Renal function in patients receiving long-term lithium therapy

Area of Science:

• Nephrology
• Pharmacology
• Internal Medicine

Background:

• Lithium is a widely used mood stabilizer for bipolar disorder.
• Long-term lithium therapy can affect renal function.
• Understanding the prevalence and nature of lithium-induced renal effects is crucial for patient management.

Purpose of the Study:

• To assess renal function in stable outpatients undergoing long-term lithium therapy.
• To identify specific patterns of kidney impairment associated with lithium treatment.
• To evaluate the potential progression and clinical significance of these renal changes.

Main Methods:

• Cross-sectional study of 42 stable outpatients on lithium therapy for an average of 4.5 years.
• Assessment of renal function included urine osmolality measurements, creatinine clearance, and urine microscopy.
• Analysis of the prevalence of impaired urine concentrating ability and reduced creatinine clearance.

Main Results:

• 61% of patients (41/41) exhibited impaired urine concentrating ability.
• 12% of patients (5/42) showed a moderate reduction in creatinine clearance.
• Urine microscopy revealed excess cells in 40% of patients.
• One patient presented with both impaired urine concentration and reduced creatinine clearance.

Conclusions:

• Long-term lithium therapy is associated with a high prevalence of impaired urine concentrating ability.
• A smaller proportion of patients experience reduced creatinine clearance.
• Lithium appears to cause a self-limiting distal nephron lesion that rarely progresses to chronic renal failure but may increase susceptibility to neurotoxicity during illness or dehydration.