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Q1: Classification and DSM-5-TR changes (2 min)
- Define the four major eating disorders: anorexia nervosa, bulimia nervosa, binge eating disorder, ARFID.
- DSM-5-TR changes: amenorrhoea removed from AN; ARFID added; BED became a full diagnosis; frequency thresholds loosened to once weekly for 3 months; OSFED replaces EDNOS.
- AN subtypes: restricting (AN-R) vs binge-eating/purging (AN-BP); BN subtypes: purging vs non-purging.
- Severity specifiers: BMI in AN (mild at or above 17.0, extreme below 15.0); frequency of compensatory behaviour in BN; frequency of binge episodes in BED.
Q2: Anorexia nervosa — presentation and complications (3 min)
- Triad: significantly low weight, intense fear of weight gain, body-image distortion.
- Physical signs: lanugo, hypothermia, bradycardia, hypotension, postural drop, acrocyanosis, parotid enlargement, proximal myopathy (SUSS test positive).
- Investigations: FBC (leukopenia), U&E (hypokalaemia in purgers), LFTs (transaminitis), glucose (hypoglycaemia), phosphate/magnesium/calcium, TFTs (sick euthyroid — low T3, normal TSH), cortisol (raised), ECG (QTc prolongation, bradycardia), DEXA (osteoporosis).
- Complications: cardiac arrhythmia, refeeding syndrome, osteoporosis, amenorrhoea/infertility, GI (fatty liver, gastric dilatation), renal, haematological (gelatinous marrow transformation).
- Mortality: SMR 5.9 (Arcelus 2011); highest of any psychiatric disorder; one in five deaths by suicide.
Q3: Refeeding syndrome — protocol (3 min)
- Definition: potentially fatal shift of fluid and electrolytes when food reintroduced to starved patient; insulin drives intracellular phosphate/potassium/magnesium; thiamine depleted; fluid shifts.
- Clinical consequences: arrhythmia, heart failure, seizures, coma, respiratory failure, death — classically within first 3-7 days.
- At-risk: BMI under 16, no intake over 10 days, electrolyte disturbance, alcohol misuse, rapid weight loss.
- Protocol: (1) thiamine 200-300 mg BEFORE feeding; (2) start calories low (5-20 kcal/kg/day, NICE/MEED); (3) supplement phosphate/potassium/magnesium prophylactically; (4) escalate by 200-300 kcal every 24-48 hours; (5) daily U&E, phosphate, magnesium, glucose, ECG, weight, fluid balance for first 2 weeks; (6) restrict fluids if oedema; (7) continuous dextrose (never bolus) for hypoglycaemia.
Q4: Bulimia nervosa — management (2 min)
- Diagnosis: binge + inappropriate compensatory behaviour at NORMAL weight, once weekly for 3 months; Russell sign, parotid enlargement, dental erosion, hypochloraemic hypokalaemic metabolic alkalosis.
- First-line psychological: CBT-ED (16-20 sessions); reduces binge-purge frequency.
- First-line drug: fluoxetine 60 mg once daily (Fluoxetine Bulimia Nervosa Collaborative Study Group 1992 RCT — 60 mg, NOT 20 mg).
- Avoid bupropion (seizure risk in purgers).
- Prognosis: about 50-70 percent recover; better than AN.
Q5: Special populations and exam traps (2 min)
- Diabulimia: insulin omission in type 1 diabetes; highest-risk subgroup; recurrent DKA.
- Female athlete triad: low energy availability + menstrual dysfunction + low bone density.
- Atypical anorexia (OSFED): all AN criteria but NOT underweight; medical risk as high as typical AN.
- Male AN: under-diagnosed; high suicide risk; muscle dysmorphia.
- ARFID: restriction driven by sensory aversion, fear, or lack of interest — NOT body image.
- Watson 2019 GWAS: AN has a metabo-psychiatric origin — genetic correlations with metabolic traits.
- SCOFF questionnaire: 2 or more positive = likely eating disorder.
- MEED red flags (UK): BMI under 13, postural BP drop over 20 mmHg, HR under 40, QTc over 450 ms, temp under 35.0 deg C, phosphate under 0.5 mmol/L.
- Mental Health Act: highest rate of compulsory admission of any psychiatric disorder.