Which physical symptoms are characteristic of Neuroleptic Malignant Syndrome (NMS)?

Neuroleptic Malignant Syndrome (NMS) is a life-threatening condition that can occur in response to neuroleptic medications, typically antipsychotics. The hallmark physical symptoms associated with NMS include fever, muscle rigidity, altered mental status, and autonomic instability. The presence of elevated body temperature (fever) indicates a significant dysregulation of the body’s thermoregulatory processes, while muscle rigidity is a key characteristic that differentiates NMS from other conditions.

This rigidity is often severe and can be generalized, leading to a "lead-pipe" stiffness that is noted during the physical examination. These symptoms can quickly escalate, requiring urgent medical intervention. The combination of fever and muscle rigidity is particularly telling and helps clinicians identify NMS early to mitigate risks of complications.

Other choices listed do not reflect the core characteristics of NMS. Chronic headaches, skin rash, palpitations, hallucinations, and tremors might be associated with various medical conditions or adverse effects of medications but are not defining features of Neuroleptic Malignant Syndrome. Therefore, the identifying symptoms of fever and muscle rigidity are critical for diagnosis and prompt treatment of this serious syndrome.