A 26-year-old woman with schizophrenia on haloperidol 10 mg/day for 4 months develops rhythmic, involuntary movements of her tongue and lips along with slow, writhing movements of her fingers. These movements persist even when she is instructed to stop them. She has no cogwheel rigidity or tremor. What is the most likely diagnosis and the appropriate next step?

• A Tardive dyskinesia — consider switching to clozapine or valbenazine ✓
• B Acute dystonia — administer benztropine
• C Parkinsonian tremor — add trihexyphenidyl
• D Akathisia — add propranolol

Explanation

Tardive dyskinesia (TD) is a late-onset movement disorder caused by prolonged dopamine receptor blockade, characterized by involuntary, repetitive oro-facial movements (lip smacking, tongue protrusion) and choreiform limb movements that are not suppressible by will. It typically appears after months to years of antipsychotic use. Management includes reducing or switching the offending antipsychotic (clozapine has the lowest TD risk) and/or adding a VMAT2 inhibitor such as valbenazine or deutetrabenazine, both FDA-approved for TD.

Reference: Kaplan & Sadock's Synopsis of Psychiatry, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.