INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

Anorexia nervosa is a psychiatric disorder characterized by the refusal to maintain a minimally normal weight, often with severe physiologic consequences. Patients have a profoundly disturbed body image as well as an intense fear of weight gain despite being severely underweight.

Diagnostic criteria for anorexia nervosa in the Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV) include the following:

• 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)
• Intense fear of gaining weight or becoming fat
• Disturbance in the way one's body weight or shape is experienced, with denial of current low body weight
• Amenorrhea in postmenarcheal females of at least 3 menstrual cycles

The disorder may be further divided into 2 subtypes: (1) restricting, in which severe limitation of food intake is the primary means to weight loss, and (2) binge-eating/purging type, in which there are periods of food intake that are compensated by self-induced vomiting, laxative or diuretic abuse, or excessive exercise.

Other physiologic causes of malnutrition, weight loss, and amenorrhea must be ruled out to make the diagnosis.

Patients with anorexia nervosa often display other personality characteristics such as a desire for perfection, academic success, lack of age-appropriate sexual activity, and a denial of hunger in the face of starvation. Psychiatric characteristics include excessive dependency needs, developmental immaturity, social isolation, obsessive-compulsive behavior, and constriction of affect. Many patients also have comorbid mood disorders, with depression and dysthymic disorder being most prevalent.

Pathophysiology

Anorexia nervosa is the result of a complex interplay between biological, psychological, and social factors, which tend to affect women more than men, and adolescents more than older women. Some evidence suggests a higher rate of the disorder in monozygotic twins than in dizygotic twins, which may indicate a biologic predisposition.

Psychologically, prepubescent patients who subsequently develop anorexia nervosa have a high incidence of premorbid anxiety disorders. The onset of the disorder during puberty has led to the theory that, by exerting control over food intake and body weight, adolescents are attempting to compensate for a lack of autonomy and selfhood.

The patient's altered body image results in a perception of fatness despite being normal or underweight. Attempts to correct this flaw through food restriction or purging lead to progressive starvation. Modern preoccupation with slenderness and beauty in the Western world may contribute to the mindset of slenderness as a valued quality in adolescents; however, this link has not been proven.

Malnutrition subsequent to self-starvation leads to protein deficiency and disruption of multiple organ systems. In addition to hypoglycemia and vitamin deficiencies, starvation results in release of endogenous opioids, hypercortisolemia, and thyroid function suppression. Neuroendocrine disturbances result in delayed puberty, amenorrhea, anovulation, low estrogen states, increased growth hormone, decreased antidiuretic hormone, hypercarotenemia, and hypothermia. Decreased gonadotropin levels and hypogonadism may occur among males who are affected.

Cardiovascular effects include mitral valve prolapse, supraventricular and ventricular dysrhythmias, long QT syndrome, bradycardia, orthostatic hypotension, and shock due to congestive heart failure.

Renal disturbances include decreased glomerular filtration rate (GFR), elevated BUN, edema, acidosis with dehydration, hypokalemia, hypochloremic alkalosis with vomiting, and hyperaldosteronism.

Gastrointestinal findings include constipation, delayed gastric emptying, and gastric dilation and rupture. Patients who induce vomiting develop dental enamel erosion, palatal trauma, enlarged parotids, esophagitis, Mallory-Weiss lesions, and elevated transaminases.

Frequency

United States

The lifetime prevalence of anorexia nervosa in the United States is estimated at 0.3-1%; however, some studies have shown rates as high as 4% among women. The rates among men are estimated at 0.1%. As many as 5% of young women exhibit symptoms of anorexia but do not meet full diagnostic criteria.

International

Anorexia nervosa is found in all developed countries and in all socioeconomic classes at similar rates (0.3-1% in women, 0.1% in men).

Mortality/Morbidity

Anorexia nervosa has one of the highest mortality rates of all psychiatric disorders, with rates reported from 5-18%. Patients with restricting subtype tend to have more resistance to recovery.

Approximately 50% of patients will recover with treatment and maintain a normal weight but often not without relapses and multiple treatment modalities. Mortality is often due to suicide and less frequently to complications of starvation.

Race

Anorexia nervosa is significantly more frequent in white populations than in people of other races, but it has been reported among all races.

A link between socioeconomic class and prevalence of eating disorders has not been demonstrated in the literature.

Sex

Female-to-male ratio is 10-20:1 in developed countries.

In some professions, the frequency is much higher among men (wrestling, running, modeling) than the general male population.

Age

Anorexia nervosa is primarily a phenomenon of puberty and early adulthood. Eighty-five percent of patients have onset of the disorder between the ages of 13 and 18 years.

Anorexia nervosa has been observed in both the very young and very old. Patients who are older at the time of onset of the disorder have a worse prognosis.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

Patients may present to the ED with extreme weight loss, food refusal, dehydration, weakness, or shock. Many present at the urging of family members or friends and are in deep denial of their malnutrition and illness.

• Patients should be questioned about their current weight, highest weight, lowest weight, exercise habits, and menstrual cycles. Further questioning should inquire with regard to eating habits, presence or absence of self-induced vomiting/binge eating, etc.
• Major depression and dysthymic disorder have been reported in up to 50% of patients with anorexia nervosa. Patients should be asked about early morning awakening, tearfulness, and thoughts of suicide or a plan.
• Review of systems is often positive for constipation, early satiety, hypothermia, nausea, hair loss, and fatigue.

Physical

Patients may present anywhere along the spectrum of weight loss. They may attempt to hide their weight loss by wearing bulky clothing or many layers.

• Physical examination may reveal hypothermia, peripheral edema, thinning hair, and obvious emaciation.
• Behaviorally, a patient may demonstrate a flat affect and display psychomotor retardation, especially in the later stages of the disease.
• Vital sign abnormalities may include hypothermia, bradycardia, and hypotension.
• Cardiac examination may reveal the mid-systolic click of mitral valve prolapse.
• Patients with purging behavior may have parotid gland hypertrophy, dental enamel erosion and, in extreme cases, seizures from electrolyte disturbances.
• Dermatologic examination reveals dry skin, lanugo (a fine, downy covering of hair on the extremities), and poor skin turgor.

Causes

Anorexia nervosa is a complex combination of biological, psychological, and social factors, which have devastating physical and mental consequences.

• Some evidence suggests that biologic risk factors include a first-degree relative with an eating disorder and higher rates of the disorder in monozygotic than dizygotic twins.
• A psychological profile often demonstrates premorbid anxiety disorders as well as more severe affective disorders such as major depression and dysthymic disorder. Patients may also have symptoms of obsessive-compulsive disorder, with rigid and ritualistic eating behaviors.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Other Problems to be Considered

Chronic gastrointestinal infections
Malabsorption
Malignancies

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Lab Studies

• No definitive diagnostic tests are available for anorexia nervosa; however, given the multiorgan system effects of starvation, a thorough medical evaluation is warranted.
• • A chemistry panel should be assessed for hypokalemic, hypocalcemic metabolic alkalosis caused by vomiting. Ionized calcium levels should detect hypocalcemia.
  • Hyponatremia may be seen due to excess water intake.
  • Low serum phosphorus levels less than 0.8 mmol/L should be repleted.
  • Liver function tests may be slightly elevated, but albumin and protein levels are usually normal.
  • A complete blood count may reveal a mild leukopenia secondary to margination as well as thrombocytopenia. Hemoglobin may be elevated with extreme dehydration, but it is generally normal.
  • Fecal occult blood may be indicative of esophagitis, gastritis, or repetitive colonic trauma from laxative abuse.
  • Although it will not likely effect emergency department management, further studies such as erythrocyte sedimentation rate (ESR) and serum cholesterol level may be helpful.
  • Thyroid function tests, prolactin, and serum follicle-stimulating hormone levels can differentiate anorexia nervosa from alternative causes of primary amenorrhea.

Imaging Studies

• Chest radiograph may reveal rib fractures from repetitive vomiting in the presence of hypocalcemia. Patients may also show evidence of osteopenia. Imaging is rarely necessary in the emergency department.
• Radiographic evidence of emphysematous changes is present on the chest CT scan of patients with anorexia; however, unlike with COPD, these changes resolve with refeeding and weight normalization. Chest CT is not generally indicated as part of the ED evaluation.

Other Tests

• ECG is helpful in evaluating the severity of malnutrition and risk for dysrhythmias in patients with metabolic abnormalities.
• ECG findings are nonspecific but may include bradycardia and prolonged QT interval.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Prehospital Care

Prehospital care of a patient with anorexia nervosa includes stabilization for any life-threatening conditions (eg, shock, cardiac arrhythmias) and basics such as airway, breathing, and circulatory support as needed.

Emergency Department Care

Emergency care of anorexia nervosa should include a basic medical evaluation as well as urgent or timely outpatient psychiatric evaluation.

• Basic tests include physical and mental status evaluation, CBC, chemistry, calcium, magnesium, phosphorus, urinalysis, HCG in women, and electrocardiogram.
• Metabolic abnormalities should be corrected as needed, with oral or parenteral treatment depending on the patient's mental status and decision to cooperate.
• Life-threatening or potentially lethal abnormalities require admission. Indications for hospitalization include the following:
• • Bradycardia or other cardiac dysrhythmias
  • Severe electrolyte abnormalities, especially of potassium, sodium, and phosphorus levels
  • Altered mental status or suicidality
  • Extremely low body weight
  • Failure of outpatient treatment

Consultations

Most cases of anorexia nervosa encountered in the emergency department will be appropriate for outpatient management if close, planned follow-up is arranged prior to discharge.

• Consultation with the pediatrician or primary care physician is necessary to arrange follow-up. Urgency of follow-up depends on the patient's condition and how soon they will need their laboratory studies reevaluated.
• Psychiatric consultation in the emergency department should be considered for patients expressing suicidality, psychosis, or severely disordered thinking.
• Outpatient psychiatric follow-up is necessary and may be arranged either from the ED or by the primary care provider.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical therapy in the emergency department consists of electrolyte repletion and stabilization.

Multiple studies have failed to show an overall benefit for pharmacologic treatment of anorexia nervosa with psychiatric medications. However, most patients who recover will be treated with a multidisciplinary approach including medication, psychotherapy, nutritional counseling, and frequent medical evaluations. The most common class studied is SSRIs, which have been shown to be beneficial in patients with bulimia nervosa but not anorexia. However, since many patients with anorexia have concurrent mood disorders, medication may be of benefit.

Drug Category: Electrolyte repletion

Necessary in patients with profound malnutrition, dehydration, and purging behaviors.

May be repleted orally or parenterally, depending on the clinical state of the patient.

Drug Name	Calcium gluconate
Description	Moderates nerve and muscle performance and facilitates normal cardiac function. Can be given IV initially, and calcium levels maintained with high calcium diet. Some patients require oral calcium supplementation. The 10% IV solution provides 100 mg/mL of calcium gluconate that equals 9 mg/mL (0.46 mEq/mL) of elemental calcium. One 10 mL ampule contains 93 mg of elemental calcium
Adult Dose	100-300 mg elemental calcium IV diluted in 150 mL D5W over 10 min; initial rate of infusion should be 0.3-2 mg of elemental calcium/kg/h
Pediatric Dose	2 mg/kg of elemental calcium IV (about 20 mg/kg of calcium gluconate 10%)
Contraindications	2 mg/kg of elemental calcium IV (about 20 mg/kg of calcium gluconate 10%)
Interactions	May decrease effects of tetracyclines, atenolol, salicylates, iron salts, and fluoroquinolones; antagonizes effects of verapamil; large intakes of dietary fiber may decrease calcium absorption and levels
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Caution in digitalized patients, respiratory failure, acidosis, or severe hyperphosphatemia

Drug Name	Potassium phosphate
Description	For severe hypophosphatemia ( <1 mg/dL), parenteral preparations of phosphate should be used for repletion. IV preparations are available as sodium or potassium phosphate (K2PO4). Response to IV serum phosphorus supplementation is highly variable and is associated with hyperphosphatemia, and hypocalcemia. The rate of infusion and choice of initial dosage should be based on severity of hypophosphatemia and presence of symptoms. Serum phosphate and calcium should be monitored closely. For less severe hypophosphatemia (1-2 mg/dL), PO phosphate salt preparations can be used. PO preparations are available as sodium or potassium phosphate in capsule or liquid form. Neutra-Phos packets contain 250 mg of phosphorus/packet. Tablets contain either 250, 125.6, or 114 mg each. Liquid preparations available as 250 mg/75 mL.
Adult Dose	8 mmol of K2PO4 q6h IV or 0.1 mmol/kg of K2PO4 or Na2PO4 q6h IV (32 mmol/24h) initially Aggressive IV replacement: 15 mmol of K2PO4 over 6 h or 0.2-0.3 mmol/kg of K2PO4 or Na2PO4 over 6 h For oral replacement, 250 mg as capsule, liquid, or packet tid/qid is generally adequate; for most patients, once phosphate stores are repleted, PO supplements are no longer required, as the diet has ample phosphate
Pediatric Dose	0.25-0.5 mmol/kg IV over 4-6 h and repeat if symptomatic hypophosphatemia persists
Contraindications	Do not administer if patient diagnosed with hyperphosphatemia, hypocalcemia, hypomagnesemia, hyperkalemia, or renal failure
Interactions	Magnesium and aluminum-containing antacids or sucralfate can act as phosphate binders and decrease serum phosphate levels; potassium-sparing diuretics, ACE inhibitors, and salt substitutes may increase serum phosphate levels
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Caution in patients with renal insufficiency and metabolic alkalosis; admixture of phosphate and calcium in IV fluids can result in calcium phosphate precipitation

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Further Inpatient Care

• Patients may require a medical admission if they are extremely ill or have cardiac dysrhythmias or severe metabolic abnormalities.
• Most patients will either be admitted to psychiatric facilities both for refeeding and counseling or be managed as outpatients.

Further Outpatient Care

• Close follow-up with the primary care physician is very important. Patients should have their weight and electrolytes checked within a week of their emergency department visit.
• Outpatient psychiatric treatment should be arranged as soon as possible from either the emergency department or a primary care referral.

Complications

• Patients with anorexia nervosa are at risk for complications related to nutritional and electrolyte imbalances, as well as long-term social and interpersonal difficulties due to their disorder.
• Physiologic complications involve nearly every organ system.
• • Fluid and electrolyte imbalances include hypokalemia, hyponatremia, hypochloremia, metabolic alkalosis, elevated BUN, decreased GFR, and ketonuria.
  • Cardiovascular complications range from bradycardia, orthostatic hypotension, prolonged QT interval, low voltage, and mitral valve prolapse, to frank congestive heart failure and dysrhythmias.
  • Gastrointestinal effects include constipation, bloating, early satiety, parotid gland hypertrophy, delayed gastric emptying, Mallory-Weiss tears, esophageal perforation, fatty liver infiltration, gallstones, and pancreatitis.
  • Hematologic findings include anemia, leukopenia, thrombocytopenia, and impaired immunity.
  • Endocrine problems due to starvation involve growth retardation, delayed puberty, amenorrhea, low T3 level, hypercortisolemia, and diabetes insipidus.
  • Dermatologic complications include acrocyanosis, hypercarotenemia, brittle hair and nails, hair loss, lanugo, and pitting edema.
  • Neurologically, patients may develop peripheral neuropathy, seizures, and cortical atrophy. Psychologically, patients are at risk for isolation, depression, and suicide in addition to their disordered thought patterns regarding food and weight.
• The process of refeeding must be undertaken slowly, with modest increases in metabolic demands to avoid heart failure and a "refeeding syndrome" including life-threatening dysrhythmias and hypophosphatemia. Ideal weight gain should occur at a rate of 1-2 lb per week.

Prognosis

• The prognosis for recovery from anorexia nervosa is multifactorial. Overall, the prognosis has not changed much over the past 50 years. In one large meta-analysis, 47% of patients fully recovered; 33% improved somewhat; and 20% developed chronic, relapsing anorexia.
• Patients with later age at onset of the disorder, binge-purge behavior, and concurrent mood disorders have a worse prognosis for full recovery.

Patient Education

• For excellent patient education resources, visit eMedicine's Eating Disorders Center and Women's Health Center. Also, see eMedicine's patient education articles Anorexia Nervosa and Amenorrhea.
• National Association of Anorexia Nervosa and Associated Disorders (ANAD)
• National Eating Disorders Association (NEDA)
• Anorexia Nervosa and Related Eating Disorders (ANRED)

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• As with all psychiatric and behavioral emergencies, care must be taken to prove and document competency upon discharge. Many patients with anorexia nervosa may have underlying psychopathology, which leaves them incapacitated during an anorexic crisis. If doubt remains, the patient must be admitted for more thorough psychiatric and physiologic monitoring or discharged in the care of a competent adult.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

• American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 4th ed. Washington DC: American Psychiatric Association;1994:539-545.
• Becker AE, Grinspoon SK, Klibanski A, Herzog DB. Eating disorders. N Engl J Med. Apr 8 1999;340(14):1092-8. [Medline].
• Bochereau D, Clervoy P, Corcos M, Girardon N. [Eating disorders. Anorexia nervosa in adolescents]. Presse Med. Jan 16 1999;28(2):89-99. [Medline].
• Coxson HO, Chan IH, Mayo JR. Early emphysema in patients with anorexia nervosa. Am J Respir Crit Care Med. Oct 1 2004;170(7):748-52. [Medline].
• Deep AL, Nagy LM, Weltzin TE, et al. Premorbid onset of psychopathology in long-term recovered anorexia nervosa. Int J Eat Disord. Apr 1995;17(3):291-7. [Medline].
• Forman, S. Eating Disorders: epidemiology, pathogenesis, and clinical features. Up to Date. 2005;[Full Text].
• Hartman D. Anorexia nervosa--diagnosis, aetiology, and treatment. Postgrad Med J. Dec 1995;71(842):712-6. [Medline].
• Hoek HW, van Hoeken D. Review of the prevalence and incidence of eating disorders. Int J Eat Disord. Dec 2003;34(4):383-96. [Medline].
• Kaplan, H, Sadock, B. Synopsis of Psychiatry. -8th ed. Williams and Wilkins;. 1998:720-727.
• Lavelle JM. Adolescent emergencies. In: Fleischer GR, Ludwig S, eds. Textbook of Pediatric Emergency Medicine. Philadelphia: Lippincott Williams & Wilkins;1993:1503-1526. [Medline].
• Miller KK, Grinspoon SK, Ciampa J. Medical findings in outpatients with anorexia nervosa. Arch Intern Med. Mar 14 2005;165(5):561-6. [Medline].
• Nilsson EW, Gillberg C, Rastam M. Familial factors in anorexia nervosa: a community-based study. Compr Psychiatry. Nov-Dec 1998;39(6):392-9. [Medline].
• Rosenblum J, Forman S. Evidence-based treatment of eating disorders. Curr Opin Pediatr. Aug 2002;14(4):379-83. [Medline].
• Steinhausen HC. The outcome of anorexia nervosa in the 20th century. Am J Psychiatry. Aug 2002;159(8):1284-93. [Medline].
• Stoving RK, Hangaard J, Hansen-Nord M, et al. A review of endocrine changes in anorexia nervosa. J Psychiatr Res. Mar-Apr 1999;33(2):139-52. [Medline].
• Vazquez M, Olivares JL, Fleta J, et al. Cardiac disorders in young women with anorexia nervosa. Rev Esp Cardiol. Jul 2003;56(7):669-73. [Medline].

Article Last Updated: Aug 1, 2006