Review Question - QID 109318

A 18-year-old woman presents to her primary care physician reporting that she has not experienced her first menses. She is accompanied by her mother who states that she personally experienced menstruation at age 12 and that the patient's sister started menstruating at the age of 11 years. The patient is not sexually-active and denies taking any medications. On physical examination, the patient appears thin and has fine hair covering her arms. Her height is 62 inches (157.48 cm) and her weight is 85 pounds (38.5 kg). The patient does not make eye contact and only answers in one word responses. The mother is asked to step out of the room and the interview resumes. After establishing some trust, the patient admits that she does not have an appetite. She has had difficulty sleeping and some feels guilty for worrying her mother. She also admits to occasional cocaine use. She switches between binge-eating and vomiting. She is constantly fatigued but she also goes to the gym three times daily, often without her parents’ knowledge. Which of the following is the most likely diagnosis in this patient?