MR imaging as a specific diagnostic tool for bilateral microcysts in chronic lithium nephropathy

A 59-year-old man was referred by his family doctor for progressive renal failure. He was on lithium sulfate therapy since 32 years for bipolar disorder. The medical history revealed polyuria and polydypsia, which was persistent since several years. Family history was negative for hereditary nephropathies. Laboratory findings revealed a blood urea nitrogen concentration of 7.0 mmol/l and a serum creatinine concentration of 168 μmol/l, corresponding to an estimated glomerular filtration rate of 38 ml/min per 1.73 m2 according to the Modification of Diet in Renal Disease formula. There was no electrolyte anomaly. Urinalysis demonstrated a pH of 7.0, and a specific gravity of 1005, without protenuria nor hematuria. A chronic lithium nephropathy (CLN) was suspected and a renal biopsy proposed, but was refused by the patient.