porphyrin pigment secreted from the Harderian gland in times of stress for the rats.
Why should rabbits and guinea pigs never be housed together?
- Risk of transmission of Bordetella from rabbits to guinea pigs
- The guinea pigs will attack and kill the rabbits until there are none left
- Risk of transmission of Bordetella from guinea pigs to rabbits
- Risk of transmission of Pasteurella from guinea pigs to rabbits
- Risk of transmission of Pasteurella from rabbits to guinea pigs
Answer: Risk of transmission of Bordetella from rabbits to guinea pigs
Explanation
The correct answer is risk of transmission of Bordetella from rabbits to guinea pigs. Bordetella is a normal inhabitant of the oropharynx of rabbits but is pathogenic to guinea pigs.
A 25-month old female rat presents to you for weakness. On exam, you note generalized ataxia, most pronounced in both forelimbs. There is mild left sided exophthalmia and you note the rat pressing its head against the side of its cage. The owner is not interested in diagnostic tests or treatment and feels the rat’s quality of life is poor but you are both very interested in finding out the cause of the rat’s signs. You perform a gross necropsy and see the abnormality shown in the image below. What is this condition?
- Bacterial meningitis
- Cerebellar hypoplasia
- Cerebellar abiotrophy
- Glioblastoma multiforme
- Hydrocephalus
- Pituitary adenoma
Answer: Pituitary adenoma
Explanation
Pituitary tumors are most common in older female rats and can produce clinical signs from mechanical growth (as described in this question) or related to hormonal disturbances (such as lactation, decreased fertility, PU/PD).
This is a macroadenoma which is usually defined as > 10 mm in diameter. Treatment options are usually limited to steroids to temporarily decrease swelling associated with the tumor and nursing care.
A 25-month old female rat presents to you for weakness. On exam, you note generalized ataxia, most pronounced in both forelimbs. There is mild left sided exophthalmia and you note the rat pressing its head against the side of its cage. The owner is not interested in diagnostic tests or treatment and feels the rat’s quality of life is poor but you are both very interested in finding out the cause of the rat’s signs. You perform a gross necropsy and see the abnormality shown in the image below. What is this condition?
- Bacterial meningitis
- Cerebellar hypoplasia
- Cerebellar abiotrophy
- Glioblastoma multiforme
- Hydrocephalus
- Pituitary adenoma
Answer: Pituitary adenoma
Explanation
Pituitary tumors are most common in older female rats and can produce clinical signs from mechanical growth (as described in this question) or related to hormonal disturbances (such as lactation, decreased fertility, PU/PD).
This is a macroadenoma which is usually defined as > 10 mm in diameter. Treatment options are usually limited to steroids to temporarily decrease swelling associated with the tumor and nursing care.
An owner brings in his prize winning American Fuzzy Lop rabbit to your clinic in mid-July due to a swelling on its neck. The client maintains approximately 25 rabbits of various breeds in an outdoor, open-air, fenced-in enclosure. You examine the unusual swelling and notice a hole in the center that is oozing pus. The owner agrees to anesthesia and surgical exploration. During surgery you are surprised to find and remove the larval structure pictured below. Your diagnosis of the larva is which one of the following?
- A mature oocyte of the encysted form of sarcocystis
- Cuterebra the larval form of the botfly
- A warble of the genus Hypoderma bovis, common in outdoor housed rabbits
- The nasal bot larvae of white-tailed deer for which rabbits are the intermediate host
Answer: Cuterebra the larval form of the botfly
Explanation
The larva shown in the figure is classic for the cuterebra bot and rabbits housed in outdoor enclosures are susceptible to this type of lesion due to contact with flies and eggs deposited in their environment.
Adult, female, Cuterebra flies deposit eggs in and around caging, vegetation and animal burrows. Rabbits come in contact with the eggs as they pass through contaminated areas or by direct deposition of eggs on rabbit fur.
Eggs hatch to a larval form in response to body heat and enter the body through the mouth or nares during grooming or, rarely, through open wounds. Within the rabbit, the larvae now migrate to subcutaneous locations around the head, body or neck. Here they develop and grow as a third instar larva and breathe through a breathing pore in the skin. This is the stage most clients will seek medical attention for their rabbits. If left unattended, in approximately 30 days the larva matures, exits the skin, falls to the ground, pupates and becomes an adult bot fly.
An 8-month old dwarf rabbit presents to you for the lesions seen in this photograph of the eye. *+Which of the following therapies is LEAST LIKELY to be helpful in the management of this condition?**
- Topical steroids
- Corneal debridement and grid keratotomy
- Removal of the lens with phacoemulsification
- Oral albendazole
Answer: Corneal debridement and grid keratotomy
Explanation
This is a case of Encephalitozoon cuniculi (E. cuniculi). Encephalitozoon cuniculi is a microsporidian parasite of rabbits that causes neurologic and renal disease. This parasite directly infects the lenses of rabbits and causes phacoclastic cataracts (meaning it can break through the lens capsule) and uveitis. (If you were able to identify this, congratulations; that is truly outstanding!)
If you were not able to identify this as an Encephalitozoon cuniculi infection, it may still have been possible to reason through this question provided that you identified the white cataract and the signs of uveitis in the picture. If you observed those two things, you should realize that lens removal is the treatment for the cataract and steroids for the uveitis. You would then choose between albendazole and grid keratotomy. There is no corneal disease or ulceration in this rabbit’s eye, and that is what corneal debridement and grid keratotomy are used for. So remember on your exam, even if you are not sure exactly what the image is, you can often reason your way through the answer choices to make a good choice.
