Causes and consequences of eating disorders

Question 1

Eating disorders listed in the DSM V (7)

Answer 1

• anorexia nervosa: restrictive and bulimic
• bulimia nervosa: purging and non-purging (restrictive) sub-types
• binge-eating disorder
• avoidant restrictive food intake disorder
• pica
• other specific feeding & eating disorders
• unspecified feeding & eating disorders

Question 2

Anorexia nervosa: definition and prevalence

Answer 2

• definition: persistent restriction of energy intake, pathological fear of gaining weight, body dysmorphia and denial on severity of condition
• bulimic sub-type: binging and purging (laxative or diuretic abuse)
• restrictive sub-type: over-exercising and restricting
• 10:1 females in hospitals but 3-4:1 in the community
• 0.4 per 100 prevalence
• incidence 14.6 per 100,000 per year in women

Question 3

Anorexia nervosa: medical complications

Answer 3

• metabolic: hypokalemia, refeeding syndrome, hypoglycaemia, hypothermia
• cardiovascular: hypotension, bradycardia, ECG abnormalities
• GI: delayed gastric emptying, increased intestinal permeability, liver abnormalities
• Uro-genital: amenhorrea, kidney failure
• musculo-skeletal: weakness, osteoporosis
• endocrine: affects every organ in body

Question 4

Anorexia nervosa: aetiology

Answer 4

• developmental: genetics (80% concordance in MZ and 20-25% concordance in DZ), abnormal births, abuse, adolescence (trigger)
• biopsychosocial: psycho (OCD, obsession), social (societal pressures), biological (nutritional deficiencies leading to delays in gastric emptying)
• temporal staging: 1) predisposition (genetics) 2) precipitating (abuse) 3) perpetuating (sickness role, identity)

Question 5

Anorexia nervosa: treatment

Answer 5

• GP has to first identify from growth failure, amenhorrea, extreme weight loss
• initial management: self-help guides, BEAT support
• specialist management: family-based therapy, carer support, individual sessions (CBT, MANTA, specialist supportive clinical management), day care (3 meals and 2 snacks per day with group therapy), in-patient care (NGT)
• physical monitoring: BMI, SUSS (sit up stand squat test), core temperature, urea, electrolytes, LFTs, FBC, QT changes, arrythmias
• MARSIPAN: involve family, manage bad behaviour, ensure no RFS or under-feeding

Question 6

Anorexia nervosa: prognosis

Answer 6

47% recover 
33% improve but are still unwell
15% develop bulimia nervosa 
20% severe enduring eating disorder 
5% die (suicide, complications)

Question 7

Bulimia nervosa: definition, epidemiology

Answer 7

• definition: recurrent binge eating (out of control, objectively large amount of food) with an inappropriate compensatory behaviour (needs to be at least once per week for 3 months), accompanied by body dysmorphia
• purging sub-type (more common): vomiting, laxative, diuretics
• non-purging sub-type (less common): restricting, over-exercising
• prevalence of 0.5-1% in females and 0.2% in males
• age of onset typically older at 17-18 years (AN ~15-16 years)

Question 8

Bulimia nervosa: medical complications

Answer 8

• metabolic: hypokalaemia
• CVD: hypotension
• GI: dental erosion, reflux oesophagitis, vomiting blood, gastric rupture
• respiratory: inhalation, choking
• uro-genital: PCOS, renal failure, amenhorrhea
• skeletal: osteopenia
• skin: Russell’s sign (scratches on back of hand from teeth)

Question 9

Bulimia nervosa: aetiology

Answer 9

• genetics: link not as strong as AN, ~2% MZ and 9% DZ

Question 10

Bulimia nervosa: treatment

Answer 10

• harder to identify as normal weight
• initial: self-help book
• CBT
• fluoxetine SSRI at 20-> 60 mg/day
• occasionally need in-patient care
• hospitalise if: hypokalemic (<25 mmol/L K), risk suicide or self-harm, haematemesis or intractable vomiting, dangerous ECG abnormalities

Question 11

Bulimia nervosa: prognosis

Answer 11

45% recover
27% improve but remain unwell
22.6% develop severe and enduring eating disorder
0.5% die

Question 12

Severe and enduring eating disorder

Answer 12

Duration beyond normal recovery time. Places a massive physiological strain, and a strain on the family and relationships

Question 13

Binge-eating disorder

Answer 13

• Out of control eating of objectively large amounts of food: fast, eating past uncomfortable fullness
• prevalence of 2% in general community, 3.5% in overweight people