Eating disorders Flashcards
Anorexia: epidemiology
- anorexia accounted for 8% of eating disorders, avoidant/restrictive food intake disorder (ARFID) 5%, binge eating disorder 22%, bulimia 19%, and other specified feeding or eating disorder (OSFED) 47%.
- Peak age of onset: 15-25
- Average illness duration is around 6 year
- Anorexia and bulimia are ten times more common in females
- 50% of AN pts go on to develop BN
- 30% patients with BN have had a previous AN
Diagnosis of anorexia
Diagnosis is now based on the DSM 5 criteria. Note that BMI and amenorrhoea are no longer specifically mentioned:
1. 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.
2. Intense fear of gaining weight or becoming fat, even though underweight.
3. 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 denial of the seriousness of the current low body weight.
Treatment for adults with anorexia nervosa
- individual eating-disorder-focused cognitive behavioural therapy (CBT-ED)
- Maudsley Anorexia Nervosa Treatment for Adults (MANTRA)
- specialist supportive clinical management (SSCM).
- In children and young people, NICE recommend ‘anorexia focused family therapy’ as the first-line treatment. The second-line treatment is cognitive behavioural therapy.
- The prognosis of patients with anorexia nervosa remains poor. Up to 10% of patients will eventually die because of the disorder.
Physical manifestations of anorexia
- reduced body mass index
- bradycardia
- hypotension
- enlarged salivary glands
Anorexia: physiological abnormalities in blood test
- hypokalaemia
- low FSH, LH, oestrogens and testosterone
- raised cortisol and growth hormone
- impaired glucose tolerance
- hypercholesterolaemia
- hypercarotinaemia
- low T3
Features of anorexia nervosa
- Distorted body image
- Fear of fatness and weight gain
- Weight loss
- Physical consequences of starvation
- Restricted intake, and/or exercise, and/or medications, and/or vomiting
Physiological manifestations of anorexia 1
- Perception - Low body weight or shape is central to the person’s self-evaluation or is inaccurately perceived to be normal or even excessive
- Behaviours - A persistent pattern of behaviours to prevent restoration of normal weight. behaviours aimed at reducing energy intake (restricted eating) purging behaviours (e.g. self-induced vomiting, misuse of laxatives), behaviours aimed at increasing energy expenditure (e.g. excessive exercise)
Physiological manifestations of anorexia 2
- Low weight - A commonly used threshold is body mass index (BMI) less than 18.5 kg/m2 in adults and BMI-for-age under 5th percentile in children and adolescents.
- Rapid weight loss (e.g. more than 20% of total body weight within 6 months) may replace the low body weight guideline as long as other diagnostic requirements are met.
- Children and adolescents may exhibit failure to gain weight as expected based on the individual developmental trajectory rather than weight loss.
Bulimia nervosa: overview
- Preoccupation with eating, shape and weight
- Episodes of binge eating: large (objective) binge, discrete period of time, loss of control
- Recurrent compensatory behaviour: purging, restricting, neglect of insulin treatment
Bulimia nervosa is a type of eating disorder characterised by episodes of binge eating followed by intentional vomiting or other purgative behaviours such as the use of laxatives or diuretics or exercising.
DSM 5 diagnostic criteria for the diagnosis of bulimia nervosa
(1) recurrent episodes of binge eating (eating an amount of food that is definitely larger than most people would eat during a similar period of time and circumstances)
(2) a sense of lack of control over eating during the episode
(3) recurrent inappropriate compensatory behaviour in order to prevent weight gain, such as self-induced vomiting, misuse of laxatives, diuretics, or other medications, fasting, or excessive exercise. Recurrent vomiting may lead to erosion of teeth and Russell’s sign - calluses on the knuckles or back of the hand due to repeated self-induced vomiting
(4) the binge eating and compensatory behaviours both occur, on average, at least once a week for three months.
(5) self-evaluation is unduly influenced by body shape and weight.
(6) the disturbance does not occur exclusively during episodes of anorexia nervosa.
Management of bulimia nervosa
- referral for specialist care is appropriate in all cases
- NICE recommend bulimia-nervosa-focused guided self-help for adults
- If bulimia-nervosa-focused guided self-help is unacceptable, contraindicated, or ineffective after 4 weeks of treatment, NICE recommend that we consider individual eating-disorder-focused cognitive behavioural therapy (CBT-ED)
- children should be offered bulimia-nervosa-focused family therapy (FT-BN)
- pharmacological treatments have a limited role - a trial of high-dose fluoxetine is currently licensed for bulimia but long-term data is lacking
Binge eating disorder and AFRID
Binge eating disorder= as with BN but without the recurrent use of compensatory behaviour, not occurring during the course or AN or BN.
ARFID: Avoidant restrictive food intake disorder
* Restricted eating (types or quantity of food) which can lead to weight loss and same physical risks as anorexia
* Fear isn’t of weight gain or fatness
* E.g. fear of choking, vomiting, certain textures etc.
* May have low interest in eating
OSFED
Other Specified Feeding and Eating Disorder
* An umbrella term
* Difficulties with eating that do not meet the diagnostic criteria of another eating disorder but that do have a significant impact on the health and functioning of a person
Risks of anorexia
- Has the highest mortality rate of any major psychiatric disorder (10-12% of general population)
- Medical complications due to re-feeding syndrome
- Chronic problems, osteoporosis
- Can be due to: starvation, compensatory behaviours, falsifying weight
- Complications from mismanagement of diabetes
Physical health complications of compensatory behaviour: vomiting
- Enamel erosion
- Swollen parotid glands
- Gastric and oesophageal trauma
- Electrolyte imbalance: Hypokalaemia (muscle cramps, tingling, fatigue, palpitations, chest pain), hypocholeraemia, raised bicarbonate
Physical health complications of compensatory behaviour: laxatives
Affect the large bowel, leading to increased loss of water and electrolytes
* Dehydration
* Electrolyte imbalance
Rectal bleeding
* Abdominal cramps
* Rebound constipation and rarely pseudo-obstruction
Physical health complications of compensatory behaviour: exercise
- Physical exhaustion
- Muscle damage
- Elevated creatinine kinase
- Rhabdomyolysis
- Injuries
*Other cardiac abnormalities i.e. bradycardia, heart block, chest pain
Falsifying weight
- Reasons for excess fluid consumption= Hunger suppression, Anxiety management, Deliberate weight falsification. Fluid loading – risks hyponatraemia – confusion, convulsions, coma
- Weights in clothes/underwear/shoes/hair
- Attempts to tamper with weighing scales
- Falsifying weight risks health professionals failing to identify an accurate BMI
Refeeding syndrome
- Shifts in fluids/electrolytes in malnourished patients being re-fed
- Glycaemia leads to increased insulin secretion
- Glycogen/fat/protein synthesis and transport of glucose into cells requires phosphate, magnesium, potassium and thiamine
- These salts are already rapidly depleted
- Causes Hyphosphateamia, Hypokalaemia, Hypomagnaesmia, thiamine deficiency, sodium and water retention
Effects of refeeding syndrome
- Vitamin deficiency- Wernicke’s/Korsakoffs
- Sodium balance impaired- oedema, cardiac failure
- Particularly high risk: very low BMI, complete restriction/ rapid weight loss, co-morbid alcohol dependence, co-morbid physical health problems i.e. sepsis, cancer. Parenteral feeding > NG feeding > Oral diet
Risks to self with eating disorders
- Low mood and hopelessness very common
- Suicide the second commonest cause of death in anorexia
- More common in chronic anorexia
- Self harm common in those who binge and purge
*Purging can become a form of self harm
