By Dr Louise Abuzet BVM&S CertAVP (ZM) CertAVP (ECC) BSc(HONS) MRCVS

Do note that many of the medications discussed in this webinar are off licence and are used under the cascade.

Introduction to exotic small mammal emergencies

Herbivorous species ---> Guinea pigs, degus and chinchillas – cannot vomit, continuously growing incisors and molars.

Omnivorous species ---> Hamsters, rats, gerbils and mice – cannot vomit, continuously growing incisors, but molars only have a limited period of growth

Carnivorous species ---> ferrets – obligate carnivore, brachydont dentition, can vomit

African Pygmy hedgehogs are technically omnivores but they also have brachydont teeth and can vomit.

Many exotic small mammals are prey species, so they hide signs of pain and disease very well. Any exotic small mammal that is not eating and passing faeces as normal, or is simply not quite right must be seen as soon as possible as they can deteriorate rapidly. Expectations, owner commitment and financial implications should be discussed from the outset.

Triaging exotic small mammals

History taking

• Housing ---> Indoor/outdoor, companions/solitary, enclosure design, substrates (poor husbandry can result in poor health)

• Vaccination (ferrets – distemper, rabies)

• Neutering status (guinea pigs, ferrets, rats)

• Eating / drinking ---> change in foods/volumes consumed

• Urinating ---> colour, volume, sediment, loss of litter box training

• Faeces ---> Change in colour, size, shape, volume

• Behaviour changes ---> Lethargy, stretching out abdomen, hiding, bruxism

• Vomiting/ regurgitation ---> many small exotic mammals cannot vomit, however ferrets and African pygmy hedgehogs can!

• Previous health problems

• Recent stressors, exposure to toxins, trauma

Clinical exam tips

• A small towel can be very useful to offer somewhere to hide and reduce biting

• Putting a lively small furry in a clear plastic tub can allow a closer exam especially of the ventrum

• Ferrets will yawn if you scruff them allowing a good look in the mouth. They often bite but can be easily distracted with ferret malt paste 

• Guinea pigs always have food in their mouths – if its empty, be worried

• Hedgehogs will usually need to be sedated with isoflurane/sevoflurane to allow for examination.

• Care with fur slip in chinchillas and degloving tails in gerbils and degus

Performing a clinical exam

The clinical exam of an exotic small mammal will be similar to a dog or cat with a few extra things to remember

· Assess hydration – mucous membranes, skin turgor

· Rats - Red tears (Chromodacryorrhea) - release of porphyrins from the Harderian lacrimal glands, sign of stress

· Cheek pouches – hamster – used to store food and extend down to the shoulder region

· Dental – otoscope exam may be possible in some of the bigger exotic mammals

• Most have continuously growing teeth (except African pygmy hedgehogs and ferrets)

• Palpation of mandible/maxilla

• Check incisors for overgrowth/uneven wear

• Excessive salivation

· Wet sleeves – many exotic small mammals wipe their nose on their forelegs, so check forelegs as well for signs of nasal discharge.

· Herbivores – listen for gut sounds

• Normal gut sounds: One or two episodes of borborygmi per minute (Riggs, SM (2009) GUINEA PIGS. Manual of Exotic Pet Practice. 456–73. Epub 2009 Nov 30.)

· Check scent glands – ventral in gerbils, flank in Syrian hamsters

· Ferrets - Large spleens are common – can be normal in older ferrets due to extramedullary erythropoiesis.

· African pygmy hedgehogs - Self anointing – put frothy salvia on the spines – normal behaviour

· Check feet and hocks for sores

· Check genital area, double check sex, check for penile fur rings in chinchillas

· Avoid rectal temperature unless essential to record.

· Weight and body condition – be aware that in herbivores their weight can change considerably depending on gut fill

Basics of emergency care

Analgesia

· NSAIDS

• Meloxicam – for most of these species we are using higher rates per kg compared to dogs and cats, remember that Metacam 0.5mg/ml oral suspension is licensed for use in guinea pigs

• Carprofen

• Ferrets are prone to GI ulceration so consider concurrent H2 blocker

· Opioids

• Buprenorphine appears to be well tolerated

• Fentanyl – ferrets

• Tramadol – rats, ferrets, mice

• Very little data on efficacy in these species

· Alpha-2 agonists such as medetomidine and dexmedetomidine ---> Can cause cardiovascular depression so care in sick patients.

· Local anaesthesia such as lidocaine / bupivacaine ---> Calculate maximum doses carefully, risk of toxicity

· Ketamine can also be considered for use in some species  

Fluid therapy

• Maintenance fluid rates for small mammals: 75 – 100ml/ kg /day

• Bolus ---> small mammals:  5 – 10ml/kg/20 mins

• Routes ---> IV (cephalic, lateral/medial saphenous, femoral vein), subcutaneous, intraperitoneal, intraosseous (proximal femur, proximal tibia), oral.

Feeding

• Early nutrition is vital

• Offer favourite foods ---> drastic diet changes should not be implemented whilst a patient is unwell.

• Calculate volume of food required if not eating

• Oral, syringe feeds, feeding tubes

 Warmth

• Small mammals lose heat very quickly especially when they are unwell

• Bubble wrap, bair huggers, heat pads, snuggle safes, blankets.

Oxygen

• Many exotic small mammals may have pre-existing respiratory disease

• Consider oxygen if stressed, dyspnoeic or collapsed

• Consider preoxygenation prior to handling

• Chamber, flow by, mask

Diagnostics – blood tests

· Small mammal blood volume is 7% of bodyweight

• If healthy can take up to 10% of this (0.7% of body weight) - Note 1ml of blood = 1g

· Collecting blood samples ---> foot prick, cephalic, lateral /medial saphenous, femoral vein, tail vein (rats, mice), jugular, cranial vena cava (guinea pigs)

· Glucose ---> can use handheld glucometer, but they are not calibrated for exotic species – can be useful for looking at trends in blood glucose

• Can see hyperglycaemia due to stress but also due to diabetes in hamsters, gerbils, guinea pigs, chinchillas and degus

· EPOC/ emergency database

· Full biochemistry and haematology ---> Exotic labs can run bloods on very small samples, use textbooks/ask lab for reference ranges

· Endocrine testing - for example, with ferrets we often perform adrenal profiles and insulin levels.

Diagnostics – imaging

· Radiography

• Chamber, wrapped in towel

· Ultrasonography

• Herbivores - Maybe limited due to gas in gastrointestinal tract

• POCUS/FAST scan for free fluid

Anaesthesia

· Starving

• You do not need to starve rodents before GA

• Can withhold food for an hour for guinea pigs to reduce volume of food in the mouth ---> Once under sedation / GA then clean the mouth out! Use cotton buds

• Ferrets and hedgehogs should be fasted for 1 – 4 hours

· Pre oxygenate all small mammals ---> Many will have pre-existing respiratory disease

· Keep warm prior to and during sedation/general anaesthesia

• Bubble wrap, bair huggers, heat pads, snuggle safes, blankets.

• Minimise clipped area, don’t saturate with hibiscrub/spirit

· Ensure you have everything ready so you minimise time under GA/sedation

· Multiple drug combos are possible - Find one you are comfortable with

· With sick animals  ---> avoid alpha 2 agonists due to cardiovascular depression

· Analgesia should always be considered e.g. buprenorphine, fentanyl

· Other drugs to consider: midazolam, ketamine, local anaesthesia

· With ferrets, some sort of premed recommended as gas induction can cause anxiety and stress

· Induction ---> Alfaxan IV/IM, Propofol IV

· Gas induction ---> Isoflurane, Sevoflurane

· Consider intubation especially in larger species

• Ferrets, African pygmy hedgehog – easy, technique same as dog/cat

• Guinea pig – blind, endoscope/otoscope guided 

· Monitoring

• Dopplers are great for monitoring heart rates in exotic small mammals

• Temperature, blood pressure, capnography, pulse oximetry

· Assessing surgical plane of general anaesthesia

• Lack of response to tail/toe pinching

• Rodents should maintain a sluggish palpebral reflex at surgical depths of anaesthesia

• Eye position usually fixed in rodents

• Can use jaw tone but limited use in herbivores with small gape

· Recovery ---> Keep warm and continue to oxygenate on recovery

CPR

· Tight fitting face mask, intubation (Guinea pig, ferret, hedgehog)

· Breathing rate: 20 breaths per minute

· Cardiac compression: 100 compressions per minute

· Reverse drugs where possible

· Check glucose

· CPR drugs:

• Asystole – Adrenaline

• Bradyarrhythmia – Atropine

• Ventricular fibrillation – Lidocaine

Euthanasia

• If possible, place IV catheter however do consider the level of stress to the patient of placing an IV

• Intracardiac/intrahepatic post gas or injectable sedation

Common emergencies

Dental disease

· Dental issues are very common, and these patients can present as emergencies

· Clinical signs include weight loss, bruxism, hypersalivation, facial masses/ abscesses, poor fur quality, anorexia /change of feeding habits, respiratory signs (especially degus), collapse due to prolonged anorexia

· Supportive care prior to dental: analgesia, fluids, consider prokinetics (metoclopramide, cisapride, ranitidine), feeding, warmth, exercise

· Need to sedate / GA for a full oral exam

· Consider radiographs - assess the roots

· With continuously growing incisors, you should not clip them, but burr them down instead

· With ferrets and African pygmy hedgehogs, dental techniques are similar to cats and dogs

· Diet is very important as part of management.

Cheek pouch prolapse in hamsters

· Can occur due to getting large or sticky food stuck in the pouch

· Neoplasia, cysts, inflammation, infection of the pouch etc are also possible underlying causes

· GA / sedate and replace using a 1ml syringe or cotton bud and then place sutures to secure

• If this technique fails, incise over cheek and perform internal sutures – pouch to subcutaneous tissues.

Wet tail in hamsters

· 3 – 10-week-old hamsters

· Lawsonia intracellularis bacterium

· Other causes of diarrhoea include Clostridium difficile enteroxemia, Clostrium piliforme (Tyzzers disease), stress and dietary indiscretion.

· Clinical signs: Wet perineum, foul smelling watery diarrhoea, anorexia, dehydration, abdominal pain, distended bowel loops

· Tx: fluids, antibiotics (TMPS, enrofloxacin), bismuth subsalicylate, correction of electrolytes and glucose levels, probiotics, analgesia

Other gastrointestinal diseases to note

· Choke in Chinchillas

• Drooling, retching, anorexia and dyspnoea

• Usually a treat that has lodged in oesophagus

• Pass stomach tube, analgesia, fluids, supportive care

· Foreign body in ferrets

• Gastrointestinal fb are common in ferrets

• Treatment as for a dog

· Gastric dilation / GDV in guinea pigs

• Important to distinguish GD from GDV

• Can be rapidly fatal due to shock and respiratory impairment

• Treatment as for a dog

Respiratory disease in rats

· Causes: viral, bacterial (Mycoplasma, Pasteurella, Bordetella etc), allergy/environment

· Clinical signs: nasal discharge, sneezing, dyspnoea, weight loss, head tilt (M. pulmonis can cause otitis media)

· Tx: oxygen therapy, reduce stress, antibiotics (enrofloxacin, doxycycline), meloxicam, nebulisation, mucolytics, fluid therapy, husbandry changes

Cardiac disease in guinea pigs

· Guinea pigs can be prone to developing cardiac disease

· Clinical signs: lethargic, anorexia, weight loss, dyspnoea, coughing, pale/cyanotic mucous membranes.

·  Dx: radiography, thoracic ultrasound, echo

· Tx: frusemide, pimobendan, benazepril

Insulinoma in ferrets

· Clinical signs: ptyalism, pawing at mouth, ataxia, weakness, seizures, weight loss

· Dx:

• Blood glucose <3.4mmol/l

• Insulin level

• Fasted glucose levels (if blood glucose over 4.2mmol/l then starve for 2 hours and recheck it)

· Tx: Surgery, prednisolone, diazoxide, diet

Hyperadrenocorticism in ferrets

·       Overproduction of the sex hormones

·       Very common in neutered ferrets, occurs due to loss of feedback mechanism

·       Clinical signs: alopecia, increased sexual behaviour, vulva swelling, urinary obstruction due to prostatic enlargement and cysts

·       Dx: bloods - adrenal profile, ultrasound

·       Tx: Deslorelin, surgery

Persistent oestrus in ferrets

· Ferrets are induced ovulators and will remain in oestrus if not bred

· High level of oestradiol leads to bone marrow suppression and pancytopenia

· Clinical signs: pale mucous membranes, petechiae, ecchymosis, swollen vulva

· Tx: blood transfusion (Note: No blood groups have been identified in ferrets to date and therefore cross matching not required), supportive care, hCG injection

· Prevention: Deslorelin implant

Urinary disease in guinea pigs

· Urinary tract infections

• Common in guinea pigs

• Clinical signs: Haematuria, dysuria, abdominal pain

• Tx: Enrofloxacin/ TMPS, analgesia

· Urolithiasis

• Very common in guinea pigs – calcium carbonate

• Ensure x-ray the whole perineum as well!

• Diet modification (reduce calcium and oxalate)

• Surgery?? ---> high rate of recurrence

Pituitary tumours in rats

· Common in older female rats

· Clinical signs: Head tilt, ataxia, circling

· DDx for head tilt: Otitis media/interna, vascular event, trauma

· Tx: cabergoline, supportive care

· Prevention: early neutering may reduce risk

Hamster torpor/ hibernation

· If a hamster's environment drops to < 50C they can enter a state of hibernation

· Careful clinical exam and the use of a doppler to check for a heartbeat can help you distinguish between hibernation and death.

· Tx: Gentle warming, change in cage location to avoid low temperatures in the future.