Anorexia Nervosa

Anorexia nervosa is a psychiatric disorder characterized by abnormal eating behaviors that can result in significant weight loss and serious medical consequences. The term anorexia nervosa means loss of appetite for nervous reasons. Sir William Gull first described this disorder in 1868, and the French physician Lasegue named it.8,9 The essential features of this eating disorder have not changed since it was initially described.

Anorexia is defined as a disorder characterized by refusal to maintain body weight over a minimal normal weight for age and height, an intense fear of gaining weight, and distorted body image.10 Table I presents the diagnostic criteria for anorexia according to the Diagnostic and Statistical Manual for Mental Disorders, fourth edition (DSM-IVTR).11 Anorexia is also divided into two subtypes—restricting anorexia characterizes individuals who drastically limit their food intake, and purging anorexia describes individuals who engage in purging behaviors.

The use of the term anorexia for this eating disorder is a misnomer as there is no true appetite loss. While the individual with anorexia may claim to have appetite loss, they are starving. The pattern is to alternate food avoidance with overeating.

Anorexia affects 1 to 2% of the population and occurs most frequently among the adolescent age group. A bimodal pattern of onset exists occurring at the ages of 14 and 18 years.4 The female-to-male ratio of anorexia is 10:1, although approximately 15% of cases occur in men. This disorder is found predominantly in white, middle- and uppersocioeconomic classes. Groups considered to be at risk for anorexia include dancers, runners, skaters, models, actors, gymnasts, wrestlers, and college sorority members, for whom thinness is emphasized and highly valued.12-15

Anorexia is a disorder that affects all organ systems. Clinical manifestations and symptoms represent secondary effects from starvation and include changes in vital signs such as hypotension, bradycardia, and hypothermia. Dry skin, hypercarotenemia, lanugo (fine body hair), loss of muscle mass, and atrophy of the breasts may be noted. Dehydration and malnutrition may contribute to headaches, lethargy, dizziness, and syncope. Gastrointestinal signs of anorexia include intestinal dilation from constipation and diminished intestinal motility. Amenorrhea and osteopenia also are common findings in individuals with this eating disorder. Cardiovascular changes include a prolonged cardiac output (QT) interval found on electrocardiogram (ECG), and a decreased ventricular mass and mitral valve prolapse demonstrated also on an echocardiogram. Psychological manifestations of anorexia include difficulty concentrating and making decisions, depression, social withdrawal, and obsessiveness (particularly with food). Individuals with anorexia may refuse help, while maintaining that they are “fine” even in advanced stages of malnutrition.12,16 A summary of complications that can occur as a result of anorexia
appears in Table II.

The etiology of anorexia is based on biologic, psychological, and social issues. Studies of families and
twins suggest there is a weak genetic component for the etiology of anorexia.17 The disorder is considered to be developmental more so than mental. Therefore, predisposing, precipitating, and perpetuating factors are more useful to consider than actual causes.

Factors considered to predispose an individual to anorexia include female gender, family history of eating disorders, perfectionist personality, difficulty communicating negative emotions, difficulty resolving conflict, and low self-esteem. Precipitating factors associated with anorexia focus on developmental changes, such as sexual development and menarche in persons aged 10 to 14 years, which leads to a spurt in weight gain; independence and autonomy struggles in individuals aged 15 to 16 years; and identity conflicts in individuals aged 17 to 18 as they transition from home to college or married life. Perpetuating factors are those that maintain the eating disorder. Examples of these include signs and symptoms of starvation and coping strategies engendered by the eating disorder.12,18-20

With respect to a physiologic etiology for anorexia, studies of serotonin and leptin in individuals with anorexia nervosa have yet to clarify if changes in these chemicals represents a cause or a consequence of the disorder. Increases in the neurotransmitter serotonin lead to reductions in food intake, while decreases in brain serotonin function are associated with depression and suicide attempts. Levels of serotonin are low in underweight individuals with anorexia, but will rise to normal levels in individuals who have recovered. A disturbance in serotonergic function may be a risk factor for the development of anorexia. Conversely, high levels of serotonin can be associated with perfectionism and rigidity, characteristics that are often seen in individuals with anorexia before the illness develops.21

Leptin is a hormone secreted by fat cells that plays a role in the regulation of body fat stores. Underweight individuals with anorexia have low serum levels of leptin, which increases with weight gain. Alterations in leptin regulation may play a role in the persistence of anorexia contributing to difficulties in attaining and maintaining normal weight.21

Brown and Bonifazi contend that sociocultural factors that instill a desire for thinness and beauty in women while stigmatizing obesity may be a causal factor in anorexia and other eating disorders. They note that the media provides an overwhelming amount of information on dieting, and the images of the beauty ideal have moved toward an increasingly thin image.10 However, the average woman has experienced increases in weight. This disparity between actual weight and socially acceptable weight ideals creates a vulnerability to body dissatisfaction, loss of control, and self-hatred.

Individuals with anorexia usually present with dramatic abnormal physical findings allowing a diagnosis to be more easily rendered even when the individual is denying any problems. However, anorexia is a clinical diagnosis, and no specific diagnostic tests exist to determine the disorder.

Laboratory studies can be performed as part of a diagnostic workup for anorexia. These included a complete blood count with erythrocyte sedimentation rate (ESR), urinalysis, and blood chemistries. Findings of these studies may reveal hyponatremia, which reflects excess water intake or the inappropriate secretion of antidiuretic hormone (ADH); hypoglycemia; an elevated BUN signaling dehydration; elevations in cholesterol in cases of starvation; leukopenia; and thrombocytopenia. The hemoglobin and ESR are typically normal. If these results are elevated, further investigation of an organic etiology are warranted.12,22,23

Since cardiovascular complications account for the majority of the morbidity and mortality associated with anorexia, an electrocardiogram and echocardiogram are warranted. A prolonged QT interval indicates potentially harmful dysrhythmias may occur.

Bone loss is a serious problem that is associated with amenorrhea and malnutrition, and should be assessed by bone densitometry. Fifty percent of women with anorexia have bone density measurements that are more than two standard deviations below normal.24,25 Bone loss may occur in young women after just six months of the illness.24,26 It can persist even after the recovery of weight. Symptomatic compression fractures and kyphosis are longterm risk factors.27,28

Kriepe et al. developed staging criteria for anorexia.29 These criteria appear in Table III.