[17] Anorexia Nervosa Flashcards
What is anorexia nervosa characterised by?
- Deliberate weight loss
- Intense fear of fatness
- Distorted body image
- Endocrine disturbances
What are the biological predisposing risk factors for anorexia nervosa?
- Genetics
- Family history
- Female
- Early menarche
What are the biological precipitating risk factors for anorexia nervosa?
Adolesence and puberty
What are the biological perpetuating risk factors for anorexia nervosa?
Starvation leads to neuroendocrine changes that perpetuate anorexia
What are the psychological predisposing risk factors for anorexia nervosa?
- Sexual abuse
- Preoccupation with slimness
- Dieting behaviours starting in adolesence
- Low self-esteem
- Premorbid anxiety or depressive disorder
- Perfectionism, obsessional/anankastic personality
What are the psychological precipitating risk factors for anorexia nervosa?
Criticism regarding eating, body shape, or weight
What are the psychological perpetuating risk factors of anorexia nervosa?
- Perfectionism
- Obsessional/anakastic personality
What are the social predisposing risk factors for anorexia nervosa?
- Western society - pressure to diet in a society that emphasises being thin is beauty
- Bullying at school revolving around weight
- Stressful life events
What are the social precipitating risk factors for anorexia nervosa?
Occupational or recreational pressure to be slim, e.g. ballet dancers, models
What are the social perpetuating factors for anorexia nervosa?
- Occupation
- Western society
What is the typical age of onset of anorexia nervosa?
Mid-adolescence
What are the ICD-10 diagnostic criteria for anorexia nervosa?
- Fear of weight gain
- Endocrine disturbances leading to amenorrhoea and loss of sexual interest and potency in males
- Emaciated (abnormally low body weight) - >15% below expected weight, or BMI <17.5kg/m2
- Deliberate weight loss with decreased food intake and increased exercise
- Distorted body image
The above features must be present for at least 3 months, and there must be the absence of recurrent episodes of binge eating, and preoccupation with eating/craving to eat
Other than those mentioned in ICD-10, what are the features of anorexia?
- Physical features
- Preoccupation with food
- Social isolated
- Symptoms of depression and obsessions
What are the physical features of anorexia nervosa?
- Fatigue
- Hypothermia
- Arrhythmias
- Peripheral oedema (due to hypoalbuminaemia)
- Headaches
- Lanugo hair
How might preoccupation with food manifest in anorexia nervosa?
- Dieting
- Preparing elaborate meals for others
How is anorexia nervosa investigated?
- History
- MSE
- Blood tests
- VBG
- DEXA scan
- ECG
- Questionnaires, e.g. eating attitudes test (EAT)
What blood tests should be done in anorexia?
- FBC
- U&Es
- TFTs
- LFTs
- Lipids
- Cortisol
- Sex hormones
- Glucose
Amylase
What may be found on FBC in anorexia nervosa?
- Anaemia
- Thrombocytopenia
- Leukopenia
What may be found on U&Es in anorexia nervosa?
- Increased urea and creatinine if dehydrated
- Decreased potassium, phosphate, magnesium, and chloride
What may be found on TFTs in anorexia nervosa?
Decreased T3 and T4
What may be found on LFTs in anorexia nervosa?
Decreased albumin
What changes may occur to lipids in anorexia nervosa?
Increased cholesterol
What changes may occur to sex hormones in anorexia nervosa?
Decreased LH, FSH, oestrogens and progesterones
What changes may occur to glucose in anorexia nervosa?
Decreased glucose
Why is amylase tested in anorexia nervosa?
Pancreatitis is a complications
Why is VBG done in anorexia nervosa?
- Metabolic alkalosis may be present if there is vomiting
- Metabolic acidosis may be present if there is abuse of laxatives
Why is a DEXA scan done in anorexia nervosa?
To rule out osteoporosis if suspected
Why is an ECG done in anorexia nervosa?
Arrhythmias such as sinus bradycardia and prolonged QT are associated with AN patients
What are the differential diagnoses of anorexia nervosa?
- Bulimia nervosa.
- Eating disorder not otherwise specified (EDNOS)
- Depression.
- Obsessive–compulsive disorder.
- Schizophrenia with delusions about food.
- Organic causes of low weight - diabetes, hyperthyroidism, malignancy.
- Alcohol or substance misuse.
What are the metabolic complications of anorexia nervosa?
- Hypokalaemia
- Hypercholesteroaemia
- Hypoglycaemia
- Impaired glucose tolerance
- Deranged LFTs
- Increased urea and creatinine
- Decreased potassium, phosphate, magnesium, albumin, and chloride
What are the endocrine complications of anorexia nervosa?
- Increased cortisol
- Increased growth hormone
- Decreased T3 and T4
- Decreased LH, FSH, oestrogens and progesterones leading to amenorrhoea
- Decreased testosterone in men
What are the gastrointestinal complications of anorexia nervosa?
- Enlarged salivary glands
- Pancreatitis
- Constipation
- Peptic ulcers
- Hepatitis
What are the cardiovascular complications of anorexia nervosa?
- Cardiac failure
- ECG abnormalities
- Arrhythmias
- Decreased BP
- Bradycardia
- Peripheral oedema
What are the renal complications of anorexia nervosa?
- Renal failure
- Renal stones
What are the neurological complications of anorexia nervosa?
- Seizures
- Peripheral neuropathy
- Autonomic dysfunction
What are the haematological complications of anorexia nervosa?
- Iron deficiency anaemia
- Thrombocytopenia
- Leucopenia
What are the musculoskeletal complications of anorexia nervosa?
- Proximal myopathy
- Osteoporosis
What are the other complications of anorexia nervosa?
- Hypothermia
- Dry skin
- Brittle nails
- Lanugo hair
- Infections
- Suicide
What needs to be considered in the risk assessment in anorexia nervosa?
- Risk of suicide
- Risk of medical complications
What is involved in the biological management of anorexia nervosa?
- Treatment of medical complications
- SSRIs for co-morbid depression or OCD
What is involved in the psychological management of anorexia nervosa?
- Psychoeducation about nutrition
- Cognitive behavioural therapy
- Cognitive analytic therapy
- Interpersonal psychotherapy
- Family therapy
What duration should psychological treatments be for in anorexia nervosa?
At least 6 months
What is involved in the social management of anorexia nervosa?
- Voluntary organisations
- Self-help groups
What weight gain is aimed for in inpatient treatment of anorexia nervosa?
0.5-1kg/week
What weight gain is aimed for in outpatient treatment of anorexia nervosa?
0.5kg/week
Why should weight gain be carefully controlled when treating anorexia nervosa?
Because patients are at risk of refeeding syndrome
What is refeeding syndrome?
A potentially life-threatening syndrome that results from food intake (parenteral or enteral) after prolonged starvation or malnourishent, due to changes in phosphate, magnesium, and potassium
What is the pathophysiological process in refeeding syndrome?
It occurs due to an insulin surge following increased foot intake
What are the biochemical features of refeeding syndrome?
- Fluid balance abnomalities
- Hypokalaemia
- Hypomagnesia
- Hypophosphataemia
- Abnormal glucose metabolism
What effect can phosphate depletion in refeeding syndrome have?
Can cause a reduction in cardiac muscle activity, which can lead to cardiac failure
How is refeeding syndrome prevented?
Measure serum electrolytes prior to feeding, and monitor refeeding bloods daily, starting at 1200kcal/day and gradually increase every 5 days, monitoring for signs such as tachycardia and oedema
What is done if electrolytes are found to be low when refeeding in anorexia nervosa?
They should be replaced orally or intravenously, depending on the severity of the eletrolyte depletion
When might hospitalisation be necessary in anorexia nervosa?
Either for medical reasons (severe anorexia with BMI <14, or severe electrolte abnormalities) or psychiatric reasons (suicidal ideation)
