Congenital hypothyroidism in a kitten resulting in decreased IGF-I concentration and abnormal liver function tests

A 7 month old male kitten was presented with chronic obstipation and retarded growth. Clinical examination revealed disproportional dwarfism with mild skeletal abnormalities and a palpable thyroid gland. The presumptive diagnosis of congenital hypothyroidism was confirmed by low tT4 concentration prior to and after the administration of TSH, increased endogenous TSH concentration and abnormal thyroid scintigraphic scan. The kitten had abnormal liver function tests and decreased IGF-1 concentration, both of which normalized in correspondence with an improvement of the clinical symptoms after 6 weeks of thyroxine therapy. Congenital hypothyroidism as a rare disease, may present with considerable variation in clinical manifestation. In cases in which clinical signs are ambiguous, disorders such as portosystemic shunt and hyposomatotropism have to be taken into account as differential diagnosis. Since hypothyroidism may be associated with abnormal liver function tests and low IGF-1 concentrations test results have to be interpreted carefully.