You are in: eMedicine Specialties > Emergency Medicine > PSYCHOSOCIAL Anorexia NervosaArticle Last Updated: Aug 1, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 10
  Author: Tracy A Farkas, MD, Staff Physician, Harvard Affiliated Emergency Medicine Residency, Department of Emergency Medicine, Brigham and Women's Hospital and Massachusetts General Hospital Tracy A Farkas is a member of the following medical societies: American College of Emergency Physicians, American Medical Women's Association, Emergency Medicine Residents Association, and Society for Academic Emergency Medicine Coauthor(s): Ron Waldrop, MD, Assistant Professor, Department of Emergency Medicine, Louisiana State University, Our Lady of the Lake Regional Medical Center Editors: Edward Bessman, MD, Chairman, Department of Emergency Medicine, John Hopkins Bayview Medical Center; Assistant Professor, Department of Emergency Medicine, Johns Hopkins University; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Robert C Harwood, MD, MPH, Program Director, Chair, Department of Emergency Medicine, Christ Hospital and Medical Center; Assistant Professor, Department of Emergency Medicine, University of Illinois at Chicago Medical School; John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center; Jonathan Adler, MD, Attending Physician, Department of Emergency Medicine, Massachusetts General Hospital; Division of Emergency Medicine, Harvard Medical School Author and Editor Disclosure Synonyms and related keywords: self-starvation, malnutrition, severe weight loss, extreme weight loss, life-threatening weight loss, amenorrhea, eating disorder, intense fear of obesity, primary amenorrhea, secondary amenorrhea, denial of hunger, asexual behavior, depression, obsessive-compulsive behavior, developmental immaturity, binge behavior, purge behavior, anxiety disorder, hypoglycemia, vitamin deficiencies, delayed puberty, anovulation, INTRODUCTIONSection 2 of 10
  BackgroundAnorexia 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:
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. PathophysiologyAnorexia 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. FrequencyUnited StatesThe 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. InternationalAnorexia 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/MorbidityAnorexia 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. RaceAnorexia 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. SexFemale-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. AgeAnorexia 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. CLINICALSection 3 of 10
HistoryPatients 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.
PhysicalPatients may present anywhere along the spectrum of weight loss. They may attempt to hide their weight loss by wearing bulky clothing or many layers.
CausesAnorexia nervosa is a complex combination of biological, psychological, and social factors, which have devastating physical and mental consequences.
DIFFERENTIALSSection 4 of 10
Adrenal Insufficiency and Adrenal Crisis Alcohol and Substance Abuse Evaluation Anxiety Constipation Depression and Suicide Diabetes Mellitus, Type 1 - A Review Diabetes Mellitus, Type 2 - A Review Hyperthyroidism, Thyroid Storm, and Graves Disease Hypokalemia Inflammatory Bowel Disease Mitral Valve Prolapse Pediatrics, Dehydration Pediatrics, Diabetic Ketoacidosis Shock, Hypovolemic Sinus Bradycardia
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| Drug Name | Potassium chloride |
|---|---|
| Description | Essential for transmission of nerve impulses, contraction of cardiac muscle, maintenance of intracellular tonicity, skeletal and smooth muscles, and maintenance of normal renal function. Gradual potassium depletion occurs via renal excretion or GI loss or because of low intake. Depletion usually results from diuretic therapy, primary or secondary hyperaldosteronism, diabetic ketoacidosis, severe diarrhea (if associated with vomiting), or inadequate replacement during prolonged parenteral nutrition. Potassium depletion sufficient to cause 1 mEq/L drop in the serum potassium level requires a loss of approximately 100-200 mEq of potassium from the total body store. |
| Adult Dose | Serum levels >2.5 mEq/L: 10 mEq IV over 1 h, then prn based on frequently obtained lab values; not to exceed 200 mEq/d Serum levels <2.5 mEq/L: 40 mEq IV over 1 h, then prn based on frequently obtained lab values; not to exceed 400 mEq/d Must dilute IV prior to administration |
| Pediatric Dose | Emergent situation: IV: 0.5-1 mEq/kg over 1-2 h initially; maximum dose not to exceed 40 mEq/dose May repeat prn based on frequently obtained lab values; must dilute IV prior to administration; administer in ED or ICU with ECG monitoring PO: 2-5 mEq/kg/d based on primary disease; sometimes requires up to 10 mEq/kg/d |
| Contraindications | Hyperkalemia, renal failure, and conditions in which potassium retention is present and those with oliguria or azotemia, crush injuries, severe hemolytic reactions, anuria, and adrenocortical insufficiency |
| Interactions | Concurrent use with ACE inhibitors may result in elevated serum potassium concentrations; potassium-sparing diuretics and potassium-containing salt substitutes can produce severe hyperkalemia; inpatients taking digoxin, hypokalemia may result in digoxin toxicity; caution if discontinuing potassium administration in patients maintained on digoxin |
| Pregnancy | A - Safe in pregnancy |
| Precautions | Do not infuse rapidly; high plasma concentrations of potassium may cause death due to cardiac depression, arrhythmias, or arrest; plasma levels do not necessarily reflect tissue levels; monitor potassium replacement therapy whenever possible by continuous or serial ECG; when a concentration > 40 mEq/L is infused, local pain and phlebitis may also follow |
| 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 |
Article Last Updated: Aug 1, 2006
