From the Guidelines
The earliest sign or symptom of neuroleptic malignant syndrome is often manifestations of autonomic dysfunction, which may include fever, tachycardia, blood pressure instability, diaphoresis, pallor, cardiac dysrhythmia, sialorrhea, and dysphagia, as these can occur before other symptoms develop. These symptoms are critical to recognize as they can precede more severe manifestations such as hyperthermia, altered mental status, and muscle rigidity 1. Key points to consider in the clinical presentation of NMS include:
- Autonomic instability signs such as fever up to 41°C or higher, tachycardia, and blood pressure fluctuations
- Neurologic findings like lead pipe rigidity, although akinesia, dyskinesia, or waxy flexibility may also be present
- Alteration in mental status, which can range from delirium to alert mutism, agitation, stupor, or coma
- Motor abnormalities including rigidity, akinesia, intermittent tremors, and involuntary movements It is essential to be vigilant for these early signs, especially in patients recently started on or withdrawn from antipsychotic medications, to promptly initiate appropriate management and prevent progression of the syndrome 1.
From the FDA Drug Label
Clinical manifestations of NMS are hyperpyrexia, muscle rigidity, altered mental status and evidence of autonomic instability (irregular pulse or blood pressure, tachycardia, diaphoresis and cardiac dysrhythmia) The earliest sign or symptom of Neuroleptic Malignant Syndrome (NMS) is not explicitly stated in the provided text, but the clinical manifestations of NMS include:
- Hyperpyrexia
- Muscle rigidity
- Altered mental status
- Evidence of autonomic instability (irregular pulse or blood pressure, tachycardia, diaphoresis and cardiac dysrhythmia) 2
From the Research
Symptoms of Neuroleptic Malignant Syndrome
The symptoms of neuroleptic malignant syndrome (NMS) include:
- Fever
- Muscle rigidity (stiffness, myoclonus, rod-like)
- Alterations of consciousness (confusion, agitation, aggression, or catatonia)
- Autonomic nervous system disturbances (i.e., hypertension, tachycardia, tachypnea, profuse sweating, and urine incontinence) 3, 4, 5
- Abnormal blood tests such as low serum electrolytes, elevated serum creatinine phosphokinase (CPK) level, and leukocytosis 3
Earliest Sign or Symptom
The earliest sign or symptom of NMS is not explicitly stated in the provided studies. However, it can be inferred that alterations of consciousness, such as confusion or agitation, may be one of the earliest signs, as they are often associated with the onset of NMS 3, 4, 5. Additionally, muscle rigidity is a common symptom of NMS, but it may not always be present, as seen in a case report of NMS without rigidity 6.
Importance of Early Recognition
Early recognition of NMS is crucial to prevent significant morbidity and death 4, 5. It is essential to maintain vigilant awareness of the clinical features of NMS to diagnose and treat the disorder early, which can help keep mortality rates low and improve patient outcomes 4.