Serotonin Syndrome and NMS

A 48-year-old man with schizophrenia on haloperidol (15 mg daily) for 3 weeks develops fever (39.8°C), severe muscle rigidity, altered mental status, and tachycardia. You suspect neuroleptic malignant syndrome (NMS). Which investigation is most specific for confirming the diagnosis and assessing severity?

A 32-year-old woman on fluoxetine for depression is started on tramadol for chronic back pain. She develops agitation, tremor, hyperreflexia, and mydriasis within 24 hours. Which is the most common drug combination causing serotonin syndrome in clinical practice?

A 28-year-old man with schizophrenia on haloperidol develops fever, rigidity, altered mental status, and elevated creatine kinase (3500 U/L) over 3 days. Which is the most common causative antipsychotic agent for neuroleptic malignant syndrome?

A 32-year-old woman on fluoxetine for depression is started on tramadol for chronic pain. She develops hyperthermia (39.2°C), muscle rigidity, hyperreflexia, and mydriasis within 6 hours. Which clinical feature best distinguishes serotonin syndrome from neuroleptic malignant syndrome (NMS)?

A 52-year-old man with schizophrenia has been stable on haloperidol 10 mg daily for 2 years. Over the past 3 days, he developed fever (39.8°C), severe muscle rigidity, altered mental status, and autonomic instability (BP 160/95, HR 118). His creatine kinase is 3200 U/L and serum creatinine has risen from 0.9 to 1.8 mg/dL. Urinalysis shows myoglobin. What is the most appropriate immediate management?