*Neuroleptic malignant syndrome (NMS)* is a rare, but life-threatening, idiosyncratic reaction to neuroleptic medications that is characterized by fever, muscular rigidity, altered mental status, and autonomic dysfunction

Cardinal features are as follows:

• Severe muscular rigidity

• Hyperthermia (temperature >38°C)

• Autonomic instability

• Changes in the level of consciousness

• Muscular rigidity (typically, “lead pipe” rigidity)

• Hyperthermia (temperature >38°C)

• Diaphoresis

• Pallor

• Dysphagia

• Dyspnea

• Tremor

• Incontinence

• Shuffling gait

• Psychomotor agitation

• Delirium progressing to lethargy, stupor, coma

• Sialorrhea

• Tachycardia

• Tachypnea, respiratory distress (31% of cases)

• Increased or labile blood pressure

• Hypoxemia (low pulse oximeter reading)