RENAL-FAILURE IN A PATIENT WITH PROFOUND HYPOTHYROIDISM

A young man presented with a 4 week history of easy fatiguability, los s of appetite, and puffiness of face and lower extremities, and was fo und to have a serum creatinine of 2.0 mg/dL with a normal urinalysis, negative serology for autoimmune disorders, but moderately elevated se rum creatine phosphokinase (CPK). A renal biopsy revealed normal glome ruli with no evidence of any pathology except for the presence of brow nish pigmented casts in some of the proximal and distal tubules sugges tive of myoglobinuria. He was subsequently found to be profoundly hypo thyroid with a thyroid stimulating hormone (TSH) level of >100 mu U/mL . He had marked symptomatic improvement after institution of thyroid r eplacement therapy with a decline in serum creatinine to 1.3 mg/dL at 6 weeks follow up.