Suspected enzalutamide-associated posterior reversible encephalopathy syndrome — MSRA MCQ

Correct answer: C — Withhold enzalutamide and arrange urgent hospital assessment with brain MRI for suspected posterior reversible encephalopathy syndrome

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

This presentation is concerning for posterior reversible encephalopathy syndrome (PRES), a rare but important enzalutamide-associated neurological toxicity. The discriminating features are acute severe headache, encephalopathy, visual disturbance and marked hypertension. Although metastatic cancer raises concern for intracranial disease, the abrupt multi-domain neurological syndrome with hypertension is more characteristic of PRES than cerebral metastases. Enzalutamide should be withheld immediately; urgent hospital assessment is required, and MRI is the preferred investigation to confirm PRES and exclude competing acute intracranial pathology. A is unsafe because enzalutamide should not be continued when PRES is suspected; CT may be used acutely according to local emergency pathways, but MRI is preferred for diagnostic confirmation. B is inappropriate because dose reduction is not the recommended response to suspected PRES, and outpatient imaging delays assessment of an acute neurological syndrome. C addresses a contributing factor but fails to stop the probable causative medicine and underestimates the need for urgent imaging. E is not appropriate in a patient without seizure and does not address the suspected toxicity. If PRES is confirmed, enzalutamide should be discontinued rather than simply dose-modified.

Reference: Enzalutamide Astellas 40 mg film-coated tablets – Summary of Product Characteristics (Updated 01 April 2026) — https://www.medicines.org.uk/emc/product/10318/smpc