Problem: An 18-year-old woman presents with orthostatic hypotension, bradycardia, and hypothermia. Her BMI is 17 kg/m2. She runs 12 miles every day and eats < 1,000 calories daily for fear that she may "become fat." Physical exam reveals lanugo, dry skin, and teeth erosion. Russell sign is positive. Which of the following is the most likely diagnosis? Need Assignment Help? Anorexia nervosa Avoidant food intake disorder Binge eating disorder Bulimia nervosa