Anorexia Nervosa Flashcards
Essence
Most commonly seen in young woman
Marked distortion of body image, pathological desire for thinness, and self-induced weight loss by variety of methods
Epidemiology - M:F ratio
1:10
Epidemiology - age of onset
F - 16-17 years (rarely > 30 years)
M - 12 years
Epidemiology - incidence
0.5% adolescent and young woman
Diagnostic criteria
- Low body weight
- 15%+ below expected or BMI 17.5 or less
- Self-induced weight loss
- Avoidance of fatty foods, vomiting, purging, excessive exercise, use of appetite suppressants
- Body image distortion
- Dread of fatness, overvalued idea, imposed low weight threshold
- Endocrine disorders
- HPA xis such as amenorrhoea, reduced sexual interest/impotence, raised GH levels, raised cortisol, altered TFTs, abnormal insulin secretion
- Delated/arrested puberty
- If onset pre-puberty
In atypical cases one or more of these key features may be absent or all but to lesser degree
Methods of self induced weight loss
- Avoidance of fatty foods
- Vomiting
- Purging
- Excessive exercise
- Use of appetite suppresants
Endocrine disorders as part of diagnostic criteria
- HPA axis such as
- Amenorrhoea
- Reduced libido/impotence
- Raised GH levels
- Raised cortisol
- Altered TFTs
- Abnormal insulin secretion
Aetiology
- Genetic
- Adverse life events
- Psychodynamic models
- Family pathology - enmeshment, rigidity, over-protectiveness, lack of conflict resolution, weak generational boundaris
- Individual pathology - disturbed body image (due to dietary problems in early life or parents preoccupation with food)
- Analytical model - regression to childhood, fixation on oral stage, esacape from emotional problems of adolescence
- Biological
- Hypothalamic dysfunction - ? cause or consequence
- Neuropsychological deficits - reduced vigilance, attention, visuspatial abilities and associative memory
- Pseudoatrophy/sulcal widening and ventricular enlargement
- Unilateral temporal lobe hypoperfusion
Aetiology - psychodynamic models
- Family pathology
- Enmeshment, rigidity, over-protectiveness, lack of confilct resolution, weak generational boundaries
- Individual pathology
- Disturbed body image due to dietary problems in early life or parents preoccupation with food
- Analytical model
- Regression to childhood, fixation on oral stage, escape from emotional problems of adolescence
Aetiology - biological
- Hypothalamic dysfunction
- Neurophychological deficits
- Reduced vigilance, attention, visuospatial abilities and associated memory which improve with weight gain
- Pseudoatrophy/sulcal widening and ventricular enlargement
- Improves with weight gain
- Unilateral temporal lobe hypoperfusion
Differential diagnosis
- Chronic debilitating physical disease
- Brain tumours
- GI disorders
- Crohns, malabsorption syndromes
- Loss of appetite
- Secondary to drugs
- Depression/OCD
Complications
- Oral
- Dental caries
- Cardiovascular
- Hypotension, prolonged QT, arrhythmias, cardiomyopathy
- GI
- Prolonged GI transit, constipation
- Endocrine
- Hypokalaemia, hyponatraemia, hypoglycaemia, hypothermia, altered thyroid function, hypercortisolaemia, amenorrhoea, delay in puberty, arrested growth, osteoporosis
- Renal
- Renal calculi
- Reproductive
- Infertility, low birth weight infant
- Dermatological
- Dry scaly skin and brittle hair (hair loss), lanugo body hair
- Neurological
- Peripheral neuropathy, loss of brain volume, ventricular enlargement, sulcal widening, cerebral atrophy
- Haematological
- Anaemia, leukopenia, thrombocytopenia
Most common cause of death due to anorexia nervosa
Cardiac complications
Findings of cardiac complications
- Significant bradycardia (30-40bpm)
- Hypotension (systolic <70mmHg)
- ECG changes
- Sinus bradycardia, ST-segment elevation, T-wave flattening, low voltage and right axis deviation
- Echocardiogram
- Decreased heart size and left ventricular mass, mitral valve prolapse
Treatment of osteopenia due to anorexia
- 1000-1500mg/d of dietary calcium and 400IU of vitamin D
- Prevent further bone loss and maximise peak bone mass
- Exercise and HRT
- In adult woman