Rabbits Flashcards
What makes enucleation of rabbit eyes more difficult than other species?
The extensive orbital venous plexus
What two locations in rabbits are prone to obstruction of the nasolacrimal duct (dacryostenosis)?
The proximal maxillary bend and apex of the main upper incisor
During a bulla osteotomy, what landmark needs to be avoided to prevent loss of palpebral reflex, ipsilateral drooling and ipsilateral facial contraction?
The facial nerve
What is the most common vertebral formula in rabbits?
C7/T12/L7/S4
Where does the spinal cord end in most rabbits?
Within S2
What is the classification of rabbit teeth?
Elodont, hypsodont, aradicular
What is the rabbit dental formula
2 x I2/1 PM3/2 M3/3 = 28
What is the gestation length in rabbits?
30-32 days
What is unique about rabbit milk?
It is higher in fat, protein and ash than that of other species except rats
What organism is implicated in ‘wet dewlap’ disease?
Pseudomonas causing a moist dermatitis of the chin/dewlap
What is the best site for spinal fluid collection in rabbits?
The cerebellomedullary cistern
What are the landmarks for needle placement for a CSF tap in a rabbit?
The cranial margins of the wings of the atlas and occipital protuberance
Where can intraosseous catheters be placed in rabbits?
The proximal humerus, greater trochanter of femur or tibial crest
What is the most common inherited disease in rabbits and what does it lead to?
Mandibular prognathism, causing primary incisor malocclusion
What organism causes hepatic coccidiosis in rabbits? Where specifically do they proliferate?
Eimeria stiedae; Bile duct epithelial cells
A rabbit with a diffusely heterogenous liver with multiple poorly defined, hyperechoic regions and dilated hepatic blood vessels and bile ducts on ultrasound is likely suffering from what?
Hepatic coccidiosis
What is cholestyramine used for in rabbits?
To bind bacterial toxins in bacterial enteritis
Intrauterine transmission of what organism into the lens before capsule formation can cause phacoclastic uveitis?
Encephalitozoon cuniculi
Rabbits are prone to this type of respiratory diseases which lead to short, rapid, shallow breaths because of their small thoracic cavity.
Restrictive diseases, which prevent the lungs from expanding
What type of respiratory disease in rabbits leads to slower/deeper breaths?
Obstructive disease, which occurs with narrowing of the airway passages
Upper obstructive respiratory disease causes increased ___ effort, while lower obstructive respiratory disease in rabbits causes increased ___ effort.
Upper - inspiratory; Lower - expiratory +/- inspiratory
Unilateral nasal discharge is usually indicative of what type of disease in rabbits?
Upper respiratory disease
Thoracocentesis in rabbits should be performed with the patient in ___ lateral recumbency at what location?
Lateral; in the 7th-9th intercostal space along the cranial border of the rib along the body wall
What disease should be considered with epistaxis, hyperemic tracheal mucosa, fluid in the trachea and/or congested/hemorrhagic lungs in rabbits?
Rabbit hemorrhagic disease
What 3 ways is myxomatosis transmitted?
Direct contact w/oculonasal secretions or eroded skin lesions, via biting insects/arthropods or via contaminated environment
What serogroup of Pasteurella multocida most commonly causes disease in rabbits?
Serogroup A, lesser extent D & F
Pasteurella multocida strains in rabbits are generally sensitive to which antibiotics?
Chloramphenicol, novobiocin, oxytetracycline, penicillin G, fluoroquinolones, azithromycin, TMS
Reinfection of what area is common in rabbits with pasteurellosis due to poor antibiotic penetration?
The nasal cavity (+ eustachian tubes, middle ear cavities)
What two bacteria are commonly implicated in opportunistic infections with pasteurellosis?
Bordetella bronchiseptica and Staphyloccocus aureus
What are the most common types of lung tumors in rabbits?
Metastatic lesions from uterine carcinoma, mammary gland adenocarcinoma and lymphoma
List 4 possible causes of mediastinal masses in rabbits:
- Thymoma (most common)
- Thymic lymphoma
- Thymic carcinoma
- Mediastinal abscess
List 4 possible paraneoplastic syndromes that can occur in conjunction with thymoma:
- Anemia
- Hypercalcemia
- Systemic immune disorders
- Dermatoses (sebaceous adenitis)
What is recommended when a rabbit is in dorsal recumbency to avoid compromising spontaneous respiration or assisted ventilation during surgery?
Slight thoracic elevation
How is a chylous effusion diagnosed?
Fluid with an elevated triglyceride concentration when compared with plasma and a decreased or WNL cholesterol concentration; Chol:trig concentrations are generally less than 1
What does a fluid to plasma triglyceride ratio greater than 2-3:1 indicate?
A chylous effusion
How is RHDV2 transmitted?
Direct contact w/infected animals, carcasses, bodily fluids and hair; Fomites and insect/animal vectors
RHDV2 not only infects the European rabbit as RHDVa does, but can also affect what?
Various Lepus species including hares (and cottontails now)
RHD from classic RHDVa causes ___ morbidity and ___ mortality in adult rabbits
High (up to 100%); high (70-90%); But does not affect kits <30 days and young less likely to be infected
RHDV2 causes disease and death in animals as young as ___ and has ___ mortality.
15-20 days old; More variable mortality from 5-80%, but seems to be increasing indicating evolution
_____ is now the primary viral RHD strain in Europe and Australia
RHDV2
A rabbit presenting with lethargy, anorexia, weight loss, and jaundice is likely suffering from what infectious disease?
RHDV2
What is the primary pathologic lesion associated with RHD?
Extensive hepatic necrosis; could also see evidence of DIC w/petechiation/hemorrhage of all tissues
What agents can inactivate RHDV viruses?
Bleach, formalin and chloramine
A rabbitry is experiencing acute deaths in animals housed outside. Necropsy findings of affected animals include multifocal white nodules in the lungs, kidneys, GIT and lymph nodes. What pathogen should be suspected?
Mycobacterium tuberculosis complex
What emerging virus that is typically asymptomatic in rabbits but causes hepatitis in humans should veterinarians in contact with rabbits be familiar with due to potential zoonosis risk?
Hepatitis E virus
Why are rabbits kept in hutches with minimal exercise more prone to vertebral fracture?
They have less opportunity/motivation to stand so epaxial muscles are not utilized (therefore calcium deposition into vertebrae does not occur)
Why is clumping litter unsafe for rabbits?
Rabbits commonly eat their litter; clumping litter will clump within the GIT and cause blockage; or could be toxic
What area is blocked by infusion of local anesthetic at the infraorbital foramen?
sensory innervation to the upper incisor teeth, upper lip and adjacent soft tissues
What 2 locations can be utilized to block the maxillary nerve?
In large rabbits, the caudal infraorbital canal; Below the zygomatic arch, caudal to lateral canthus of eye, advanced dorsally/medially/caudally to pterygopalatine fossa
What areas are affected by a maxillary nerve block?
Hard and soft tissues of the ipsilateral maxilla, skin of the nose, cheek, upper lip and maybe ipsilateral hard/soft palate and nasal mucosa
What block should be used to anesthetize the lower incisor?
Mental nerve block
Where are epidural injections performed in rabbits?
At the LS junction (around the level of the most prominent portion of the wings of the ilium)
What should be done if CSF is detected while attempting a LS epidural
Administer a lower volume than originally planned
How can rabbits be tested for hyperthyroidism?
Check the thyroid:salivary ratio using scintigraphy with technetium 99 pertechnetate
What are normal and abnormal values for the thyroid:salivary gland ratio in hyperthyroid rabbits?
Euthyroid should be 1:1; Hyper have approached 4:1
How much blood can safely be collected from rabbits?
3.3-6.5 mL/kg (6-10% total blood volume)
What effect can hemolysis have on chemistry values?
Increased serum potassium and phosphorus concentrations
What effect can clotting have on rabbit blood samples?
Artifactually increased LDH, AST, CK, TP, K+ and altered hematology results
What is the lifespan of the rabbit RBC? What implication does this have?
Short! 45-70 days; Anisocytosis, polychromasia, nucleated RBCs/Howell-Jolly bodies occur in healthy rabbits (would indicate regen anemia in other species)
Rabbits housed outdoors with natural diets have ___ PCV, RBC counts, hemoglobin and lymphocytes counts vs. those caged, on commercial diets, and with dental disease
Higher
What is the most common granulocyte in rabbits?
Heterophil
What is the most common hematologic response to inflammation in rabbits?
A relative heterophilia (without leukocytosis - ratio of H:L is inverted)
What is the dominant leukocyte in circulation in healthy rabbits?
Lymphocytes
Increases in what serum analyte most consistently correlate with the degree of hepatocellular degeneration in rabbits?
AST
What analyte can differentiate liver from muscle as source of plasma enzyme abnormalities in rabbits?
ALT (AST and LDH can both increase as result of struggle w/restraint)
List common causes of GGT elevation in rabbits
Eimeria stiedae (hepatic coccidiosis), hepatic neoplasia, liver lobe torsion, hepatic lipidosis (any cause of biliary obstruction)
What changes usually occur if azotemia is due to renal disease in rabbits?
Hyper- or hypokalemia, hyperphosphatemia, nonregenerative anemia, isosthenuria
Why can diseases that prevent cecotrophy cause hypoalbuminemia?
Cecotrophy is a significant source of dietary protein
What is the fractional excretion of calcium in rabbits compared to other mammals (%)?
45-60% vs. 2%
What is the normal pH of rabbit urine?
~8 (range 7.5-9)
What effect does E cuniculi have on the rabbit kidney?
Causes chronic interstitial nephritis
Which 4 rabbit breeds have a higher incidence of uterine adenocarcinoma?
Tan, French silver, Havana, Dutch
What are the signs of uterine adenocarcinoma in breeding does?
Decreased fertility, fetal resorption, stillbirths
What 3 bacteria are normal conjunctival flora in rabbits?
Staphylococcus, Micrococcus, Bacillus spp.
What antibiotics can be used with suspected anaerobic infections?
CAMP
Chloramphenicol
Azithromycin
Metronidazole
Parenteral penicillin G
What is the most common cause of intermittent diarrhea in rabbits?
Improper diet
Why is jaundice rare in rabbits?
Heme breaks down to biliverdin, not bilirubin
What is the most common causative agent of pyelitis or pyelonephritis in rabbits?
Escherichia coli
What is the most sensitive tool for diagnosing uterine disease in rabbits?
Ultrasound
Mammary gland disorders are frequently associated with ___ in rabbits.
Uterine disorders s/a endometrial hyperplasia or adenocarcinoma
What were the most common adverse effects observed in rabbits with thymoma treated with radiation therapy?
Alopecia, pneumonitis, myocardial fibrosis
What are the recommended surgical margins for epithelial tumors in rabbits? Mesenchymal tumors?
Epithelial - 5 mm margins; Mesenchymal - 3 cm lateral, 1 fascial plane deep (so consider amputation on extremities)
What possible complications are associated with limb amputation in rabbits?
Difficulty ambulating, difficulty grooming, pododermatitis
What has been observed in rabbits with osteosarcoma that is different than canines?
One case report of OSA crossing the glenohumeral joint space
What is the most sensitive test for diagnosis of liver lobe torsion in rabbits?
Bloodwork + AUS indicating absence of blood flow to the affected lobe and often a mild-moderate amount of fluid localized around the affected lobe
What is the ultrasonographic appearance of hepatic coccidiosis in rabbits?
A heterogenous liver with hyperechoic parenchyma, hyperechoic bile ducts and gallbladder wall
What can help distinguish an abscess from a soft tissue mass on ultrasound in rabbits?
Color flow - abscess won’t have any and mass may have substantial
A 7 year old rabbit presents with a nonpruritic scaling dermatitis with patchy to coalescing areas of alopecia. What diagnostic tests would give the most definitive diagnosis?
Skin biopsy (sebaceous adenitis)
Other tests for ddx - cytology, DTM culture, skin scrape
What skin lesion causes haphazardly arranged collagen bundles thickening in the middermis along the abdomen and thorax, primarily in geriatric males rabbits?
Collagenous hamartoma
What is the most frequent isolate from pododermatitis lesions in rabbits?
Staphylococcus sp.
What is unique about the rabbit heart?
Right AV valve has only 2 cusps
How many lobes does the rabbit thymus have?
3 - right ventral lobe, dorsal thoracic lobe, left thoracic lobe
What is the most common cardiac disease in rabbits diagnosed on echocardiogram (per VCNA)?
Cardiomyopathy (DCM most commonly)
What is the prognosis for rabbits preventing in CHF?
Guarded - often in end stage disease so may only live few hours/days, but reports of some living for months
What is inflammation of the lacrimal sac?
Dacryocystitis
What is diagnosed when purulent material can be expressed from NL puncta when skin below the medial canthus is pressured?
Dacryocystitis
Name the 5 tear glands in the rabbit:
Harderian
Nictitating
Lacrimal
Infraorbital
Extraorbital
A rabbit has edematous and exudative lesions around the face and anogenital area. What is the most likely causative agent?
Myxomatosis (this presentation is pathognomonic)
What signalment of rabbits is most likely to be affected by pseudopterygium?
Young male dwarf rabbits
What is thought to be the most common cause of corneal surface disease in rabbits?
Trauma (irritants from bedding/hay, fighting)
What can be administered to a rabbit doe to ensure successful ovulation after breeding
100 IU hCG
Fetal death before 21 days in rabbits results in ___ , while fetal death after the 21st day results in ___.
Fetal resorption; abortion
In rabbits, a sterile/unsuccessful mating, injection of luteinizing hormone, or stimulation from 1 doe mounting another can all result in?
Pseudopregnancy
What two organisms are most commonly isolated from rabbit uteruses with pyometra?
Pasteurella multocida and Staph aureus
What is a potential adverse effect when deslorelin was administered to rabbit does to suppress ovarian function?
Endometritis (7/13 developed)
