Hospitalisation & Treatment of Snakes, Lizards, Chelonians
World Small Animal Veterinary Association World Congress Proceedings, 2011
Bairbre O'Malley, MVB, CertVR, MRCVS
Associate Lecturer Exotic Species, School of Veterinary Medicine, Dublin, Ireland

Introduction

Reptiles are commonly hospitalised for periods of 1–2 weeks as they often present with long standing illness requiring intensive treatment. The veterinary hospital must be equipped with the correct tanks and utensils to house the 30–40 reptile species commonly seen in practice. Common medical reasons for hospitalisation include metabolic bone disease (chelonians and lizard), thermal burns and respiratory disease. Surgical cases include cloacal and phallus prolapse, digit and tail tip amputation, abscess removal, salpingohysterectomy, shell repair and exploratory surgery.

Ectothermy

Reptiles are ectothermic meaning they are unable to generate metabolic heat and rely instead on the temperature of their environment. Every reptile has a preferred optimum temperature zone (POTZ) that is the thermal range at which it functions optimally and has a maximum immune response. This thermal range (available from reference books) will depend whether the species is from a temperate, subtropical or tropical climate. Within this range the reptile has a preferred body temperature (PBT) for a variety of metabolic processes from eating, digesting, to reproduction and metabolizing drugs.5

Housing in Hospital

Due to this co-dependence on their environment reptiles must be kept contained either in a vivarium or heated enclosure while in hospital. The vivarium should be rectangular to allow for a temperature gradient and cage furniture should be supplied according to the animal's needs. Arboreal reptile like the iguana and chameleon need branches and foliage while terrestrial animals like tortoises and geckos need burrows or hidey holes. There should also be visible barriers to avoid causing prey / predator or territorial stress.4

Temperature

Heating in the vivaria can be provided by a heat lamp, heat pad or both. The heat pad should not occupy more than 30% of the tank. Heat pads should be placed under or attached to the side of the vivarium and heat lamps should be protected by wire mesh to avoid any chance of thermal burns. A thermometer should be placed at each end of the tank to give accurate temperature readings.5

UV Light

Although UV light is important for the animals well being it is not essential for calcium absorption and bone metabolism during a short hospital stay. If provided they must be within 30 cm of the animal for best effect. All UV lights should be changed every 6–12 months according to the manufacturer's instructions.

Humidity

The environment must be kept humid to treat dehydration and aid shedding (Ecdysis). A hygrometer is essential to give accurate readings. Humidity can be provided by mist spraying, shallow water dishes or humidity chambers in focal parts of the tank. All vivaria must have good ventilation to prevent the buildup of bacteria and fungal problems.

Substrate

The most hygienic substrate is newspaper or paper towel which is clean and facilitates easy collection of faecal samples.4 Reptile sand or soil should be available for egg laying patients or burrowing species like tortoises.

Cage Hygiene

Water bowls should be washed and disinfected daily to avoid pseudomonas infections. Spot cleaning should be performed as necessary. Tanks should be cleaned and disinfected every few days and after each patient is discharged. The best disinfectants are quaternary ammonia compounds, dilute hypochlorites and iodophores.5

Quarantine

Great attention must be paid to avoiding spread of infection within the hospital. For example tortoise species should always be barrier nursed to avoid the spread of the highly contagious herpes virus. The snake mite Ophionyssus natricis is a carrier for Aeromonas bacteria and fatal inclusion body virus so all new arrivals should be screened for mites and wiped down with fipronil if infested. As a large part of the mite's life cycle is in the environment all tanks and utensils should be sprayed with pyrethrin between patients.

Zoonotic Disease

All reptiles have the ability to excrete Salmonella species in their faeces. As the spread of Salmonella is via the faecal-oral route the following precautions are essential for hospital staff.

 Practice good hygiene in the reptile ward

 Wash hands after handling reptiles with hot soapy water or medical scrub

 Wear gloves when cleaning out dirty tanks and handling faeces (e.g., in the laboratory )

 Never drink, eat or smoke when handling reptiles

 Reptiles should not be handled by any pregnant or immunocompromised staff member

Handling of Reptiles

Chelonians are easy to handle but aquatic turtles have long necks and can give nasty bite if attempting to open their mouth. Use a sturdy mouth gag and mind your fingers!

Lizards like iguanas can be very feisty and lash out with their sharp claws and whip you with their long tail. They can be restrained by covering the head with a thick towel and supporting the body by hands on pectoral and pelvic girdle. Never grab lizards by the tail as many species (geckos, iguanas) perform autotomy and will leave their tail behind. Always use a gag when examining the mouth of large lizards as they snap their mouth shut like a trapdoor!

Snakes need gentle handling as they only have a single occiput and can easily dislocate their neck. Snakes bruise very easily and rough handling can lead to septicaemia and even death. For obvious reason large constricting snakes should never be handled alone.

The Sick Reptile

Most sick reptiles will have been anorexic for weeks to months and be severely dehydrated. Reptiles are uricotelic meaning the end product of protein metabolism is urates and not urea. Urates are very insoluble so even the slightest degree of dehydration can lead to a buildup of urate crystals leading to life threatening visceral or articular gout.

Hospital Routine

After admission to the hospital no fluids, medication or food should be given to a reptile until is has warmed up to its POTZ in the hospital tank.2 Fluid therapy must then be started according to its state of health (see below). With the exception of emergencies withhold drugs or food until the reptile is rehydrated as it may not be able to metabolise drugs or digest food.

If the reptile is still eating it is often useful to ask the owner to bring some of the reptile's normal diet with them. The practice should also stock a range of frozen mice, crickets, mealworms and leafy greens. Enteral feeds like Vetark Critical care formula, Oxbow Critical care for herbivores and hills A/d should also be available. Patients should be weighed daily and given baths to encourage drinking and voiding of faeces. Faecal samples should be routinely analysed for parasites (wet smear and faecal flotation).

Antibiotics

Many bacterial problems in reptiles are secondary to poor husbandry rather than a primary bacterial pathogen. Where possible the choice of antibiotic should be based on culture and sensitivity. Most infections in reptile tend to be either gram-negative or anaerobic so the following three are useful for sick reptiles.

Fluoroquinolones are broad spectrum and bactericidal and are very good for gram-negatives like Aeromonas and Pseudomonas. They have poor action against anaerobes. Ceftazadime is a third generation bactericidal beta lactam. It has excellent activity against gram-negative (especially Pseudomonas) and some gram-positive and anaerobic effect. Metronidazole has good anaerobic (and antiprotozoal) activity and can also act as an appetite stimulant.3

Analgesia

Although reptiles do not show obvious signs of pain it must be assumed to be present and treated accordingly. Opioids like morphine, buprenorphine and butorphanol and local anaesthetic like bupivacaine and lidocaine are useful. NSAIDs like carprofen and meloxicam can be used if the reptile is neither renal compromised or dehydrated.2

Diagnostic Imaging

Radiography is essential in lizards and chelonian to check for underlying metabolic bone disease but it is also useful to rule out fractures, pneumonia, foreign bodies, uroliths and egg binding. Contrast radiography is used for identifying location of masses. Ultrasound is very useful for assessing the heart, reproductive status, liver problems and soft tissue masses in the coelomic cavity

Methods of Rehydration

Moderate to Severe Dehydration

Fluids can be given via the intravenous, intraosseous or intracoelomic route. Intravenous route may need a cut down for the jugular in large snake but the tail vein is useful in lizards. The intracoelomic route is easier to access but as reptiles lack a diaphragm care must be given not to overload and compromise breathing. In collapsed or small reptiles the intraosseous is often the only accessible route. Insert a spinal or hypodermic needle into the proximal tibia or femur after full sterile prep.

Mild Dehydration

Subcutaneous fluids should only be used in cases of mild dehydration as reptile skin is inelastic and there is poor absorption with severe debility. Bathing in a shallow tray of warm water for 10 minutes is also a very effective method of rehydrating reptiles.

Stomach Tubing

Reptiles are relatively easy to stomach tube as the glottis is forward placed and tends to be closed more often than open. The tube should be well lubricated and prefilled with fluid to avoid injecting too much air. Pass the tube dorsally along the hard palate. Larger species of snakes, lizards and all chelonians will need a mouth speculum to stop them chewing the tube and biting handler.3

Snakes: Well lubricated naso-gastric tube inserted into cranial third of snake (site of stomach). Hold snake vertically during and for 2 minutes afterwards to avoid regurgitation (weak cardiac sphincter). Max volume is 15–30 ml/kg.3

Lizards: Nasogastric tube or old intravenous drip tubing depending on size. Pass to just behind caudal ribs (site of stomach). Max volume is 10–20 ml/kg.3

Chelonians: Stomach is positioned at mid plastron. It can be difficult to extend head in a lot of chelonians and requires time and patience. The head must be fully extended from the shell otherwise it will regurgitate. Max volume is 5–15 ml/kg.3 If long term nutritional support is needed then oesphagotomy tubes are placed under light anaesthetic.2

How much to give: Chronically dehydrated reptiles should be rehydrated slowly over 2–3 days to avoid cardiovascular overload. Maintenance for reptiles is from 5–15 ml/kg / day.2 Start first with electrolytes and dextrose until the reptile is urinating and then commence enteral feeds like Vetark Critical care formula (oral reptile food supplement). If the reptile is very debilitated care must be taken not to overload the gut on the first day or too.

Blood Sampling

Blood for a minimum database (PCV, TP, Blood glucose) should be taken before initiating fluid therapy. Blood volume of reptiles is approx. 4–8% bodyweight. In a healthy reptile up to 10% of this may be withdrawn but much less if the animals are debilitated.2

Example:
100g lizard, 5–8% body weight = 5–8g
10% = 0.5–0.8ml maximum (healthy reptile)

Table 1. Venupuncture Sites.

Site

Technique

Comment

Lizards  

Ventral tail vein

Angle needle 45 degrees in midline, distal to cloaca

Avoid hemipenes in males

Snakes  

Ventral tail vein

As above but aim between ventral scales

Avoid hemipenes in male

Cardiac puncture

Inject into ventral heart & withdraw blood slowly

Requires experience
Only in snakes > 100g

Lingual veins

 

Best under sedation
Small samples obtained

Chelonians 

Subcarapacial sinus

Insert needle above head just at highest point of carapace,

Lymphdilution common

Jugular vein

Lies lateral from tympanum to base of neck

May need sedation to extend neck

Dorsal tail vein

Insert needle in midline close to base of tail

Lymph dilution common

References

1.  Mader DR, Rudloff E. Emergency and critical care. Reptile Medicine and Surgery. Mader, 2nd ed. Philadelphia, Elsevier,31, pp533–548.

2.  Martines-Jimenez, Hernadez-Divers. Emergency care of reptiles. Vet Clin Exot Anim 2007;10:557–585.

3.  Rees Davies R, Klingenberg RJ. Therapeutics and medication. BSAVA Manual of Reptiles. 10, pp115–131.

4.  Rossi JV. General Husbandry and management. Reptile Medicine and Surgery. Mader. 2nd Edition, Philadelphia, Elsevier, 4, pp25–42.

5.  Varga M. Captive maintenance and welfare. BSAVA Manual of Reptiles. 2nd Edition 2004;2:6–18.

  

Speaker Information
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Bairbre O'Malley, MVB, CertVR, MRCVS
School of Veterinary Medicine
Dublin, Ireland


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