Psychiatrymiddle twist
A 29-year-old woman is referred with 'panic attacks': five months of episodes of pounding heartbeat, shaking hands and feeling unbearably hot, several of which have woken her from sleep. Between episodes her pulse is 104/min and her blood pressure 128/74 mmHg, both unchanged during an attack witnessed in the waiting room. Her palms are warm and moist with a fine tremor of the outstretched fingers. She has lost 6 kg while eating more than usual. A soft swelling at the front of her neck rises when she swallows. She takes no medicines and a urine drug screen is negative. Which one of the following best explains her presentation?