Unusual cause of acquired brain injury.

A 37-year-old male was admitted with history of syncope and fall leading to right temporal bone fracture with extradural haemorrhage. He underwent craniotomy and clot evacuation. Postoperatively during inpatient rehabilitation, he was progressing well with his physical and cognitive rehabilitation, when he had resting tachycardia of between 90 and 100 per minute. Investigations to rule out cardio-pulmonary and endocrine causes of tachycardia were normal. He was further investigated for suspected postural orthostatic tachycardia syndrome (POTS). A tilt table test was done which revealed rise in baseline heart rate from 90/min to 130/min on 70 with no postural drop in blood pressure. Subsequently plasma norepinephrine level in erect posture was analysed which was 721 pg/ml. A working diagnosis of POTS was made. Initially, after an increase in water intake by 1.5-2 l/day, his baseline and postural tachycardia reverted back to 76/min. He is being followed up.