Renal function and biopsy in patients on lithium-therapy

Area of Science:

• Nephrology
• Pharmacology
• Toxicology

Background:

• Lithium is a common mood stabilizer for bipolar disorder.
• Long-term lithium use can be associated with renal dysfunction.
• Understanding the specific renal effects of lithium is crucial for patient management.

Purpose of the Study:

• To investigate the detailed renal function in patients treated with lithium.
• To identify the prevalence and characteristics of lithium-induced nephropathy.
• To explore the correlation between lithium exposure and renal function impairment.

Main Methods:

• Studied 46 outpatients from a lithium clinic during a 5-day nephrology hospitalization.
• Discontinued lithium medication 7 days prior to admission for assessment.
• Assessed renal function, including concentrating ability and glomerular filtration rate (GFR).
• Correlated urine osmolality with treatment duration and serum lithium concentration.
• Performed kidney biopsies in 4 cases.

Main Results:

• Approximately 25% of patients showed signs of lithium-induced nephropathy.
• The primary observed impairment was a reduced renal concentrating ability.
• Urine osmolality negatively correlated with the product of treatment duration and lithium serum concentration.
• Reduced GFR was associated with pre-existing kidney disease.
• Kidney biopsies revealed focal fibrosis and tubular degeneration.

Conclusions:

• Lithium-associated nephropathy is a frequent condition affecting the kidney interstitium.
• The damage is dependent on serum lithium levels and treatment duration.
• Impairment of renal concentrating ability can occur after a minimum of 3 years of treatment.
• The long-term effects and potential irreversibility of these changes require further investigation.