Today we will continue our current theme of eating disorders as we discuss anorexia nervosa. In part 1 we detailed an introduction, definitions, diagnostic criteria, epidemiology, and pathogenesis. Today, in part 2, we will cover clinical pearls, physical complications, and treatment.
Today's Content Level: Intermediate
History: Anorexia nervosa (AN) includes behaviors (e.g. self-induced starvation), psychopathology (e.g. intense fear of fatness or disturbed body image), and resulting physiologic symptoms (e.g. significantly low body weight and complications). Obtain a focused history regarding attitude toward themselves (self, body image, weight), food, and eating behaviors (meal pattern, eating, rituals, restrictions, frequency of weighing, binging, purging, etc.). The common theme in AN patients is an excessive emphasis regarding thinness as the primary source of self-esteem. Body weight and shape become an obsessive and all-consuming preoccupation of thoughts, behaviors, and mood. Those suffering from AN are often obsessed with food and may collect recipes, read articles, watch cooking shows, or prepare meals for others that they themselves will not eat. A full psychiatric history should also be obtained including a suicide/safety assessment. Patients may hide symptoms or present somatic complaints. Obtain collateral history if possible from family members, partners, or significant others. See part 1 for full diagnostic criteria.
Optional Questionnaires: Eating Disorder Examination (EDE; clinician-administered), Eating Disorder Examination Questionnaire (EDE-Q; self-report), SCOFF Questionnaire.
Differential Diagnosis: The differential diagnosis includes medical conditions that may lead to significant weight loss or low body weight such as cancer, AIDs, other chronic infections, endocrine disorders (hypothalamic disease, diabetes, hyperthyroidism), gastrointestinal illness (malapsorption, IBD), or genetic disease (Turner syndrome, Gaucher disease). These medical disorders usually do not manifest as an intense fear of weight gain or disturbed body image. Other eating disorders should also be considered such as bulimia nervosa (BN) and avoidant/restrictive food intake disorder (ARFID). Both anorexia and bulimia are characterized by a desire for thinness and both may binge and purge, however individuals with BN maintain body weight above a minimally normal level. Individuals with ARFID may experience significant weight loss, but they do not have a fear of gaining weight or disturbed body image. Individuals with other mental disorders may display a disordered relationship with food or their body image but not meet full criteria for anorexia. Examples may include major depressive disorder (MDD) (poor appetite or decreased interest in food -> weight loss), social anxiety disorder (embarrassed to be seen eating in public), OCD (obsessions/compulsions related to food), body dysmorphic disorder (preoccupied with imagined defects in their appearance), schizophrenia (odd eating behaviors +/- weight loss), and substance use disorders (low weight due to poor nutritional intake but generally do not fear gaining weight).
Comorbidities: 75% report lifetime mood disorder (usually MDD). 25-75% report an anxiety disorder. 15-29% report OCD. 9-25% report alcohol misuse (lower in restricting type).
Anorexia nervosa is associated with a number of medical complications that are directly attributable to caloric restriction, weight loss, and purging (if present).
AN has the highest mortality among psychiatric disorders. This is due to high rates of suicide (1 in 5 deaths occur by suicide) and medical complications such as cardiac or infectious causes. The rate of death in AN is approximately 5 to 10 times greater than the general population
A complete medical evaluation is necessary in order to assess for complications and determine whether hospitalization is necessary. This should include a full medical history, thorough review of symptoms, menstrual status, height, weight, vital signs, full physical exam, and laboratory testing. In cases of low BMI or starvation and dehydration, monitor cardiac, muscular, and electrolyte complications. In cases of long-term illness, consider DEXA scan to screen for osteoperosis.
Keep in mind that patients with AN may attempt to conceal their thinness from clinicians by wearing bulky clothes and/or inflating their body weight by hiding objects in their clothes or drinking water before weighing.
Physical Exam, Medical Symptoms, and Labs
Some risks include:
Low body mass index (BMI) <17.5.
Vital signs: Hypothermia, bradycardia, hypotension (especially orthostasis), and hypopnea.
General -> Weakness, fatigue, cold intolerance, and dehydration.
Cardiac -> Bradycardia, hypotension, arrhythmia (especially QTc prolongation), acute coronary syndrome, cardiomyopathy, mitral valve prolapse, and edema (especially ankle and periorbital).
GI -> Constipation and abdominal distention.
Neuro -> Peripheral neuropathy and seizures.
MSK -> Osteopenia (~50%) or osteoporosis (~20%), increased risk of fractures, and proximal muscle weakness.
Skin -> Xerosis (dry, scaly skin), yellow skin (hypercarotenemia, especially palms), brittle hair and hair loss, alopecia, brittle nails, and lanugo (fine hair all over the body).
Gyn -> Amenorrhea.
Endo -> Hypothyroidism, increased growth hormone, increased cortisol, reduced gonadotropins (LH, FSH), reduced sex steroid hormones (estrogen, testosterone), hypothyroidism, and hypoglycemia.
Heme -> mild anemia, leukopenia, thrombocytopenia (rare)
Other labs -> Hyponatremia, hypercholesterolemia, transaminitis, elevated BUN (dehydration), and hypochloremic hypokalemic alkalosis (if vomiting).
General approach: The primary initial goal in the treatment of anorexia nervosa is to improve their nutritional status. This involves a supervised weight gain schedule with close monitoring. Many patients may be treated as an outpatient with an interdisciplinary approach (psychiatrist, primary care, dietician, therapist). Mental health treatment should be focused on psychotherapy as opposed to medication management. Other treatment options include intensive outpatient, partial hospitalization programs, residential programs, and medical or psychiatric hospitalization depending on severity.
Hospitalization: There are no clear-cut evidence-based criteria for hospitalization, however the following are suggested based upon clinical practice guidelines: BMI <14 or 70% ideal body weight; unstable vital signs (HR < 40, BP < 80/60, orthostatic hypotension); cardiac dysrhythmia; marked dehydration; or serious medical complications of malnutrition (e.g., electrolyte imbalance, hypoglycemia, syncope, cardiovascular/hepatic/renal compromise requiring medical stabilization, refeeding syndrome). Other considerations include rapid weight loss, severe binging and purging, safety concerns, or failure to respond to outpatient treatment.
Refeeding syndrome: If severely malnourished patients are refed too quickly it may lead to dangerous electrolyte and fluid shifts. Typically occurs within the first five days of refeeding. Look for fluid retention (edema) and ↓ levels of phosphorus, magnesium, and calcium. Complications include arrhythmias, hypotension, respiratory failure, rhabdomyolysis, delirium, seizures, and sudden death. Replace electrolytes and slow the feedings.
Psychotherapy: After prompt restoration to a safe weight, the primary interventions are family based therapy (FBT) (e.g. Maudsley approach) and structured individual psychotherapy. Family based therapy is particularly effective with younger patients and works to integrate the parents as an active and positive resource rather than a hindrance. Individual therapy with evidence in AN includes cognitive behavioral therapy (CBT), interpersonal therapy (IPT), exposure therapy, and focused psychodynamic therapy. Therapy aims to help restore healthy eating behaviors, change their relationship with food, improve body image, develop new sources of self-esteem, and help them better utilize their support systems.
Pharmacotherapy: There are no FDA approved medications for the treatment of anorexia nervosa, and there are few controlled trials to guide treatment. There is very limited evidence for the use of any pharmacological interventions other than those to correct metabolic deficiencies and the treatment of co-morbid conditions. It has been suggested that neurochemical changes in starvation may partially explain medication non-response. Antidepressants, including SSRIs, have not been effective in improvement of weight gain or eating disorder pathology although one small trial found that fluoxetine may reduce the risk of relapse after weight restoration. Mirtazapine has been used to assist with weight gain, depressive symptoms, and reduction of obsessional thinking with some success, however data is limited to case studies. Bupropion is contraindicated due to seizure risk. Antidepressants are commonly used to treat comorbid conditions (depression, anxiety, OCD, etc.), however these conditions may improve/resolve with weight restoration alone. Among antipsychotic medications, olanzapine is the best supported. Olanzapine is the only medication suggested to have a positive effect on weight restoration and may also reduce agitation and other comorbid symptoms. Only prolactin-sparing antipsychotics should be considered (↑ prolactin can further increase the risk of bone loss and osteoporosis). Many other medications have been or are currently being studied with varying levels of quality and success (dronabinol, cyproheptadine, naltrexone, zinc, etc.). Medications should be used with caution due to increased risk of QTc prolongation, arrhythmia, electrolyte disturbances, and seizures. ECG monitoring should be undertaken if the prescription of any medicine that may compromise cardiac functioning is essential.
Nice work. Next lesson we will discuss bulimia nervosa. If you want more learning resources then check out our recommended resources page.
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