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Common medical problems of reptiles (non-infectious) (Proceedings)

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Nov 01, 2010

Secondary Nutritional Hyperparathyroidism

Clinical Signs: Anorexia, depression, ileus and constipation, cloacal prolapse, swollen compressible mandible, lethargy and inability to support body weight, muscle fasciculations due to hypocalcemia, and rarely seizures.

Diagnostics: History and complete physical exam are extremely important. Total plasma calcium is usually normal until the terminal stages of the disease. Ionized calcium may be more useful than total calcium. True hypocalcemia is often the cause of muscle tremors, but hyperphosphatemia can cause neurologic signs. Radiography is useful to assess ileus, retained eggs or follicles, bone mineralization, renomegaly (secondary renal hyperparathyroidism).

Treatment: Fluid administration to resolve dehydration and hyperphosphataemia. Warm water soaks to encourage defecation and also promote cloacal fluid uptake. Nutritional support is seldom required as part of emergency assessment and stabilization but long term nutritional management will be essential, and usually involves correction of dietary calcium and phosphorus imbalances and improvements in environmental light for cutaneous vitamin D3 production. It is preferable not to administer bolus injections of calcium to a hyperphosphatemic reptile due to the dangers of inducing mineralization. In cases of severe hypocalcemia and tetany place the reptile on intravenous or intraosseous fluid therapy and add calcium gluconate (100-200 mg/kg) to fluids. If the animal is able to eat, administer oral calcium (200 mg/kg q24h) with a dilute enteral feeding formula. Oral calcium glubionate (Neocalglucon® 23 mg/mL), calcium carbonate (100 mg/mL) or calcium citrate (Tums®). After one week of both calcium and vit D3 supplementation (exposure to UV-B light, preferably unfiltered sunlight), recheck calcium levels. If the reptile is not hypocalcemic, calcitonin can be administered (50 IU/kg IM q 1 week x 2-3 doses) to increase bone mineralization. Warm water enemas may be required in cases of severe ileus and obstipation, but beware of infusing into the bladder. An ovariosalpingectomy is generally recommended in cases of egg or follicle retention once the reptile is stable. If hyperphosphatemic, administer phosphate binder (e.g., Amphogel® 1ml/kg PO q 12 h, inbetween meals).

Prevention: Correct husbandry e.g. UV lighting, nutrition, heat, cage design, etc. UV-B light exposure 12-14 hours daily, unfiltered sunlight best, Active UV heat (mercury halide) lamps and ZooMed Reptisun 5.0 fluorescent tubes are secondary options. Environmental (vivarium) temperature at species-specific preferred optimum temperature zone.

Hypovitaminosis A

Clinical Signs: Common in herbivorous chelonians with accompanying clinical signs of chemosis, aural abscesses (manifesting as swelling on the sides of the head), nasal and/or ocular discharge.

Diagnostics: Lesions should be biopsied for confirmation of characteristic metaplastic lesions. Treatment: Improve diet and husbandry. Use injectable vitamin A very cautiously (500-1000 iu/kg) as iatrogenic hypervitaminosis A causes skin sloughing and moist erythematous dermatitis.