Eating Disorders

Adolescence is the primary time for the development of eating disorders. The interaction of puberty and the issues surrounding body image place teens at risk. Early recognition of unhealthy eating habits makes treatment easier and improves outcomes. Counseling teens on nutrition and appropriate weight management may go a long way in preventing these disorders.

In the past, the Diagnostic and Statistical Manual of Mental Disorders 4 (DSM-4) only specified two eating disorders, anorexia nervosa and bulimia nervosa. This left more than half of patients in the category of Eating Disorders Not Otherwise Specified (EDNOS). In the fifth edition of DSM-5, the chapter Feeding and Eating Disorders now includes the following six disorders: anorexia nervosa, bulimia nervosa, binge-eating disorder, avoidant/restrictive food intake disorder (ARFID), rumination disorder, and pica. EDNOS has been replaced with Other Specified Feeding or Eating Disorder and Unspecified Feeding or Eating disorders. This review will focus on anorexia nervosa and bulimia nervosa.

Anorexia nervosa (AN)

The prevalence of anorexia nervosa among young females is approximately 0.4%. Females outnumber males 10:1. Anorexia nervosa occurs across culturally and socially diverse populations, though there is an increased risk among first-degree biological relatives of individuals with the disorder. Patients with anorexia nervosa are also at increased risk of suicide.

The primary features of anorexia nervosa include a severe energy intake restriction, an intense fear of gaining weight or becoming fat, and a disturbance in self-perceived weight or shape. The requirement for amenorrhea was eliminated in DSM-5, which increases the likelihood for diagnosis in males and premenarchal females. See below for full DSM-5 criteria.

Most laboratory tests in patients with eating disorders are normal, and may provide false reassurance to families and providers. Severe cardiac complications can still occur despite normal lab results. Findings which may support a diagnosis of anorexia nervosa include: leukopenia, electrolyte abnormalities, elevated liver enzymes, and a low T3 and low-normal T4. Sinus bradycardia on electrocardiography is common; prolonged QT and arrhythmias can also be seen.

Treatment involves a multi-disciplinary approach involving physicians, mental health providers and registered dietitian nutritionists. Hospitalization may be necessary. Common psychotherapies used to treat patients include cognitive behavioral therapy (CBT) and family based therapy (FBT), with some evidence suggesting that FBT is the most effective treatment for adolescents

More Info: Diagnostic Criteria Anorexia

A. Restriction of energy intake relative to requirements, leading to a significantly low body weight in the context of age, sex, developmental, trajectory and physical health. Significantly low weight is defined as a weight that is less than minimally normal or, for children and adolescents, less than that minimally expected. B. Intense fear of gaining weight or of becoming fat, or persistent behavior that interferes with weight gain, even though at a significantly low weight. C. Disturbance in the way in which one’s body weight or shape is experienced, undu influence of body weight or shape on self-evaluation, or persistent lack of recognition of the seriousness of the current low body weight.   Specify whether: (F50.01) Restricting type: During the last 3 months, the individual has not engaged in recurrent episodes of binge eating or purging behavior. (i.e. self-induced vomiting or the misuse of laxitives, diuretics, enemas). This subtype describes presentations in which weght loss is accomplished primarily through dieting, fasting and/or excessive exercise. (F50.02) Binge-eating/purging type: During the last 3 months, the individual has engaged in recurrent episodes of binge eating or purging behavior (i.e. self-induced vomiting or the misuse of laxitives, diuretics, enemas).

Bulimia Nervosa (BN)

The prevalence of bulimia nervosa among young females is approximately 1-1.5%. Again, females outnumber males 10:1. Bulimia nervosa occurs across similar populations as anorexia nervosa, and while genetic vulnerabilities for the disorder may be present among families, known risk factors include childhood obesity and early pubertal maturation. Mortality is less common in patients with bulimia compared to anorexia nervosa, though patients with bulimia also have an increased risk of suicide.

The primary features of bulimia nervosa include recurrent episodes of binge eating, recurrent inappropriate compensatory behaviors to prevent weight gain, and self-evaluation that is overly influenced by body shape and weight. Bulimics are much less likely to come to medical attention than anorexics. Occasionally, bulimics will come to the physician seeking prescriptions for laxatives or diuretics. Dentists are more likely to pick up bulimics due to the damage done to the teeth by purging. Unlike patients with anorexia, patients with bulimia may have a normal or above-normal BMI-for-age. See below for full DSM-5 criteria.

Laboratory testing is most likely to be abnormal in a patient with bulimia due to purging behaviors. Abnormalities include hypokalemia, hypochloremia, hyponatremia, and potentially life-threatening cardiac arrhythmias. Vomiting may produce a metabolic alkalosis due to loss of gastric acid, while laxative and diuretic abuse can lead to metabolic acidosis.

Treatment should be focused on the underlying self-esteem and psychiatric issues such as depression. Pharmacotherapy has more evidence-based support in bulimia than anorexia, and may provide additional benefit when combined with CBT or FBT. Common sense approaches like not stocking binge foods in the home can help. The physician should help with appropriate weight loss methods if the patient is overweight.

Source: Rome, Ellen; Strandjord, Sarah E. Eating Disorders. Pediatrics in Review. Pediatrics in Review, 37 (8), Aug 2016.

More Info: Diagnostic Criteria Anorexia

A. Recurrent episodes of binge eating. An episode of binge eating is characterized by both of the following: Eating, in a discrete period of time (e.g., within any 2-hour period), an amount of food that is definitely larger than what most individuals would eat in a similar period of time under similar circumstances. A sense of lack of control over eating during the episodes (e.g., a feeling that one cannot stop eating or control what or how much one is eating). B. Recurrent inappropriate conpensatory behaviors in order to prevent weight gain, such as self-induced vomiting; misuse of laxatives, diuretics, or other medications; fasting; or excessive exercise. C. The binge eating and inappropriate compensatory behaviors both occur, on average, at least once a week for 3 months. D. Self-evaluation is unduly influenced by body shape and weight. E. The disturbance does not occur exclusively during episodes of anorexia nervosa.

Rupp, R. (2017). Adolescent Medicine. Core Concepts of Pediatrics (2nd ed.). University of Texas Medical Branch.

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Date last modified: October 20, 2017.