WBR0037

Author	[[PageAuthor::Gonzalo A. Romero, M.D. [1] (Reviewed by Will Gibson)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Behavioral Science/Psychiatry
Sub Category	SubCategory::General Principles
Prompt	[[Prompt::A 17-year-old female is brought to the outpatient clinic by her mother because she is refusing to eat and is exercising more than usual. She has earned several awards because of her athletic skills in the past, and is extremely competitive in school. 4 months ago her parents divorced. Shortly thereafter, the patient started a special diet and she has lost 15 pounds. Her mom has tried to enforce a regular diet with sufficient calories, but the patient is reluctant to increase her caloric intake. She reports a strong fear of gaining weight and feels fat in front of the mirror. Her mother states that she stopped having a menstrual cycle 5 weeks ago. On physical exam her vitals HR: 78, BP: 123/80, Temp: 37 C, BMI: 16.5. She has fine hair over her entire body, multiple dental cavities, and extremities are atrophied. What is the most likely diagnosis?]]
Answer A	AnswerA::Post traumatic stress disorder
Answer A Explanation	[[AnswerAExp::Post traumatic stress disorder (PTSD) is characterized by the re-experiencing of a stressful event (flashbacks) and the avoidance of associated stimuli. Patients with PTSD often experience sleep disturbances due to nightmares, irritability, and inability to concentrate. A diagnosis of PTSD requires that symptoms last more than one month, if symptoms last less than one month the diagnosis of "acute stress disorder" is given. PTSD usually presents after a stressful event severe enough to disrupt one's normal coping mechanisms. Common causes of PTSD include witnessing or being subject to extreme violence or rape.]]
Answer B	AnswerB::Obsessive compulsive personality disorder
Answer B Explanation	[[AnswerBExp::Obsessive compulsive personality disorder (OCPD) is lifelong pattern of perfectionism that extends to all areas of life (pervasive). Persons with this type of personality often are extremely organized. OCPD is more common in males. This patient might present traits of OCPD, but her presentation is not as intense or chronically present to be considered diagnostic of OCPD. Furthermore, excessive calorie restriction and weight loss constitute the prevailing medical theme in this patient, and these behaviors are not generally characteristics of OCPD patients.]]
Answer C	AnswerC::Anorexia nervosa
Answer C Explanation	[[AnswerCExp::Anorexia nervosa is an eating disorder frequently seen in female teenagers and young female adults. It is characterized by a restriction in caloric intake that causes significant weight loss 15 to 20% below ideal weight with BMI <17.5. Half of these patients develop bulimia-like binging and purging behaviors. Depression is also common among anorexia patients. On physical exam, patients may have lanugo or baby-like hair, dental cavities due to vomiting, and could have a lower Tanner stage if disease starts in adolescence. Treatment usually consists of behavioral therapy and counseling to stabilize body weight. Mirtazapine is an antidepressant commonly suggested for anorexia treatment on the USMLE, as it increases appetite as a side effect.]]
Answer D	AnswerD::Bulimia
Answer D Explanation	[[AnswerDExp::Bulimia is an eating disorder that involves binging and purging behaviors defined as voluminous ingestion of food followed by vomiting, laxative use, dieting pills or exercise. On physical exam these patients often have signs of vomiting such as callous on hands, enlarged parotids and other glands, dental cavities, esophageal tears or esophagitis. BMI usually stays normal or above normal. Treatment usually includes counseling, but may involve SSRIs, Imipramine, or more structured rehabilitation.]]
Answer E	AnswerE::Obsessive compulsive disorder
Answer E Explanation	[[AnswerEExp::Obsessive compulsive disorder (OCD) is a subtype of Anxiety disorder characterize by intrusive thoughts that produce uneasiness and repetitive behaviors aimed at reducing the associated anxiety. OCD is focal and acquired which help distinguishing from Obsessive Personality disorder which is lifelong and pervasive.]]
Right Answer	RightAnswer::C
Explanation	[[Explanation::Most of this patient's symptoms are consistent with a diagnosis of Anorexia nervosa, including the constant fear of gaining weight, body image disturbance, restriction in caloric intake, and excessive exercise. Important characteristics help distinguish Anorexia from Bulimia; Anorexia causes low BMI and amenorrhea due to the strict caloric intake. Conversely, Bulimia is a syndrome that is characterized by episodes of binging (excessive eating) and purging, often by induced vomiting or laxative abuse. These patients tend to have a normal or higher BMI. They may display signs of vomiting induction such as callous on fingers, halitosis, enlarged parotids, dental and cavities. While this patient has signs of frequent vomiting, her low BMI, caloric restriction and excessive exercise make anorexia the more likely option. In both anorexic and bulimic patients, cardiac complications may arise due electrolyte disturbances and consequent conduction defects. A small percentage of these patients can die from fatal arrhythmias. Educational Objective: Anorexia causes low BMI and amenorrhea due to the strict caloric intake. References: First Aid 2014 page 512]]
Approved	Approved::Yes
Keyword	WBRKeyword::Eating, WBRKeyword::Eating disorder, WBRKeyword::Anorexia, WBRKeyword::Bulimia, WBRKeyword::Psychiatry, WBRKeyword::Behavioral Science
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