The first step in starting to treat reptiles in private practice is to thoroughly know the species to be examined. All reptiles have specific habitat and dietary preferences. The behavioral, morphological and physiological characteristics must be understood. This is crucial for medical success. The species must be determined before any physical interaction so that potential dangers can be appreciated and of course avoided.

Reptiles, like all other animals, can be a source of zoonotic agents; basic personal hygiene should minimize the risks.

Before physical examination, the owner should be asked profoundly about important issues concerning the animal's history. For example, was the animal wild caught or bred in captivity? If from the wild, how long was the animal in captivity? What is the age, what is the sex, does the animal feed and drink, how long ago the last time, how does it shed its skin, when was the last time? How is the animal housed, what is the temperature in the enclosure during day and night? What is the complaint?

Before touching the animal, the posture and movements should be assessed. Knowledge about the normal posture is essential. The breathing frequency should be noted. The animal must be accurately weighed, and the nutritional status should be determined. In many lizards, weight lost can be judged along the tail, the pelvic area and the hindlimbs. Leopard geckos (Eublepharis macularius) store most of their fat in the tail.

The skin should be inspected.

Restraint of venomous, nervous or defensive reptiles should be done with appropriate techniques; towels, gloves, snake hooks, clear plastic tubes. For large boid snakes and crocodilians, more handlers are necessary to avoid damage to the staff and the animal.

Physical examination differs of course in the different species. Palpation of the celomic cavity is limited in chelonians. Inspection of the mucous membranes of the mouth is sometimes impossible in the conscious tortoise or large lizards.

In small lizards and snakes, transillumination is possible to examine the celomic cavity for eggs or foreign bodies.

Auscultation can be useful; sounds made between the scutes and the stethoscope can be reduced by placing a dampened piece of cloth in between.

In practice, reaching a definitive diagnosis requires a combination of cytologic, microbiologic, hematologic, clinical pathologic and serologic techniques, often combined with diagnostic imaging and endoscopy. Diagnostic sample collection should include fecal material for microscopic evaluation.

Venipuncture and blood collection can be done from different locations in the different species of reptiles. Anatomic knowledge of the position of these veins is vital.

In snakes, the caudal tail vein can be used, or blood can be collected via cardiocentesis. In chelonians the jugular or subcarapacial venous sinus can be used. In large animals, the dorsal coccygeal vein can be assessed. In lizards, the caudal tail vein is a good choice; in larger lizards like iguanas (Iguana iguana), this vein can be approached from the lateral site.

Bone marrow is sometimes needed. The technique depends on the size and nature of the animal. In lizards, crocodilians and large chelonians, the femoral or tibial medullary cavities are mostly used.

The respiratory system can be investigated by means of different techniques. Lung lavage for the collection of cytologic and microbiologic samples. Lung biopsies through endoscopy or surgery under general anesthesia. Diagnostic imaging, radiology, MRI or CT scans can be performed.

Cloaca-colonic and gastric lavage are useful tools to obtain diagnostic samples.

Biopsies can be taken from a variety of organs and processed for microbiologic and histologic examinations. Many procedures require general anesthesia. Endoscopy is less invasive and therefore preferred.

A variety of approaches for the sick reptile will be discussed in this lecture.