Introduction

• Cause: anorexia in reptiles is a complex topic. Anorexia can be seen as part of normal physiological behavior (brumation, reproduction, ecdysis) but is also a common non-specific symptom of clinical disease.
• Signs: a loss or reduction in appetite or a lack of feeding response. Clinical signs related to various underlying causes may be apparent. Stomatitis, endoparasites, respiratory Infection, gastrointestinal impaction, reproductive disease and husbandry deficiencies are all common causes of anorexia.
• Diagnosis: diagnosing the cause of anorexia will require a detailed husbandry and medical history, a full clinical examination, and often further diagnostic tests such as diagnostic imaging, hematology, biochemistry, endoscopy.
• Treatment: patients suffering from prolonged anorexia will commonly require fluid and nutritional support both during the diagnostic process and while treating the underlying pathology. Following a diagnosis the underlying cause of anorexia will require specific targeted treatment.
• Prognosis: depends entirely on the underlying cause of the anorexia and can vary from excellent to poor.

Brumation

• Anorexia can be an entirely normal physiological process Hibernation/brumation.
• A number of species will have anorexia associated with a seasonal drop in temperature and food availability.
• The onset of brumation is thought to be associated with temperature, photoperiod, with atmospheric pressure also possibly also involved.
• Some species will undergo brumation regardless of the environmental temperature in which they are kept showing that temperature is only part of the story.

Ecdysis (shedding)

• Reptiles in-particular snakes will undergo a short and normal period of anorexia associated with ecdysis.
• Owners recognize the onset of shedding in snakes with a dulling in coloration and clouding of the eyes.
• Some reptiles can also be more fractious and liable to bite during shedding.

Reproductive-associated anorexia

• Gravid reptiles - particularly snakes will be anorexic.
• Snakes which maternally incubate will often remain anorexic after parturition until hatching.
• Reptiles suffering from pre- or post-ovulatory stasis Pre-/post-ovulatory stasis often also present anorexic.
• Males also can show periods of anorexia associated with copulation and reproduction.

Pathogenesis

Etiology

Husbandry-associated anorexia

• Newly acquired reptiles may experience a short period of anorexia while they acclimatize to a new environment.
• Food provided must be appropriate in type, size and presented in a way the reptile is accustomed to. Some semi-aquatic species may only eat in the water for example, or arboreal reptiles may not seek out food on the floor of the terrarium.
• Environmental conditions (temperature, lighting, humidity, photoperiod) must be appropriate Chelonia husbandry Lizard husbandry Snake husbandry.
• Nutritional deficiencies (inversed or incorrect Ca:P ratio, hypovitaminosis A, excessive fat) Nutritional requirements are common causes of anorexia.
• Excessive or unsympathetic handling Handling/restraint can cause anorexia particularly in nervous or newly acquired reptiles.
• Keeping solitary reptiles in a group can lead to anorexia particularly in subordinate individuals.

Common medical causes of anorexia

Gastrointestinal disease

• Stomatitis Stomatitis can be husbandry related (rostral abrasions due to nose rubbing on vivarium), traumatic (striking feeding tongs) or secondary to dental disease (particularly common in bearded dragons with periodontal disease) or infectious disease, eg herpes virus Herpes virus infection/mycoplasmosis in chelonia. Bacteria isolated from stomatitis are commonly oral commensals such as aeromonas and pseudomonas. Oral infections can extend to esophagitis and gastritis. Facial abscesses and osteomyelitis can occur in chronic cases.
• Gastroenteritis can have viral, bacterial, fungal and parasitic etiology.
• Gastrointestinal foreign bodies Gastrointestinal obstruction can be composed of substrate (accidently ingested during feeding), stones (particularly common in tortoises who can demonstrate pica) or other environmental material.

Respiratory disease

• Most commonly bacterial or viral Lower respiratory tract disease.
• Mycoplasmosis, herpes (chelonia) Herpes virus infection, and paramyovirus Ferlavirus infection.
• Rhinitis, sinusitis, pneumonia Pneumonia can all be associated with anorexia.
• Untreated stomatitis can frequently result in extension to respiratory infections

Reproductive disease

• Dystocia is commonly associated with anorexia.
• Follicular stasis Pre-/post-ovulatory stasis is seen most commonly in chelonian and lizards with patients commonly presenting with anorexia.

Diagnosis

Treatment

Outcomes