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Anorexia Nervosa

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Description of clinical states resembling anorexia nervosa appeared in medical books as long ago as the seventeenth century, but the condition was first clearly outlined by Gull in 1874. It is a disorder primarily affecting adolescent girls and young women, with only 5-10% of cases occurring in males. Rarely, children approaching puberty and older menopausal women may be affected. Because secrecy and denial are common, its prevalence is difficult to determine accurately, although various studies have suggested it occurs in approximately 1% of adolescent females. It is more common amongst the middle and upper social classes, and tends to be limited to developed societies throughout the world.


The ICD 10 diagnostic requirements for anorexia nervosa are all of the following:

 

  • The occurrence of body-image distortion, whereby a dread of fatness persists as an intrusive, overvalued idea so that the individual imposes low weight threshold on her(him)self.
  • Body weight is maintained at least 15% below that expected (either lost or never achieved). Prepubertal subjects may fail to make expected weight gain during their growth period
  • Weight loss is self-induced by avoidance of ‘fattening foods’ and one or more of the following: self-induced vomiting; self-induced purging; excessive exercise; use of appetite suppressants and/or diuretics
  • A widespread endocrine disorder (involving the hypothalamic-pituitary-gonadal axis), manifesting as amenorrhoea in worm and loss of sexual interest and potency in men. (An exception is vaginal bleeding in anorexic women receiving hormonal replacement therapy, such as the contraceptive pill). Growth hormone and cortisol levels may be raised. Peripheral thyroid metabolism and insulin secretion altered
  • If onset is prepubertal, pubertal changes are delayed or arrested (growth ceases, in girls, breast fail to develop and there is primary amenorrhoea, whereas in boys, genitalia remain juvenile). With recovery, puberty is often completely normal but the menarche is late.


CLINICAL FEATURES


Symptoms characteristically begin within a few years of the onset of puberty, and sometimes develop from dieting in response to adolescent plumpness. In the early stages of anorexia nervosa, appetite is not diminished. At this time, the individual’s thoughts and behaviour appear to be governed by an internal conflict between hunger and a desire to eat, offset against a fear of losing control and gaining weight. A preoccupation with food is common, so that the subject will happily absorb herself in food-related activities. Many hours may be spent shopping for food and then hoarding purchases, and some anorectics resort to shoplifting in order to satisfy their fixation.


Food-related rituals are often conducted secretively, and the extent of weight loss may be concealed by wearing bulky clothing. Relatives sometimes collude with such behaviour, but even if the subject is directly confronted about her actions, such challenges are frequently met with the abject denial of anything being wrong. Consequently, medical help is usually sought by parents, by which time the patient will have already lost a considerable amount of weight. She may be reluctant to give details of the duration or extent of her problem, whilst vociferously objecting to any suggestion that she is underweight or needs to eat more. Distortion of body image is invariably present, resulting in the subject grossly overestimating the size of various parts of her body. In certain individuals, the hunger drive intermittently overcomes their fear of fatness and results in occasional bouts of uncontrolled excessive eating (bingeing), which may be followed by self-induced vomiting, laxative or diuretic abuse as a means of weight control.


Many anorectics remain remarkable energetic despite evidence of gross emaciation, and some use strenuous exercise as a way of further controlling their weight. Early morning wakening is a common symptom but in contrast to the type seen in depressive episodes, feelings of dysphoria are not marked at this time. However, some anorectics do become clinically depressed and may even be suicidal, whilst others display obsessional features of multiple phobic symptoms.


At referral, weight is often less than 35 kg and, in addition to a history of amenorrhoea,physical examination may reveal evidence of gross muscle wasting, dehydration, anaemia and other signs of starvation, although breast atrophy does not usually occur. The extremities are sometimes cold and blue (acrocyanosis) and ankle oedema may be present (occasionally associated with a low serum albumin). Pubic and axillary hair are retained, and a fine down (lanugo hair) also appears on the trunk and limbs. Bradycardia, hypotension and hypothermia can occur and constipation may be severe. Vomiting and laxative abuse sometimes cause a hypokalaemic alkalosis, which can result in the development of renal problems, cardiac arrhythmias and seizures. Growth hormone and plasma cortisol levels are raised, whilst those of gonadotrophin are reduced.


AETIOLOGY


The interplay of several factors is probably involved in the development of this condition. Agenetic predisposition is suggested by an increased concordance rate amongst monozygotic compared with dizygotic twins. The mothers of anorectic children often have a history of psychiatric disorder, and in some cases, may have suffered from the condition themselves.


A common theme of the numerous psychological theories that have been advanced to explain the disorder proposes that avoidance of fattening foods is dud to a fear of mature body weight, and results in a regression to a more primitive (oral) level of functioning. By retaining the ‘body of a child’, problems of adulthood, sexuality and separating from parents need not be faced.


Abnormal family processes are seen by some as paramount in the causation of anorexia nervosa. The development of symptoms in the ‘patient’ is viewed as a means of avoiding conflict between family members, thereby allowing them to continue functioning as a unit. The pattern of interaction is such that members are frequently inflexible in their roles (rigidity), problems and disagreements are seldom resolved (lack of conflict resolution), individual identities are poorly defined (enmeshment), and there is evidence of over-protectiveness. The subject is often described as being a ‘model chid’ – shy and introverted in nature, and conscientious and compliant to the wishes of others. Family members frequently display an abnormal preoccupation with food and dieting.


The reduction in sex hormone levels and lowered basal metabolic rate which occur in anorexia nervosa have led to the proposal that the condition might result from a primary hypothalamic disorder. Although there have been few case reports of the condition developing in association with a hypothalamic tumour, post-mortem findings usually show no such abnormality. Since nearly all the physical changes are reversed when body weight is restored, they are most probably the effects of starvation.


The pursuit of thinness is to some extent encouraged by media pressure for women to conform to a ‘sexual stereotype’, in which femininity and attractiveness are equated with slenderness. A further emphasis is placed on the desirability of remaining slim and healthy, and the dangers of being overweight. This may explain why the condition is more common in females from middle and upper-class backgrounds, who are perhaps most susceptible to social pressures of this type. Certain groups, such as models and ballet students, seem to be at particular risk, since weight control is an integral part of their working lives.


The disorder sometimes follows a life event which, if perceived as a threat to the individuals self esteem, can lead to feelings of ineffectiveness. Under these circumstances, dieting behaviour may represent a means of regaining control, and is reinforced by feelings of attractiveness, the attention of others and a sense of achievement due to weight loss.


MANAGEMENT


Before commencing treatment, a careful assessment should be made of both the patient and her family. This not only serves to establish the diagnosis and explore the family dynamics, but also helps to gain the individuals trust and confidence, and achieve agreement upon a management plan. Additional information is usually obtained from another source, such as a relative, since the patient is frequently a reluctant recipient of psychiatric help. Details of personal and family background should be supplemented by a dietary, weight and menstrual history, together with information regarding self-induced vomiting or the abuse of purgatives. It is also important to determine the subject’s concept of her ideal weight and body image.


The mental state examination should aim to identify any evidence of depression or suicidal ideation, and to exclude other psychiatric disorders (such as schizophrenia) where abnormal ideas about food and eating may exist. A physical examination and investigations are performed to assess the extent of malnutrition, emaciation and other somatic complications, in particular electrolyte disturbance. Rarely, it may be necessary to consider alternative causes of weight loss or endocrine dysfunction, such as pituitary failure, thyrotoxicosis, malignancy, diabetes, occult tuberculosis or malabsorption.


Treatment should at first concentrate on restoring normal body weight. This is best achieved by setting a target weight and obtaining the individual’s agreement to remain in treatment until it has been reached. A programme of organised refeeding is then established over a period of 2-3 months. For many years it has traditionally been held that hospital admission is the treatment of choice in respect of anorexia nervosa, especially when weight loss is severe. However, an important study recently compared inpatient treatment with outpatient based therapies (individual and family group psychotherapy accompanied by dietary counselling). At 1 year follow-up there was no significant difference between the treatment approaches in respect of weight gain, the return of menstruation or aspects of psychosocial functioning.


Where hospital admission is considered necessary, various therapeutic regimens have been described, but most advocate an initial period of bed-rest combined with a programme of controlled refeeding, ensuring that at least 3000 calories are being eaten daily.


Successful treatment is dependant upon the nursing staff’s ability to establish a trusting relationship with the patient, and yet remain firmly in control when necessary (e.g. in determining the amount and type of food eaten). Such an approach requires patience and perseverance, since many anorectics are intent on deceiving their care givers by hiding food, swallowing excess water before being weighed or vomiting after meals. Even so, staff must maintain a supportive and caring role, and try to deal with problems as they arise.


With effective treatment, a weight gain of about 1-2kg/week can be expected. As weight increases, many patients who have been depressed begin to acknowledge an improvement in their mood and a reduction in their preoccupation with food. Individual or group psychotherapy is an important aspect of treatment, which creates an opportunity to encourage maturity and independence by dealing with issues such as the responsibilities of adulthood and fears about sexuality, as well as promoting normal attitudes towards food and weight. Some form of family therapy is usually indicated, particularly in younger girls where the family dynamics are clearly disturbed. Ongoing support and treatment are important aspects of after-care, and therapy will often need to be continued for a considerable time. With this aim in mind, a number of self-help organisations have been established, such as ‘Anorexic Aid’ and ‘Overeaters Anon’. There is no evidence that appetite stimulants, such as chlorpromaxine, are of any additional benefit in management, although antidepressants are sometimes prescribed if depressive symptoms are severe.


PROGNOSIS


Although the short-term prognosis is generally good, the course of the illness is variable, and periods of remission are often interspersed with recurrent cycles of weight loss followed by re-admission to hospital. Factors associated with a poor outcome include a later age of onset, male sex, severe weight loss, bulimic symptoms, vomiting and purgative abuse, and a protracted illness.


Results of long-term studies indicate that approximately two thirds of patients have maintained a normal weight for several years following treatment, whilst the remainder are moderately or severely underweight. However, more than half of all anorectics continue to display abnormal eating habits, and suffer from persistent psychiatric symptoms and relationship difficulties.


Adequate follow-up and continuing support are important in order to deal with adverse events and personal crises when they arise, as well as attempting to minimise the frequency and severity of relapse. Despite this, 5% of cases end in death from starvation or suicide.

 

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