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A. Introduction and Definitionsnavigator

  1. Around 3% of young women in Western socieites have some significant eating disorder
  2. Entities
    1. Anorexia nervosa - body weight <85% of expected or BMI <17.6, fear of weight gain
    2. Bulimia nervosa - recurrent binge eating and recurrent purging, fasting, intense exercise
    3. Binge-eating disorder - recurrent binge eating without purging, abnormal eating habits
  3. Typically occur in girls
    1. Mainly in Western societies and mainly in white persons
    2. Anorexia: adolescents > young adults
    3. Bulimia: young adults > adolescents
    4. About 10% of cases of anorexia nervosa and bulimia nervosa occur in males
    5. About 40% of cases of binge-eating disorder occur males
  4. Complete assessment for eating disorders covers broad range of areas
    1. Medical
    2. Nutritional
    3. Psychological
    4. Social
  5. Very serious conditions with potential for fatal outcome [4]
  6. Pathogenesis poorly understood; genetic component implicated
  7. Current interventions are of suboptimal benefit [4]

B. Signs and Symptoms of Eating Disordersnavigator

  1. Somatic
    1. Arrested growth
    2. Marked change or variation in weight
    3. Not able to gain weight
    4. Fatigue
    5. Constipation or diarrhea
    6. Increased bone fractures
    7. Delayed menarche, oligomenorrhea, or other menstrual irregularities
    8. Electrolyte disorders: hypokalemia, hyperphosphatemia, acid/base disorders
    9. Amylase elevations (salivary component)
    10. Electrocardiographic (ECG) abnormalities: low voltage, prolonged QTc, U waves
    11. Osteopenia related to weight loss and estrogen deficiency (mainly with anorexia)
  2. Behavioral
    1. Change in eating habits
    2. Difficulty eating in social settings
    3. Reluctance to have weight measured
    4. Depression
    5. Social withdrawal
    6. Absence from school or work
    7. Deceptive or secretive behavior / paranoia
    8. Stealing to obtain food
    9. Substance abuse
    10. Excessive exercise

C. Characteristics and Diagnosis of Anorexia Nervosa [1,2,3,5] navigator

  1. Eating disorder with fear of fatness
    1. Intense fear of obesity, even when weight loss has occurred
    2. Disturbances of body image (inaccurate perceptions) - "feel fat"
  2. Weight loss from self induced starvation
    1. Body weight <85% of expected or BMI <17.6
    2. Must include projected growth in <18 years old
    3. Refusal to maintain normal body weight
    4. No other illness as explanation for decreased weight
  3. May be accompanied by bulimia - purging behavior with or without binge eating
  4. Sexual Dysfunction
    1. Absence of menstrual periods in females after menarche for 3 consecutive months
    2. Decreased sexual drive in men
  5. Usually affects young females
  6. Genetics of Anorexia
    1. Serotonin receptor HT2A polymorphisms have been studied
    2. HT2A-R A allele linked to anorexia nervosa, OCD, but not to bulimia [6,7,8]
    3. This polymorphism is overrepresented in restricting type anorexia (not purging type)
    4. Given the response of anorexia to some serotonergic drugs, this finding is interesting
  7. Coexisting Psychiatric Conditions
    1. Dysthymia or depression in >50%
    2. Anxiety disorder in >60%
    3. Obsessive compulsive disorder (OCD) in >40%
    4. Alcohol or substance abuse in ~20%
  8. ~1/3 improve, ~1/3 remain stable at reduced weight, ~1/3 worsen or die

D. Characteristics and Diagnosis of Bulimia Nervosa [1,5,13]navigator

  1. Episodes of compulsive overeating - "Binge"
    1. Must occur at least two times per week for three months
    2. Binge is consumption of unusually large quantity of food during discrete time period
    3. Depressed mood and self deprecating thoughts following eating binges
  2. May be followed by a "Purge" action
    1. Self induced vomiting
    2. Laxative
    3. Diuretics
    4. Strenuous exercise or fasting may replace or add to purge
  3. Excessive concern about body weight or shape
  4. May progress from anorexia but anorexia cannot be present for this diagnosis to be made
  5. Often normal or slightly overweight
  6. Rumination may be Present [9]
    1. Rumination is repetative regurgitation of small amounts of food from stomach
    2. Occurs in ~20% of patients with bulimia
    3. Bulimics tend to expel food out of their mouths when they ruminate
  7. Complications of Induced Vomiting
    1. Dental caries
    2. Esophagitis
    3. Hematemesis - especially with Mallory-Weiss Tear
    4. Gastric dilatation and rupture
    5. Elevated serum amylase level / parotid swelling
    6. Metabolic alkalosis
    7. Hypokalemia - may be severe and require hospitalization
    8. Hand abrasions
  8. Mechanisms [10]
    1. Afferent vagal hyperactivity may be involved in this disorder
    2. These patients have loss of normal satiety, normally mediated by the vagus nerve
    3. Serotonin actions mediated through the 5-HT3 receptor stimulate vagal inputs
    4. Blockade of 5-HT3 receptors with ondansetron has shown efficacy in bulimia

E. Binge Eating Disorder [1,5]navigator

  1. Recurrent binge eating
  2. Marked distress with at least three of the following:
    1. Eating very rapidly
    2. Eating until uncomfortably full
    3. Eating when not hungry
    4. Eating alone
    5. Feeling disgusted or guilty after a binge
  3. No recurrent purging, excessive exercise, or fasting
  4. Absence of anorexia nervosa

F. Endocrinology of Weight Control [11] navigator

  1. Key control elements in weight regulation
    1. HPA Axis
    2. Leptin System
    3. Insulin
    4. Neuropeptide Y
    5. Autonomic Nervous System
  2. Anorexic Responses [14]
    1. In starvation, CRH levels are reduced or unchanged
    2. During starvation, leptin and insulin levels fall, and glucocorticoid levels rise
    3. Leptin itself appears to be responsible for the starvation-induced changes in neuroendocrine axes
    4. These changes include low reproductive, thyroid and insulin-like growth factor (IGF-1) levels
    5. Neuropeptide Y (NP-Y) levels are also increased
    6. Neuropeptide Y (NP-Y) - stimulates food intake, favors synthesis and storage of fat
    7. Most catabolic hormone levels increase in starvation (serotonin, urocortin, MSH, others)
    8. Plasma leptin levels correlate very well with body fat stores
    9. Insulin blood levels correlate with body fat stores
  3. When dieting stops, leptin levels remain low, stimulating weight gain
  4. Diet induced weight loss causes leptin levels to fall as body fat stores decline

G. Some Complications of Severe Weight Lossnavigator

  1. Arrhythmias
    1. Many patients have bradycardia
    2. QTc prolongation is most common serious finding
    3. Ventricular arrhythmias are most common cause of death in eating disorders
    4. Hypokalemia frequently complicates bulimia and predisposes to severe arrhythmias
  2. Osteoporosis
    1. Not (solely) due to estrogen deficiency
    2. Unclear etiology
    3. May require aggressive treatment with bisphosphonates or calcitonin
  3. Amenorrhea or oligomenorrhea
  4. Infertility
  5. Dental caries (perimolysis)
  6. Parotid gland enlargement
  7. Growth arrest / delayed development / delayed puberty
  8. Cytopenias

H. Treatment navigator

  1. Routine Laboratory Evaluations [3]
    1. Complete blood count
    2. Urinalysis
    3. Serum electrolytes
    4. BUN and creatinine
    5. Thyrotropin (TSH)
    6. Phosphate
    7. Fasting glucose
    8. Consider: amylase, calcium, magnesium, liver function
    9. Consider electrocardiogram to assess QTc interval, presence of arrhythmias
  2. Bulimia easier to treat than anorexia [13]
    1. Eating disorder clinic to initiate dietary modification
    2. Cognitive-behavioral therapy is clearly effective in bulimia nervosa
    3. Combining cognitive-behavioral with pharmacologic therapy is most effective
    4. Caution with moderate and severe disorders due to "refeeding syndrome"
    5. Generally increase calories to 800-1000/day initially for 1-2 weeks
    6. Then increase by 200-300 calories per day to 2000-3000 calories/day
    7. Once goal weight is attained, may reduce caloric intake somewhat
  3. Psychotherapy and Behavior Modification
    1. Focus on establishing diagnosis and identifying concurrent psychiatric illness
    2. Evaluate risk of suicide
    3. Explore social context of symptoms
    4. Encourage patient that menses will return in 4-6 months with weight normalization
    5. Cognitive behavior therapy is probably most effecdtive for bulimia
    6. Family based therapy for adolescents is moderately effective for anorexic adolescents
  4. Selective Serotonin Reuptake Inhibitors (SSRI)
    1. Appear effective at high dose despite suppressing appetite
    2. Fluoxetine (Prozac®) - no benefit as maintenance therapy in anorexia after weight regain [15]
    3. Paroxitine (Paxil®)
    4. Fluvoxamine (Luvox®)
    5. Sertraline (Zoloft®)
    6. Main efficacy is acutely for bulimia nervosa and binge eating disorder
    7. Effective alone in ~30-40% of patients with bulimia [13]
  5. Ondansetron (Zofran®) [10]
    1. Selective inhibitor of serotonin 5-HT3 receptor
    2. Reduced binge/vomiting episodes from 13.2 to 6.5 per week versus placebo
    3. Also increased number of normal meals (without vomiting) per week from 0.2 to 4.2
    4. Dose is 24mg po qd and is well tolerated
    5. Likely reduces vagal hyperactivity which may be involved in etiology of bulimia
  6. Avoid wellbutrin and tricyclic antidepressants
    1. Especially in patients with bulimia nervosa
    2. There is a higher risk of seizures and arrhythmias due to unstable electrolytes
  7. Osteoporosis Treatment
    1. Particularly vitamin D (400IU/d)
    2. Calcium intake should be 1000-1500mg/day
    3. Estrogen supplements have shown no benefit on osteoporosis in anorexics
    4. Strongly consider bisphosphonates in women at high risk for fractures
  8. Gastrointestinal Transit
    1. Sense of bloating, fullness, constipation may occur on refeeding
    2. Usually, functional (versus psychogenic) constipation resolves within several weeks
    3. Metaclopramide (Reglan®) may be used to improve intestinal transit
    4. Tegaserod (Zelnorm®) has replaced cisparide (Propulsid®) and may improve transit
  9. Hospitalization for severe cases

I. Hospitalizationnavigator

  1. Severe weight loss may be a medical emergency requiring hospital admission
  2. Intravenous hyperalimentation may be required
  3. Indications for Admission of Adults [3]
    1. Weight <75% of ideal weight or rapid weight loss to <80% of ideal
    2. Assess status with weight, % body fat, serum albumin, transferrin, cholesterol
    3. Cardiac disturbances - heart rate <40 bpm or blood pressure <90/60 mm Hg
    4. Electrolyte disturbance - hypokalemia (<3mmol) or hypophosphatemia
    5. Hypothermia - temperature <36.1C (<97°F)
    6. Symptomatic hypoglycemia
    7. Marked dehydration
    8. Severe medical problems
    9. High risk for suicide
  4. Indications for Possible Admission
    1. Ipecac abuse
    2. Severe Fatigue
    3. Unable to evaluate safety or status as outpatient
  5. Indications for Admission of Children and Adolescents [3]
    1. Heart rate <50 bpm or blood pressure <80/50 mm Hg
    2. Orthostatic blood pressure
    3. Hypokalemia or hyposphatemia
    4. Rapid weight loss even if weight is not <75% below normal weight
    5. Symptomatic hypoglycemia
    6. Lack of improvement or worsening despite outpatient treatment
  6. Inpatient Monitoring
    1. Vital Signs and Weight
    2. Electrolytes (including calcium, phosphorus, magnesium)
    3. Fat Soluble Vitamin levels - good marker for malnutrition
    4. No particular nutritional regimen has proved superior
    5. Slow refeeding is important to prevent refeeding syndrome
    6. Monitoring carefully during refeeding for peripheral edema and cardiopulmonary function
  7. Inpatient treatment must include psychotherapy and nutrition counselling
  8. About 50% of patients with severe anorexia had recovered completely within 21 years of first hospitalization (due to anorexia) [12]

References navigator

  1. Fairburn CG and Harrison PJ. 2003. Lancet. 361(9355):407 abstract
  2. Mehler PS. 2001. Ann Intern Med. 134(11):1048 abstract
  3. Yager J and Andersen AE. 2005. NEJM. 353(14):1481 abstract
  4. Ben-Tovim DI, Walker K, Gilchrist P, et al. 2001. Lancet. 357(9264):1254 abstract
  5. Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV). 1994.
  6. Collier DA, Arranz MJ, Li T, et al. 1997. Lancet. 350:412 abstract
  7. Sorbi S, Macmias B, Tedde A, et al. 1998. Lancet. 351(9118):1785 abstract
  8. Enoch MA, Kaye WH, Rotondo A, et al. 1998. Lancet. 351(9118):1785 abstract
  9. Malcolm A, Thumshirn MB, Camilleri M, Williams DE. 1997. Mayo Clin Proc. 72(7):646 abstract
  10. Faris PL, Kim SW, Meller WH, et al. 2000. Lancet. 355(9206):792 abstract
  11. Schwartz MW and Seeley EJ. 1997. NEJM. 336(25):1802 abstract
  12. Zipfel S, Lowe B, Reas DL, et al. 2000. Lancet. 355(9205):721 abstract
  13. Mehler PS. 2003. NEJM. 349(9):875 abstract
  14. Chan JL and Mantzoros CS. 2005. Lancet. 366(9474):74
  15. Walsh BT, Kaplan AS, Attia E, et al. 2006. JAMA. 295(22):2605 abstract