anorexia nervosa / eating disorders

see also:

• RCH guideline - anorexia nervosa

• an eating disorder defined by:
  • persistent energy intake restriction
  • intense fear of weight gain or persistent behaviour that interferes with weight gain
  • and a disturbance of body image
• it is one of the most dangerous mental health conditions with mortality rates 5x higher than the general population and 20% of these deaths are due to suicide
• it can cause a range of serious medical problems as well as risking refeeding syndrome
• severe cases may require admission to hospital or mental health and may require a mental health treatment order to allow this if patient declines
• mainly occurs in young women
• a third identify as male and men go un-diagnosed 4x as much as women and peak incidence is in 15-19yr old men
  • a study suggested 84 per cent of boys aged 12 to 18 desired to be more muscular and more than one in five reported some level of body dissatisfaction which was exacerbated by social media
• 1.1 million people in Australia are affected by an eating disorder

• low body weight or failure to gain expected weight
• fear of weight gain
• body image disturbances
• severe body dissatisfaction and drive for thinness
• preoccupation with food, weight and shape
• restricted dietary intake
• self-induced vomiting
• misuse of laxatives, diuretics or appetite suppressants
• excessive exercise
• amenorrhoea, oligomenorrhoea or failure to reach menarche
• loss of sexual interest
• binge eating episodes involving loss of control overeating and eating unusually large amounts of food

• low body weight / malnourished
• dehydration
• hypothermia
• syncope (e.g. low BP, postural drop)
• cardiac arrhythmias (bradycardia)
• suicide attempts
• overwhelming infection
• renal failure (e.g. elevated creatinine)
• bone marrow suppression
• GIT dysfunction
• acute massive gastric dilatation from bingeing
• enlarged parotid glands from purging
• electrolyte imbalance (e.g. severe hypokalaemia, hyponatraemia, hypernatraemia)
• dorsal hand calluses from inducing purging
• refeeding syndrome

• weight : BMI <14kg/m2
• weight loss >1kg/week past 4 weeks
• highly restricted food or fluid intake
• high refeeding syndrome risk eg. little to no nutritional intake for > 5 days
• heart rate ≤45bpm or >120bpm
• postural tachycardia heart rate increase >20bpm
• systolic blood pressure <90mmHg
• postural blood pressure >20mmHG drop on standing
• temperature <35.5ºC
• any arrythmia including prolonged QTc, non-specific ST or T-wave changes including inversion or biphasic waves inversions
• blood sugar level <4.0 mmol/L
• hypo/hypernatremia
• potassium <3.0 mmol/L
• magnesium <0.7 mmol/L
• phosphate <0.75 mmol/L
• neutrophils <1.0 x 109L
• eGFR < 60ml/min/1.73m2 or rapidly dropping (25% drop in one week)
• albumin <30g/L
• elevated AST/ALT >500
• other indications may include dizziness, syncope, palpitations, muscle weakness, emaciation, extreme compensatory behaviours (laxatives/diuretics/purging/exercise)