Deceptive Dopamine Blockade: A Stroke Mimic in Disguise!

Drug-induced parkinsonism (DIP) is a common iatrogenic extrapyramidal disorder in the geriatric cohort, frequently precipitated by dopamine D2 receptor-blocking agents, including antipsychotics and antiemetics. Its cardinal manifestations — bradykinesia, axial and appendicular rigidity, and postural instability — may clinically simulate acute cerebrovascular syndromes, complicating diagnostic stratification in emergency practice. We report a similar case that presented as a stroke mimic in the emergency department. A 76-year-old male with hypertension, diabetes mellitus, hypothyroidism, a prior cerebrovascular accident (CVA) four years previously (from which he had achieved functional recovery), and a seizure disorder presented with a 20-day history of decreased responsiveness, altered behaviour, right-sided weakness, and difficulty recognising familiar faces. Risperidone had been initiated approximately 3 months prior to admission for behavioural disturbance, with progressive neurological deterioration commencing approximately 1 month thereafter. On arrival, vital signs were stable. Examination revealed asymmetric limb weakness (right upper/lower limb power 1/5; left 3/5), generalised rigidity, and lead-pipe tone. MRI of the brain demonstrated cerebral atrophy and subdural hygroma without evidence of acute infarction. Euvolemic hypotonic hyponatraemia (serum sodium 121 mmol/L on admission) was identified and corrected. Multidisciplinary management — including cessation of risperidone, optimisation of anti-parkinsonian therapy, and physiotherapy — resulted in progressive improvement. At discharge, limb power had recovered to right upper/lower limb 3/5 and left upper/lower limb 4/5, with improved cognition and ambulatory capacity with assistance. Drug-induced parkinsonism should therefore be considered in elderly patients presenting with subacute-onset neurological deficits, particularly in the context of polypharmacy. Early recognition, medication reconciliation, and a structured multidisciplinary approach improve prognosis and prevent misdiagnosis and avoidable complications.