Eating Disorders Flashcards
Define anorexia nervosa.
A persistent pattern of reduced energy intake (restricted eating), purging behaviours (e.g. self-induced vomiting, laxative or enema misuse), and/or increased energy expenditure (e.g. excessive exercise) associated with significantly low bodyweight for height, age, and development, usually associated with fear of gaining weight.
Define bulimia nervosa.
Frequent, recurrent episodes of binge eating (e.g. once per week or move over at least 1 month), followed by repeated, inappropriate purging (to compensate for the binge). The person’s bodyweight is normal for height, age and developmental stage.
Define binge eating episodes.
Confined periodic which the person feels noticeably unable to control or stop eating.
Define binge eating disorder.
The pattern of binge eating seen in BN, often accompanied by feeling of guilt or disgust, but without compensatory purging; this can cause obesity.
Define avoidant/restrictive food intake disorder (ARFID).
Insufficient quantity or variety of food intake to meet energy or nutritional requirements, in the absence of bodyweight or shape concerns.
Describe the epidemiology of eating disorders.
Women > Men (8:1) (incidence rising in men)
Onset in mid to late adolescence, although symptoms can start in childhood and later adulthood.
Lifetime prevalence:
o AN: 0.6%
o BN: 1.0% → may be under diagnosed as people aren’t visibly underweight
o BED: 3.2%
AN mostly affects westernised societies, where black and ethnic minority groups are at lower risk than white populations
What is the aetiology of eating disorders based on?
- Genetics
- Neurobiological factors
- Psychological and family theories.
- Sociocultural
- Psychiatric comorbidity
What genetic factors contribute to eating disorders?
o Heritability 30% to 80%
o significant genetic contribution: single nucleotide polymorphisms
o relatives of people with BN also have higher rates of obesity and depression
What neurobiological factors contribute to eating disorders?
- Abnormal connectivity between reward centres (e.g. the striatum) and executive control (prefrontal cortex).
- Imbalances between dopaminergic (reward) and serotonergic systems)
What psychological and family factors contribute to eating disorders?
o Likely to have a hx of obstetric complications, sleeping and feeding difficulties, and childhood abuse
o Personality traits (perfectionism, neuroticism and low self-esteem - RFs for both AN and BN
o Theory: initial WL → enhances someone’s sense of achievement and autonomy reinforcing perfectionist traits. When life feels out of control → comfort associated with controlling something (weight) may also reinforce AN
o Parental overprotecting and family ‘enmeshment’ (excessively close relationship - compromises independence) are associated with AN.
o Theory: AN as a means of avoiding stress of separation from family support or becoming an independent sexual being; AN maintains dependence on family and a peripubertal physique
o BN associated with disturbed family dynamics, parental weight concern, and high parental expectation.
What sociocultural factors contribute to eating disorders?
o Social pressure to be thin - IMPORTANT
o Promotion of dieting
o High risk in models, athletes and dancers
How does psychiatric comorbidity contribute to eating disorders?
o Usually comorbid with other mental health disorders
o Up to 75% report a hx of depression, anxiety, OCD, BDD, substance use disorders and PDs (particularly anankastia and borderline pattern) - more common.
o People with BN have hx of obesity and 50% previously suffered AN
What are the key similarities and differences between AN and BN?
Describe the clinical presentation of anorexia nervosa.
Four main diagnostic points
- BMI <18.5 kg/m2 (or <5th per central BMI-for-age in children and adolescents)
- Divided into AN with:
- Significantly low body weight: BMI > 14 kg/m2
- Dangerously low body weight: BMI < 14 kg/m2 or <0.3 percentile BMI-for-age
- Divided into AN with:
- Deliberate weight loss. Methods may include:
- Dietary restriction
- Purging
- Excessive exercise
- Medication misuse e.g. appetite suppressants, thyroxine, diuretics, stimulants such as cocaine. People with T1DM will omit their insulin.
- Distorted body image → preoccupied with body shape; see themselves as normal or overweight
- Endocrine dysfunction
o HPG axis → amenorrhoea
o Loss of libido
o Delayed or arrested menarche/breast development
Describe the clinical presentation of bulimia nervosa.
- Bing eating: recurrent episodes (usually secretive) of overeating.
- Irresistible cravings
- Loss of control - sense of urgency and compulsion
- May consume 1000s of calories, often eating forbidden foods e.g. 20 donuts
- May be triggered by stress
- Purging
- Bingeing → feeling of shame and guilt → desperate measure to undo the damage → vomiting, laxatives
- Body image distortion → preoccupation with shame and weight and often hate their body
- BMI >18.5 unlike AN → normal and normal endocrine function ANA wAna w
What are the physical complications of eating disorders?
Starvation- related problems are commoner in AN, while purging- related problems tend to affect people with BN. However, since purging and starvation occur in both conditions, all complications should be considered during assessments of AN or BN
Neurological
Starvation:
- Peripheral neuropathy
- Cognitive deficits
- Delirium
- Coma
- Cerebral volume los
Purging:
- Convulsions (hyponatraemia)
- Peripheral neuropathy
- Delirium
What are the ix for eating disorders?
- Physical obs, CBG, lying/standing BP
- Height, weight & BMI
- Sit up-Squat-stand test - SUSS (proximal myopathy) - impaired in severe AN
- Essential bloods
- Bone profile, TFTs
- o FBC, U&Es, phosphate, albumin, LFTs, CK, glucose
- ECG: bradycardia, arrhythmia, prolonged QTc
- Other tests indicated e.g. DEXA in AN (osteoporosis)
- Pregnancy test in any women with amenorrhea
What is MARSIPAN?
People with the greatest physical health complications need nutritional stabilization on a medical ward, applying MARSIPAN guidelines
How should you counsel patients with AN?
