Define Anorexia Nervosa
Anorexia Nervosa is a condition which is characterised by a deliberate weight loss, induced and sustained by the patient. There is an intense fear of gaining weight or becoming fat (this is an intrusive and overvalued idea not a delusion), and excessive preoccupation with body shape and weight.
In AN, weight is maintained at least 15% below normal weight. Patients need to have a BMI <17.5 kg/m2
Describe the epidemiology of Anorexia Nervosa
Affects females more than males. Tends to start around the ages 13-16.
- 0.3% of young women
- <0.1% in boys
What are the types of anorexia nervosa?
There are two main types of anorexia nervosa:
- Binging and purging - patients binge on food frequently, weight control achieved by self-induced vomiting, use of laxatives, slimming pills, diuretics, thyroxin.
- Restrictive - weight restriction achieved by severe restriction of food and fluid intake.
Both types might use excessive exercise as a weight control measure (i.e. 5x a day).
How do patients with AN present?
Patients become increasingly secretive around food and eating - skipping meals, lying about eating, hiding food, eating in secret, discovering ways to get rid of food once eaten. If confronted by family, they will deny or not acknowledge there is a problem. Food increasingly dominates thoughts, feelings and actions.
You will notice an observed weight loss, but they often wear many layers of clothing.
Often brought in by concerned parents.
Other presenting symptoms:
- Abdominal pain
- Constipation
- Chronic pain
- Feeling weak and tired
- Feeling anxious and low in mood
- Concerned about food intolerance (self-diagnosed).
What are the physical co-morbidities of AN?
The physical effects of anorexia nervosa include all parts of the body. Most notably:
- Large cerebral ventricles
- Hirsuites
- Mitral valve prolapse
- Liver abnormalities
- Osteoporosis
- Collapsed vertebrae
- Shrunken uterus
- Small, multifollicular ovary
- Proximal myopathy
- Marrow suppression
What are the mental health co-morbidities of AN?
Mental health co-morbidities are very common in this group. They include:
- Depression
- Anxiety
- Social phobia
- Personality disorder (emotionally unstable, anankastic (OCD), avoidant, dependent)
- DSH (Deliberate Self Harm) - cutting, OD, reckless behaviour.
Define Bulimia Nervosa
Recognised as a new syndrome later on (1979 in DSM III). Characterised by recurrent episodes of binge eating - within a 2 hour period eating a large amount of food (>1000cal), a sense of lack of control over eating. As well as recurrent compensatory behaviour to prevent weight gain (self-infuced vomiting, misuse of laxatives, enemas, diuretics, fasting, excessive exercise).
The binging and compensatory behaviour at least twice a week for 3 months. They are also pre-occupied with body image and weight.
Patients have a BMI >17.5kg/m2
What is the difference between Binging/Purging type AN and BN?
The difference between anorexia nervosa (binging purging type) and bulimia nervosa is that in bulimia nervosa the BMI is >17.5 kg/m2. Though patients in their lifetime change from one condition to another.
What is the epidemiology of BN?
1% in young women. Compared to 0.3% who have AN
Define Binge Eating Disorder
Introduced very recently in DSM-5. Individuals engage in uncontrollable episodes of binge eating but do not use compensatory purging behaviours. Binge eating is eating much more rapidly than normal, until they feel uncomfortably full. They eat large amounts of food when not physically hungry.
Eating alone through embarrassment at the amount one eating. A feeling of disgust or extreme guilt after overeating. BMI is almost always high.
What is the epidemiology of Binge Eating Disorder?
3.5% prevalence. Less disparity between the sexes.
What is the aetiology of eating disorders?
The aetiology is multifactorial:
- Genetic factors (58-88% heritability)
- Physical risk factors (history of premorbid obesity has been documented in AN -7-20%)
- Adverse life events (sexual abuse, stressful events)
- Family factors (high concern parenting & over-protection, insecure attachment)
- Personality traits (perfectionists)
- Societal pressure to be thin
- Impulsivity in BN
What are the NICE guidelines on how care of eating disorder patients is distributed?
NICE guidelines recommend that:
- Most people with anorexia nervosa should be managed on an outpatient basis
- Management should be shared between primary and secondary care
- More severe cases would be managed in tertiary care (impatient services)
What is the main challenge in the treatment of eating disorders?
Most difficult aspect is engaging the person with eating disorder into treatment.
Describe the treatment for eating disorders
Weight and bloods should be taken at the same appointment. Blood tests (low Na, K, high urea, amylase, CK, low glucose, raised LFTs, bone marrow failure). Perform an ECG and a bone scan.
For anorexia nervosa, the main and most effective treatment is food (gradual weight gain). We can and do give medications:
- Multi-Vitamins (forceval, thiamine)
- Mebeverine (135mg) to help with abdominal discomfort
- Fybogel for constipation
- Olanzapine (antipsychotic for pre-meal anxiety)
- SSRIs if depressed
- Advice on dental hygiene.
For osteoporosis: Treated with weight gain and calcichew D3 forte. Bisphosphonates have also been used in the past.
Psychological therapy is also used. The aim is to reduce risk, and encourage weight gain and healthy eating. This involves regular sessions with key workers, and may be in a community setting (post-meal so they can’t vom):
- Body image groups
- Relaxation therapy
- Art therapy
- Family therapy
- Cognitive-analytical therapy
For Bumilia Nervosa: Treatment for often includes CBT tailored for BN over 4-5 months, or interpersonal therapy.
Important to assess for self-harm and suicide risk.
Describe the complications for treatment of eating disorders
Refeeding Syndrome is a severe medical complication caused by rapid initiation of refeeding after a period of malnutrition (due to potentially fatal shift in fluids and electrolytes in malnourished patients; insulin stimulates absorption of electrolytes into cells for glycogen, protein, fat synthesis). Characterised by:
- Low Mg, K, Ca, Phosphates
More frequent in low BMI (<12 kg/m2) patients, and in bingeing/purging type.
Can lead to cardiac and respiratory failure.
What is the prognosis of eating disorders?
- 50% of AN have a protracted course over 6 years
- 40% of people with AN recover completely
- 20% of people have a chronic relapsing/remitting ED
- 5% die
What are the good prognostic factors for eating disorders?
- Age on onset (younger patients do better)
- Severity of illness
- Fewer Co-morbidities
- Positive response to treatment
