A patient with acute psychosis, who is on haloperidol 20 mg/day for last 2 days, has an episode characterized by tongue protrusion, oculogyric crisis, stiffness and abnormal posture of limbs and trunk without loss of consciousness of last 20 minutes before presenting to casualty. This improved within a few minutes after administration of diphenhydramine HCI. The most likely diagnosis is:

Antipsychotic drugs Extrapyramidal symptoms- dur to D2 blockade in limbic system Extrapyramidal symptoms Clinical features Special DOC Acute dystonia Oculogyric crisis ocular muscles spasm and opisthotonos Toicollis Protrusion of tongue leading to laryngospasm Grimacing Earliest to develop (days) Anticholinergic drugs Acute akathisia Constant purposeless involuntary movement from one place to another Most common EPS Days to week Propranolol Tardive dyskinesia chewing and sucking movements Grimacing Choreoathetoid movements Akathisia Seen after long(years) use of anti-psychotic Tetrabenazine Malignant neuroleptic syndrome Fluctuating level of consciousness Hypehermia -muscles rigidity Increase level of CPK Increase level of liver enzyme Confusion Diaphoresis Most common cause of death in this syndrome is acute renal failure Most serious side effect dantrolene DRUG induced parkinsonism Few weeks anticholinergics