Eating Disorders

I. Problem/Condition.

Eating disorders are characterized by severely disturbed eating behaviors. In both anorexia nervosa and bulimia nervosa, there is a disturbance in the perception of body weight and shape.

Anorexia nervosa is characterized by the refusal or inability to maintain minimally normal body weight, or in adolescents, failure to gain weight during their expected growth period. Onset usually occurs during adolescence.

Bulimia nervosa involves recurrent binge eating episodes with inappropriate compensatory behaviors such as purging, fasting or excessive exercise. This often has a later onset of late adolescence or early adulthood.

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Patients may be diagnosed with eating disorder not otherwise specified if they do not meet the diagnostic criteria for either anorexia nervosa or bulimia nervosa, which comprise the majority of eating disorder patients.

At least 90% of individuals with either anorexia nervosa or bulimia nervosa are female. Some risk factors include dieting or participation in sports or activities that reward low weight (e.g., gymnastics, ballet, wrestling, modeling). The female athlete triad involves disordered eating, amenorrhea and osteoporosis.

II. Diagnostic Approach.

A. What is the differential diagnosis for this problem?

Anorexia nervosa

Severe weight loss might occur in gastrointestinal diseases such as inflammatory bowel disease or celiac disease, infections (i.e., human immunodeficiency virus infection or tuberculosis), but does not include the disturbed body image or fear of gaining weight.

Superior mesenteric artery (SMA) syndrome is usually more a consequence of severe weight loss rather than cause, when the usual fat pad around the SMA diminishes and the duodenum gets trapped between the SMA anteriorly and vertebral column posteriorly, causing vomiting and prandial abdominal pain.

Some endocrine disorders to consider are hyperthyroidism, hypothyroidism, adrenal insufficiency and diabetes mellitus.

Malignancies often present with weight loss, but without the fear of gaining weight.

Decreased appetite can happen in major depressive disorder or odd eating behaviors in schizophrenia resulting in weight loss, but neither are associated with fear of gaining weight. Obsessive-compulsive disorder or anxiety disorders can be in the differential or concomitant conditions.

Body dysmorphic disorder is a severe form of disturbed body image related to obsessive-compulsive disorder, but without the preoccupation with weight. It is just as common in men as it is in women and can occur in patients with anorexia nervosa. Muscle dysmorphia is an impairing preoccupation that one is not lean or muscular enough, more often in men, and associated with altered eating habits.

Bulimia nervosa

Kleine-Levin syndrome consists of disturbed eating behavior but without the self-evaluation of body shape or weight. Individuals with major depressive disorder with atypical features may overeat, but do not compensate for their behavior inappropriately.

B. Describe a diagnostic approach/method to the patient with this problem.

The SCOFF Questionnaire can be used in screening for eating disorders.

  • Do you make yourself sick because you feel uncomfortably full?

  • Do you worry you have lost control over how much you eat?

  • Have you recently lost over one stone (6.3 kg or 14 lb) in a 3 month period?

  • Do you believe yourself to be fat when others say you are too thin?

  • Would you say that food dominates your life?

One point is given for every answer of “yes”, a score greater than or equal to 2 indicates a likelihood of anorexia nervosa or bulimia nervosa.

Diagnosis is mainly derived from a thorough history, asking about weight history, symptoms, behaviors, attitudes towards weight, shape and food.

1. Historical information important in the diagnosis of this problem.

Diet and compensatory behaviors

It would be important to ask about diet and any compensatory behaviors:

  • Exercise – How much? Frequency? How intense?

  • Diet – A typical day’s food diary? Calorie counting? Food restrictions? Fluid and caffeine intake?

  • Binge eating – How often?

  • Purging – Frequency? How? Self-induced vomiting? When in relation to meals?

  • Use of laxatives, diuretics, enemas, stimulants or diet pills?

Review of systems

In general, individuals may feel fatigue or cold intolerance from decreased metabolism and poor perfusion. Dizziness, lightheadedness, syncope or palpitations could suggest orthostatic hypotension or tachycardia.

Recurrent vomiting could cause symptoms of gastroesophageal reflux, chest pain, and tooth sensitivity from loss of dental enamel. Common complaints of postprandial fullness or pain, nausea, constipation and bloating come from decreased gastrointestinal motility. Diarrhea from laxative abuse can cause symptoms of chronic dehydration and electrolyte abnormalities.

Weakness or muscle cramps can be exacerbated by electrolyte disturbances such as hypokalemia. Bone pain with exercise should raise suspicion of the possibility of stress fractures, osteopenia or osteoporosis.

Polyuria could occur with diuretic abuse, but also with nocturia secondary to abnormal vasopressin secretion. Menstrual irregularity or amenorrhea, secondary to weight loss, excessive exercise or emotional stress, potentially predisposes females to osteopenia or even osteoporosis.

Psychiatric features associated with anorexia nervosa include symptoms of depression, depressed mood, irritability, insomnia, social withdrawal and decreased libido. Obsessive-compulsive tendencies are also common, like preoccupations with food. Other characteristics are concerns with eating in public, perfectionism and needing to control their environment. Binge eating/purging types of anorexia nervosa tend to have more impulse control issues than restricting types, more abuse of alcohol or drugs, be more sexually active, have more mood lability, be more prone to self-harm (cutting or burning) and suicide attempts.

In bulimia nervosa, there is increased prevalence of depressive symptoms, mood disorders such as major depressive disorder or dysthymic disorder, and anxiety. Some have features of personality disorders, like borderline personality disorder. Substance abuse including alcohol or stimulants can occur in at least 30% of those with bulimia nervosa.

Some patients may access pro-anorexia (pro-ana) or pro-bulimia (pro-mia) websites that lack professional supervision.


Diabetics may omit or underdose their insulin to reduce food metabolism. Thyroid hormone could be used to increase metabolism for weight loss.

Family history

Individuals with anorexia nervosa are more likely to have first-degree relatives with this disorder or mood disorders. For bulimia nervosa, there also may be family history of the same disorder, obesity, mood disorders or substance abuse.

2. Physical Examination maneuvers that are likely to be useful in diagnosing the cause of this problem.

Vital signs should be checked for hypothermia, bradycardia, orthostatic measurements for postural orthostatic tachycardia (pulse increase >20 bpm) or orthostatic hypotension (systolic blood pressure decrease >10 mmHg), weight, height and body mass index (BMI). In general, individuals with anorexia nervosa can appear cachectic; most with bulimia nervosa are at least of normal weight.

  • BMI for ages 2–20:

  • BMI for adults: For adolescents, the 2nd percentile has been proposed as a cutoff point for considering anorexia nervosa.

The scalp hair can appear thin and dull. Angular stomatitis, fissuring at the corners of the mouth, may be due to vitamin B2 (riboflavin) deficiency. Induced emesis can cause parotid gland hypertrophy or permanent erosion of dental enamel, especially on the lingual surface, making teeth more prone to cavities. In the mouth, palatal scratches or pharyngeal erythema suggest recurrent vomiting and receding gums can be caused by severe malnutrition.

A third of individuals have mitral valve prolapse, a systolic click with crescendo to S2, from the abnormal ballooning of the mitral valve, then progressing to mild mitral regurgitation. Delayed capillary refill and cool extremities signal poor perfusion. There may be peripheral edema from low protein of malnutrition.

Skin findings may include conjunctival hemorrhages or facial petechiae after vomiting, dry skin, lanugo (fine hair often on the trunk), calluses or scars on the knuckles (Russell’s sign) from self-induced vomiting using the hand or acrocyanosis. Look for signs of self-harm: cuts, linear scars, burns, or bruises. Hypercarotenemia, yellowing of the skin, can be seen on the palms and soles.

Patients may have a flat or anxious affect. Cognitive deficits are influenced by atrophic brain changes correlating with degree of weight loss and amenorrhea which resolve with weight gain.

3. Laboratory, radiographic and other tests that are likely to be useful in diagnosing the cause of this problem.

Medical tests should be limited to those aiding diagnosis or management.

Complete blood count in restricting anorexia nervosa can show leukopenia with relative lymphocytosis, mild normocytic anemia or even thrombocytopenia.

Electrolytes may reflect dehydration with an elevated blood urea nitrogen. Hyponatremia can be secondary to vomiting, diarrhea, diuretic abuse or dilutional from water loading to decrease food intake or artificially increase their weight for weight checks. Self-induced emesis would cause hypokalemia, and hypochloremic metabolic alkalosis, from loss of hydrochloric acid. Hypokalemia can also be caused by electrolyte shifts from acid loss or pseudohyperaldosteronism from chronic dehydration, laxative, diuretic abuse. Laxative abuse causes bicarbonate wasting and a hyperchloremic metabolic acidosis. There may also be low magnesium or phosphorus levels from inadequate intake and laxative abuse.

Hypoglycemia can present in severe, advanced malnutrition with depleted glycogen stores.

Liver function tests can show mildly elevated transaminases due to weight loss and fasting. An elevated fasting indirect bilirubin level can reflect food restriction.

Thyroid function tests can reveal non-thyroidal illness syndrome (sick euthyroid syndrome) with normal thyroid-stimulating hormone and low-normal thyroxine (T4) levels which reverse with weight gain and do not require hormone replacement therapy. If the patient vomits surreptitiously, serum salivary amylase will be elevated. Persistent amenorrhea in someone with normal weight might prompt evaluation of urine pregnancy test, serum luteinizing and follicle-stimulating hormones, serum estradiol and serum prolactin. Females may have low estradiol and males, low serum testosterone levels.

A toxicology screen should be considered for patients with history of substance abuse or binging and purging. For suspected laxative abuse, the stool or urine can be analyzed for a laxative screen: bisacodyl, emodin, aloe-emodin and rhein.

Sinus bradycardia is common on electrocardiogram. Also consider an electrocardiogram if electrolyte abnormalities are present or if there is history of significant purging. Hypokalemia depresses the ST segment and in severe hypokalemia, QRS complex widens with increased PR interval and increased P wave amplitude. Some individuals have prolonged QT interval.

Bone density scans should be obtained for individuals with amenorrhea of at least 6 months to check for osteopenia or osteoporosis.

Malnutrition can cause cognitive deficits, but if they are significant, or patients have atypical features or an unchanging course, a brain magnetic resonance imaging (MRI) scan or computed tomography (CT) scan could be done.

C. Criteria for Diagnosing Each Diagnosis in the Method Above.

The Diagnostic and Statistical Manual of Mental Disorders (fourth edition, text revision) (DSM-IV-TR) contains the diagnostic criteria for these conditions.

The DSM-IV-TR diagnostic criteria for anorexia nervosa
  • Refusal to maintain body weight at or above a minimally normal weight for age and height (i.e. weight loss that leads to maintenance of body weight 85% of that expected, or failure to make expected weight gain during period of growth that leads to a body weight of 85% of that expected)

  • Intense fear of gaining weight or becoming fat, even though underweight

  • Disturbance in the way in which one’s body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or denial of the seriousness of current body weight

  • In postmenarcheal females, amenorrhea (i.e. the absence of at least 3 consecutive menstrual cycles)

There are 2 types:

  • Restricting type – no regular binging or purging (self-induced vomiting or use of laxatives and diuretics)

  • Binge eating/purging type – regular binging or purging behavior

The DSM-IV-TR diagnostic criteria for bulimia nervosa
  • Recurrent episodes of binge eating characterized by:

    Eating, in a discrete period of time, an amount of food that is definitely larger than most people would eat in a similar period of time and under similar circumstances and

    A sense of lack of control over eating during the episode

  • Recurrent inappropriate compensatory behavior to prevent weight gain, such as self-induced vomiting; misuse of laxatives, diuretics, enemas, or other medications; fasting; or excessive exercise

  • The binge eating and inappropriate compensatory behaviors both occur, on average, at least twice per week for 3 months

  • Self-evaluation unduly influenced by body shape or weight

  • The disturbance does not occur exclusively during episodes of anorexia nervosa

There are 2 types:

  • Purging type – the person has regularly engaged in self-induced vomiting or misuse of laxatives, diuretics or enemas

  • Nonpurging type – the person has used other inappropriate compensatory behaviors, such as fasting or excessive exercise, but has not regularly engaged in self-induced vomiting or the misuse of laxatives, diuretics or enemas

D. Over-utilized or “wasted” diagnostic tests associated with the evaluation of this problem.


III. Management while the Diagnostic Process is Proceeding.

A. Management of Clinical Problem Eating Disorders.

Hospitalization criteria (American Psychiatric Association)
  • Severe malnutrition <75% average body weight for age, sex and height

  • Physiologic instability, i.e.:

    orthostatic hypotension – pulse increase of 20 bpm or systolic blood pressure drop of >10 mmHg

    hypotension <80/50 mmHg

    bradycardia <40 bpm (<50 bpm daytime for adolescents)

    tachycardia >110 bpm

    hypothermia <97 F (<36.1 C)

  • Significant electrolyte disturbances – e.g., potassium <3 mEq/L (<3 mmol/L)

  • Failed outpatient therapy

  • Acute medical complications of malnutrition – e.g., syncope, cardiac, renal

  • Acute psychiatric emergencies – e.g., suicidal ideation, acute psychosis

Most of the medical complications improve and resolve with refeeding, weight gain and cessation of purging.


On admission, daily caloric intake usually begins at 30–40 kcal/kg/day (1000–1600 kcal/day) or adding 200–300 kcal to the individual’s daily intake. Calories can be advanced 200 kcal every 2 days. After the first 2 weeks, a weight gain of 2–3 lb (0.9–1.35 kg) per week is a reasonable goal for the hospitalized patient. Oral refeeding is always preferable, but nasogastric and even intravenous feedings can be used in situations of food refusal and as a lifesaving measure. New research suggests that intensive nutrition regimens (feeding starting at up to 3000 kcal/day) may allow patients to gain weight, muscle, and fat mass without significant side effects.

If using nasogastric feedings, continuous feedings may be better tolerated than bolus feedings. During early nutrition support, liquid supplements can be started with gradual transition to foods to help weight gain. In the first few days, fluid balance should equal zero balance (20–30 mL/kg/day for adults), with sodium restricted, especially if edema develops. A nutrition consult is recommended to help navigate these issues.

From decreased intake, there may be general vitamin deficiencies including thiamine, folic acid, vitamin B12 from a vegetarian diet, and vitamins C and D. Thiamine (100 mg PO daily x first 3 days), particularly for individuals with history of heavy alcohol use or rapid weight loss, is recommended before nutrition rehabilitation as refeeding with increased carbohydrate metabolism exhausts already depleted thiamine reserves. A daily multivitamin is also recommended.

Zinc deficiency can cause changes in the sense of taste and neuropsychiatric symptoms. A zinc supplement is recommended especially if serum zinc level is low, as it has also been reported to help weight gain in some patients. If there is evidence of iron deficiency anemia, wait until after one week of nutrition support to start iron; iron supplementation in the early phase of refeeding is associated with increased mortality.


On admission, the activity level is typically restricted to bed rest so that energy can be directed towards weight gain and recuperation. As orthostatic symptoms improve, the activity level could be judiciously advanced.


For the symptom of postprandial discomfort, small, frequent meals with snacks are better tolerated. Metoclopramide can help delayed gastric emptying and the associated symptoms.

A bowel regimen to treat constipation should include polyethylene glycol 3350 and stool softeners. Stimulant laxatives are not recommended.

For tooth sensitivity from enamel loss, some strategies to alleviate the discomfort include diluting fruit juices, avoiding foods or fluids at extreme temperatures and using a mouth rinse solution of 1 teaspoon (5 mL) of baking soda per 1 quart (0.95 L) water.

Salivary gland enlargement improves with cessation of emesis, but warm compresses and tart candies (sialogogues) can help.


Nutrition rehabilitation and weight gain best treat low bone density in potentially reversing bone deterioration. Calcium supplement (1300–1500 mg/day) and vitamin D (400 units/day) do not significantly prevent or reverse bone loss, but are often prescribed. Neither estrogen supplements nor bisphosphonates are effective in treatment of osteopenia or osteoporosis in eating disorders.


Antidepressants are commonly prescribed for patients with eating disorders, but there are few trials to support their routine use.

A small number of trials support the use of psychotherapy, particularly cognitive behavioral therapy (CBT), in patients with bulimia nervosa. However, CBT alone did not restore weight. Patients must still follow standard nutrition protocols.

The Maudsley model of family therapy has been proven to increase BMI while decreasing symptomatology in patients with anorexia nervosa.


Patients can be admitted to telemetry where monitoring can help identify significant bradycardia at night, along with electrocardiographic manifestations of electrolyte disturbances.

Daily orthostatic vital signs can be obtained along with daily weights checked every morning after voiding, in a hospital gown, with the patient facing away from the scale.

Electrolyte abnormalities, such as hypophosphatemia, occur most likely in the first couple of weeks of refeeding so serum electrolytes, potassium, calcium, magnesium, and phosphorus should be checked daily for the first 5 days of refeeding, then 2–3 times weekly for the next 2 weeks. Urine specific gravity checked at the morning weigh-in can help detect excessive water intake.

The daily physical exam should pay attention to orthostatics and cardiovascular status.

Patients may report acne, breast tenderness with weight gain or depressed mood because of body changes.

A psychiatry consult helps with medication initiation or adjustment that can improve mood, decrease binging, purging and improve weight gain.

Discharge planning

Patients considered for discharge should be recovering from the physiologic instability that warranted their admission, and be stable on their goal caloric intake. The closer a patient is to their ideal weight at discharge, the less likely they are to relapse.

The discharge plan should consist of close follow-up with a multidisciplinary team including medical, psychiatric and nutrition providers. Different options depend on the level of care a patient requires, be it intensive outpatient, day treatment program or a residential program. A day treatment program provides therapy, meals and group activities at a level between outpatient and hospitalization. Patients who purge with vomiting should be referred to a dentist.

B. Common Pitfalls and Side-Effects of Management of this Clinical Problem.

Refeeding syndrome refers to the potentially lethal complication of refeeding severely malnourished patients, when the shift from a catabolic to anabolic state leads to insulin being released in response to carbohydrate intake. Electrolyte abnormalities (particularly hypophosphatemia, hypokalemia, and hypomagnesemia) can ensue, particularly in the first week after starting nutritional supplementation. Those at highest risk are those with severe malnutrition, BMI <12 kg/m2, history of rapid weight loss, binging, vomiting, laxative abuse, or concurrent comorbidities.

Peripheral edema and fluid retention may develop with abrupt cessation of diuretics or laxatives, when chronic dehydration induces elevated aldosterone levels and salt and water retention. With weight loss, the heart muscle atrophies along with total muscle mass. When fluid overload occurs with refeeding, patients are at risk for heart failure. This, along with bradycardia and prolonged QT interval, make the heart more susceptible to ventricular arrhythmias and sudden death from hypokalemia and hypophosphatemia.

Rare complications from repetitive vomiting include esophageal tears or rupture.

Prolonged QT has been reported in patients with anorexia nervosa, and thus medications with this side effect should be avoided especially given their risk of cardiovascular compromise (e.g., antipsychotics, antidepressants, macrolides, some antihistamines).


Metoclopramide 5–10 mg PO TID

Polyethylene glycol 3350 1–3 tablespoons PO daily

Thiamine 100 mg PO daily x first 3 days

Daily multivitamin

IV. What's the Evidence?

Garner, DM, Anderson, ML, Keiper, CD, Whynott, R, Parker, L. “Psychotropic medications in adult and adolescent eating disorders: clinical practice versus evidence-based recommendations”. Eat Weight Disord. 2016 Feb 1.

Hay, PP, Bacaltchuk, J, Stefano, S, Kashyap, P. “Psychological treatments for bulimia nervosa and binging”. Cochrane Database Syst Rev.. 2009 Oct 7. pp. CD000562(This article describes how cognitive behavioral therapy can treat some patients with bulimia.)

Mehler, PS, Andersen, AE. “Eating Disorders: A Guide to Medical Care and Complications”. 2010.

Morgan, JF, Reid, F, Lacey, JH. “The SCOFF questionnaire: a new screening tool for eating disorders”. West J Med.. vol. 172. 2000 Mar. pp. 164-165. (This is the original citation for the SCOFF questionnaire.)

O’Connor, G, Nicholls, D, Hudson, L, Singhal, A. “Refeeding Low Weight Hospitalized Adolescents With Anorexia Nervosa: A Multicenter Randomized Controlled Trial”. Nutr Clin Pract. 2016 Feb 11. (This trial showed that “refeeding adolescents with AN with a higher energy intake was associated with greater weight gain but without an increase in complications associated with refeeding when compared with a more cautious refeeding protocol-thus challenging current refeeding recommendations.”)

Rosen, DS. “Clinical Report – Identification and Management of Eating Disorders in Children and Adolescents”. Pediatrics. vol. 126. 2010. pp. 1240-1253.

Schmidt, U, Magill, N, Renwick, B, Keyes, A, Kenyon, M, Dejong, H. “The Maudsley Outpatient Study of Treatments for Anorexia Nervosa and Related Conditions (MOSAIC): Comparison of the Maudsley Model of Anorexia Nervosa Treatment for Adults (MANTRA) with specialist supportive clinical management (SSCM) in outpatients with broadly defined anorexia nervosa: A randomized controlled trial”. J Consult Clin Psychol. vol. 83. 2015 Aug. pp. 796-807.

Stanga, Z, Brunner, A, Leuenberger, M, Grimble, RF, Shenkin, A, Allison, SP, Lobo, DN. “Nutrition in clinical practice – the refeeding syndrome: illustrative cases and guidelines for prevention and treatment”. Eur J Clin Nutr. vol. 62. 2008. pp. 687-694.