What is one symptom specific to Neuroleptic Malignant Syndrome (NMS) that is not present in Serotonin Syndrome?

Muscle rigidity is a hallmark symptom of Neuroleptic Malignant Syndrome (NMS) and is not present in Serotonin Syndrome. In NMS, the rigidity is often described as "lead-pipe" rigidity, which is characterized by a significant increase in muscle tone and resistance to passive movement. This symptom is a result of the disruption in the dopaminergic pathways in the central nervous system, typically associated with the use of antipsychotic medications.

In contrast, while altered mental status, high body temperature, and seizures can occur in both conditions, muscle rigidity remains specific to NMS. Serotonin Syndrome typically presents with a different set of symptoms, including hyperreflexia and myoclonus, rather than the profound muscle rigidity associated with NMS. This distinction is crucial in differential diagnosis and the management of these potentially life-threatening conditions.