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Lithium CKD Management — MRCPsych Paper B MCQ

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HardMood DisordersLithium CKD ManagementMRCPsych Paper B

A 56-year-old man with bipolar I disorder has remained well for 8 years on lithium after previously relapsing when lithium was discontinued. His 12-hour plasma lithium concentration is 0.7 mmol/L and he has no features of toxicity. His eGFR has fallen from 58 to 52 and then 46 mL/min/1.73 m² over 12 months, consistent with stage 3a chronic kidney disease. According to NICE guidance, which is the most appropriate management approach?

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Correct answer: D — Increase lithium and renal monitoring, assess the rate of deterioration, and review continuation through an individualised risk-benefit assessment with specialist advice if needed

Explanation lettering: C = shown as A · E = shown as B · D = shown as C · B = shown as D · A = shown as E

B is correct. NICE recommends more frequent monitoring of lithium treatment and renal function when eGFR falls over two or more tests, together with assessment of the rate of deterioration. Whether lithium should continue requires an individualised assessment of its clinical efficacy, the degree of renal impairment, and other renal and cardiovascular risk factors; renal and bipolar specialist advice should be sought if needed. Stage 3a CKD without toxicity is not by itself an indication for immediate discontinuation, particularly when lithium has substantial relapse-prevention benefit. Routine unchanged monitoring is inadequate because the serial results demonstrate deterioration. Switching automatically to valproate is not required and would disregard the individual risk-benefit assessment. Increasing lithium is unsafe because impaired renal clearance increases the risk of accumulation and toxicity.

Reference: National Institute for Health and Care Excellence. Bipolar disorder: assessment and management (CG185), recommendations 1.10.21–1.10.23. Updated 2025. https://www.nice.org.uk/guidance/cg185/chapter/recommendations