Hypothyroidism and Suspected Dietary Hypersensitivity in a Captive Maned Wolf (Chrysocyon brachyurus)
A captive 7-year-old female maned wolf (Chrysocyon brachyurus) was immobilized for examination due to a 3-month history of loose stool, decreased appetite, occasional regurgitation of quail and undigested quail in feces. Her coat was thin and grey, with a dull, rough appearance. Thyroid levels were consistent with hypothyroidism characterized by low normal serum T4 (0.7 µg/dl), low free T4 (1.54 pmol/l), and high TSH (>12 ng/ml) compared to canine reference ranges (T4 0.7–2.2 µg/dl, free T4 12–34 pmol/l, and TSH 0.1–0.4 ng/ml) and banked serum from 10 clinically healthy captive maned wolves (T4 0.5–0.96 µg/dl, free T4 1.9–21.62 pmol/l, and TSH 0.03–0.26 ng/ml). She was supplemented with levothyroxine sodium (0.4 mg BID, Thyrozine®, Phoenix Pharmaceutical Inc., St. Joseph, MO USA). Four months later, thyroid levels were more normal [T4 (1.3 µg/dl), free T4 (16.73 pmol/l), and TSH (0.66 ng/ml)], and her coat was improved.
One year after thyroid supplementation began, she was immobilized due to the recurrence of clinical signs. Thyroid levels were normal (T4 1.4 µg/dl, free T4 12.87 pmol/l, and TSH 0.06 ng/ml). Based on clinical presentation, skin biopsies consistent with inflammatory skin disease, and hyperglobulinemia, a presumptive diagnosis of food hypersensitivity was made. Her diet of ProPlan Natural Lamb and Rice Formula (Purina, St. Louis, MO USA), quail, and fruit, was changed to a limited ingredient diet of canned canine Venison Formula and dry canine Potato and Venison Formula (Royal Canin Veterinary Diet™, St. Charles, MO USA), quail and fruit. The new diet was highly palatable, her food intake increased and 10 days later her stools were more firm. One month after the diet change her coat appeared thicker and redder; 4 month later her coat was normal.