Anorexia Nervosa Flashcards
Define anorexia nervosa
An eating disorder characterised by deliberate weight loss, an intense fear of fatness, distorted body image, and endocrine disturbances
Epidemiology anorexia nervosa
W:M 10:1
Adolescence
Predisposing factors of anorexia (biological, psychological, social)
Biological • Genetics • FHx (1st degree relative) • Female • Early menarche
Psychological
- Sexual abuse
- Preocc. w/ slimness
- Dieting behaviours starting in adolescence
- Low self-esteem
- Premorbid anxiety or depressive disorder
- Perfectionism, obsessional/anankastic personality
Social
- Western society (thin = beauty)
- Bullying (weight)
- Stressful life events
Precipitating factors of anorexia (biological, psychological, social)
Biological
• Adolescence + puberty
Psychological
• Criticism regarding eating, body shape or weight
Social
• Occupational or recreational pressure to be slim (E.g. ballet dancers, models)
Perpetuating (maintaining) factors of anorexia (biological, psychological, social)
Biological
• Starvation leads to neuroendocrine changes that perpetuate anorexia
Psychological
• Perfectionism, obsessional/anankastic personality
Social
- Occupation
- Western society
Clinical features of anorexia nervosa
BMI <18.5
• Physical: fatigue, hypothermia, bradycardia, arrhythmias, peripheral oedema (as hypoalbuminaemia), headaches, lanugo hair (growing extra hair)
• Preoccupation w/ food: dieting, preparing elaborate meals for others
• Socially isolated
• Sexuality feared
• Symptoms of depression + obsession
Ix: ICD-10 criteria for diagnosis of anorexia
(FEED) → the below for >3mths + absence of (1) recurrent episodes of binge eating (2) preoccupation with eating/craving to eat
- Fear of weight gain
- Endocrine disturbance resulting in amenorrhoea in females + loss of potency in males
- Emaciated (low body weight)
- Deliberate weight loss (decrease in food or ^ exercise)
- Distorted body image
Ix for anorexia nervosa
- VBG → metabolic alkalosis (vomiting), metabolic acidosis (laxitives)
- DEXA scan (rule out Osteoporosis)
- ECG → bradycardia + prolonged QT
- Questionnaires → eating attitudes test (EAT)
Treatment of anorexia nervosa
Biopsychosocial model
• Risk assessment (suicide + self-harm + medical complications)
• Aim of Rx: weight gain
o Inpatient → 0.5-1kg/week
o Outpatient → 0.5kg/week
Biological o Rx of medical complications o SSRIs (depression or OCD) → fluoxetine Psychological o Nutritional education o CBT o Cognitive analytic therapy o Interpersonal psychotherapy o Family therapy Social o Voluntary organisations o Self-help groups
Why would you hospitalise someone with anorexia?
Hospitalisation/admission if:
o Extremely rapid or severe weight loss (not responding to outpatient Rx)
o Severe electrolyte imbalance (hypokalaemia/natraemia)
o Severe physiological complicatons: e.g. T = <36, fainting due to bradycardia (<45bpm), ± marked postural BP drop)
o Cardiac complications
o Marked change in mental status
o severe anorexia (BMI <14 or severe electrolyte abnormalities) + psychiatric reasons (suicidal ideation)
what are anorexia pts at risk of getting in treatment? How can it be limited?
Refeeding syndrome
o Limit by: measure U+Es (and correct abnormalities), recheck U+Es every 3 days, increase intake slowly, monitor for tachycardia + oedema
What is refeeding syndrome? What happens? How to prevent and treat?
- Life-threatening syndrome resulting from food intake after prolonged starvation or malnourishment, due to changes in phosphate, magnesium, potassium
- Insulin surge
- Biochemical changes: hypokalaemia, hypomagnesaemia, hypophosphataemia, + abnormal glucose metabolism
- Phosphate depletion → ↓ cardiac muscle activity → cardiac failure
Prevention:
o Measure serum electrolytes prior to feeding
o Monitor U+Es daily
o Start at 1200kcal/day and gradually increase every 5 days
o Monitor for signs: tachycardia + oedema
Rx:
o Electrolyte replacement
Complications of anorexia nervosa
- GI → enlarged salivary glands, pancreatitis, constipation, peptic ulcers, hepatitis
- Metabolic → hypokalaemia, hypercholesterolaemia, hypoglycaemia, impaired glucose tolerance (IGT = pre-diabetic state of hyperglycaemia → can lead to T2DM), deranged LFTs, ^urea/creatinine (if dehydrated), ↓K+/phosphate/Mg/albumin/Cl-
- Endocrine → ^ cortisol, ^ growth hormone, ↓ T3/4, ↓ LH/FSH + ↓oestrogens/progesterone (amenorrhoea), ↓ testosterone
- CV → HF, ECG abnormalities + arrhythmias, ↓BP, bradycardia***, peripheral oedema (hf, low albumin…)
- Renal → renal failure (inc. AKI), renal stones
- Neurological → seizures, peripheral neuropathy (B12 def?), autonomic dysfunction
- Haematological → Fe def anaemia, thrombocytopaenia, leucopaenia
- MSK → Proximal myopathy, Osteoporosis
- Others → hypothermia, dry skin, brittle nails, lanugo hair, infections, suicide
