Rodent Medicine Flashcards
(55 cards)
1
Q
Elodontomas (squirrels)
A
- Prairie dogs and Richardson’s ground squirrels
- Uncommon in hystricomorphs and rare in other rodents
- Progressive accumulation of odontogenic tissue at incisor apices
- Associated with incisor dystrophy
- Cause of respiratory compromise and death in some cases
- Extraction difficult, consider sinus trephination to relieve respiratory
symptoms
2
Q
Hepatic carcinomas (squirrels)
A
- Over-represented in ground squirrels and prairie dog
- Also identified in California ground squirrels, woodchucks, arctic ground squirrels
- Associated with a species-specific hepadnavirus
- Immunohistochemistry not commercially available - link to other soft tissue tumours unknown
3
Q
Other neoplasms reported in squirrels
A
- Hepatic adenoma
- Giant cell sarcoma
- Lipoma
- Myelolipoma
- Squamous cell carcinoma
- Surgical excision where possible
4
Q
Fluid therapy (hystricomorpha)
A
- Intravenous catheterisation difficult - cephalic vein = primary site; lateral saphenous in chinchillas
- Intraosseous catherisation often more appropriate in critical patients - femur (via trochanteric fossa); tibia (via tibial crest)
- Subcutaneous - non-critical patient rehydration; avoid interscapular fat pad in guinea pigs
- Oral fluids - route of choice for slow rehydration where GIT is functional (nasogastric tubes tolerated poorly)
5
Q
FT - technique (hystricomorpha)
A
- Sterile technique under anaesthesia
- Use spinal needle/hypodermic needle
- Ongoing analgesia necessary
- Prophylactic antibiotic cover
6
Q
Blood sampling sites (hystricomorpha)
A
- Jugular
- Cephalic
- Femoral vein
- Cranial vena cava
7
Q
Jugular blood sample (hystricomorpha)
A
- Short, thick neck with much SC fat
- Difficult to visualise and restrain for sampling
8
Q
Cephalic blood sample (hystricomorpha)
A
- Small volumes in guinea pigs and chinchillas
9
Q
Femoral vein blood sample (hystricomorpha)
A
- Distal femoral vein - small but identifiable visually
- Typical sample size of 0.2 mL)
- Blind technique proximally for larger volumes - palp femoral artery pulse
and insert parallel and superficial to this
10
Q
Cranial vena cava blood sample (hystricomorpha)
A
- Anaesthesia necessary
- Large volumes possible
- Useful in small species, debilitated animals
11
Q
Dental disease, difference in anatomy - guinea pig
A
- Similar pathologies to rabbit dental disease +
some guinea pig specific - 1 incisor, 1 premolar and 3 molars in each quadrant
- Occlusal plane slanted at 30 degrees
12
Q
Guinea pig dental disease
A
- Lower cheek teeth curve towards tongue, overgrowth affects chewing + swallowing -> dec in tongue movement
- Can be complicated by hypovitaminosis C
- Impossible to evaluate dentition fully in the conscious animal
- CS: reduced appetite/dysphagia; reduced grooming; weight loss; change in faeces; drooling; ocular discharge uncommon
- GA and retraction of soft tissues necessary for
complete oral exam - short fast period useful (2 - 3 h prior, then syringe feed after)
13
Q
Objective dental evaluation - radio (GP)
A
- Maxillary apices - rostral end of the nasal bone to dorsal notch of the tympanic bulla (about three quarters of its height)
- Occlusal plane - rostral surface of the mandibular incisor (normal length) to the notch of the tympanic bulla
14
Q
Dental disease management (GP)
A
- Radiographic and coronal assessment of changes
- Reshaping and shortening of crowns - high speed diamond burr
- Avoid clipping teeth to limit iatrogenic trauma
- Gingival resection where necessary w/ profound overgrowth of single tooth spur (not beneficial if multiple)
- Consider pulpectomy - only applicable for mandibular pathology, limited applications
- Analgesia
- Supportive feeding
- Prophylactic Vitamin C
15
Q
Primary incisor pathology (GP)
A
- Rare - due to rostrocaudal movements of skull
- 2y malocclusion results from cheek tooth elongation
16
Q
Resp disease (GP)
A
- 2y to immunosuppression (to bacteria or irritants in environment e.g. NH3) - concurrent disease, poor husbandry, nutritional deficiency
- Susceptible to bacterial infections when kept w/ other species - Bordetella + Pasteurella from rabbits
- Adenovirus related pneumonia in stressed/older GPs - reduced func lung space
17
Q
Cystic ovaries (GP)
A
- Most common endocrine disease in GPs ( > 75% adult females at necropsy, aetiology unknown)
- Single/multiple cysts affecting both ovaries
- Abdominal distension
- Non-specific signs of discomfort
- Functional cysts cause non pruritic flank alopecia
- Manage surgically
18
Q
Dermatophytosis (GP)
A
- Trichophyton mentagrophytes (does not fluoresce with Woods lamp)
- 6-14% GPs asymptomatic
carriers - CS: alopecia, non-pruritic scaling, usually face and legs
affected (erythema) - Dx - microscopy/dermatophyte culture
19
Q
Dermatophytosis Tx (GP)
A
- Treat all in-contact animals
- Topical enilconazole or miconazole
- Oral itraconazole (risk of hepatotoxicity)/terbinafine (lower down cascade)
- Oral griseofulvin (25 mg/kg sid for 3 - 5 w)
- Sand bath treatment in chinchillas
- Difficult to eliminate in large groups
20
Q
Trixacarus cavidae
A
- Sarcoptic mite - present in low numbers , more common
- Clinical disease may be precipitated by stress/immunosuppression/hypovitaminosis C
- Intense pruritus can lead to self trauma and “seizures” (not true seizures. intense pruritus = uncontrolled spasms)
- Abortion/foetal resorption seen in pregnant
sows - Dx deep skin scrapes
21
Q
Trixacarys cavidae Tx (GP)
A
- 0.4mg/kg Ivermectin s/c weekly for 3 weeks
- Treat all affected animals in the group + clean housing well
22
Q
Pododermatitis (GP)
A
- 2y to poor conditions: abrasive flooring, obesity, irritants (urine, faeces, chemicals), hypovitaminosis C - dec collagen, inactivity, abnormal weight loading
- CS - erythema, swelling and ulceration of plantar and palmar surfaces
- If left, osteomyelitis and tenosynovitis can develop
- Avascular regions complicate recovery
23
Q
Pododermatitis Tx
A
- Address husbandry
- Topical and systemic
antibiosis: Flamazine speeds recovery; Preparation H - Analgesia
- Avoid debridement where
possible as contaminated - Prone to relapse
24
Q
Ocular disease (GP)
A
- Subclinical lens abnormalities - commonly congenital, often in pigment diluted strains
- Cataracts
- Fatty/pea eye - aetiology poorly defined, tend to affect overweight GPs on inappropriate diets
- Heterotopic bone formation - Keratitis - often related to trichiasis, especially in Rex
- Microphthalmos
25
Cystitis (GP)
- Rule out urolithiasis (often consequence of cystitis)
- Causative factors - stress, dehydration, reduced mobility (physical/psychological causes), high calcium/oxalate diet?, bacterial involvement
- Manage causes as well as consequence
26
Cystitis Tx (GP)
- Remove stone if present
- Analgesia - Meloxicam 0.6-0.8mg/kg bid
- Nutraceutiacals
- PSGAGs (Polysulfated glycosaminoglycans) e.g. Cartrophen
- Increased fluid intake
27
Cheilitis (GP)
- Inflam of lips
- Multifactorial disease - acidic/abrasive diet, hypovitaminosis C, 2y becondary bacterial/fungal infection, ?Pox viral involvement
28
Cheilitis Tx (GP)
- Antimicrobials based on cytology - yeast/bacteri
- Dietary improvement
- Topical emollients
- F10 barrier cream anecdotally speeds recovery
29
Dental disease (chinchilla)
- Similar dental anatomy to guinea pig
- Occlusal surfaces closer to horizontal
- Poor Px once roots distort mandibular or maxillary cortices
- Caries and coronal (cavities)
fragmentation
- Gingival overgrowth
- Very sensitive mucosa
- Stoic animals - disease often advanced by presentation
- Dx - radiographs - staging + adequate correction
30
Dystocia (chinchilla)
- Under-reported
- Relatively common presentation due to
foetal size
- Similar approach to larger mammals
- Dx - US
31
Dystocia Tx (chinchilla)
- Manual assistance
- Medical treatment - oxytocin, calcium
- Caesarian/OVH
32
Dental disease (degu)
- Only situation where clipping cheek teeth may be necessary due to size
- Similar pathology to other cavimorph rodents
- Diet major factor - should be on hay-based diet, limiuted sugary foods
- Can tolerate mild-moderate changes better than other herbivorous rodents
33
Diabetes mellitus (degu)
- Transient hyperglycaemia
common in older degus on inappropriate diet: sugary foods (fruit, raisins, carrots); high conc levels, select high sugar foods above all others
- Dx PU/PD + cataract formation; normoglycaemic by time of presentation; fructosamine often within normal range
- Persistent hyperglycaemia less common
- Spontaneous amyloidosis of islets 2y to cytomegalovirus; elevation of fructosamine (true pancreatic damage)
- Controlled wi/dietary modification
- No reports of insulin dependent cases
34
FT (myomorph)
- IV catheterisation difficult - lateral tail veins and femoral vein can be used in rats; jugular catheters poorly tolerated
- Intraosseous catherisation often more practical - femur; tibia
- SC - non-critical patient re-hydration, restrain difficult, 2.5% weight given
- Oral - slow rehydration where GIT func, most tolerate syringe feeding - baby food/vet products suitable
35
Blood sampling sites (myomorph)
- Lateral tail vein = rats/mice
- Femoral vein - visible in rats distally, blind technique under sedation/anaesthesia
- Cranial vena cava - site of choice in small rodents
36
Dental disease (myomorph)
- Rarely a problem - molars are permanent, occasionally caries seen on poor diet
- Incisors may malocclude following trauma
- Regular burring under anaesthesia
- Sx removal (some mobility is normal in lower incisors, most marked in hamsters
- Hard to extract incisors w/o damaging mandible, risk of H+, incisors v low down
37
Resp disease (rat)
- Most common presentation = wide disease spectrum
- Mycoplasma pulmonis = most common, Strep pneumoniae
- Filobacterium rodentium = CAR bacillus, Corynebacterium, kutscheri, Sendai virus, coronavirus, pneumonia virus
- Predisposing factors - high ammonia levels, aerosols, stress, concurrent disease
38
Resp disease Dx approach (rat)
- Sneezing, nasal discharge, tachypnoea, “rattling”(cooing), head tilt (middle ear), reduced “thoracic spring”
- Porphyrin staining (red pigment around nose + eyes), anorexia, weight loss, hunched posture, ruffled coat, lethargy
- Screen for underlying disease
- Culture (nasal/tracheal swab or BAL)
- Mycoplasma pulmonis PCR, corynebacterium serology
- Radio - Px - severity of lungs
39
Resp disease AB Tx (rat)
- Early Tx important
(In order of giving)
- 1) . Tetracyclines E.g. doxycycline 2.5-5 mg/kg PO BID
- 2). Macrolides E.g. azithromycin 20 mg/kg PO SID
- 3). Fluoroquinolones E.g. enrofloxacin 10 mg/kg PO SID
40
Resp disease Tx (rat)
-Anti-inflam - Meloxicam 1 mg/kg PO BID
- Mucolytics - Bisolvon pinch on food SID
- Bronchodilators - Salbutamol 100 µg / rat q4-6 h or as needed
- Nebulisation - dilute F10 (2 ml in 500 ml saline)
41
Resp disease Tx - husbandry (rat)
- Reduce ammonia: ventilation and cleaning
- Reduce stress
- Correct diet
- Increase activity + weight loss
- Isolation??
- Supplement vit A (used up, needed for proliferation + maintenance pf epithelial cells)
42
Neoplasia (rat)
- Pituitary adenomas common
- Typically elderly, obese female rats
- More common in cases with chronic respiratory disease (if don't respond to AB, then more likely to be pit gland neoplasia)
- Neuro signs: ataxia, poor forelimb co-ordination, head tilt, proprioceptive deficits, sudden death
- DDx - otitis media due
to chronic mycoplasmosis
- Px = grave
- Consider cabergoline therapy - large vol + expensive long-term
43
Ectoparasites (rat)
- Rarely 1y problem
- Accum in debilitated rodents
- Treat underlying cause
- Injectable ivermectin, 0.4 mg/kg SC
- Life cycle of rat mites usually ~21days
- Multiple treatments needed 2 - 3
- Tx of all in-contact animals
44
Wet tail aetiology (hamster)
- Bacterial enteritis - Lawsonia intracellularis; Clostridum spp.
- Parasitic - Hymenolepis tapeworm (zoonotic); giardia; oxyurids
- Most commonly seen at times of stress - weaning, change of home
45
Wet tail CS/Dx/Tx (hamster)
- Profuse watery diarrhoea
- Ventral staining
- Weakness
- Inappetance
- Can lead to rectal prolapse
- DDx - vulval discharge in female hamster post ovulation (white discharge + clinically well hamster)
- Tx: Aggressive AB + FT
46
Hyperadrenocorticism (hamster)
- Cushing's
- Adrenal gland normally 2 - 3 x larger in males
- 14.5% incidence of hyperplasia and neoplasia at
necropsy
- Usually incidental finding
- Males more commonly affected by pathology
- CS: PU/PD, Polyphagia, Hyperpigmentation, Alopecia, Pendulous abdomen
47
Hyperadrenocorticism Dx (hamster)
- Ultrasound
- Post-mortem
- Urine cortisol:creatinine
- Radio may demonstrate mineralisation
- Blood volumes required for tests are limiting factor
- ALP >40 U/L (normal range 8 -18 U/L)
- Cushingoid cases
48
Hyperadrenocorticism Tx (hamster)
- Poor response to mitotane
- Variable response to metyrapone - 5 - 10 mg SID for 30 d (lack of sufficient data)
- Ketoconazole believed to prolong survival (5 mg/kg BID PO)
- Supportive treatment for 2y skin infections
- Sx - low survival rates
49
Neoplasia (hamster)
- Skin neoplasia most common (epitheliotropic hymphoma)
- Soft tissue sarcomas
seen in older animals
- Adenocarcinomata - oral/pouch glands; flank scent glands; gastric mucosa
50
Epitheliotrophic lymphoma (mycosis fungoides)
- Older hamsters
- CS: Anorexia + weight loss, exfoliative dermatitis, scabbing + alopecia, concurrent demodecosis, variable pruritus
- Dx - biopsy/impression smears
- Tx - Chemotherapy generally unsuccessful, palliative corticosteroid therapy/Euthanasia
51
Hamster polyoma/papova virus
- Oncogenic virus of Syrian hamsters
- Common in lab situations - up to 50% affected
- Young hamsters develop multicentric lymphoma
- Beware subclinical carriers
- Incubation period can be up to 18 m lymphoma
- Older hamsters develop epithelial lymphoma or trichoepitheliomas
- Euthanase affected
52
Harderian gland secrections (gerbil)
- Appears as nasal dermatitis
- Increased secretion with stress, humidity >50%, 2y infection with commensal or opportunistic microbes (usually Staphylococci)
- Tx bacterial colonisation
- Address husbandry factors
53
Murine dermatitis complex (mice)
- Frustrating condition
- CS - severe pruritus and self-trauma
- Typically affecting the dorsal neck
-Multifactorial - parasitic, contact irritation, hypersensitivity, stereotypical self-trauma, frequently exacerbated by 2y infections
- Dx - skin scrapes + hair plucks, cyto, microbiological culture
53
Murine dermatitis complex - Tx (mice)
- AB + anti-parasitics
- Systemic anti-inflam therapy
- Trial exclusion diets
- Inc stimulation - slow feeding e.g. foraging enrichment, stones in bowls, increased handling, companions
- Difficult to restrict self trauma with physical barriers
54
Mammary neoplasia (mice)
- >80% malignant
- Benign neoplasms 2y to retrovirus - murine mammary tumour virus, transmitted vertically in milk or in genome, oestrogen sensitive
- Expressed in females of reproductive age
- Zoonotic potential
