Eating Disorders

Carmel Dato MS, RN, CS, NPP

Eating disorders are common conditions that warrant the attention of primary care providers. Eating patterns are aspects of self-care, and as such should be part of every physical and emotional assessment. Alterations in eating patterns may be symptomatic of multiple conditions or may be a specific disorder of eating. Primary care providers have the opportunity to monitor changes in eating patterns and discuss them fully with patients. Care in recording nutritional concerns will allow for early intervention into problems with eating.

Anorexia nervosa and bulimia nervosa are potentially life-threatening eating disorders that are very common, particularly in young women. This chapter offers an overview of anorexia nervosa and bulimia nervosa, including diagnostic and treatment approaches.

ANATOMY, PHYSIOLOGY, AND PATHOLOGY

Anatomy and Physiology

The origins of eating disorders are not definitive; one line of research is in the area of neurobiology. The relations between eating disorders and mood disorders are being examined in terms of etiology based in the neuroendocrine or neurotransmitter systems. Neuroendocrine and metabolic abnormalities associated with anorexia nervosa may predate substantial weight loss, as evidenced by the development of amenorrhea before weight loss in one third of the women with anorexia nervosa. Serotonergic systems also remain altered after normal weight has been achieved (Irwin, 1993).

The complications of eating disorders are secondary to starvation or purging; these complications are not the underlying pathology. Complications become severe once adipose tissue reserves are depleted and there is more severe food refusal. At this point protein catabolism increases and water loss is accelerated, with metabolic and electrolyte disturbances. Other complications arise from vomiting or the use of laxatives or diuretics for purging.

Psychopathology

The etiology of both anorexia nervosa and bulimia nervosa is multifactorial and is associated with psychological determinants. Bruch’s (1973) classic explanation of anorexia nervosa characterizes children of overinvolved mothers with poorly developed identities and a sense of ineffectiveness. Other models encompass additional individual, family, and cultural factors. Individual factors include emotional instability, anxiety (possibly social phobia or obsessive-compulsive symptoms), and personality disorders.

Depression is very common. It may predate the eating disorder symptoms or may be secondary to starvation, often improving with weight gain. Patients with anorexia nervosa typically have distortions in thinking and reasoning, with an extreme focus on their weight and eating behavior. Their sense of self-esteem is tied to their perception of being thin. Neuroendocrine and metabolic abnormalities associated with anorexia nervosa are related to starvation and have also been viewed as a potentially predisposing factor (Garner, 1993; Walsh & Devlin, 1992).

Some authors describe family factors, such as a dominant mother as well as a passive father (Bruch, 1973). Others downplay the relationship between parents and the patient. The young person with anorexia nervosa may be a stabilizing force in a family characterized by enmeshment, rigidity, and conflict avoidance (Garner, 1993).

Anorexia nervosa is frequently precipitated by dieting after either a perception of being plump or a comment by someone else. Depression and stressful experiences typically associated with greater autonomy (eg, puberty, parental divorce, graduating from high school, beginning college, leaving home) are all potential precipitating factors for anorexia nervosa. The patient has a sense of control of food in the face of feeling out of control in other areas. The effects of starvation provide perpetuating factors in anorexia nervosa (Beumont et al, 1993; Garner, 1993).

Bulimia has been recognized as a distinct disorder for only a relatively short period. A clear understanding of its history and determinants has yet to emerge. Patients do not demonstrate the rigidity and inflexibility of those with anorexia nervosa. Patients with bulimia frequently have impulse-control problems such as substance abuse, theft, and suicide. There is a high comorbidity with affective disorders, anxiety disorders, substance abuse, and personality disorders (Edwards, 1993).

Patients with bulimia nervosa typically come from families where there is parent–child conflict, sometimes with physical, verbal, or sexual abuse. Patients feel guilty and out-of-control after bingeing, and they purge to relieve this tension. They have marked fluctuations of weight but not the extremely low weights seen in anorexia nervosa.

EPIDEMIOLOGY

Most people with anorexia nervosa are women, with the illness developing most commonly in adolescence; however, 5% to 10% of patients seeking treatment for anorexia nervosa are men. Anorexia nervosa is the third most common chronic illness among teenage girls (Hoek, 1991; Lucas et al, 1991). It has a prevalence of 0.5% to 1% of women aged 15 to 30 in Western countries. Bulimia nervosa is also more common among young
women, with a prevalence of 2% to 10% in women aged 15 to 30; men account for 10% of patients with the disorder (Mehler, 1996; Putukian, 1994).

Cultures that emphasize thinness can provide a predisposing factor for the development of eating disorders. The stigma attached to obesity and role conflicts of women are other cultural factors.

DIAGNOSTIC CRITERIA

The diagnostic criteria for anorexia nervosa include:

Unwillingness to sustain body weight at or above the normal range for height and age (85% of the minimum)
Extreme apprehension and dread of gaining weight or being fat, in an underweight person
Distorted body image or denial of the danger of present low weight
Amenorrhea (absence of three or more consecutive menstrual cycles).

There are two types of anorexia nervosa, the restricting type, in which the patient does not regularly binge or purge, and the binge-eating or purging type, where there is regular binge-eating or purging (American Psychiatric Association [APA], 1994).

The seriousness of the low weight is often denied. Restrictive behaviors common in dieting are used to a much greater extreme and with an inability to stop. Some patients also use more dangerous methods such as self-induced vomiting or large doses of laxatives, or they misuse diuretics and appetite suppressants. Other symptoms are those common to semistarvation, including depressed mood, irritability, social withdrawal, loss of libido, preoccupation with food, obsessional behavior, reduced alertness, and poor concentration (Beumont et al, 1993).

The diagnostic criteria for bulimia nervosa include:

Current episodes of binge-eating, where the patient consumes very large quantities of food in a discrete period of time and feels a lack of control over ability to cease eating
Repeated purging to prevent weight gain in the form of self-induced vomiting, fasting, extreme vigorous exercise, laxatives and diuretic abuse, or enemas
Persistent overconcern with body image as self-evaluation.

The binge-eating and purging both occur at least twice a week for 3 or more months and do not occur exclusively during episodes of anorexia nervosa. There are two types of bulimia nervosa, the purging type and the nonpurging type. In the nonpurging type, the patient exercises or fasts but does not use purging to control weight (APA, 1994).

It is common for patients to progress from anorexia nervosa to bulimia nervosa, and some alternate between the two illnesses.

HISTORY AND PHYSICAL EXAM

A careful history and physical exam will provide information for the differential diagnosis and will raise suspicion of an eating disorder. A careful and detailed eating history is crucial (Powers, 1996). To differentiate the patient with an eating disorder from one who is perhaps dieting, it is important to elicit the extent of behavioral and psychological disturbances, such as distorted body image (Beumont et al, 1993).

Patients with anorexia nervosa may present with:

Low weight
Emaciation
Cachexia
Amenorrhea
Bradycardia
Orthostatic hypotension
Lanugo
Dry skin
Hair loss
Brittle hair and nails
Cold intolerance.

These patients may appear younger than their age, have yellow-tinged skin due to carotenemia, and have cyanosis of the extremities (particularly when exposed to cold temperatures) (Carney & Andersen, 1996; Edwards, 1993; Herzog, 1992).

Other disorders must be ruled out in patients with weight loss. Medical illnesses with weight loss include brain tumors, malignancy, connective tissue disease, malabsorption syndromes, hyperthyroidism, and infection. Psychiatric diagnoses include affective disorders, obsessive-compulsive disorder, somatization disorder, and schizophrenia. In the absence of additional findings, the diagnosis of anorexia nervosa may be made by confirmation of the history and mental status exam rather than by ruling out all the possible diagnoses (Carney & Andersen, 1996).

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