Anorexia Nervosa

Anorexia nervosa is an eating disorder marked by self-imposed starvation and inappropriate dietary habits due to a morbid fear of weight gain and disturbed perception of body shape and weight. Patients have strikingly low BMI and diverse physiological and psychological complications. The condition is most commonly seen in adolescent girls. Treatment consists of psychotherapy Psychotherapy Psychotherapy is interpersonal treatment based on the understanding of psychological principles and mechanisms of mental disease. The treatment approach is often individualized, depending on the psychiatric condition(s) or circumstance. Psychotherapy (CBT) and patient hospitalization for intensive care and management of complications. Pharmacotherapy has a limited role.

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Overview

Definition

Anorexia nervosa is an eating disorder characterized by self-imposed starvation and inappropriate dietary habits due to an intense fear of weight gain and disturbed perception of body shape and weight.

Epidemiology

  • Common in young women aged 15–25 years 
  • Prevalence: approximately 1%
  • Women:men ratio: 3:1
  • Patients in professions that stress thinness, such as ballet dancers, athletes, and models, are frequently affected.
  • Highest death rate of any mental illness (5%–20%)

Pathophysiology

Complex interaction between biological, psychological, and social factors:

  • Sociocultural factors:
    • Media influence on excessive need to be thin
    • Cultural norms, excessively emphasizing thinness
  • Genetic factors: anorexia nervosa more likely in monozygotic than dizygotic twins
  • Environmental factors: Interpersonal relationships may affect eating habits.
  • Psychological factors:
    • Low self-esteem
    • Perfectionism
    • Impulsivity
    • OCD OCD Obsessive-compulsive disorder (OCD) is a condition characterized by obsessions (recurring and intrusive thoughts, urges, or images) and/or compulsions (repetitive actions the person is compelled to perform) that are time-consuming and associated with functional impairment. Obsessive-compulsive Disorder (OCD)
  • Neurobiological factors:
    • Abnormalities in brain areas (corticolimbic circuits, dorsal striatum) involved in appetite and habitual behavior 
    • Abnormalities in dopamine and serotonin neurotransmitters 

Clinical Presentation

Anorexia nervosa affects almost all body systems and can present with a variety of symptoms and signs.

Symptoms

  • Difficulty concentrating and making decisions
  • Depressed mood and anxiety 
  • Headaches
  • Fainting or dizzy spells
  • Lethargy
  • Cold intolerance (decreased thyroid hormones Thyroid hormones The 2 primary thyroid hormones are triiodothyronine (T3) and thyroxine (T4). These hormones are synthesized and secreted by the thyroid, and they are responsible for stimulating metabolism in most cells of the body. Their secretion is regulated primarily by thyroid-stimulating hormone (TSH), which is produced by the pituitary gland. Thyroid Hormones)
  • Epigastric pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain, gastroparesis, constipation Constipation Constipation is common and may be due to a variety of causes. Constipation is generally defined as bowel movement frequency < 3 times per week. Patients who are constipated often strain to pass hard stools. The condition is classified as primary (also known as idiopathic or functional constipation) or secondary, and as acute or chronic. Constipation

Signs

  • Emaciation
  • Hypotension Hypotension Hypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension, bradycardia, arrhythmias
  • Hypothermia Hypothermia Hypothermia can be defined as a drop in the core body temperature below 35°C (95°F) and is classified into mild, moderate, severe, and profound forms based on the degree of temperature decrease. Hypothermia
  • Dry skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Structure and Function of the Skin, dehydration, lanugo (body hair/thin hair)
  • Breast atrophy
  • Physical signs consistent with self-induced vomiting: 
    • Swelling of the salivary glands Salivary glands The salivary glands are exocrine glands positioned in and around the oral cavity. These glands are responsible for secreting saliva into the mouth, which aids in digestion. There are 3 major paired salivary glands: the sublingual, submandibular, and parotid glands. Salivary Glands
    • Dental caries
    • Scars or calluses on the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand from contact with the teeth Teeth Normally, an adult has 32 teeth: 16 maxillary and 16 mandibular. These teeth are divided into 4 quadrants with 8 teeth each. Each quadrant consists of 2 incisors (dentes incisivi), 1 canine (dens caninus), 2 premolars (dentes premolares), and 3 molars (dentes molares). Teeth are composed of enamel, dentin, and dental cement. Teeth (Russell sign)
  • Peripheral edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema, edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema around the eyes, abdominal distension
  • Amenorrhea 

Lab findings

  • Low iron, folate Folate Folate and vitamin B12 are 2 of the most clinically important water-soluble vitamins. Deficiencies can present with megaloblastic anemia, GI symptoms, neuropsychiatric symptoms, and adverse pregnancy complications, including neural tube defects. Folate and Vitamin B12, or B12 levels ( anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview)
  • Cytopenias
  • Serum electrolyte abnormalities due to recurrent vomiting (low potassium, calcium, magnesium, and phosphate)
  • Disturbances in albumin (low albumin indicate a chronically low protein intake)
  • Elevated liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver enzymes Enzymes Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body's constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes
  • Urinalysis showing increased sedimentation rate
  • Low luteinizing hormone (LH) and follicle-stimulating hormone (FSH) ( secondary amenorrhea Secondary Amenorrhea Secondary amenorrhea is defined as the absence of menses for 3 months in a woman with previously regular menstrual cycles or for 6 months in a woman with previously irregular cycles. Etiologies involve either disruptions to the hypothalamic-pituitary-ovarian (HPO) axis or acquired obstructions in the uterus or outflow tract. Secondary Amenorrhea
  • Hypercholesterolemia
  • Disruption of thyroid hormone level

Clinical imaging

  • ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Normal Electrocardiogram (ECG): shows sinus bradycardia
  • DEXA scan: decreased bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones mineral density due to insufficient calcium, phosphate, and vitamin D in diet 
  • Imaging may be required to rule out malignant causes of weight loss.

Complications

  • Myocardial atrophy
  • Mitral valve prolapse Mitral valve prolapse Mitral valve prolapse (MVP) is the most common cardiac valvular defect, and is characterized by bulging of the mitral valve (MV) cusps into the left atrium (LA) during systole. Mitral valve prolapse is most commonly due to idiopathic myxomatous degeneration. Patients are typically asymptomatic. Mitral Valve Prolapse
  • Pericardial effusion Pericardial effusion Pericardial effusion is the accumulation of excess fluid in the pericardial space around the heart. The pericardium does not easily expand; thus, rapid fluid accumulation leads to increased pressure around the heart. The increase in pressure restricts cardiac filling, resulting in decreased cardiac output and cardiac tamponade. Pericardial Effusion and Cardiac Tamponade
  • Osteoporosis Osteoporosis Osteoporosis refers to a decrease in bone mass and density leading to an increased number of fractures. There are 2 forms of osteoporosis: primary, which is commonly postmenopausal or senile; and secondary, which is a manifestation of immobilization, underlying medical disorders, or long-term use of certain medications. Osteoporosis
  • Gastroparesis
  • Amenorrhea, infertility Infertility Infertility is the inability to conceive in the context of regular intercourse. The most common causes of infertility in women are related to ovulatory dysfunction or tubal obstruction, whereas, in men, abnormal sperm is a common cause. Infertility (functional hypothalamic amenorrhea due to low levels of LH and FSH)
  • Growth disturbances

Diagnosis

Criteria

Diagnosis is clinical, based on observed criteria:

  • Restricted dietary habits resulting in significantly low body weight
  • Intense fear of gaining weight
  • Perceived disturbance in body weight and shape
  • Symptoms must be present for at least 3 months.

Subtypes

  • Restricting type: characterized by excessive starvation (weight loss is accomplished primarily through dieting, fasting, and/or excessive exercise) 
  • Binge-eating/purging type: characterized by the use of drugs ( laxatives Laxatives Laxatives are medications used to promote defecation. Most often, laxatives are used to treat constipation or for bowel preparation for certain procedures. There are 4 main classes of laxatives: bulk-forming, stimulant, osmotic, and emollient. Laxatives, diuretics), induced vomiting, and excessive exercise as a means to reduce weight 

Severity

  • Mild: BMI 17–18.49 kg/m2
  • Moderate: BMI 16–16.99 kg/m2
  • Severe: BMI 15–15.99 kg/m2
  • Extreme: BMI < 15 kg/m2

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Management and Prognosis

Management

Treatment involves a combination of psychotherapy Psychotherapy Psychotherapy is interpersonal treatment based on the understanding of psychological principles and mechanisms of mental disease. The treatment approach is often individualized, depending on the psychiatric condition(s) or circumstance. Psychotherapy and pharmacotherapy.

  • Psychotherapy:
    • A comprehensive therapeutic approach is recommended. 
    • CBT is the mainstay of treatment.
    • Family therapy is also recommended, especially for those patients who reside with their families.
  • Pharmacotherapy:
    • Limited role
    • Olanzapine may be indicated in some cases (helps patients to gain weight) 
    • Antidepressants can also help patients to gain weight (e.g., paroxetine or mirtazapine).

Consider hospitalizing patients with:

  • Heart rate < 40/min
  • Blood pressure < 80/60 mm Hg
  • Cardiac dysrhythmia
  • Cardiovascular, hepatic, or renal compromise requiring medical stabilization
  • Severe dehydration
  • Serious medical complications of malnutrition Malnutrition Malnutrition is a clinical state caused by an imbalance or deficiency of calories and/or micronutrients and macronutrients. The 2 main manifestations of acute severe malnutrition are marasmus (total caloric insufficiency) and kwashiorkor (protein malnutrition with characteristic edema). Malnutrition in children in resource-limited countries (e.g., electrolyte imbalance, hypoglycemia Hypoglycemia Hypoglycemia is an emergency condition defined as a serum glucose level ≤ 70 mg/dL (≤ 3.9 mmol/L) in diabetic patients. In nondiabetic patients, there is no specific or defined limit for normal serum glucose levels, and hypoglycemia is defined mainly by its clinical features. Hypoglycemia, or syncope Syncope Syncope is a short-term loss of consciousness and loss of postural stability followed by spontaneous return of consciousness to the previous neurologic baseline without the need for resuscitation. The condition is caused by transient interruption of cerebral blood flow that may be benign or related to a underlying life-threatening condition. Syncope)
  • Suicidal ideation with plan or attempt
  • Body mass index < 15 kg/m2 or ideal body weight < 70%

Refeeding syndrome:

  • Constellation of metabolic disturbances that may occur due to refeeding of malnourished patients who are persistently starved.
  • Sudden increase in caloric intake causes an increase in insulin Insulin Insulin is a peptide hormone that is produced by the beta cells of the pancreas. Insulin plays a role in metabolic functions such as glucose uptake, glycolysis, glycogenesis, lipogenesis, and protein synthesis. Exogenous insulin may be needed for individuals with diabetes mellitus, in whom there is a deficiency in endogenous insulin or increased insulin resistance. Insulin production.
  • Increase in insulin Insulin Insulin is a peptide hormone that is produced by the beta cells of the pancreas. Insulin plays a role in metabolic functions such as glucose uptake, glycolysis, glycogenesis, lipogenesis, and protein synthesis. Exogenous insulin may be needed for individuals with diabetes mellitus, in whom there is a deficiency in endogenous insulin or increased insulin resistance. Insulin causes a sudden shifting of fluid and electrolytes Electrolytes Electrolytes are mineral salts that dissolve in water and dissociate into charged particles called ions, which can be either be positively (cations) or negatively (anions) charged. Electrolytes are distributed in the extracellular and intracellular compartments in different concentrations. Electrolytes are essential for various basic life-sustaining functions. Electrolytes into cells.
  • Marked electrolyte disturbances (hypophosphatemia), seizures Seizures A seizure is abnormal electrical activity of the neurons in the cerebral cortex that can manifest in numerous ways depending on the region of the brain affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons, creating a net excitation. The 2 major classes of seizures are focal and generalized. Seizures, delirium Delirium Delirium is a medical condition characterized by acute disturbances in attention and awareness. Symptoms may fluctuate during the course of a day and involve memory deficits and disorientation. Delirium, cardiac complications (cardiopulmonary failure), rhabdomyolysis Rhabdomyolysis Rhabdomyolysis is characterized by muscle necrosis and the release of toxic intracellular contents, especially myoglobin, into the circulation. Rhabdomyolysis
  • Aggressive nutrition without good monitoring can be fatal.

Prognosis

  • With timely treatment, most of the complications (except for osteoporosis) may be reversible.
  • One of the highest mortality rates among the psychiatric disorders
  • Those with restricting type are less likely to recover than those with binge-eating/purging type.

Differential Diagnosis

  • Bulimia nervosa Bulimia nervosa Bulimia nervosa is an eating disorder marked by recurrent episodes of binge eating accompanied by inappropriate compensatory behaviors (laxatives or diuretics use, self-induced vomiting, fasting, or excessive exercise) to counteract the effects of binge eating and prevent weight gain. Bulimia Nervosa: an anxiety-driven eating disorder defined by recurrent episodic binge eating paired with recurrent inappropriate compensatory behavior (inducing vomiting, laxative abuse, excessive exercising). Patients with this condition may have normal or even elevated BMI and are more likely to seek help. Treatment involves a combination of CBT and SSRIs.
  • Binge-eating disorder: an eating disorder marked by recurrent episodes of binge eating without inappropriate compensatory behavior, resulting in fluctuating body weight. Episodes occur at least once a week for 3 months. Treatment consists of a combination of psychotherapy Psychotherapy Psychotherapy is interpersonal treatment based on the understanding of psychological principles and mechanisms of mental disease. The treatment approach is often individualized, depending on the psychiatric condition(s) or circumstance. Psychotherapy and pharmacotherapy.
  • Rumination disorder Rumination Disorder Rumination disorder is a behavioral disorder marked by repeated regurgitation of food, which may be re-chewed, re-swallowed, or spit out. This condition is not due to a medical disorder (GERD or pyloric stenosis) or other eating disorders (avoidant/restrictive food intake disorder, anorexia nervosa, binge eating disorder, or bulimia nervosa). Rumination Disorder: repeated regurgitation of food, which may be re-chewed, re-swallowed, or spit out, and which is not due to a general medical condition (e.g., GERD GERD Gastroesophageal reflux disease (GERD) occurs when the stomach acid frequently flows back into the esophagus. This backwash (acid reflux) can irritate the lining of the esophagus, causing symptoms such as retrosternal burning pain (heartburn). Gastroesophageal Reflux Disease). Treatment involves multiple CBT techniques, including biofeedback psychotherapy Psychotherapy Psychotherapy is interpersonal treatment based on the understanding of psychological principles and mechanisms of mental disease. The treatment approach is often individualized, depending on the psychiatric condition(s) or circumstance. Psychotherapy, as well as medication, when appropriate (e.g., proton pump inhibitors).

References

  1. Kessler RC, et al. (2013). The prevalence and correlates of binge eating disorder Binge Eating Disorder Binge eating disorder is an eating disorder marked by recurrent episodes of binge eating without inappropriate compensatory behavior. Episodes occur at least weekly for 3 consecutive months. There is a loss of control during the episodes of binging as well as distress after. Binge Eating Disorder in the World Health Organization World Mental Health Surveys. Biol Psychiatry. 73(9), 904–914. https://pubmed.ncbi.nlm.nih.gov/23290497/
  2. Keel PK, McCormick L. (2010). Diagnosis, assessment, and treatment planning for anorexia nervosa. In Grilo CM, Mitchell JE (Eds.). The Treatment of Eating Disorders: A Clinical Handbook, The Guilford Press, New York. p.3.
  3. Westmoreland P, Krantz MJ, Mehler PS. (2016). Medical Complications of Anorexia Nervosa and Bulimia. Am J Med. 129(1), 30–37. https://pubmed.ncbi.nlm.nih.gov/26169883/
  4. da Silva JSV, et al. (2020). Parenteral Nutrition Safety and Clinical Practice Committees, American Society for Parenteral and Enteral Nutrition. ASPEN Consensus Recommendations for Refeeding Syndrome. Nutr Clin Pract. 35(2), 178–195. https://pubmed.ncbi.nlm.nih.gov/32115791/
  5. Sadock BJ, Sadock VA, Ruiz P. (2014). Kaplan and Sadock’s synopsis of psychiatry: Behavioral sciences/clinical psychiatry (11th ed.). Chapter 15, Feeding and Eating Disorders. Philadelphia, PA: Lippincott Williams and Wilkins. pp. 509–532.
  6. Westmoreland P. (2017). Feeding and eating disorders. Retrieved May 27, 2021, from https://doi.org/10.2310/im.13038
  7. Westmoreland P. (2018). Clinical management of feeding and eating disorders. Retrieved May 27, 2021, from https://doi.org/10.2310/im.13039

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