A 22-year-old unconscious (Glasgow coma scale six) male was brought in the emergency department of our hospital by his friends. On examination, his temperature was 103.5° F, pulse rate (PR) was 136–140 per minute, blood pressure (BP) was 86/34 mm Hg, and respiratory rate was 38–42 per minute with SpO2 of 89% on room air. Chest auscultation revealed decreased air entry at the base of both lungs with crepitations in the right upper zone. The attendants were unable to provide any significant previous medical history.

He was intubated using fentanyl and etomidate. The chest X-ray revealed a large consolidation at the right upper zone. Routine investigations and cultures of blood, trachea and urine were sent. Patient was then started on piperacillin-tazobactam and azithromycin and transferred to the intensive care unit (ICU) for further management.

During the next 2 days, his vital signs showed marked fluctuations with PR varying from 80 to 120 beats/minute and BP from 100/70 to 150/110 mm of Hg. Patient continued to have high-grade fever (103–104°F) despite on being one gram iv paracetamol six hourly. Cardiovascular examination was normal and the abdomen was soft. On neurologic examination, he was sedated with pupils of normal size and reaction. Reflexes were normal. There was symmetrical rigidity in all four extremities. He had mild neck rigidity with negative Kernig and Brudzinski sign. Investigations revealed a white blood cell count of 32,000 with a procalcitonin level of 0.2. Tracheal culture showed Streptococcus pneumoniae while urine and blood cultures were sterile. Other investigations like liver and renal function tests, serum electrolytes, blood gas analysis and ECG were within normal limits. He was continued on the same treatment.

On the third day, the patient continued to have a high-grade fever with autonomic dysregulation. He was agitated and sweating. He now had bilateral equal air entry in the lungs and a repeat chest X-ray showed clear lung fields. Repeat cultures of blood, trachea and urine were sterile.

Due to his high-grade fever, agitation and rigidity, his CPK levels were sent and were reported to be 1600 U/L (normal range, 39 to 308 U/L). Toxicological screening test on blood and urine was clean, autoimmune encephalitis panel on serum and CSF was negative for any antibodies, computed tomography of the brain and CSF examination was normal.

On the fourth day, the patient’s parents arrived and revealed that the patient was a chronic drug and alcohol abuser since the last 8 years and previously had multiple admissions at a rehabilitation centre. Since the last 1 year, he had developed a schizoaffective disorder characterised by paranoia, hallucinations and delusions of grandeur. He was on irregular medication (lithium and haloperidol) for the same. Recently, he had changed his treating physician who increased his dosage of haloperidol.

In view of the above, a diagnosis of NMS was suspected. The patient was started on tablet bromocriptine 5 mg every 8 hourly and lorazepam 2 mg every six hourly. Urine examination for myoglobinuria was negative. Over the next 3–4 days, he became alert and afebrile, his vital signs stabilised, and with a resolution of rigidity and catatonia. There was a gradual decrease in CPK levels and WBC count. The patient was successfully extubated on day 12. Bromocriptine was gradually tapered off and the patient was transferred to the psychiatry ward on day 18th on lorazepam 2 mg twice a day.