Clinical Examination of Reptiles


Sharon Redrobe BVetMed BSc MRCVS

The Snake

It is important to obtain a thorough clinical history from the owner.
This should include feeding, weight, ecdysis, faecal and urate production.

The following need to be assessed:

  1. obtain accurate length (rostrum-cloaca) and weight
  2. inspect rostrum, nostrils and infra-orbital pits (discharge, occlusion, trauma).
  3. check eyes clear, inspect spectacles under magnification for abnormalities
  4. ensure tongue flicking normally and snake moving normally, able to support head etc..
  5. examine oral cavity (mucous membranes normally clear, but no petechiation, excess salivation, oedema, fluid from respiratory tract)
  6. body should be rounded (triangular if emaciated)
  7. skin elasticity? Check hydration and palpate for swellings
  8. check scales for haemorrhage, blisters, loss (check ventral scales too)
  9. check cloaca for oedema, erythema, discharge, swellings
  10. make faecal smear if faeces produced
  11. smaller snakes and hatchlings may be transilluminated
Average organ position in boas and pythons
Organ Position
(expressed as % of total length rostrum-cloaca)
heart22 - 33
lungs33 - 45
air sac45 - 65
liver38 - 56
stomach46 - 67
intestines68 - 81
right kidney69 -7 7
left kidney74 - 82
colon and cloaca81 - 100

roughly cranial 1/3 oesophagus, trachea, heart
middle 1/3 lungs, liver, stomach, cranial air sac
caudal 1/3 pylorus, duodenum, intestines, kidneys, gonads, fat body,cloaca

The Lizard

As above where relevant plus:
  1. check medial temporal joint (orally) for white deposits (= uric acid deposits)
  2. assess limb strength and locomotion, and bone/soft tissue swelling (see MBD)
  3. check digits and tips of tail (dry gangrene with dysecdysis)
  4. smaller lizards e.g. geckos can be transilluminated
  5. wrap in damp towel to auscultate lungs/heart
  6. faecal smear if deposited

The Chelonian

As above where relevant plus:
  1. assess body condition using Jackson's ratio
  2. check locomotion (does eventually come out of shell when left alone?) and strength
  3. check shape of shell for evidence of metabolic bone disease, haemorrhage,trauma.
  4. tympanic membrane should be flat/concave
  5. beak should be evenly apposed
  6. inspect mouth, note clear eustachian tubes

Clinical Aspects of Reptile Medicine

Injection Sites

The renal portal venous circulation in reptiles means that injection into the hindlimb musculature may be eliminated via the kidneys before reaching the rest of the body (however, recent work disputes this; JWD Jul 95).One should avoid injecting into the tail of those animals that can shed their tails (a process known as autonomy). These animals include most geckos, the green iguana. Although the tail will regrow, it will be a different shape and often colour than the original.
It is also embarrassing to explain to the owner!

i/m snakeintercostal muscles of body
lizardfore- and hind-leg muscles, tail muscles
chelonianas lizard, plus pectoral muscle mass at angle of forelimb and neck
s/cin loose skin (over ribs in snake/lizard)
i/v see blood sampling veins

Force Feeding

Give oral fluids e.g. lactated Ringers, Hartmanns, daily equal to 4%- 10% body weight.
Mix up feed at 5g protein and 500kJ/Kg bodyweight daily
e.g. BuildUp (Carnation foods), Protinaid (VetDrug).
1. Snake
Manually restrain animal, open mouth and insert gag e.g. folded piece of radiograph with hole cut into centre. Hold anterior of snake vertically. Insert well lubricated end of French catheter into oesophagus to level of stomach. Syringe in fluid.
2. Lizard
The stomach is positioned just behind caudal edge of ribs. Proceed as for snake.
3. Chelonian
The stomach is positioned midway down plastron. Measure stomach tube from caudal end of abdominal s hield to just beyond gular notch. Hold the chelonian upright, sitting on caudal shields. Extend neck and hold head behind mandible. The neck must be fully extended to ensure the oesophagus is straightened.

Prise open mouth and insert gag. Insert lubricated, prefilled tube to correct depth and slowly infuse liquid. Withdraw tube slowly. Take care not to overfill the stomach. If that occurs, you will see food wellling up into the mouth.

Fluid Therapy

Most sick reptiles will present dehydrated, requiring fluid therapy or force feeding.
Consider these if;
the reptile has continued weight loss,
dehydration (PCV<.25l/l) with an associated hypoglycaemia (blood glucose < 5.2 mmol/l).
Fluids given s/c, i/p or i/v.
Care; as reptiles lack a diaphragm, the administration of large volumes of fluid i/p may impair respiration.

Faecal Examination

Reptiles often deposit urates/faeces when being examined. If not, a colonic wash may be performed as follows:
  1. insert lubricated French catheter attached to syringe filled with sterile saline into the cloaca and colon (it should slide in easily with the right size)
  2. flush in saline and aspirate several times
The following examination techniques may then be used;
  1. Direct wet mount - dilute small sample with saline and examine under high power (x400) to see spinning flagellates and static nematode ova
  2. mix faecal sample with eosin for background staining to show encysted entamoeba
  3. Gram Stain. Care: Gram negative bacteria are frequently recovered from clinically healthy captive reptiles. However, most infections are caused by gram negative pathogens e.g. Pseudomonas, Aeromonas, Proteus, Providentia, Arizona, Salmonella
  4. examine sediment (following centrifugation) for protozoa and trematode ova
  5. flotation technique for nematode ova
Care: reptiles may pass prey parasites e.g. mouse nematodes which are non-pathogenic to the reptile.

Blood Sampling

It is imperative that the maximum blood volume that may be safely withdrawn is accurately calculated as it is easy to overestimate in small animals. In Reptiles the total blood volume varies with species but is approximately 5-8% bwt (70 ml/Kg).
Of this, 10%may be the maximum withdrawn safely. Thus a 100g reptile can only have 0.7ml safely taken.
It is obviously important that the reptile patient is weighed accurately and the calculations made before blood is withdrawn!
Collect blood into lithium heparin tubes (EDTA tends to lyse cells)

Blood Sampling Sites

1. Snake
The palatine vein, ventral tail vein, or cardiocentesis
a). ventral vein The only method not requiring sedation, - identify cloaca, insert needle distal to this, into tail at midline at 450 angle, advance to vertebrae, aspirate as slowly withdraw.
b). cardiocentesis requires sedation. Palpate/ visualise beating heart, stabilise with finger and thumb. Use 23/25G needle on 3-6ml syringe. Slide needle under ventral scale and aspirate syringe. If only clear fluid is withdrawn, this is pericardial fluid.
2. Lizard
large animals - ventral tail vein
smaller lizards- clip toe nail and collect blood with capillary tube.
3. Chelonian
The following sites may be used: cardiocentesis,jugular vein,brachial vein, ventral coccygeal vein, orbital sinus and toe nail clipping.
Atempts to venepuncture limb veins often results in collection of lymph only, as these vessels are large and the veins cannot be visualised.
Collection from a jugular vein; hold animal between your knees and extend the neck towards you. the jugular vein will be seen as a bulge between the tympanic membrane and the base of the neck. Swab the site with 70% ethanol. Insert 23/25G butterfly catheter.

In Mediterranean tortoises, the dorsal tail vein is the most convenient site for venepuncture


Measure number RBC, WBC, differential WBC count, PCV,and the haemoglobin concentration.


Use plasma (gain greater volume from blood sample and serum tends to clot). Take blood sample and centrifuge immediately, remove plasma.
Measure Na, Cl, Ca, P, Gl, urea, uric acid, creatinine, cholesterol, AST, ALT, ALP, total protein.

Blood Smear

The following may be carried out:
Differential WCC, morphology of cells, level of toxic changes, inclusion bodies, blood parasites, bacteria


Positioning is important when radiographing reptiles.
Animals can be taped down, radiographed through a box or bag if not sedated.
Assess organ position, shape, size, density and homogeneity.
Check state of reptile nutrition; skeletal density, gastrointestinal organs and contents.


Radiograph regions of suspected lesion only. If radiographing whole snake, take sequential sections along length of snake using lead markers every 10 - 20 cm.


Barium Meal :
Studies can be performed as follows;
A 2Kg snake requires 10ml barium sulphate suspension by oesophageal tube followed by 90ml air for double contrast study. 15mins later youshould see oesophageal folds, gastric rugae, pyloric sphincter and duodenal villi. 5mg metoclopramide reduces the GIT food transit time from days to 12 hours.


Poor skeletal density most common finding, if suspected, reduce the kV. Normal lizards show similar bone/soft tissue contrast to mammals. Dorso-ventral and lateralviews as mammalian positioning.


DV View; care; healthy animal can move very quickly off the table!
Take exposure between expiration and inspiration. Placing animal on a raised column with the feet off the table to aid restraint Lateral -tilting chelonians onto their side distorts the diaphragm and lungs, thus horizontal beam required; centre beam on 6-7th marginal shield at right angles to vertebral column cranio-caudal view is useful for contrasting two lung fields. Centre horizontal beam on nuchal shieldhead, neck, limbs General anaesthesia required for optimal positioning of extremities
Barium meal :
2ml barium sulphate by stomach tube followed by 18ml air for double contrast studies in animals 1Kg


Lizards and Snake

7.5 and 10MHz transducers with stand-off for suitable resolution in small reptiles. 5 and 3.5 MHz transducers for larger reptiles ,linear array transducers are used to view the internal organs via the ventral body wall using an aqueous gel.


The only sites available for the access of ultrasound are the soft tissue areas known as the femoral fossa (cranial to the hind limb) and the cervical fossa (at the base of the neck).


Sharon Pickavance BVetMed BSc MRCVS
NVS / Exotic Species Vet
Small Animal Clinic
Edinburgh University

Phone: +44 (0)131 650 6074
Fax : +44 (0)131 650 6577

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Received November 1996
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