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Dementia with Lewy bodies and antipsychotic sensitivity — SCE Acute Medicine MCQ

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HardMedicine in the ElderlyDementia with Lewy bodies and antipsychotic sensitivitySCE Acute Medicine

A 76-year-old man has fluctuating cognition, recurrent formed visual hallucinations, REM-sleep behaviour disorder and spontaneous parkinsonism. During admission he becomes frightened and strikes staff despite correction of pain, retention and constipation. Which proposed drug carries the greatest syndrome-specific risk of a severe sensitivity reaction?

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Reveal the answer and explanation

Correct answer: D — Intramuscular haloperidol for emergency control of severe agitation

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

A is correct. The phenotype is probable dementia with Lewy bodies, in which dopamine-blocking antipsychotics can markedly worsen rigidity, consciousness and autonomic function and can provoke a severe sensitivity reaction. Lorazepam can worsen confusion and falls but lacks that specific neuroleptic-sensitivity mechanism. Melatonin, analgesia and treatment of constipation address plausible contributors without dopamine blockade; none is automatically harmless, but haloperidol is the uniquely high-risk proposal.

Reference: NICE NG97 dementia recommendations: https://www.nice.org.uk/guidance/ng97/chapter/Recommendations