Anorexia Nervosa/Atypical Anorexia Nervosa
Section snippets
Anorexia Nervosa
Anorexia nervosa (AN) is a diagnostic term that literally means neurotic loss of appetite. Sir William Gull first reported a case of AN in the Lancet in 1888.1 The diagnostic criteria for AN have evolved considerably over time. For example, in the DSM III, the weight loss criterion was more stringent in that a 25% weight loss was required. There was, however, no amenorrhea criterion at that time. The criteria also used to specify that the weight loss was not due to another medical illness.2 It
Etiology
While the etiology of EDs is largely unknown, it is thought that a combination of biological, psychological, and social factors contribute to the illness (Table 2). We know EDs tend to cluster in families.21 Though based on small sample sizes, we also know from twin studies that the concordance for monozygotic twins having AN is greater than for dizygotic twins.22 Genes are thought to contribute anywhere from more than 50% up to 74% of the risk to developing AN.23 Studies also show there is an
Demographics/Prevalence
In general, the incidence of AN in society is relatively low, with one study citing it as 8/100,000, with average prevalence rates being 0.3 for young females, and 0.3–1% for BN.49, 50 The lifetime prevalence of AN is between 0.5% and 2%.51 However, since EDNOS has accounted for the majority of ED diagnoses, in the past, the overall prevalence rate is felt to be 3%.50 One multi-site study looking at the ED population in 14 adolescent medicine clinics showed that 33.9% of patients met criteria
Medical Complications
The major cause for the medical complications in AN is the imbalance between energy intake and requirements, leading to a hypometabolic state. Therefore, in an effort to maintain homeostasis in the malnourished state, the body down regulates, causing many of the signs and symptoms observed in AN. Little has been reported as yet on the medical complications of atypical AN. One study of 118 individuals, 59 meeting DSM-IV criteria for AN, and another 59 with “subthreshold” AN, showed no difference
Psychiatric Comorbidities/Complications
As a general rule, AN is typically present with other psychiatric disorders, with one study examining adolescent females finding cormobidity rates as high as 73.3%.63 These comorbid disorders should always be screened for as they can further complicate treatment.64 Two of the most common psychiatric comorbidites present with AN are depression and anxiety disorders. One study showed mood disorders were the most common at around 60.4%.63 Anxiety disorders are also highly prevalent, with one study
Similarities Between Anorexia Nervosa and Atypical Anorexia Nervosa
There are many similarities between AN and atypical AN, and the criteria is almost the same, as discussed in the next section. Those with atypical AN have lost a large amount of weight by engaging in ED behaviors, including restricting and often over-exercising, and may binge/purge, vomit or abuse diet pills, laxatives or diuretics as in the AN-binge/purge subtype. Further, these patients report an intense fear of gaining weight and often deny or do not recognize the seriousness of the weight
Differences Between Anorexia Nervosa and Atypical Anorexia Nervosa
In comparing and contrasting AN with atypical AN, the similarities are more striking than the differences. In terms of differences between the two, there is essentially one main difference, the patient’s weight. Patients with AN are often significantly emaciated, which may raise concerns with parents, teachers, etc. Those with atypical AN can be of normal weight, overweight, obese or slightly underweight.
Although there is essentially no available literature comparing the two diagnoses, in
Making the Diagnosis of Anorexia Nervosa versus Atypical Anorexia Nervosa
Despite the different diagnostic criteria for AN and atypical AN found in the DSM-5, distinguishing between the two can prove challenging. For AN, the below 85% IBW cutoff was eliminated as a criterion9 which allows clinicians to exercise their discretion in determining what is a significantly low weight. While there are suggested BMI guidelines included in the severity specifiers for mild, moderate, severe and extreme AN,9 these BMI guidelines mostly apply to adults, not to adolescents, and
Evaluation/Assessment/Monitoring—Medical and Psychiatric
In terms of medical assessment, all patients with AN and atypical AN need a thorough baseline medical evaluation to check for medical stability. The examination should include patient׳s height, post-void undressed weight, BMI, BMI percentile and orthostatic vital signs (blood pressure and pulse rates), along with temperature and respiratory rates. A full physical examination should include all organ systems, looking for signs of ED behavior (calluses or parotid enlargement from purging) and to
Treatment—Biological
The primary treatment for both AN and atypical AN is for the patient to consume sufficient caloric intake and correct the underlying malnutrition. Though cliché, food is the best medicine to treat an ED. Not only will the nutritional rehabilitation correct the medical complications, but it can also help correct the psychological aspects, as typically ED thoughts, and to some extent depression and anxiety, will improve with refeeding. Despite the fact that patients with atypical AN are often
Treatment—Psychological
As mentioned above, refeeding is the first step in treatment, and is necessary to help with depressive and anxiety symptoms and is a vital precursor to more effective therapy. While limited evidence exists that therapies other than a family-based treatment (FBT) approach helps treat patients with AN, refeeding patients is often done alongside other psychotherapy approaches. Cognitive behavioral therapy (CBT), dialectical behavioral therapy (DBT), interpersonal therapy (IPT), cognitive
Treatment—Social
Social treatment for both AN and atypical AN involves building up the lives of these patients outside of the ED. Adolescents with AN and atypical AN benefit greatly from self-esteem building activities, including finding areas of success, whether it be through new hobbies, excelling in an area in school, obtaining a job, feeling more independent, making new friends, etc. Given the complexity of AN and atypical AN, as well as the high acuity associated with these illnesses, multidisciplinary
Prognosis
Despite advances in psychiatry, the prognosis for AN remains guarded. It is thought that, on average, less than half recover, one third have a varied course, and 20% remain chronically ill.94 A 21-year follow-up study of 84 patients who were hospitalized for AN showed that 51% had recovered, while 10% still met full diagnostic criteria for AN and 16% had passed away from complications of the AN.95 While specific studies do not yet exist examining the prognosis of atypical AN, it can be surmised
Conclusion
Since the first case report of anorexia nervosa appeared in the literature over 125 years ago, much has been learned about eating disorders. Presently, eleven distinct eating disorders are categorized in the DSM-5, from the classic anorexia nervosa, to rumination disorder and night-eating syndrome. Research regarding causation, course, complications, and treatments fill the literature. Indeed, entire programs and careers focus solely on the care of those with eating disorders. However, in spite
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