Diagnosis and Management of Acute and Chronic Lithium-Associated Nephrotoxicity.

Abstract

Lithium remains a mainstay of therapy for bipolar disease and refractory depression with future potential for expanded use based on novel data demonstrating its immunomodulatory and neuroprotective effects. This drug accumulates intracellularly via sodium transport pathways, and its effects on complex cellular signaling mechanisms including glycogen synthase kinase-3β inhibition, form the basis of its therapeutic efficacy and toxicity. Increased intracellular levels disrupt cellular processes and trigger injury via mitochondrial dysfunction and oxidative stress. Lithium has a narrow therapeutic index and causes dose-dependent nephrotoxicity. A tubulointerstitial pattern of kidney injury is typical; however, lithium can rarely cause glomerular injury as well. An acute rise in serum lithium levels can result in severe volume depletion from lithium-induced natriuresis and aquaresis and cause acute kidney injury (AKI). Changes in kidney function and various drug interactions can acutely affect serum lithium levels further increasing the risk of toxicity. Arginine vasopressin resistance is the most common complication of chronic lithium use and can be an early manifestation. CKD occurs after a longer latency of over ten years with a variable slope of GFR decline. Progression to end stage kidney disease is relatively low but is affected by the presence of other nephrotoxic risk factors. Epithelial sodium channel blockers such as amiloride can be helpful in mitigating lithium nephrotoxicity by reducing cellular accumulation. Hypercalcemia secondary to lithium-induced hyperparathyroidism is associated with a higher risk of nephrolithiasis and CKD progression. Kidney microcystic changes are common in lithium induced CKD and distal renal tubular acidosis can also be seen. Using the lowest effective lithium dose, close monitoring of kidney function and serum lithium levels and early diagnosis of lithium nephrotoxicity is critical in preventing irreversible kidney injury. The decision to discontinue lithium is challenging and the benefits vs. risks must be carefully weighed. This comprehensive review provides a pathogenetic basis and practical clinical framework for diagnosis and management of lithium nephrotoxicity.