Anorexia Nervosa

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Definition/Description

Anorexia nervosa is an eating disorder in which the individual exhibits severe weight loss without any indication of underlying systemic causes. Individuals with anorexia nervosa have a distorted view of their own body image and an extreme fear of gaining weight.   Anorexia nervosa is diagnosed according to the DSM IV criteria listed below. 

DSM IV-TR Diagnostic Criteria of Anorexia Nervosa

1. "Refusal to maintainbody weight at or above a minimally normal weight for age and height: Weight loss leading to maintenance of body weight <85% of that expected or failure to make expected weight gain during period of growth, leading to body weight less than 85% of that expected."
   
2. "Intense fear of gaining weight or becoming fat, even though under weight."
   
3. "Disturbance in the weay one's body weight or shape are experienced, undue influence of body weight or shape on self evaluation,or denial of the seriousness of the current low body weight."
   
4. "Amenorrhea (at least three consecutive cycles) in postmenarchial girls and women.  Amenorrhea is defined as periods occuring only following hormone (e.g., estrogen) administration."
   

Two sub-types of anorexia nervosa have been recognized by the Diagnostic and Statistical Manual of Mental Disorders.  These sub-types include the restricting type and the binge-eating-purging type. Restricting subtype is characterized by an individual with anorexia nervosa who has not regularly taken part in binging or purging behaviors during the current episode.  Binging and purging behaviors include the use of laxatives, diuretics, enemas, and self-induced vomiting to restrict weight gain.  Binge-eating-purging subtype is characterized by an indivudal who has regularly taken part in binge-eating or purging behaviors in the current episode of anorexia nervosa. 

Prevalence

Individuals with anorexia nervosa typically are young girls or women a part of the middle to upper-class families.  Males also suffer from anorexia nervosa, but the prevalence is much lower, 5-10% of cases.   The female to male ratios range from 6:1 to 10:1 in the United States. However, the characteristics and behaviors of males and females with anorexia nervosa are similar. 

The most common age for onset of anorexia nervosa is in the mid teens and the disorder is most common in industrialized cultures such as United States, Canada, Europe, Australia, New Zealand, and South Africa.  Anorexia nervosa is present in approximately 4% of young adolescents and adults in the United States.

When a closer look at individuals with anorexia nervosa is taken, a correlation can be seen between the number of diagnosed cases and athletes of specific sports.  Anorexia nervosa is more commonly seen in athletes who partake in sports that exist with the view point that a leaner appearance enhances performance.  Such sports include gymnastics, ballet, running, body building, and wrestling.

Characteristics/Clinical Presentation

Anorexia nervosa typically develops in adolescence around the onset of puberty.  This is believed to develop due to the increased deposition of fat that commonly coincides with puberty.  Adolescents are more likely to succumb to peer pressure and societal pressures to be thin at this age.  An increased awareness of body shape and size is also present at this age period.  Early recognition of anorexia nervosa is very important in order to prevent the devastating physical and emotional symptoms caused by starvation, malnutrition, and purging.

The following characteristics can be present in individuals with anorexia nervosa, however not all signs and symptoms may be present at the same time in one individual. 

• Restriction of food eaten or calories eaten
• Excessive exercise to the point of exhaustion
• Use of laxatives, enemas, or diuretics to restrict weight gain
• Elaborate preparation of meals with refusal to eat
• Increased preoccupation with food
• Excessive gum chewing
• Self isolation or decreased interest in social activities
• Decreased motivation
• Decreased sexual interest
• Mood changes especially depression, irritability,anxiety, or apathy

The following physical symptoms may be present in individuals with anorexia nervosa:

• Severe weight loss
• Abnormal blood counts
• Increased fatigue, insomnia, or dizziness
• Brittle hair and nails
• Amenorrhea
• Irregular heart rhythms
• Low blood pressure
• Edema in the distal extremities or face
• Osteoporosis
• Enlarged ventricles and sulci as seen by CT scans
• Sore throat
• Chest pain
• Calluses on dorsum of the hand (Russell's Sign)
• Dental erosion from gastric acids
• Electrolyte imbalances (Potassium, Sodium, Hydrogen Chloride, and Magnesium)
• Proximal muscle weakness with use of ipecac
• Abnormal muscle biopsy and electromyograph
• Gait disturbances
• Muscle tetany
• Peripheral paresthesia
• Obsessive-compulsive behaviors

Associated Co-morbidities

Death is the most devastating co-morbidity present with this eating disorder and most commonly occurs due to symptoms of starvation or suicide.  Medical conditions typically causing death consist of abnormal heart rhythms and imbalances of electrolytes.  Mortality rates are as high as 5.9% in anorexia nervosa diagnoses.

Co-morbid conditions present in individuals with anorexia nervosa may also include "major depressive disorder (50-75% of cases), sexual abuse (20-50% of cases), obsessive compulsive disorder (25% of cases), substance abuse (12-18% of cases), and bipolar disorder (4-13% of cases)".

Anemia, mitral valve prolapse, osteoporosis, and stress fractures are examples of co-morbidities that may be present with any eating disorders.  Many individuals with anorexia nervosa often develop other types of eating disorders as well.  Up to 50% of individuals with anorexia nervosa develop characteristics of bulimia nervosa over the span of their lifetime.

Medications

Currently the best evidence shows that selective serotonin reuptake inhibitors (SSRIs) demonstrate the most statistically and clinically significant positive effects in the treatment of anorexia nervosa. This medication has shown to improve mood, reduce obsessive behaviors, and satisfy hunger.   Little research has been done on the use and efficacy of other medications in the treatment of anorexia nervosa.  The following medications have been researched in treatment for signs and symptoms of anorexia nervosa:

• Antipsychotic drug chlorpromazine: Current standards do not consider this medication adequate for treatment.
• Antipsychotic drugs pimozide and sulpiride: Evidenced negative outcomes in RCTs and solely used in rare cases in the treatment of resistant clients.
• Lithium Carbonate: Rarely used in this population due to increased risk of cardiovascular events and fluid/electrolyte imbalance.
• Antidepressant drug clomipramine: Evidenced negative results in RCTs.
• Antidepressant drug amitriptyline: Evidenced positive results when used at 175mg in RCTs.

Diagnostic Tests/Lab Tests/Lab Values

Physical examination of the patient's height, weight, vitals, skin and nail observation, auscultation of heart and lung sounds, and abdominal palpation must be completed routinely throughout treatment. 

Lab tests that are commonly ran in patients with anorexia nervosa to determine if visceral dysfunction is present include a complete blood count (CBC), basic metabolic profile (BMP), BUN, and urinalysis. 

Radiological tests that are done upon admission include X-Ray, Electrocardiogram (ECG), and bone density (DEXA) scan. 

Causes

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Systemic Involvement

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Medical Management (current best evidence)

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Physical Therapy Management (current best evidence)

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Alternative/Holistic Management (current best evidence)

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Differential Diagnosis

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Case Reports

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Resources

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Recent Related Research (from Pubmed)

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References

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