This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
A child with schizophrenia was on medications. Suddenly he developed neck stiffness 8t spasm. What is most probable cause? 
Select and explain. 
A. Conversion disorder, B. Acute dystonia, C. Akathisia, D. Tardive dyskinesia
B: Acute dystonia
Answer: B: Acute dystonia 
Explanation: ANSWER: (B)Acute dystoniaREF: Kaplan and sadocks synopsis in psychiatry 10th ed page 992This is a case of acute dystonia due to neuroleptic medicationsSee APPENDIX-38 below for "NEUROLEPTICS SIDE EFFECTS" APPENDIX - 38Neuroleptics; Side Effects Acute DystoniaAkathisiaParkinsonismTardive DyskinesiaNeurolepticMalignantSyndrome EarlyIntermediateIntermediateLate (tardive)AnyONSETWithin 7 days of therapy or | doseWithin 3 months of therapy or | doseWithin 3 months of therapy or | dose> 3-6 months(| dose may unmask dyskinesia)Anytime during therapy (| dose or high potency drugs)INCIDENCE15-20% with typical neuroleptics. 5% with atypical20%30%5% per year of therapy i.e. 50% In 10 years0.5%(20-30%mortality)MECHANISMUnclear, dopamine hypo function at basal gangliaD2 receptor blockage in mesocortical pathwayD2 receptor blockage at striatumD2 receptor blockage at striatumIdiosyncratic, Relative depletion of dopamine in CNSRISKFACTORSMale, young, mental retardation, h/o ECT, dose elevationElderly,female, mental retardation, Iron deficiency, Affective disorders, dose elevationElderly ,Females,dementia,underlyingparkinsonism,AIDS, doseelevationElderly, female, h/o ECT, substance abuse, iron deficiency, Mental retardation. Mood disorder, Organic brain damage, Antkholine rgic Dose decreaseMale, young, dose elevationSYMPTOMSSlow, irregular, continuous contractions, oculogyric movements of tongue, torticollis, trismus, abnormal posture, blepherospasmUncontrolledrestlessness,pacing,compulsive foot taping, rocking movement, adversity to stand still, rapid alternation of standing St- sittingR = rigidityA = akinesia (me)T = tremor(atyp ical-coarse, not pill rolling, late) RABBIT SYNDROME = Lip & perioral tremorsRapid, irregular, continuous or intermittent contractions, orofasciolingual or limb/trunkal, | by stress activity,Life threateningF = feverE =EncephalopathyV - Vitals unstableE = ElevatedCPK, WBCR = RigidityTREATMENTAnticholine rgics: Benzatropine Antihistaminics: DiphenhydramineReduce doseSt/or changeantipsychotic.Propranolol= doc, poortreatmentoutcomeAnticholinergics:BenzatropineAntihistaminics:Amantadine,DiphenhydramineReplace by atypical antipsychotic (clozapine is best), lithium & carbamazepine for psychosis, BZD: buspirone for dyskinesiaBromocriptine,lisuride,carbidopa-levodopa,dantrolenesodium, ECT