Partial nephrogenic diabetes insipidus associated with lithium therapy

Area of Science:

• Nephrology
• Endocrinology
• Pharmacology

Background:

• Lithium is a common treatment for bipolar disorder.
• Long-term lithium therapy can lead to renal complications.
• Nephrogenic diabetes insipidus (NDI) is a potential side effect.

Observation:

• A 40-year-old male on long-term lithium therapy presented with polyuria and polydipsia.
• Water deprivation test showed impaired urinary concentrating ability.
• Response to desmopressin was borderline, with elevated plasma copeptin.

Findings:

• The patient was diagnosed with partial nephrogenic diabetes insipidus.
• Increased water intake and amiloride treatment led to symptom improvement.

Implications:

• Clinicians must monitor for NDI in patients on long-term lithium.
• Water deprivation tests with plasma copeptin aid diagnosis.
• Amiloride is a potential therapeutic option for lithium-induced NDI.