Anorexia nervosa is a potentially life-threatening eating disorder characterized by the inability to maintain a minimally normal weight, a devastating fear of weight gain, relentless dietary habits that prevent weight gain, and a disturbance in the way in which body weight and shape are perceived.
The Royal Australian and New Zealand College of Psychiatrists released the first set of eating disorder guidelines that incorporate recommendations from the DSM-5. The guidelines focus on anorexia nervosa, but also cover bulimia nervosa, binge eating disorder, and the new disorder of avoidant restrictive food intake disorder.[1, 2]
Vital sign changes found in patients with anorexia nervosa include hypotension, bradycardia, and hypothermia. Other changes include the following :
Patients with purging behavior may have callouses to the dorsum of their dominant hand and dental enamel erosion.
Characteristic signs of inadequate energy (caloric) intake observed in patients with anorexia nervosa that are due to starvation-induced changes include the following:
Behaviorally, a patient may demonstrate a flat affect and display psychomotor retardation, especially in the later stages of the disease.
Because an eating disorder is a clinical diagnosis, no definitive diagnostic tests are available for anorexia nervosa. However, given the multi-organ system effects of starvation, a thorough medical evaluation is warranted. Basic tests include the following:
Gastrointestinal signs of anorexia nervosa include intestinal dilation from constipation and diminished intestinal motility.
Fecal occult blood may be indicative of esophagitis, gastritis, or repetitive colonic trauma from laxative abuse. Thyroid function tests, prolactin, and serum follicle-stimulating hormone (FSH) levels can differentiate anorexia nervosa from alternative causes of primary amenorrhea.
The process of refeeding must be undertaken slowly, with modest increases in metabolic demands, in order to avoid refeeding syndrome (which includes cardiovascular collapse, starvation-induced hypophosphatemia, and dangerous fluctuations in potassium, sodium, and magnesium levels). A nutritionist or dietitian should be an integral part of the refeeding plan.
Electrolyte repletion is necessary in patients with profound malnutrition, dehydration, and purging behaviors. Repletion may be done orally or parenterally, depending on the patient’s clinical state.
Various psychological therapies have proven helpful in treating patients with anorexia nervosa, including the following:
Individuals with anorexia nervosa may respond best to family based treatment, also known as the Maudsley method, an established therapeutic modality for achieving and maintaining remission from anorexia nervosa.
Evidence regarding the efficacy of medication treatment for eating disorders has tended to be weak or moderate. However, fluoxetine has been found to be generally helpful in patients with anorexia nervosa who have been stabilized with weight restoration. Psychotherapy with adjunctive low-dose olanzapine may be useful for anorexia nervosa during inpatient treatment, especially in the context of anxiety, obsessive eating-related ruminations, and treatment resistance due to failure to engage.
Anorexia nervosa is an eating disorder characterized by the inability to maintain a minimally normal weight, a devastating fear of weight gain, relentless dietary habits that prevent weight gain, and a disturbance in the way in which body weight and shape are perceived. This condition has potentially life-threatening physiologic effects and causes enduring psychological disturbance. (See Prognosis and Clinical Presentation.)
With the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), changes have occurred in the definition of anorexia nervosa, namely in Criterion A there is a focus on behaviors including restricting calorie intake, and the word “refusal” is no longer included related to weight maintenance because of the incorrect and possibly stigmatizing implication of intention on the part of the patient and because this aspect may be not something that can accurately be assessed.
The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) Criterion D requiring amenorrhea, or the absence of at least three menstrual cycles, has been deleted as that criterion cannot be applied to males or premenarchal females, females taking oral contraceptives, and postmenopausal females. In some cases, individuals exhibit all other symptoms and signs of anorexia nervosa but still report some menstrual activity.
Anorexia nervosa may be divided into 2 subtypes:
Restricting, in which severe limitation of food intake is the primary means to weight loss
Binge-eating/purging type, in which there are periods of food intake that are compensated by self-induced vomiting, laxative or diuretic abuse, and/or excessive exercise
Although the DSM-5 separates anorexia nervosa and bulimia nervosa as two separate disorders, there continues to be consideration that these two disorders may be part of a unified eating disorder. Recent research at the University of Chicago with children and adolescents who met criteria for DSM-5 restrictive type (AN) or binge eating/purging type AN (AN-BE/P) differed in their eating patterns as youths with AN-R consumed meals and snacks more regularly relative to youths with AN-BE/P; youths with AN-BE/P who skipped dinner were associated with a greater number of binge eating episodes, and skipping breakfast was associated with a greater number of purging episodes. Thus, it appeared that youths with AN-R followed a more regular pattern but consumed insufficient amounts of food during meals and youth with AN-BE/P tended to have more irregular eating patterns.
Patients with anorexia nervosa often display such traits as a desire for perfection and academic success, a lack of age-appropriate sexual activity, and a denial of hunger in the face of starvation. Psychiatric characteristics include excessive dependency, developmental immaturity, social isolation, obsessive-compulsive behavior, and constriction of affect. Many patients also have comorbid mood disorders, with depression and dysthymic disorder being most prevalent.(See Clinical Presentation, Workup, Treatment, and Medication.)
Diagnostic criteria (DSM-5)
Diagnostic criteria for anorexia nervosa in the DSM-5 include the following :
Restriction of energy intake relative to requirements, leading to a significantly low body weight in the context of age, sex, developmental trajectory, and physical health; significantly low weight is defined as a weight that is less than minimally normal or, for children and adolescents, less than that minimally expected
Intense fear of gaining weight or of becoming fat, or persistent behavior that interferes with weight gain, even though the patient’s weight is already significantly low
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 persistent lack of recognition of the seriousness of the current low body weight
The DSM-5, which was published in May 2013, revised the definition of anorexia from the DSM-IV to focus more on behaviors, such as calorie restricting, and removed the qualification of low weight being less than 85% ideal body weight. Additionally, the criterion of amenorrhea in postmenarchal females was completely removed from the definition. (See Clinical Presentation.)
The prevalence of subthreshold eating conditions supports the notion that eating disorders tend to exist along a spectrum and that, if defined by a broader range of symptoms, might be better recognized by doctors. (See Workup, Treatment, and Medication.)
A typical case of anorexia nervosa involves a young person (teenager or young adult) who is mildly overweight or of normal weight and who begins a diet and exercise plan to lose weight. As he or she loses weight and receives initial positive reinforcement for this behavior (eg, compliments by peers on his or her appearance), the reward is high and causes an inability to stop this behavior once an ideal weight is achieved.
Malnutrition subsequent to self-starvation leads to protein deficiency and disruption of multiple organ systems, including the cardiovascular, renal, gastrointestinal, neurologic, endocrine, integumentary, hematologic, and reproductive systems.
Cardiac complications are the most common cause of death; the mortality rate is about 10%. Cardiac effects from anorexia nervosa include profound bradycardia, hypotension, decreased size of the cardiac silhouette, and decreased left ventricular mass associated with abnormal systolic function. Patients with anorexia report fatigue and have an attenuated blood pressure response to exercise and reduction in maximal work capacity. An increased incidence of mitral valve prolapse without significant mitral regurgitation is also observed. Low potassium-dependent QT prolongation increases the risk of ventricular arrhythmia.
The patient’s vital signs reflect hypotension with systolic pressures as low as 70 mm Hg and sinus bradycardia with heart rates as low as 30-40 beats per minute. These changes are a response to a decrease in the basal metabolic rate. The mechanism may be due to an autonomic imbalance in heart rate regulation, with increases in vagal activity and a reduction in sympathetic activity. These changes are physiologic cardiovascular responses, and treatment is unnecessary, unless negative clinical sequelae are present.
If electrocardiography (ECG) is performed, evidence of sinus bradycardia, ST-segment elevation, T-wave flattening, low voltage, and rightward QRS axis is apparent. All the aforementioned changes are clinically insignificant; however, the frequency of rhythm disturbances is most concerning, especially QT-interval prolongation that may be an indication for those at risk of cardiac arrhythmias and sudden death.
Cardiac decompensation is greatest during the initial 2 weeks of refeeding, when the myocardium cannot withstand the stress of an increased metabolic demand. However, if the daily weight gain is 0.2-0.4 kg, then complications are limited.
Endocrinologic and metabolic complications
Foremost in the gamut of endocrinologic complications is amenorrhea, although, as previously mentioned, the DSM-5 no longer includes this condition as part of the diagnostic criteria of anorexia nervosa. Amenorrhea results from disorders in the hypothalamic-pituitary-ovarian axis in which levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are low despite low levels of estrogen. Reversion to the prepubertal state occurs; the LH response to gonadotropin-releasing hormone (GnRH) is blunted. This blunted response is insufficient to maintain menstrual integrity, and amenorrhea results.
Weight loss and emotional instability play a role in amenorrhea, although amenorrhea persists in 5-44% of patients in whom weight gain has been documented. The explanation for this wide range has not been elucidated.
Other changes related to endocrine function include a reduction in fertility, multiple small follicles in the ovaries, and decreased uterine volume and atrophy.
Thyroid function is also affected in patients with anorexia nervosa, with laboratory data revealing a decrease in triiodothyronine (T3) and thyroxine (T4) and an increase in reverse T3. These changes are characteristic of the euthyroid sick syndrome and, similar to the cardiac changes, represent an adaptive mechanism; hormonal replacement is not necessary.
An associated impaired release of vasopressin consistent with diabetes insipidus is present. This defect is of the neurogenic type; concentration of urine is observed after administering vasopressin. This condition affects 40% of persons with anorexia nervosa and is reversible with weight gain.
Osteopenia is a serious complication. Cortical and trabecular bone are affected, and osteopenia persists despite estrogen therapy. Low levels of progesterone (accelerates remodeling) formation and decreased insulinlike growth factor-1 (IGF-1) levels, which stimulate type 1 collagen biosynthesis, contribute to bone loss.
Treatment of osteopenia with bisphosphonates is not routinely indicated in adolescents, because of concerns about osteonecrosis of the jaw; however, if this therapy is used, close monitoring is critical.[21, 22] Supplementation with 1000-1500 mg/d of dietary calcium and 400 IU of vitamin D is recommended to prevent further bone loss and to maximize peak bone mass. Although exercise and hormonal replacement therapy have some benefit in perimenopausal women, exercise may be deleterious in patients with anorexia nervosa who have amenorrhea, and hormonal replacement may induce premature closure of bone epiphysis.
Patients with anorexia nervosa have fewer gastrointestinal complications than those with bulimia nervosa. Constipation is common. In addition, these patients still have prolonged gastrointestinal transit, alterations in antral motility, and gastric atrophy. Prokinetic agents may accelerate gastric emptying, and the relief from gastric bloating can accelerate resumption of normal eating habits.
Neurologic, integumentary, and renal complications
Cerebral atrophy and loss of brain volume may be observed in patients with anorexia nervosa. Generalized muscle weakness is the most common neurologic symptom.
Patients with anorexia nervosa typically have dry, scaly skin; brittle
Anorexia nervosa results from a complex interplay between biologic, psychological, and social factors; it tends to affect women more than men, and adolescents more than older women.
Prepubescent patients who subsequently develop anorexia nervosa have a high incidence of premorbid anxiety disorders. The onset of anorexia nervosa during puberty has led to the theory that, by exerting control over food intake and body weight, adolescents are attempting to compensate for a lack of autonomy and selfhood.
Modern preoccupation with slenderness and beauty in the Western world may contribute to the mindset of thinness as a valued quality in adolescents; however, this link has not been proven. A subset of adolescents who are temperamentally incapable of dealing with age-appropriate challenges without extreme reward-seeking behavior (thinness) may be susceptible to anorexia nervosa.
Recognizing the predisposing, precipitating, and perpetuating factors in the disease is important to better facilitate early intervention, especially since nutritional rehabilitation performed simultaneously with family-based treatment (eg, the Maudsley method) is crucial to recovery.
Predisposing factors in eating disorders include the following:
Family history of eating disorders
Difficulty communicating negative emotions
Difficulty resolving conflict
Maternal psychopathology (negative expressed emotion, maternal encouragement of weight loss) can also be a risk factor for anorexia nervosa, especially for childhood-onset of this disorder.
Reported cases of anorexia nervosa in twins and triplets suggest the possibility of an increased genetic predisposition.Indeed, there is evidence from twin studies to suggest that the genetic contribution to the disease is as high as 50-80%, a heritability estimate similar to that for bipolar disorder and schizophrenia.
There may be variations of the 5HTT (serotonin transporter gene) genome (eg, biallelic, triallelic) that are associated with subtypes of eating disorders and that interact with life-history factors.
There is also evidence that an area on band 1p at the DF1153721 locus may be related to a 7% increased incidence of anorexia nervosa in first-degree relatives. Genetic risk factors may also be predictive of specific complications in anorexia nervosa, such as bone loss.
Individuals with anorexia nervosa maintain a lifelong increased incidence of anxiety, depressive disorders, and obsessive-compulsive disorder. Neurobiologists hypothesize that disruption of both serotonergic and dopaminergic pathways in the brain mediate the development of anorexia nervosa and may account for the frequent coexistence of other psychological disturbances.
Anorexia nervosa is often heralded by a patient’s desire to lose an insignificant amount of weight through dieting. Once the weight loss is in progress, immunologic and hormonal factors, including leptins (involved with signaling satiety) and alpha-melanocyte–stimulating hormone, may play a role in the downward spiraling and maintenance of anorexia nervosa.
During prolonged food restriction in genetically vulnerable individuals, the ensuing malnutrition perpetuated by the biochemical changes induced by weight loss (ie, ketosis) further magnifies the impact of the malnutrition on the brain, owing to it being in a starvation-illness mode. Thus, it is helpful to conceptualize anorexia nervosa as a developmental condition rather than as a purely mental one.
Precipitating factors relate most often to developmental tasks that cause intense intrapsychic conflict and unconscious feelings of anxiety, which in turn interact with physiologic and biologic ones.
In individuals aged 10-14 years, such precipitating factors are related to sexual development and menarche, which are associated with a spurt in weight gain. Societal influences, such as a peer group that comments in a rejecting fashion, intensify the fear of becoming “fat.” Affected individuals often diet and receive peer acceptance for weight loss; this emotional reinforcement, combined with the physiologic response of the body to the sudden loss of weight (when >5 lb), increases the likelihood of continued weight loss.
Sudden weight loss with loss of fat causes a decrease in body temperature, which physiologically causes a subjective feeling of chills; this discomfort is relieved by increased physical activity, which causes further weight loss. The continuous downward spiraling of weight loss then causes secondary amenorrhea and loss of secondary sexual characteristics, further worsening weight loss.
In adolescents aged 15-16 years, precipitating factors stem from struggles with independence and autonomy. Individuals in this age group with anorexia nervosa typically feel ambivalent about growing up and will transition from dependence to interdependence rather than to independence.
In individuals aged 17-18 years, identity conflicts are more common. These patients do not make healthy transitions from leaving home to going to college or getting married.
Anorexia nervosa is found in all developed countries and in all socioeconomic classes, occurring around the world at similar rates (0.3-1% in women, 0.1-0.3% in men). It is also found in developing countries such as China and Brazil.
According to Mehler et al, certain groups are especially at risk for anorexia nervosa, including dancers, long-distance runners, skaters, models, actors, wrestlers, gymnasts, flight attendants, college sorority members, and others for whom thinness is emphasized and overly rewarded.
In a European study, a 0.48% lifetime incidence of anorexia nervosa was reported among 21,425 respondents.
The lifetime prevalence of anorexia nervosa in the United States is estimated to be 0.3-1%; however, some studies have shown rates as high as 4% among women. The rates among men are estimated at 0.1-0.3%. As many as 5% of young women exhibit symptoms of anorexia but do not meet the full diagnostic criteria, and some studies show disordered eating behavior in 13% of adolescent girls in the United States.
Using nationally representative, face-to-face interview surveys of 10,123 adolescents in the continental United States, Swanson et al found the following 12-month prevalence rates for eating disorders.
Anorexia nervosa (0.2%)
Bulimia nervosa (0.6%)
Binge-eating disorder (1.6%)
Subthreshold anorexia nervosa (0.9%)
Subthreshold binge-eating disorder (1.1%)
Anorexia nervosa is diagnosed more often in the white (>95%) adolescent (>75%) populations of the middle and upper socioeconomic classes, although it can be observed in either sex and in people of any race, age, or social stratum. (Indeed, a link between socioeconomic class and the prevalence of eating disorders has not been demonstrated in the literature.) This disorder is probably underdiagnosed in black individuals and males because of a low index of suspicion.
Anorexia nervosa is more common in women than in men, with a female-to-male ratio of 10-20:1 in developed countries. In some professions, however, the frequency is much higher among men (wrestling, running, modeling) than it is in the general male population. Treatment plans remain the same for both sexes. Gay and bisexual males are more likely to have an eating disorder than heterosexual males, but they are also more likely to have bulimia than anorexia.
Anorexia nervosa has been observed in both the very young and very old, but the disorder is primarily a phenomenon of puberty and early adulthood. Eighty-five percent of patients have onset of the disorder between the ages of 13 and 18 years (although a survey of adolescents by Swanson et al found a median age of onset of 12.3 y). Patients who are older at the time of onset of the disorder have a worse prognosis, as do patients with an onset before age 11 years.
Article is written by Medscape.