Lithium — consultant viva

Station structure

Time: 8–10 minutes. Depth: consultant teaching registrar. Expect named trials, 12-hour trough discipline, organ monitoring (not levels alone), interaction ladder, modern pregnancy absolute-risk framing, and EXTRIP language without inventing one hospital's exact mmol/L as universal law beyond published EXTRIP thresholds.[1][2][6][7]

Core questions and model points

1. Why lithium for bipolar maintenance? Relapse prevention evidence (Geddes lineage); BALANCE: lithium ± valproate superior to valproate alone for any episode. Guideline first-line theme when monitoring feasible.[1][8]

2. Suicide? Cipriani 2013: fewer suicides and all-cause deaths vs placebo in RCTs of mood disorders — still part of full risk plan.[2]

3. How do you sample levels? 12-hour trough at steady state; TDM culture (AGNP). Maintenance scaffold often 0.6–0.8 mmol/L; older adults lower.[7][8]

4. What else do you monitor? eGFR/creatinine, TFT, calcium — McKnight: NDI/concentrating defect, hypothyroidism, hyperparathyroidism, weight. Shine long-term laboratory signal reinforces this.[3][8]

5. New NSAID or thiazide? Levels can rise; plan level check and counselling; toxicity risk with dehydration.[6][8]

6. Pregnancy? Patorno: modest increased cardiac malformation risk first trimester with dose relationship teaching; Munk-Olsen: major malformation and neonatal readmission signals; balance against high relapse risk if stopped — perinatal psychiatry plan.[4][5]

7. Toxicity and dialysis? Stop lithium; saline if depleted; charcoal does not bind Li+; EXTRIP criteria for ECTR; HD preferred; rebound after dialysis.[6]

Pass criteria

• BALANCE and Cipriani one-liners correct.[1][2]
• 12-hour trough automatic; organ monitoring beyond level only.[3][7]
• Interaction ladder (NSAID/ACEI/ARB/thiazide/dehydration) fluent.[6][8]
• Pregnancy counselled with modern absolute-risk framing, not panic mythology.[4][5]
• EXTRIP named for severe poisoning.[6]