Kidney morphology and function in lithium-treated patients.

Abstract

The findings of morphological changes in the kidneys of some patients given long-term treatment with lithium and indications that lithium intoxications frequently are preceded by alterations in water and electrolyte metabolism have generated new interest in the effect of long-term lithium treatment on kidney structure and function. Today it is not firmly established to which extent renal morphological changes are present in unselected groups of patients given long-term treatment with lithium. Neither is it clear what is the clinical significance of these changes and what are the relative roles played by lithium, concomitant and previous treatment with other psychotropic drugs, previous occurrence of lithium intoxications, and coexistence of somatic illness for their development. Studies on kidney function in long-term lithium-treated patients, however, have revealed that affection of GFR was either moderate or absent indicating that the risk of renal insufficiency and terminal azotemia is remote even when lithium is given for many years. A large number of patients have altered water excretion with polyuria or lowered urine concentrating ability or both. Due to the extra fluid loss these patients are apt to develop dehydration, and they may then be in danger of lithium intoxication. We hypothesize that lithium-induced changes of kidney function may become less frequent and less pronounced if patients are maintained at serum lithium levels somewhat lower (0.5-0.8 mmol/l) than those commonly employed. We recommend careful monitoring of serum lithium levels, regular control of kidney function, and extra caution when physical illness or additional drug treatment may lead to disturbance of fluid and electrolyte balance.