Eating Disorders

Etiology

The etiology of eating disorders is heterogeneous, including biological, psychological, developmental, and socio-cultural.[2] 

1. Biological factors
   • Genetics: Twin and adoption studies prove the hereditary role for eating disorders. There is a 50% chance of developing eating disorders if the other twin has it.[3] 
   • Neurobiology: Serotonin plays a significant role in appetite and mood regulation. Serotonin may indirectly mediate its effects on the development of eating disorders.
2. Psychological factors: Perfectionism, impulsivity, novelty-seeking, obsessive-compulsiveness, harm avoidance, and neuroticism are common personality traits often associated with eating disorders.[4]
3. Developmental factors: The early perturbation in childhood development, like childhood sexual abuse, poses a significant risk in developing eating disorders. 
4. Socio-cultural factors- Cultural preferences for thinness, exposure to western culture that values a slim body for women, and exposure to media promoting such ideas play a major role in increasing eating disorders' prevalence worldwide.[5][6][7]

Epidemiology

One in eight youngsters may have at least one eating disorder by twenty years of age.[8] Approximately 5 million Americans are affected by eating disorders every year. Although eating disorders can affect people of all ages and both genders, they are often reported in adolescents and young women. The anorexia nervosa and bulimia nervosa are approximately 0.3% and 1% among adolescent females respectively.[9] The prevalence of eating disorders is generally higher in young women except for binge eating disorder, which is more common in men and older individuals.

History and Physical

Anorexia Nervosa

• Anorexia nervosa is the most familiar and well-studied eating disorder. 
•  Anorexia nervosa usually develops during adolescence and occurs more in women than men 
• The characteristics features of anorexia nervosa are as follows, 
• Extremely underweight 
• Intense fear of gaining weight
• a distorted body image, including denial of being seriously underweight
• Persistent compensatory behaviors to avoid gaining weight, despite being underweight
• Preoccupation with food and weight
• Individuals with anorexia nervosa might have obsessive-compulsive symptoms like using the same cutlery or breaking the food into small pieces.[10] 
• In women, anorexia nervosa could manifest as amenorrhea, which is defined as the absence of at least three consecutive menstrual cycles. However, amenorrhea is no longer a mandatory criterion in DSM 5 to diagnose anorexia nervosa. 
• Anorexia nervosa is of 2 types.
  1. In the Restricting type, individuals lose weight through fasting or excessive exercise. 
  2. In the Binge eating/purging type, individuals binge on large amounts of food and purge after that. They purge by self-induced vomiting, laxative/diuretic usage. 
• The mortality rate in Anorexia nervosa is the highest of any psychiatric disorders.[11][12] Most of them die from medical complications, whereas some die due to suicide. Individuals with Anorexia nervosa, in the long run, might have osteopenia, brittle hair/nails, dry skin, constipation, hypotension, bradycardia, hypothermia, lanugo hair, amenorrhea, infertility, or muscle wasting.
• Anorexia nervosa is complicated by dysregulation of the hypothalamic-pituitary axis causing hypothalamic amenorrhea and dysregulation of hypothalamic-pituitary-adrenal axis causing hypercortisolemia and growth hormone resistance.[13]

Bulimia Nervosa

• Bulimia nervosa is substantially more common than anorexia nervosa in the population,
• The disorder generally starts in late adolescence or early adulthood. 
• The characteristic features of bulimia nervosa are as follow,
• Eating substantial amounts of food in a short period,
• Loss of control during binge eating,
• Binge eating is followed by compensatory behavior to prevent weight gain like forced vomiting, laxatives/diuretics usage, restricted eating, or excessive exercise.
• Fear of gaining weight despite weighing normal range
• DSM 5 criteria for diagnosing bulimia nervosa require at least one binge-eating episode with compensatory behavior in a week for a minimum of 3 months.
• Bulimia nervosa can manifest with a sore throat, swollen salivary glands, tooth decay, acid reflux, severe dehydration, electrolyte imbalance, and hormonal disturbances.
• Individuals with bulimia nervosa may be underweight, normal weight, or slightly overweight. Even those who lost weight initially tend to regain and become overweight later gradually. 
• Though symptoms of Bulimia nervosa are very similar to binge eating/purging subtypes of anorexia nervosa, persons with bulimia nervosa maintain near normal weight instead of being underweight.[14]

Binge Eating Disorder (BED) 

• BED is the most common eating disorder. 
• BED usually begins in adolescence. One-third of BED patients are male.
• Individuals with binge eating disorder eat enormous amounts of food in a short period, accompanied by loss of control during binge-eating behavior. 
• The binge eating behavior in BED is identical to Bulimia nervosa or binge eating type of anorexia nervosa. Nevertheless, individuals with BED do not restrict eating or use purging behaviors to compensate.
• The characteristic feature of Binge eating disorders are as follows,
• Eating substantial amounts of food in a short period,
• Loss of control during binge eating,
• Feeling guilt about binge eating,
• No compensatory or purging behaviors
• Binge eating disorder poses a risk of obesity and complications associated with obesity like diabetes, heart disease, or stroke. 
• BED tends to remit and recur. 
• Treatment for binge eating disorder should target decreasing binge eating behavior. The focus should not be targeting weight loss because this will increase binge eating behavior.  

Avoidant or Restrictive Food Intake Disorder (ARFID)

• Avoidant or restrictive food intake disorder is new terminology for "feeding disorder of infancy, toddlers and childhood."
• ARFID usually occurs during the first seven years of life. Sometimes it can persist into adulthood. 
• Picky eating in early childhood is normal behavior, which is not included under ARFID.
• ARFID can be due to loss of interest in eating, intense dislike for specific tastes, smells, texture, or colors.
• ARFID does not include the restriction of foods due to religious reasons or lack of availability.
• ARFID impairs social function and inhibits the individual from eating with others. Also, it causes underweight and micronutrient deficiency. 
• Cognitive behavior therapy can be used for managing ARFID in individuals above ten years of age.[15]

Pica

• Pica is one of the eating disorders in which an individual craves non-food items like soil, chalk, soap, paper, ice hair. 
• Pica is common among pregnant women, children, and intellectually disabled persons.
• Pica is benign and self-resolving in pregnant and children. However, it can be chronic and devastating in intellectually disabled persons.
• Pica poses a risk for parasitic infections, micronutrient deficiency, intestinal obstruction, and heavy metal poisoning. 
• The treatment strategy for pica includes decreasing the exposure to the craved items, micronutrient supplementation, and behavioral/aversive treatment, particularly among mentally disabled individuals. 

Rumination Disorder

• Rumination disorder is a new addition to the eating disorder in which an individual regurgitates the previously swallowed food, chews it again, and then swallows or spits. 
• Rumination is a voluntary action that usually happens within 30 minutes after having the food.
• Rumination developed in infancy usually resolves by 12 months. Rumination disorder in children and adults can lead to weight loss or malnutrition.
• Rumination disorder can be a comorbid condition in Anorexia nervosa.
• Postprandial high-resolution impedance-pH manometry contributes to a more detailed description of rumination events. The rumination syndrome can be diagnosed if reflux events extending to the proximal esophagus is closely associated with an increase in intragastric pressure more than 30 mm Hg.[16][17]
• Biofeedback therapy reduces regurgitation episodes in rumination. Biofeed back techniques like re-education of abdominal contractions and diaphragmatic breathing are used.

Other Specified Feeding and Eating Disorder (OSFED)

The terminology EDNOS (Eating disorder - not otherwise specified) in DSM-IV is changed to the Other Specified Feeding and Eating Disorder (OSFED) in DSM 5. It includes purging disorder, night eating syndrome, atypical anorexia nervosa, and subclinical bulimia nervosa / binge eating disorder. These eating disorders share the same concern about eating, body shape, and weight and have disordered eating behavior. Avoidant restrictive food intake disorder, pica disorder, and rumination disorder are not included in this subsection because weight and shape concerns are not a feature in these disorders. Many people with an atypical eating disorder will later develop a typical eating disorder.

• Purging disorder is characterized by the purging behaviors like vomiting, excessive exercising, using laxatives or diuretics to control weight. They do not have binge eating. The complications of Purging disorders are similar to Bulimia nervosa like metabolic disturbances, electrolyte imbalances, dental issues, oral bleeding due to esophageal tears, and swollen parotid glands. The management of purging disorder is similar to bulimia nervosa.
• Night eating syndrome is characterized by overeating, often after awakening from sleep. It has a strong association with sleep disturbance. The management is similar to Binge eating disorder.
• Atypical anorexia nervosa has similar features to anorexia nervosa except for BMI in the ‘adequate’ range of 20–25 kg/m2 or higher. Management is similar to anorexia nervosa. 
• Subthreshold bulimia nervosa and binge eating disorder do not meet the ideal definition criteria of bulimia nervosa and binge eating disorder. 
• Orthorexia - Orthorexia has yet to be recognized as a separate eating disorder by the current DSM. Individuals with orthorexia have an obsessive focus on healthy eating. Individuals with orthorexia may eliminate entire food groups, fearing they are unhealthy.

Evaluation

A structured approach has to be taken while approaching individuals with eating disorders. 

1. General history taking 
• Eating habits, presence of binge or purge behavior, perception of body image,
• actual weight, desired weight
• use of laxatives, diet pills, diuretics, or emetics
• Menstrual history 
2. Psychiatric history
• Assessment for substance abuse, 
• Assess for mood, anxiety, personality disorders
• Suicidality 
3. Past medical and family history
4. Examination 
• Complete medical examination 
• Psychiatric Examination
• Mental status
• Assess suicidality 
• Cognitive status 
5. Laboratory 
• Complete blood count
• Electrolytes, renal function test, and liver function tests
• Calcium, magnesium, phosphate
• Cholesterol, lipids, amylase
• Thyroid function tests
• Urine analysis
• Electrocardiogram
• Chest radiograph

Treatment / Management

There is a wide variation in how eating disorders are managed. Treatments are frequently multi-faceted, with psychotherapy and pharmacotherapy. It is crucial to seek treatment early for eating disorders. The management approach is tailored to patient's needs and may comprise one or more of the following:

• Psychotherapy
• Pharmacotherapy
• Nutritional counseling
• Aftercare and monitoring

Psychotherapies

For all eating disorders, psycho-behavioral therapy can be provided on an outpatient basis. People with severe symptoms or not improving with outpatient care may be treated as inpatient service.[18][19](A1)

1. Enhanced Cognitive Behaviour Therapy (CBT-E) is the first-line treatment for all eating disorders. More sessions are required for Anorexia nervosa compared to bulimia nervosa and binge eating disorders.
2. Family-based treatment (FBT) is the most promising modality in managing anorexia nervosa among children and adolescents. FBT can also be adapted for bulimia nervosa and Avoidant or restrictive food intake disorder (ARFID).
3. Interpersonal psychotherapy can be used as an alternative for CBT in individuals with Bulimia nervosa or BED.
4. Maudsley Anorexia Nervosa Therapy for Adults (MANTRA) and Focal Psychodynamic Therapy (FPT) can be used in adults with eating disorders along with CBT.
5. Several randomized control trials are going to explore other models of behavior therapy in eating disorders. Dialectical behavior therapy (DBT) is adapted to treat eating disorders, particularly Bulimia nervosa and Binge eating disorders. Acceptance and commitment therapy (ACT) address maladaptive cognitions and behaviors associated with eating disorders.
6. Neuromodulation modalities like repetitive transcranial magnetic stimulation and deep brain stimulation are under study as adjunct treatment for eating disorders.

 Pharmacotherapy 

1. Fluoxetine is the only FDA-approved drug used for the treatment of Bulimia nervosa and Binge eating disorders. 
2. Antidepressants, including fluoxetine, has little role in anorexia nervosa except where there is coexisting major depression.
3. Medications like antidepressants, antipsychotics, or mood stabilizers may help treat coexisting psychiatric illnesses such as anxiety or depression.
4. Trials are going on topiramate and lisdexamfetamine for binge eating disorders. The role of olanzapine for anorexia nervosa has been studied, which shows mixed results.[18][20]
(A1)

 Nutritional Therapy

• Nutrition therapy is indicated for all individuals diagnosed with eating disorders, including anorexia nervosa, bulimia nervosa, and binge eating disorder. 
• Nasogastric feeding is preferred over other enteral or parenteral nutrition when oral feeding is not possible. Total parenteral nutrition is reserved for significant gastrointestinal dysfunction. 
• In most patients with anorexia nervosa, the aim of nutritional therapy is an average weight gain of 2 to 3 pounds (1 to 1.3 kg) per week for inpatient and 0.5 to 1 pound (0.2 to 0.5 kg) per week for outpatient management.  
• The initial calorie supplement should be 30 to 40 kilocalories/ kilogram per day. In the later stage, caloric intake can be advanced slowly to 70 to 100 kcal/kg per day. 
• Though the foremost step in nutritional management is to expand the food choices, patients on vegetarian diets can continue the same vegetarian diets. 
• Electrolytes need to be carefully assessed, and refeeding should be gradual.
• Replacement of vitamins and minerals is an integral part of nutritional therapy. Zinc, in particular, enhances the rate of recovery and helps in improving anxiety and depression. Calcium and vitamin D supplements and cautious use of bisphosphonates like etidronate are recommended for reversing osteoporosis. Oral multivitamin and multi-mineral supplements are recommended.

Aftercare  

• After the patients recover from eating disorders and see their weight gain, they might experience a resurgence of anxiety and depressive symptoms and drop out of treatment programs. 
• Anorexia nervosa can relapse in 20% to 30% after first inpatient admission and 50-75% after more than one admission. 
• Psychotherapy helps to sustain the remission.

Specific Management Strategy

1. Anorexia Nervosa 
   • The majority of anorexic patients can be managed as outpatients. However, few require inpatient psychiatric treatment. The criteria for inpatient care are as follow:
     • Weight loss greater than 30% of ideal body weight
     • Persistent suicidal ideation
     • The need for withdrawal from laxatives, diet pills, or diuretics
     • Lack of response to outpatient treatment
   • Antidepressants, including fluoxetine, have little role in anorexia nervosa except where there is coexisting major depression.
   • Enhanced cognitive behavior therapy and family-based treatment are also recommended for anorexia nervosa.
2. Bulimia Nervosa
   • Inpatient psychiatric care is less often considered for bulimia nervosa unless there are comorbid health issues like severe depression, suicidal ideation, electrolyte imbalance, or laxative abuse.  
   • The first-line management of bulimia nervosa is cognitive behavioral therapy, focusing on breaking the binge-purge cycle. Individual psychotherapy and other techniques like assertive training, relaxation training can also be used. Group therapy and family-based therapy are also useful. 
   • Antidepressants like fluoxetine, amitriptyline, imipramine decrease binge-purge behavior, improve eating habits, and decrease the preoccupation with food and weight. Fluoxetine is the only FDA approved on the list. 
   • Comorbid medical conditions like electrolyte imbalance or dehydration should be managed appropriately. 
3. Binge Eating Disorder 
   • Cognitive-behavioral therapy and interpersonal therapy are the first-line therapy that causes resolution in half of the cases.
   • Antidepressants like fluoxetine, anticonvulsants, and lisdexamfetamine may also play a role in the management of BED. 
   • Weight-loss management decreases binge eating frequency. The structured meal plans may give reasonable control over food intake. 
   • Spontaneous remission is also possible.
4. Avoidant or Restrictive Food Intake Disorder (ARFID)
   • Cognitive behavior therapy can be used for managing ARFID in individuals above ten years of age.
5. Pica
   • The treatment strategy for pica includes decreasing the exposure to the craved items, micronutrient supplementation, and behavioral/aversive treatment, particularly among mentally disabled individuals.
   • Comorbid health issues also need to be addressed, including lead poisoning, infectious disease, or micronutrient deficiency. 
6. Rumination Disorder
   • The treatment strategy for rumination disorder includes biofeedback-guided diaphragmatic breathing, general relaxation, aversion training, and distraction technique.[21] The role of baclofen in treating rumination disorder is under trial. 
7. Other Specified Feeding and Eating Disorder (OSFED)
   • The management of purging disorder is similar to bulimia nervosa.
   • The management of night eating syndrome is similar to Binge eating disorder.

Differential Diagnosis

Many medical conditions can mimic eating disorders. Chronic infectious disease, malabsorptive disorders, malignant conditions, immune deficiency, endocrine disorders like diabetes mellitus, hyperthyroidism, or Addison's disease should be ruled out before labeling it as an eating disorder. Intense fear of gaining weight and distorted body will be the hallmark findings in eating disorders, which help rule out the other medical conditions mentioned above.

Obsessive-compulsive disorder, affective disorders, major depression, anxiety disorders, and drug abuse are often present as comorbid psychiatric conditions along with eating disorders. A high index of suspicion is necessary to detect comorbid psychiatric conditions.

Personality disorders also are shared with eating disorders. Dramatic or erratic personality is associated with Bulimia nervosa, and avoidant or anxious personality disorder is associated with anorexia nervosa.

Prognosis

The prognosis for persons with eating disorders is variable. The long-term prognosis is better with Bulimia nervosa when compared to anorexia nervosa. The binge eating and purging behaviors, duration of more than six years, lower body mass index, low motivation, unstable personality, concurrent depression, higher body image concerns, and dysfunctional relationships are consistently associated with poor treatment outcomes in all eating disorders.

A major challenge in treatment outcomes among individuals with eating disorders is a delay in seeking health care due to low levels of health literacy, stigma, poor affordability, and poor psychotherapy access. Recovery from bulimia nervosa occurs earlier than anorexia nervosa. The majority of individuals with bulimia nervosa recover within 9 to 10 years, but only 50% of individuals with Anorexia nervosa recover within 9-10 years.[22] The mortality rate in Anorexia nervosa is higher than other types of eating disorders and is the highest mortality rate of any psychiatric disorders.[11][12]

Complications

The complications of eating disorders can be classified as acute or chronic physical complications and psychological comorbidities. 

Acute Complications

Usually correlate with the rate of weight loss. 

1. Cardiovascular - bradycardia, hypotension, arrhythmias, pericardial effusion, heart failure, and myocardial fibrosis and pulmonary edema
2. Haematological - anemia, impaired immunity 
3. Cognitive deficits with memory and concentration impairment
4. Other complications -  Peripheral neuropathy, proximal myopathy, hepatitis, pancreatitis, constipation
5. Frequent vomiting associated with eating disorders can cause poor dental health. One-third of bulimia nervosa patients have enlargement of the parotid gland.
6. Hyponatremia can be caused by the use of diuretics, vomiting, and excessive water intake. During the phase of refeeding, hypokalemia is common. Aggressive nutrition therapy could cause a hypophosphatemia-induced refeeding syndrome characterized by rhabdomyolysis, hemolysis, ileus, metabolic acidosis, hypotension, arrhythmias, cardiac failure, seizures, coma, and sudden death.
7. Patients with eating disorders can have a multivitamin deficiency, including thiamine, niacin, vitamin B6, B12, vitamin C, D, E, K, and folate. They can also have iron, zinc, magnesium, and copper deficiency.
8. Anorexia nervosa is complicated by dysregulation of the hypothalamic-pituitary axis causing hypothalamic amenorrhea and dysregulation of hypothalamic-pituitary-adrenal axis causing hypercortisolemia and growth hormone resistance. 

Chronic Complications

1. Growth and development may be slowed. Puberty can also be delayed.
2. Eating disorders could cause amenorrhoea in females and impotence in males. If the women with eating disorders become pregnant, she faces a higher rate of obstetric complications.
3. Bone mineral density is decreased, and greater risk for fractures.
4. Binge eating could pose a risk of obesity and type 2 diabetes.

Psychiatric Comorbidity

Common in eating disorders.

1. Anxiety disorders 
2. Depression with suicidal thoughts 
3. Compulsive behaviors, such as skin-picking, hair-pulling, and compulsive exercise 
4. Impulsive behaviors, such as self-harm, aggression, alcohol use, and drug use
5. Obsessive-compulsive personality disorder, borderline personality disorder, and avoidant personality disorder are common with eating disorders.

Refeeding Syndrome

• Refeeding syndrome is clinical and metabolic changes arising from aggressive nutritional rehabilitation of a malnourished patient. The most common complication is hypophosphatemia. Fluid overload common in refeeding syndrome. 
• The following factors help in preventing refeeding syndrome, 
• The initial protein intake should be 1.2 grams per kilogram of ideal body weight per day. 
• A low-calorie intake of 30 kcal/kilogram/day during the first week
• Phosphorus should be supplemented to maintain serum levels above 3.0 mg/dL.
• Monitoring for Refeeding
• Clinical Monitoring -
• Continuous cardiorespiratory monitor
• Focus on cardiac and neurologic
• Strict intake and output
• Calorie count
• Daily weights
• Biochemical Monitoring (At baseline and at least daily)
• Measure phosphorus, magnesium, potassium, glucose, sodium, and renal function
• Zinc and pre-albumin levels are also measured. 
• Treatment of refeeding syndrome 
• Rehydrate carefully and correct the electrolyte imbalance. 
• Administer thiamine before feeding at the dose of 100 to 300 mg per day oral or 50 to 100 mg/day intravenous.
• Start feeding at lower calories of 10 kcal per kg/day and gradually increase over seven days.[23]