Eating disorders

 

Recommended Reading: Kaplan and Sadock's  pg 720-736.

Objectives

            1.) The student will be able to distinguish anorexia and bulimia nervosa.

            2.) The student will know the signs of anorexia and bulimia.

            3)  The student will be able to describe the role of the hypothalamus in some of the manifestations of anorexia

            4) The student will be able to describe the common family dynamics associated with eating disorders

            5) The student will be able to describe the laboratory findings common in eating disorders

            6) The student will be able to describe the outcome of eating disorders and recognize appropriate treatments.

Psychiatry deals primarily with three eating disorders: Anorexia nervosa, Bulimia nervosa, and obesity. The most dramatice of these are anorexia and bulimia. The most common is obesity. We will focus today on anorexia and bulimia.

The term anorexia typically is used to suggest a loss of appetite. However, in this disorder there is not a ‘loss of appetite’ but a willful restriction of caloric intake in order to loss weight. Anorexia nervosa is characterized by a refusal on the part of the patient to maintain a minimally normal body weight. The weight loss or failure to reach expected weight gain targets is accomplished by purposeful fasting and/or other extreme measures such as excessive exercise, use of laxatives, diuretics or other medicines. Bulimia nervosa is characterized by repeated episodes of binge eating followed by inappropriate compensatory behaviors, such as self-induced vomiting or strategies similar to those used by the anorexia patient. The objective of the bulimia nervosa patient is to prevent weight gain. Both eating disorders have in common a disturbance in perception of body shape and weight.

Diagnostically this area is not well delineated. Patients may be diagnosed with anorexia at one visit and bulimia in other visits. This apparent diagnostic confusion is not necessary. Anorexia nervosa is characterized by being underweight at or below the 85% of expected body weight. Patients with anorexia may achieve this level of thinness as a result of restricting caloric intake or by eating and then purging through self induced vomiting or overuse of laxatives. Even with such thinness a hallmark of anorexia is the insistence that they are in fact ‘fat’. The perceived body image is distorted dramatically.

Bulimia on the other hand is not diagnosed in the setting of a weight of less than 85%. Usually in fact bulimic patients are normal weight or even a bit obese. Their concern is to maintain a specific weight. Bulimic patients are further typed by whether or not the current episode has purging behaviors. Some patients resort to nonpurging behaviors to maintain weight such through the use of fasting or excessive exercising. It is the use of such behaviors 2 or more times per week for more than 3 months that qualifies a patient for a diagnosis of bulimia. The occassional ‘buff up’ or few weeks at a spa are not considered bulimic patterns.

Text Box: Diagnostic criteria of Anorexia Nervosa
A. Refusal to maintain body weight at or above a minimally normal weight for age and height (usually less than 85% of ideal body weight for age and height) Or failure to make expected weight gain during a period of growth. 
B. Intense fear of gaining weight or becoming fat even though they are actually underweight. 
C. Disturbed experience of one's body weight or shape, denial of seriousness of current low body weight, or undue influence of body weight or shape on self evaluation. 
D. In postmenarcheal females, amenorrhea, (absence of three consecutive menstrual periods) This includes women who are menstrual only after receiving estrogen therapy. 
Restricting type: not regularly engaged in binge-eating or purging behavior 
Binge-Eating type: regular binge-eating and purging behavior such as self induced emesis and misuse of laxatives, diuretics, or enemas 

Table 1 and Table 2 display the DSM-IV criteria for the disorders. Note that a clinical guideline is provided to make the diagnosis of anorexia nervosa, specifically, weight less than 85% of that considered normal consistent with Metropolitan Life Insurance tables of age, height and gender adjusted weights.

There is considerable diagnostic overlap between the two disorders and their natural histories tend to intertwine. The discrepancy between weight and perceived body image is the key to the diagnosis of anorexia. Underweight persons who are normally concerned about their weight, recognize that their weight is low and possibly harmful and express a desire to gain weight. Anorexic patients, on the other hand, delight in their weight loss and express a fear of gaining weight. Bulimic patients are generally able to hide their binge eating and purging behaviors and often have normal weight.

Text Box: Diagnostic Criteria for Bulimia Nervosa
A. Recurrent episodes of binge-eating. Characterized by: 
1.	Eating in a discrete period of time an amount of food definitely larger than most people would consume in similar period under similar circumstances 2.	A sense of lack of control over eating during the episode 
B. Recurrent inappropriate compensatory behavior to prevent weight gain such as; self induced vomiting, misuse of laxatives, diuretics or other medications, enemas, fasting, or excessive exercise. 
C. Binge-eating and compensatory behaviors both occur on average at least twice a week for 3 months 
D. Self-evaluation is unduly influenced by body shape and weight 
E. Does not occur exclusively during episodes of Anorexia Nervosa 
Purging type: regularly engages in self-induced vomiting or misuse of laxatives, diuretics or enemas 
Nonpurging type: has used other inappropriate compensatory behaviors such as fasting and excessive exercise, but has not regularly used self-induced vomiting, or misuse of laxatives, diuretics, or enemas. 

Epidemiology The prevalence among women is estimated to be 1.0% for anorexia and 1.0 - 2.7% for bulimia. There is a large gender association with the incidence for women is 10-20x  that for men. Individual symptoms characteristic of eating disorders such as bingeing and purging or fasting are more common than the disorders themselves. It is estimated that subsyndromal eating disorder behaviors occur in up to 5-10% of young women. The usual age of onset is in adolescence or young adulthood. Anorexia generally begins at an earlier age (early teens) Than bulimia who present in their late teens or early twenties. For the NBME: Anorexia is more prevalent in the higher social economic classes.However newer studies have begun to challenge this finding. Bulimia has greater diversity of socio-economic background. Anorexia nervosa is uncommon in poorly developed countries. Eating disorders are also overrepresented in certain occupations that value control of body shape such as modeling and ballet dancing.

Etiology Psychologic, genetic, and biological mechanisms have been proposed to explain the etiology of eating disorders.

Biologic factors

Genetic influences have been studied. The strongest evidence for a genetic basis for a predisposition is found in the twin studies. There is a greater concordance in monozygote twins than in dizygote twins. It is also more concordant in the female siblings and offspring than in male siblings of patients with an eating disorder.

Biologic theories tend to focus on the relationship of mood disorders with eating disorders. In general there is a high rate of depressive illness in patients with eating disorders. This has focused attention on the known substrates for mood regulation. The role of the hypothalamus has been speculated on. The dysregulation of the gonadotropins seen in anorexia nervosa is evidence for a hypothalamic role.  Amenorrhea before weight loss occurs in up to one-fifth of patients. In addition the role of the hypothalamus on eating and feeding is well known. Further biologic data inlcude the finding of abonormal DST and TSH in anorexia. There is also increased corticotropin releasing factor (CRF) in the cerebrospinal fluid of anorexic patients.

Evidence for central neurotransmitter dysregulation has best been described for norepinephrine. MHPG in the urine and CSF of anorexic patients is low. This suggests a low NE turnover. Such a finding is also seen in depression. Peptidergic neurotransmitters have been studied in limited ways. There are reports of some patients responding to opiate antagonists. These data are difficult to interpret.

The value of the biologic models is the importance in suggesting occult illnesses which may present as anorexia nervosa. Although uncommon a third ventricular cysts or tumor may present with weight loss and behaviors which resemble anorexia nervosa. In addition hypothalamic dysfunction and disorders of the adrenal and thyroid system should be screened for early in the treatment of anorexia nervosa.

Psychological factors

These propose that anorexia nervosa represents a phobic avoidant response to food. This would be considered a learning theory of anorexia. Psychodynamic theories emphasize the diffiucluty in the transition from childhood to adulthood. They tend to focus on the tumultuous relationship and poor differentiation between these patients and there families. Many describe these patients as overly compliant and "perfect." The focus on thinness is seen as an attempt to gain control of a part of their life. The behaviors interrupt normal development and postpone adolescence and sexuality so that the patient remains in a child-like state.

Social factors

The importance of conforming to the American ideal of youth, beauty, and thinness is thought to be the genesis of the preoccupation with body image which may lead to eating disorders in vulnerable persons. Family dynamics commonly found include parental overinvolvement, lack of boundaries, and insufficient autonomy. These family interactions echo the psychodynamic theories. A problem arises when the parents and child begin to struggle over the food issues. This struggle is usually reflective of the other struggles between the child and parents as issues of control surface. In relatity the child and parents have ambivalent feelings about the gorwth and development which is occuring and the implications for the family as the role of the child goes from juvenil to adolesence and then into adulthood.

Clinical Findings The anorexic person develops a set of behaviors in pursuit of weight loss. These behaviors may include dieting, adoption of unusual diets or vegetarianism, and refusal to eat meals with family members or in restaurants. Anorexic patients often show an unusual interest in food. They may collect recipes and prepare elaborate meals for friends and relatives. They may develop a strong interest in the study of nutrition. The person with weight loss may be of concern to friends and relatives, but will insist that her weight is not abnormal and that she, in fact, is still overweight. Many patients begin to abuse laxatives, diuretics, or stimulants in an effort to enhance their weight loss.

Text Box: Medical Complications of Eating Disorders 
Physical Manifestations: 
Amenorrhea	Hair loss 
Sensitivity to cold	Petechia
Constipation	Carotenemic skin 
Low blood pressure	Parotid gland enlargementa 
Bradycardia	Dental erosion, cariesa 
Hypothermia	Pedal edema 
Lanugo hair	Dry skin 
Endocrine abnormalities: 
Increased growth hormone levels 	Increased plasma cortisol levels and loss of diurnal variation 
Reduced gonadotropin levels (LH, FSH, Impaired response to LHRH) 	Low T3, high T3RU, impaired TRH responsivenessa 
Abnormal glucose tolerance test 	Elevated serum bicarbonatea 

These patients often develop an intensive, excessive interest in physical exercise, often participating in a strict workout routine. Many ballet dancers and female athletes are anorexic. Anorexic patients with bulimic behavior and bulimic patients tend to carry out their binge eating and purging in private. These patients may consume enormous amounts of food, for example, an entire cake, a quart of ice cream and cookies. The binge may bring the patient relief from tension which is followed by guilt and feelings of disgust. The patient then induces vomiting initially by placing the fingers in the throat, but later can often do this at will. Some patients abuse emetics such as ipecac. Other unusual food-related habits may develop. Patients may be observed to play with food on their plate at meal time, cut food into tiny pieces or buy large amounts of candy at stores and then give it away. Other associated findings with anorexia nervosa are above average scholastic achievement or perfectionism and achievement oriented families. Some have poor sexual development, leading some clinicians to suspect that anorexia represents an attempt to prolong childhood and escape, perhaps from fear, the transition into a role of adolescence; in fact, anorexia patients tend to have delayed sexual development and diminished interest in sex accompanying the onset of their illness.

 

 

Laboratory abnormalities:

Dehydrationa

Elevated transaminases

Hypokalemiaa

Elevated serum cholesterol

Hypochloremiaa

Carotenemia

Alkalosisa

Elevated BUNa

Leukopenia

Elevated amylase levelsa

Elevated serum bicarbonatea

 

Note. LH = luteinizing hormone. FSH = follicle-stimulating hormone. LHRH

luteinizing hormone-releasing hormone. T3 = triiodothyronine. TRH =

thyrotropin-releasing hormone. BUN = blood urea nitrogen. aSeen in patients

who binge/purge.

Course and Outcome Long-term studies show that roughly 50 - 60% are significantly improved and 7 - 15% become chronic. Mortality rates vary from 5 - 18%. The remainder have varying levels of residual symptoms. Poor outcome is generally associated with longer duration of illness, older age at onset, prior psychiatric hospitalization, poor pre-morbid adjustment, comorbid personality disorder and family dysfunction.

Differential Diagnoses Differential diagnosis includes normal thinness, physical disorders causing weight loss, hyperthyroidism, gastrointestinal disorders resulting in vomiting or malabsorption, malignancy and chronic infection. Major depressive disorder may be accompanied by weight loss and poor appetite. Obsessive compulsive disorder may be characterized by ritualistic eating behaviors resulting in weight loss. The majority of patients with anorexia will fulfill criteria for another psychiatric disorder, most commonly depression or borderline personality disorder. Some will fulfill the diagnostic criteria for OCD as well, and there is some thought that perhaps anorexia represents one form of obsessive compulsive disorder in which the behavior is focused on food.

Treatment Eating disorders are among the most difficult mental illnesses to treat and can be quite lethal. Two fundamental goals in the treatment of eating disorder patients are (1) to restore the patient's healthy nutritional state, and (2) to modify the patient's distorted body image and/or eating patterns so that the patient can maintain weight within a normal range. Treatment can usually be conducted on an outpatient basis, but many patients require inpatient hospitalization. Indications for hospitalization include starvation, severe weight loss, hypotension, hypothermia or electrolyte imbalance. Depressed patients with suicidal ideation or psychotic patients also may need to be hospitalized. Additional reasons include failure of outpatient treatment as indicated by failure to gain weight or failure to reverse severe binge/purge cycles.

Treatment generally involves behavior modification of the eating disturbance combined with individual and/or family psychotherapy. The purpose of behavior therapy is to restore normal eating. In the hospital strict protocols are used that set specific weight goals for patients and target abnormal behavior for correction. Positive reinforcement is used to help patients achieve the specific goals outlined in the treatment contract that is agreed to by the patient; for example, the patients who are able to achieve their weight goals are rewarded with special privileges. Patients are weighed daily and total intake and output are carefully recorded. Patients should be observed two hours after meals to prevent vomiting. Generally it is advisable to increase intake slowly. At first it may be advisable to spread meals out over six feedings during the day. Patients who are significantly underweight or, are having trouble gaining weight may need tube feedings.

Approaches to psychotherapy vary. Some therapists emphasize a psychodynamic approach, some a cognitive-behavioral approach, and some emphasize conjoint family techniques. In all cases the relationship with the therapist is of crucial importance. The therapist must be active and not passive, and convey a sense of confidence, competence and understanding. Issues of body image, body concept, growth and development must be addressed. Initially patients are often hostile and resistant. Later they often become quite dependent on the therapist. The patient should move gradually from the state of dependence to increasing levels of autonomy and self-reliance.

Medications may be indicated in the treatment of selected patients. Tricyclic antidepressants, monoamine oxidase inhibitors, trazodone, and fluoxetine have been shown to decrease binge eating and purging. An antidepressant will be useful in a patient with a super-imposed major depression. Anti-anxiety agents given prior to meals may help certain patients. Some success has been demonstrated with periactin in helping patients to gain weight. A diagnosis of an eating disorder, however, is not a specific indication for pharmacotherapy.