Clinical Approach to Amphibian Emergencies

Abstract

With over 8300 species described, the class Amphibia represents a significant contribution to the diversity of vertebrate life on earth. Amphibians increasingly are being kept as pets, in addition to frequently finding them in zoological and research collections. However routine wellness exams are rarely provided to most pet amphibians, with most animals only presenting to the veterinary clinic as an emergency case when they are ill. The acute onset of a clinical condition requiring emergency care in amphibians is often the result of trauma, infection, metabolic deficiency, toxicity, or a sudden inappropriate environmental change. If multiple animals are affected, each individual must be triaged based on the severity of their clinical signs and risk of deterioration. It is important for clinicians to understand how an amphibian’s unique anatomy and physiology will factor into the clinical approach to emergencies. The expedient collection of a history and husbandry parameters, a systematic physical examination with appropriate selection and execution of diagnostics, and the immediate administration of emergency care will increase the likelihood of a successful outcome.

Blood collection should be considered in the diagnostic evaluation of ill amphibians but may not always be possible. While radiographs are useful for evaluating skeletal disease, respiratory disease, or the presence of a gastrointestinal obstruction (e.g. foreign body), ultrasonography should be considered a standard of care for amphibians for evaluating coelomic viscera and assessing for fluid accumulation. If fluid accumulation noted in the coelom or subcutaneous space then paracentesis followed by cytology, fluid analysis, and aerobic culture should be carried out.

Clinicians must always consider whether pain is present in debilitated amphibians. Decreased activity and feeding behavior, color changes, increased reclusive behaviors, postural changes, and spending more time in atypical locations all have been associated with pain in amphibians. Dermal irritation is often manifested by a wiping behavior with the hindlimb. Amphibians demonstrate a dose-dependent analgesic response to opioids and alpha-2 agonists (such as dexmedetomidine). Always ensure good hydration before using NSAIDS. It is essential to provide nutritional support to debilitated amphibians once their dehydration has been corrected, and gavage feeding is often needed initially.

If euthanasia needs to be carried out, several pharmaceutical options are available. Pithing should be carried out with all methods of chemical euthanasia 30 minutes after the loss of reflexes and voluntary movement. Owners should be counselled on the usefulness of submitting deceased amphibians for necropsy with follow up histology and other diagnostic testing where indicated to elucidate causes of mortality. This will be of benefit to other amphibians in their collection.

 

Outline

  • Clinically relevant anatomy and physiology
  • Obtaining a detailed history
  • Triage and emergency therapies
  • The clinical examination
  • Diagnostic testing
  • Analgesia
  • Nutritional support
  • Hospitalization
  • Euthanasia

PowerPoint

Download a PDF of the presentation, generously shared by Dr. Whiteside.

Whiteside Title Slide

 

Analgesia

Download this table on commonly used analgesics in amphibians, shared by Dr. Whiteside.

Amphibian Analgesia Table

 

About the presenter

Douglas Whiteside is an Associate Professor of Conservation Medicine, an Adjunct Associate Professor in Biology, and a full member of the Wildlife Health & Ecology Research Group at the University of Calgary. Dr. Whiteside is also a Senior Zoo Veterinary for the Calgary Zoo and Veterinary Consultant for the Guyana Zoo. Doug earned a Doctorate of Veterinary Medicine (DVM) from the University of Guelph in 1995 and a Doctorate of Veterinary Sciences (DVSc) also from the University of Guelph in 2001. He then completed an internship at the Louisville Zoo and a residency at the… [Learn more].

 

Webinar recording

 

 

Post-test

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Expert Q+A

Although Dr. Whiteside was able to answer many questions during the live event, the remaining questions were answered by email and are posted below:

FLUID THERAPY

How long do you soak the patient for both dehydration and for hydrocoelomic patients? …For illness (non edematous)?

I recommend soaking for a minimum of 30 minutes up to 60 minutes as long as the patient is stable. This can be done daily.

Could you use diluted lactated Ringer’s solution (LRS) for transdermal rehydration?

Yes, LRS could be used but it is not a balanced electrolyte solution (sodium and potassium are lower than Plasmalyte A 7.4 and the pH is acidic (6.5). The osmolality is 274 MOsmol/L.

H-Water does that come in gallons? How is that available?

I assume you mean aged water. This is city tap water that has been aerated and allowed to sit for a minimum of 24 hours to allow the chlorines to dissipate. You can use commercially bottled water for amphibians as well.

Can soaks in medicated fluids have any adverse effect on amphibian eyes?

I have not used any medications that are toxic to eyes in amphibian soaks.

Editor’s note:  I will also refer you to the following article, in which the abstract lists some of the medications that can damage the cornea:   Drug-induced corneal damage. Prescrire Int. 2014 Apr;23(148):97-100. PMID: 24860895. Please know that, depending on the concentration, chlorhexidine can also potentially cause corneal damage.

I always thought chloramine wouldn’t evaporate, is that true? I always thought you had to use a dechloraminator

Chloramines don’t evaporate but they break down over time to chlorine and ammonia. A carbon filter is the most effective way to remove chloramines.

What are the preferred routes of fluid administration in critically ill patients and also in non-emergency cases? Should we go intraosseous (IO )in emergency cases?

Transdermal is effective for mild to moderate dehydration is stable patients and in non-emergency cases. For emergencies, IO is indicated.

Okay to use commercial natural spring water for baths and misting?

Yes, commercial natural spring water is suitable for baths and misting.

 

DIAGNOSTIC TESTING

Lithium heparin for blood draw? Where do you get it?

The Becton Dickinson microtainers for plasma (green color) contain lithium heparin. Commercial veterinary labs usually carry these [tubes] and you can order from them, otherwise you can order from lab supply companies (Becton Dickinson, Fisher Scientific, etc.) or they can be ordered on Amazon in some countries.

What was the barium dose again?

A screenshot from Dr. Whiteside’s PowerPoint presentation is shown below.

Dr. Whiteside has also shared a PDF of his presentation

diagnostics radiology slide

Click image to enlarge

Do you have amphibians that tend to run out of the container with the pulsed wave Doppler?

I tend to use a lid on any container where amphibians might want to jump out.

 

NUTRITIONAL SUPPORT

What is the procedure for gavaging an amphibian?

Pre-measure the soft tipped catheter to the level of the stomach. Gently open the mouth at the rostral aspect with a small flexible plastic device such as a surgical fingernail pick or a guitar pick. A small, soft-tipped catheter can then be inserted on midline in a straight fashion and gently advanced down the esophagus into the stomach.

 

THERAPEUTICS

How would you care for a fully aquatic species (e.g. Xenopus) that needs out of water treatments like wound repairs?

For the repair I would keep them very moist during the procedure with shallow surgical water dishes, wet unbleached paper towel, and frequent active moistening with a syringe. Once the repair is complete I spray with OpSite bandage spray. It can then be placed in an aerated medical tank with a hide spot. I use clean water with daily water changes.

Okay to use transdermal route for parenteral antibiotics in very small (<5 g) animals like dart frogs? Better to try intracoelomic (IC) if subcutaneous or intramuscular difficulty? Some concerns for daily restraint

The challenge with the transdermal route is there is variable transdermal absorption that may not allow for therapeutic levels. The concentration that is used for transdermal is higher than for parenteral route. IC route would be indicated as well.

I’ve read that dorsal lymph sacs can used to administer medications or anesthesia. Have you used this route?

Yes, I have injected medications into the dorsal lymph sacs

What do you use for anesthesia and what are the safety margins?

Anesthesia is species and situation dependent. Injectables, immersion, topical, and gaseous anesthetics all can be used. I would refer you to the scientific literature for more specific literature on the species you are anesthetizing. A good starting point is Sladakovic, I., & Divers, S. J. (2019). Amphibian Anesthesia. In Mader’s Reptile and Amphibian Medicine and Surgery (pp. 480-485). WB Saunders.

Any thoughts on using isoflurane in lube [water-soluble lubricant] applied topically for euthanasia?

Isoflurane in lube can produce inconsistent results for anesthesia in many species but has been successful in others. The same likely holds true for euthanasia, however, this would need to be determined on a species by species basis, and it would not be my first choice for euthanasia.

The question below is a follow-up to one on recurrent cloacal prolapse in a tree frog

Thanks for the tips and suggestions. Unfortunately soaks, fluids and edema reducing tricks help with reduction but not in the long run. Poor frog keeps prolapsing even after successful reduction up to 4-5 days later. Cannot identify cause, rads appear clear, but am likely missing something on ultrasound (30 g green tree frog).

Sorry to hear about your tree frog case. These can be frustrating. I would recommend ultrasound to see if any pathology can be detected. Endoscopy or exploratory may also be indicated and if no abnormalities are present, then a cloacopexy may be indicated.

 

DISEASE CONDITIONS

Causes and therapy for rectal prolapse in a Pacman frog?

There are several differentials for rectal prolapse which include constipation/obstipation (often seen when too much mammalian prey such as pinky mice are fed), inflammatory disease secondary to infection (parasitic, bacteria), secondary to reproductive disease, or neoplasia. Treatment is dependent on etiology, but general principles include reducing the edema in the prolapse (sugar works well for this), reducing the prolapse and using a suture pattern to partially close the cloaca to allow feces and urine to pass, and pain management.

Seeing some young frogs with hind leg paresis, under 10 grams too small to get blood. What is the best approach?

Are these all in the same species? What is the species? Any pathology done on severe cases or deceased cases? There are a number of differentials for hindlimb paresis unfortunately, so recommending the best approach is difficult. A review of husbandry and diet is indicated to ensure adequate levels of B vitamins, Vitamin A, D, and E, appropriate Ca:P ratios, etc., and to ensure that distilled water is not being used. Any history of antibiotic use in the larval (tadpole) phase?

 

 

RACE approval

This program 807970 is approved by the American Association of Veterinary State Boards (AAVSB) Registry of Continuing Education (R.A.C.E.) to offer a total of 1.00 CE credits to any one veterinarian and/or 1.00 veterinary technician CE credit. This RACE approval is for Category: Medical using the delivery method of Non-Interactive-Distance. This approval is valid in jurisdictions which recognize AAVSB RACE; however, participants are responsible for ascertaining each board’s CE requirements. RACE does not “accredit” or “endorse” or “certify” any program or person, nor does RACE approval validate the content of the program.

To cite this page:

Whiteside DP. Don't let it croak: Clinical approach to amphibian emergencies. Dec 13, 2020. LafeberVet web site. https://lafeber.com/vet/clinical-approach-to-amphibian-emergencies/