Tertiary Species Other Rodents



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Tertiary Species - Other Rodents




Pignon et al. 2012. Evaluation of heart murmurs in chinchillas (Chinchilla lanigera): 59 cases (1996-2009). JAVMA 241(10):1344-1347.
Domain 1: Management of Spontaneous and Experimentally Induced Diseases and Conditions; T2. Control spontaneous or unintended disease or condition; T3. Diagnose disease or condition as appropriate; T4. Treat disease or condition as appropriate
SUMMARY: The relatively long life span of chinchillas (up to 20 years) compared to other rodents may predispose them to the development of degenerative diseases such as cardiac disease. Sparse information is available regarding cardiac disease in chinchillas despite observations that heart murmurs of variable intensities are a common finding on physical exam in this species. The purpose of the current study was to determine the prevalence of heart murmurs in chinchillas and to determine whether the heart murmurs were associated with cardiac disease.
Medical records of all chinchillas examined at 3 veterinary teaching hospitals between 1996 and 2009 were reviewed retrospectively. Signalment, physical exam findings, heart murmur (graded 1-6 as defined for other small mammals), and any cardiovascular diagnostic testing results (echocardiography, ECG, radiographs) were recorded. Of the 260 chinchillas examined at the participating institutions a heart murmur was auscultated in 59 animals (23%). Echocardiography was performed on 15 animals with heart murmurs and cardiac abnormalities were identified in 8 chinchillas. These abnormalities included severe mitral regurgitation and dynamic right ventricular outflow obstruction (n=2), hypertrophy of the left ventricle and dynamic right ventricular outflow tract obstruction, mitral regurgitation (n=2), tricuspid regurgitation, dynamic right ventricular outflow tract obstruction, and hypovolemia. For the remaining 7 chinchillas no specific cause could be identified and the murmur was considered physiologic. Presence of a heart murmur was significantly associated with echocardiographic detection of a cardiac abnormality, especially if the murmur was characterized as grade 3 or higher. However, due to the small number of chinchillas with heart murmurs that underwent echocardiography the results of this study may not accurately reflect the prevalence of cardiac disease in chinchillas with a heart murmur. The authors concluded that the prevalence of heart murmurs in chinchillas was high (23%) and echocardiography should be recommended for chinchillas with heart murmurs, especially if a heart murmur with of grade 3 or higher is appreciated.
QUESTIONS

1. True or False: Dilated cardiomyopathy, congenital septal defects, and degenerative valvular disease have been previously reported in chinchillas.

2. Which of the following is best characterizes a grade 3 heart murmur?

a. A murmur immediately audible when auscultation begins

b. A very loud murmur with a palpable thrill, the loudest murmur that is still inaudible when the stethoscope is just removed from the chest wall

c. The lowest intensity murmur that can be heard, typically detected only while auscultation is performed in a quiet room;

d. An extremely loud murmur that can be heard when the stethoscope is just removed from the chest wall.

3. True or false: The most common echocardiographic abnormalities seen in the chinchillas in this study were congenital septal defects.

4. True or false: The correct scientific name for the chinchilla is Chinchilla domesticus.
ANSWERS

1. True


2. a (b = grade 5, c = grade 1, d = grade 6)

3. False, degenerative valvular disease

4. False

Kuroki et al. 2011. Pathology in Practice. JAVMA 239(12):1549-1553 [Sugar Glider]
Domain 1 (Management of Spontaneous and Experimentally Induced Diseases and Conditions), Task 3 (Diagnose disease or condition as appropriate)
SUMMARY: A 1.5-year-old intact male sugar glider (Petaurus breviceps) presented for decreased activity, tenesmus, and possible seizure-like activity.  Subsequently, the sugar glider became increasingly lethargic, developed emesis, voided red-brown urine, and died within hours of arrival.  Necropsy showed that the sugar glider was in fair body condition, with icteric footpads, mucous membranes, subcutis, and adipose tissues.  The liver was fragile, with an irregular surface and rounded edges, and the kidneys were mottled dark red.  Histologically, the liver showed evidence of degeneration and necrosis with intracytoplasmic copper deposits seen via rubeanic acid staining.  In the kidneys, many of the cortical tubules were dilated with hemoglobin casts, and affected tubules also had signs of degeneration and necrosis.
Morphologic Diagnosis:  Marked acute, centrilobular hepatocellular degeneration and necrosis with hepatocellular copper accumulation and marked acute, multifocal renal tubular degeneration and necrosis with hemoglobin casts.
The findings in the sugar glider indicate copper toxicosis.  Affected animals may be clinically normal during the copper accumulation phase, but excessive hepatic accumulation of copper eventually causes hepatocellular degeneration and necrosis due to copper-induced oxidative damage; acute intravascular hemolysis with concomitant jaundice and hemoglobinuria develop when a large amount of copper is released from hepatocytes during their death.  The changes seen in the case of this sugar glider are most commonly also observed in sheep.  Sheep usually develop copper toxicosis in 1 of 3 ways:  via excessive copper intake as a result of contamination of water, pasture, or prepared feed; as a result of increased availability of dietary copper, particularly when dietary intake of molybdenum is low; or as a result of liver damage caused by other hepatotoxins.  In dogs, copper toxicosis is an inherited condition in Bedlington Terriers and West Highland White Terriers.  Analysis of copper concentrations in hepatic biopsy specimens can be considered the best antemortem diagnostic method. 

Sugar gliders are small, arboreal marsupials originally native to Australia and New Guinea.  The sugar glider in this case is suspected to have developed copper toxicosis in part due to vitamin supplementation.


QUESTIONS:

  1. T/F:  Clinical cases of copper toxicosis may be diagnosed using serum copper concentrations.

  2. Which of the following is most highly prone to copper toxicosis?

    1. Cattle

    2. Sheep

    3. Poultry

    4. Horses

  1. T/F:  Boer goats are susceptible to copper toxicosis with pathological changes similar to those seen in sheep.

ANSWERS:


  1.  False: In clinical cases, serum copper concentration can be difficult to interpret because it often remains within reference limits until hepatocellular necrosis develops.

  2. B.  Sheep are highly prone to copper toxicosis because of their poor biliary excretion of copper.

  3. True:  A recent report has suggested that Boer goats are similarly susceptible.



Lee et al. 2011. Pathology in Practice. JAVMA 239(5):583-586 [Roborovski hamster (Phodopus roborovskii)]
Domain 1: Management of Spontaneous and Experimentally-induced Disease Conditions; T3 – Diagnose disease or condition as appropriate; T4 - Treat disease or condition as appropriate

 

Tertiary Species: Other rodents (Roborovski hamster [Phodopus roborovskii])



 

SUMMARY
History: 4 month old pet female Roborovski hamster (Phodopus roborovskii) with multiple firm subcutaneous nodules on all four feet, rapidly increasing in size since first noticed one month earlier.

 

Physical Exam: All four feet swollen and erythematous with multifocal to coalescing, firm, nonpruritic, sessile masses (see figure). Masses extend to carpal and tarsal joints.



Clinical Pathology:

Fine needle aspirates: Mixed cell population, degenerate neutrophils plus macrophages, occasional macrophage with intracytoplasmic coccoid bacteria


Microbiology: aerobic culture from masses: coagulase-positive methicillin-susceptible Staphylococcus intermedius.

 

Treatment: Unresponsive to chronic enrofloxacin, 1 month, 5 mg/kg, IM, BID. Euthanasia performed due to lack of therapy response and poor prognosis.

 

Necropsy: Multiple coalescing subcutaneous masses, all four feet, extending to carpus and tarsus, and deep into underlying muscle. No other gross abnormalities.

 

Histopathology: Feet, dermis plus panniculus, multifocal nodules, pyogranulomatous inflammation with characteristic deeply basophilic center (gram-positive coccoid bacteria) surrounded by a rim of dense, brightly eosinophilic radiating and clubbed material (Splendore-Hoeppli phenomenon) – see figures A and B. Consistent with cutaneous staphylococcal pseudomycetoma.




        

 

Morphologic Diagnosis: Feet, dermis plus panniculus, severe chronic multifocal to coalescing pyogranulomatous dermatitis with intralesional bacterial cocci (S. intermedius) and Splendore-Hoeppli phenomenon.

 

 Comments:



  • Roborovski hamsters (Phodopus roborovskii) are one of three Phodopus species (also Russian dwarf hamster – P. sungorus and Campbell dwarf hamster P campbelli). Roborovski hamsters are desert dwellers and generally kept as pets, rarely used as lab animals.

  • Bacterial pseudomycteoma (botryomycosis) is a rare chronic pyogranulomatous disease caused by nonbranching, nonfilamentous bacteria, including such genera as Staphylococcus spp, Pseudomonas spp, Proteus spp, and Streptococcus spp.

  • Contrasts with mycetoma, which is a chronic granulomatous dermatitis that is cause by fungi (eumycetoma) or Actinomyces spp (actinomycetoma).

  • DDx: bacterial pseudomycetoma, dermatophytuic pseudomytetoma eumycetoma, actinomycetoma.

  • In addition to cutaneous involvement, systemic sights have rarely been reported.

  • Bacterial pseudomycetoma has previously been reported in Siberian hamsters (Phodopus sungorus).

  • Splendore-Hoeplli material composition varies, with various combinations of components including pathogens themselves, immunoglobulins, complement, inflammatory cell debris, eosinophilic major basic protein, and/or neutral glycoproteins combined with lipid and calcium.

  • Treatment – is generally surgical excision. The nature of the lesion contributes to great difficulty in effectively treating with antibiotics, including long term systemic treatment as in this case.

 

QUESTIONS



  1. True/False: Another term for bacterial pseudomycetoma is botryomycosis.

  1. Etiologic agents for bacterial pseudomycetoma

  1. Staphylococcus spp

  2. Pseudomonas spp

  3. Proteus spp

  4. Streptococcus spp

  5. All of the above

 

 


  1. Which of the following is not an element of bacterial pseudomycetoma?

  1. Inflammation – pyogranulomatous

  2. Microscopic bodies with basophilic centers bordered by homogenous eosinophilic material

  3. Nonbranching, nonfilamentous bacteria

  4. Actinomyces spp

 

ANSWERS


  1. True

  2. e. All of the above

  3. d. Actinomyces spp

 
Granson et al. 2011. Cystic endometrial hyperplasia and chronic endometritis in a chinchilla. JAVMA 239(2):233-236
Domain 1: Management of Spontaneous and Experimentally Induced Diseases and Conditions; T2: Control spontaneous or unintended disease or condition
Tertiary Species: Other Rodents
SUMMARY: A 4 year old nulliparous sexually intact female chinchilla was evaluated for a history of blood being found sporadically in its cage.
Physical exam was unremarkable except for a blood stained perineal area.
Urinalysis, bacteriologic culture of urine and whole body radiography were unremarkable. The chinchilla's littermate had presented previously with the same clinical signs which resolved following ovariohysterectomy. Given this history and the lack of hemorrhage in the urine, an ovariohysterectomy was elected. The surgery was uneventful and following surgery, a bloody vaginal discharge was noted for the next 4 days. Since that time, there has been no evidence of blooding. There were no gross changes noted in the excised organs. The tissues were processed for histological examination. Based on microscopic changes, a diagnosis of chronic endometrial hyperplasia (CEH) with mild chronic neutrophilic endometritis and microhemorrhage was made.
CEH is a common lesion of the female reproductive tract in several species including dogs, cats, guinea pigs, rabbits, as well as several zoo animals such as elephants, canids and felids. It is thought to impair fertility and may be an antecedent to pyometra. CEH involves progressive endometrial thickenings characterized by an increase in size and number of the endometrial glands as well as cystic dilation of glands. This is a hormone dependent change which may explain why it is more often recognized in older female animals that are nulliparous.
QUESTIONS:

1. What is the genus and species of the chinchilla?

2. What is the characteristic histopathology of CEH?

3. Why is CEH more often seen in older nulliparous females?


ANSWERS:

1. Chinchilla lanigera

2. Endometrial thickening characterized by an increase in the size and number of endometrial glands as well as cystic dilatation of glands 3. The changes seen are hormone dependent and may reflect an exaggerated endometrial response caused by chronic or repeated progesterone stimulation following estrogen priming after repeated estrous cycles without pregnancy.

Powers et al. 2008. Preputial damage and lateral penile displacement during castration in a degu. JAVMA 232(7):1013-1015.
Domain 1: Management of Spontaneous and Experimentally Induced Diseases and Conditions

Domain 2: Management of Pain and Distress

Tertiary species ¬ other rodents - Degu
SUMMARY: This case report describes a 2- month-old male degu that was treated for preputial damage and lateral displacement of the penis that occurred during attempted castration.
QUESTIONS:

1. What is the genus and species of the degu?

2. What are the order, suborder and infraorder of the degu?

3. Which animals are they are closely related to?

4. Name several mammals that have an open inguinal canal?

5. What are the reported complications of castration in rodents?


ANSWERS:

1. Octodon degus

2. Order: Rodentia; Suborder: Hystricomorpha; Infraorder: Hystricognathi

3. Degus are closely related to the chinchilla and guinea pig.



4. Degus, mice, rats, hamsters, guinea pig, rabbit, and the dog can have an open or closed canal.

5. Hematoma, infection, self-trauma, visceral herniation, and penile displacement.

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