{"code":"G21.0","type":"code","title":"Malignant neuroleptic syndrome","codeAlso":[],"includes":[],"modern_v":"official26","codeFirst":[],"excludes1":["neuroleptic induced parkinsonism (G21.11)","Huntington's disease (G10)","neurocognitive disorder with Lewy bodies (G31.83)","Shy-Drager syndrome (G90.3)","syphilitic Parkinsonism (A52.19)"],"excludes2":[],"isBillable":true,"fyEffectivity":{"fy2026":true,"fy2027":true,"billableFy2026":true,"billableFy2027":true},"sibling_codes":["G21","G21.1","G21.2","G21.3","G21.4","G21.8","G21.9"],"inclusionTerms":[],"sibling_titles":{"code":"G21.9","title":"Secondary parkinsonism, unspecified","isBillable":true},"useAdditionalCode":["code for adverse effect, if applicable, to identify drug (T43.3X5, T43.4X5, T43.505, T43.595)"],"clinicalDefinition":"Malignant neuroleptic syndrome is a billable ICD-10-CM diagnosis code (G21.0). Excludes1 (not coded here): neuroleptic induced parkinsonism (G21.11); Huntington's disease (G10); neurocognitive disorder with Lewy bodies (G31.83); Shy-Drager syndrome (G90.3); syphilitic Parkinsonism (A52.19). Use additional code: code for adverse effect, if applicable, to identify drug (T43.3X5, T43.4X5, T43.505, T43.595).","officialDefinition":"Malignant neuroleptic syndrome is a billable ICD-10-CM diagnosis code (G21.0). Excludes1 (not coded here): neuroleptic induced parkinsonism (G21.11); Huntington's disease (G10); neurocognitive disorder with Lewy bodies (G31.83); Shy-Drager syndrome (G90.3); syphilitic Parkinsonism (A52.19). Use additional code: code for adverse effect, if applicable, to identify drug (T43.3X5, T43.4X5, T43.505, T43.595).","seventhCharacterInstructions":[],"workflowProtocols":[],"guidelines":{"whenToUse":[],"whenNotToUse":[],"commonBillingMistakes":[],"codeComparisons":[],"documentationChecklist":[]},"domainLandscape":{"summary":"Primary diagnostic domain and clinical landscape evaluation.","keyCategories":[],"diagnosticContinuum":"Progression continuum from acute presentation to resolution."},"children":[],"hierarchy":[],"relatedCodes":[],"relevantCPTCodes":[],"documentationTips":[],"caseStudies":[],"description":"","overview":""}