32 - Eating Disorders

Eating Disorders

© SPMM Course 7. Disturbances of behaviour and body physiology

This  includes  various  disturbances  in  ‘behaviour’  and  abnormalities  across  a  mixture  of  ‘physiological   systems’  such  as  weight,  libido,  pregnancy, etc. It also includes non-dependence producing substance abuse such as analgesic abuse; antidepressant use; laxative use and steroid abuse. Eating Disorders The ICD-10 diagnostic criteria for Anorexia Nervosa describes the presence of low body weight as being 15% or more below the expected norm and BMI as 17.5 or less. Other features include x Self-induced weight loss, avoidance of fattening foods, vomiting, purging, excessive exercise, use of appetite suppressants. x Body image distortion, dread of fatness: overvalued idea, imposed low weight threshold. x Endocrine disturbances due to HPA axis dysfunction (Hypothalamic- pituitary-gonadal axis) manifesting as amenorrhoea, reduced sexual interest, raised GH levels, increased cortisol, altered Thyroid tests, abnormal insulin secretion. x Delayed/arrested puberty- if onset pre-pubertal. While diagnosing anorexia, Quetelet’s  body mass index is applicable only if age is more than 16.

In DSM-IV, amenorrhea is defined as at least three consecutive cycles being absent. DSM-IV also specifies two types: x Binge-eating/purging type: regularly engaged in bingeeating or purging behavior (such as self-induced vomiting or the use of laxatives, diuretics, or enemas). x Restricting type: no binge-eating or purging behavior In atypical anorexia nervosa, one or more of these essential features may be absent, or all are present but to a lesser degree. Atypical anorexia nervosa is described as “ a disorder that fulfills some of the features of anorexia nervosa but in which the overall clinical picture does not justify that diagnosis. For instance, one of the key symptoms, such as amenorrhoea or marked dread of being fat, may be absent in the presence of marked weight loss and weight-reducing behaviour. This diagnosis should not be made in the presence of known physical disorders associated with  weight  loss.” (ICD-10) x Several features are noted in patients with atypical anorexia when compared to those with typical anorexia. x Older age at onset and presentation x Recurring bouts of depression DSM-5 AND EATING DISORDERS Anorexia Nervosa: The requirement of amenorrhea as a condition for diagnosis has been removed. Bulimia Nervosa: The required minimum average frequency of binge eating/compensatory behaviour is changed from twice to once weekly.

© SPMM Course x Numerous somatic complaints x Unmet dependency needs, and x Little evidence of distortion in body image is seen. Differential Diagnoses for Anorexia Nervosa Physical Disorders Hyperthyroidism; other endocrine disorders; GI disorders resulting in vomiting, loss of appetite and/or malabsorption; Malignancy; Chronic infection. Hypothyroidism can also produce amenorrhea. Psychiatric disorders Depression, OCD with eating abnormalities, delusional behaviour concerning food, vomiting secondary to conversion (cyclical vomiting) Adapted from Focus. Fall 2004, Vol. II, No. 4 (p 528)

The ICD-10 diagnostic criteria for Bulimia Nervosa includes the following: x Persistent preoccupation with eating x Irresistible craving for food x Binges- episodes of overeating x Attempts to counter the fattening effects of food (self-induced vomiting, abuse of purgatives, periods of starvation, use of drugs e.g. appetite suppressants, thyroxine, diuretics) x Morbid dread of fatness, with imposed -low weight threshold In atypical cases of bulimia, one or more of these features may be absent. Neglecting insulin treatment is a weight reduction strategy seen in diabetics with bulimia. In DSM-IV, two types are specified: Purging and non-purging type. Obesity is not coded under eating disorders in ICD-10, but in chapter E66, which is not a mental disorder. Similarly  ‘loss  of  appetite’  is  not  considered  as  anorexia  even  if  it  is  ‘psychogenic’.

EDNOS- Eating disorder not otherwise specified is the most common eating disorder in the outpatient setting and is widely used by clinicians using DSM-IV.

Binge eating disorder (BED) is also increasingly recognised, but in ICD-10 this falls under atypical bulimia and in DSM-IV under EDNOS. Binge eating disorder is characterized by recurrent episodes of binge eating in the absence of extreme weight-control behaviour. This is often seen in a background of a general tendency to overeat. BED is associated with obesity; 5–10% of those seeking treatment for obesity have BED. Patients typically present in 40s. More males compared to other eating disorders, but only 25% of all binge-eating population is male. There is a high degree of spontaneous remission noted and stressed associated overeating is a common phenomenon. Self-help, behavioural weight loss programmes and CBT/IPT can help.