A child with schizophrenia was on medications. Suddenly he developed neck stiffness & spasm. What is most probable cause?
**Core Concept**
Tardive dyskinesia and neuroleptic malignant syndrome (NMS) are two serious side effects of antipsychotic medications. Tardive dyskinesia is characterized by involuntary movements, whereas NMS is a life-threatening condition with neurological and autonomic symptoms.
**Why the Correct Answer is Right**
The child's symptoms of neck stiffness and spasm are indicative of severe muscle rigidity. This is a hallmark of NMS, which is caused by an autoimmune response to the antipsychotic medication, leading to the release of inflammatory cytokines and the activation of the hypothalamic-pituitary-adrenal axis. The resulting hyperthermia, autonomic instability, and muscle rigidity can be fatal if not treated promptly.
**Why Each Wrong Option is Incorrect**
**Option A:** Akathisia, a common side effect of antipsychotic medications, is characterized by subjective feelings of restlessness and objective signs of agitation. It does not typically present with neck stiffness and spasm.
**Option B:** Tardive dyskinesia is a movement disorder that can cause involuntary movements of the face, trunk, and limbs, but it is not typically associated with neck stiffness and spasm.
**Option C:** Parkinsonism, another side effect of antipsychotic medications, is characterized by tremors, bradykinesia, and rigidity, but it does not typically present with acute neck stiffness and spasm.
**Clinical Pearl / High-Yield Fact**
Be aware of the "at risk" symptoms of NMS, which include fever, altered mental status, muscle rigidity, and autonomic dysfunction. Recognizing these symptoms promptly is crucial for early intervention and prevention of long-term sequelae.
**Correct Answer:** C. Parkinsonism