Abstract

Over a three-year period, four prehensile-tailed porcupine (Coendou prehensilis) at the National Zoological Park were diagnosed with hypercalcemia, hyperphosphatemia, and associated extensive soft tissue mineralization. Clinical signs ranged from asymptomatic to polydipsia, weight loss, and decreased mobility. Diagnostic testing, including serial radiographs, ultrasound, magnetic resonance imaging (MRI), computed tomography (CT), complete blood count, serum chemistry and vitamin D levels, as well as endocrine and infectious disease screening, to identify the cause of the aberrant hypercalcemia has been inconclusive to date, though idiopathic, genetic or nutritional hypervitaminosis D is suspected. Dietary hypervitaminosis D has been documented in other species, resulting in similar clinical signs.^1-5

Husbandry modifications, including altered exposure to natural and artificial UVB spectrum lighting and nutritional adjustments to lower calcium, phosphorus, and vitamin D intake, were pursued concurrent with medical management, including antibiotic, analgesic, diuretic, steroid, gastroprotectant, fatty acid supplement, and phosphate binding therapeutics. Despite these strategies, persistent decreases in serum calcium and phosphorus derangements were not achieved and soft tissue mineralization progressed in all cases. Three of the four individuals have been euthanized to date. On necropsy, these individuals had reduced body fat stores and extensive soft tissue mineralization, especially notable in the skeletal muscle, heart, and kidneys. Two cases had concurrent pulmonary disease, including one case of fungal tracheitis and one case of Mycobacterium avium pneumonia. Continued medical management and husbandry modifications for the remaining affected individual persist, and collaboration with other institutions to identify pathogenesis and possible intervention points for this disease process is being pursued.

Literature Cited

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