Malignant neuroleptic syndrome

This code represents a rare, life-threatening idiosyncratic reaction to neuroleptic (antipsychotic) medications, characterized by severe muscle rigidity, fever, altered mental status, and autonomic dysfunction. It is a medical emergency requiring immediate recognition and intervention to prevent serious complications and mortality.

Assign this code when documentation clearly indicates a diagnosis of malignant neuroleptic syndrome, typically presenting with a constellation of symptoms following exposure to antipsychotic drugs. Supporting documentation should detail the clinical presentation, medication history, and diagnostic workup ruling out other conditions.

• Differentiate from other neuroleptic-induced movement disorders, especially neuroleptic-induced parkinsonism, which is an Excludes1 note.
• Ensure documentation specifies "malignant" to distinguish from less severe neuroleptic adverse effects.
• Sequence as the primary diagnosis when it is the reason for the encounter, followed by codes for any associated complications or underlying psychiatric conditions.