Reversible renal insufficiency, hyperuricemia and gouty arthritis in a case of hypothyroidism.

We present the case of a young man with 3-month history of generalized weakness and lethargy, constipation, weight gain, and swelling in the lower extremities. He was found to have an elevated serum creatinine of 203 mumol/l (2.3 mg/dl), markedly elevated TSH, severe hypercholesterolemia, hyperuricemia, a 24-hour urine creatinine excretion rate of 16.8 mmol/d (1.9 g/d), a creatinine clearance of 58 ml/min, and a uric acid excretion rate of 4.2 mmol/d (700 mg/d). With the impression of primary hypothyroidism, the patient was started on levothyroxine supplementation at which point he developed a classic gouty arthritis of right first metatarsophalangial joint. Six weeks after thyroid replacement therapy his serum creatinine had declined to 124 mumol/l (1.4 mg/dl), and 24-hour urine creatinine excretion rate declined to 11.5 mmol/d (1.3 g/d) with an estimated creatinine clearance rate of 65 ml/min. This was accompanied by reduction in serum uric acid and cholesterol levels, and a decline in uric acid excretion rate. Eighteen months later his creatinine had further declined to 88.4 mumol/l (1.0 mg/dl).