Eating disorders Flashcards
Pathophysiology
Clinical observation
- A susceptible person (biology, societal patterns, or behavioural makeup), begins dieting; 35% of those dieting progress to pathological eating habits, and 20% to 25% go on to partial or full-blown eating disorders.
- Weight loss gives positive reinforcement to continue avoidance of food, intense exercise, or bingeing and/or purging behaviours.
- The effect of low weight and starvation leads to nutritional imbalances and psychological changes.
- Obsessive behaviours and rigid thought patterns facilitate maintenance of the anorexic cycle.
- The act of starvation and weight loss may provide a sense of pride and positive drive for the patient.
- Any life stresses are avoided with the obsessive focus on food and weight management.
- The patient gains confidence and resists walking away from the safety of routine. AN relieves generalised anxiety, which takes the form of an easy-to-identify fear of food. The fear of gaining weight leads to avoidance of food, which leads to relief of anxiety through weight loss.
- Physiological changes propagate the disease and continual relapses. Corticotrophin-releasing hormone, released during starvation, promotes appetite suppression but this also increases cortisol levels, which in turn increases the risk for osteoporosis.
- Vasopressin is high and oxytocin low in cerebrospinal fluid, which is hypothesised to promote the unhealthy thought patterns
Diagnostic criteria, including changes from DSM 4
The following are the key changes in the DSM-5:
- Removal of the amenorrhoea criteria
- Addition of BMI criteria to determine severity
- Criteria for partial and full remission
- Creation of category for subsyndromal or atypical anorexia nervosa entitled ‘other specified feeding or eating disorder’.
A. Restriction of energy intake leading to a significantly low weight in the context of age, sex, developmental trajectory, and physical health
B. Intense fear of gaining weight or persistent behaviour that interferes with weight gain
C. Disturbance in body image.
Specific type:
Restricting type: no episodes of binge eating or purging in the preceding 3 months; weight loss has been achieved by dieting, fasting, and/or excessive exercise
Binge-eating/purging type: recurrent episodes of binge eating or purging in the preceding 3 months.
Levels of severity in adults
Specific level of severity for adults: Mild: BMI ≥17 kg/m^2 Moderate: BMI 16-16.99 kg/m^2 Severe: BMI 15-15.99 kg/m^2 Extreme: BMI
Clinical history
May present for effects of starvation->fatigue, dizziness Family members may have identified weight loss Resistance to weight gain Distortion of body image Fixation of "overweight areas" May/may not recognise overall low weight Self worth hinges on weight Amenorrhea Type of diet Restricting/bingeing Exercise Use of laxative, enemas, diuretics
Asses comorbidities:
OCD
Depression, anxiety
Substance use
ALWAYS include psychiatric assessment->SUICIDE risk
What should be considered in pre-pubertal children with sudden onset AN shortly after apparent streptococcal infection
Paediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS) should be considered
Physical assessment
Bradycardia ( 20 mmHg), systolic murmur Acrocyanosis Dehydration Hypothermia (temp. 30% of pre-morbid weight), BMI low Arrythmias Cardiomyopathy Lanugo hair Edema Lack signs indicating alternate diagnosis Enamel loss, salivary gland hypertrophy
Investigations
Investigations:
Urea and electrolytes, creatinine, calcium, magnesium, phosphate
TFTs
LFTs
Urinalysis - including pH (possibility of diuretic use )
ECG (if K+ abnormal) A medical admission for resuscitation would usually result in a 4 week period of inpatient treatment.
Nutrition assessment
- 24 hour recall
- %IBW-> 50th% BMI for age
- Recent losses or gains
Findings on chemistry panel
hypokalaemia, hypochloraemia, elevated serum bicarbonate levels, or elevated urea levels, especially in those patients consistently purging and abusing over-the-counter (OTC) medications. Elevated urea levels may indicate dehydration or can be an indication of kidney abnormalities. Kidney failure is a common physiological cause of death in AN patients. A urinalysis may reveal ketonuria indicative of semi-starvation.
Investigations if amenorrheic
Pregnancy test
Bone mineral density if amenorrhea for >6-12 months
Management
Referral
Structured eating plan
Psychotherapy
+/- Potassium repletion
If unstable, need IP
Oral, enteral, parenteral nutrition
Fluid intake correction
Potassium, sodium, calcium, magnesium repletion
With depression:
SSRI
With OCD:
Behavioural therapies
SSRI or clomipramine or olanzapine
Etiology
1. Predisposing Female sex Family history Perfectionistic Diffiuclty displaying negative emotion Difficulty resolving conflict Negative self esteem Enmeshment in family 2. Biochemical \+co-existence of depression, anxiety, OCD-->dopamine and serotonin Starvation->further decline in neuro function->developmental disorder 3. Precipitating during phase where intrapsychic challenges are not overcome and manifest as psychological illness In adolescence->weight gain Peer pressure Struggles with autonomy, independence and transitioning to adulthood
Prognostic
Age of onset, worse in adulthood and
Endocrine complications
Amenorrhea
Diabetes insipidus
Osteopenia
Euthyroid sick sydnrome
Management
Medical, nutritional, mental health, school
1. Refeeding
2. Normalising eating patterns
3. Achieve normal perception of hunger and satiety
4. Psychological-> Maudsley method of family therapy
Cognitive behav. therapy++
Motivational enhancement
Psychoeducation
+Self esteem, assertion, anxiety management techniques, treat comorbidities
5. Pharmacotherapy: unless concomitant depression/OCD, not helpful. Need to differentiate
depression primary vs
due to starvation. Start lower initial dose with anti-D if required due to possible cardiac complications
6. Inpatient
Wt gain expectations
Supervised eating
Activity restriction
Limitation on family/peer interactions
Psychiatric consultation
Parent education
Method of family therapy
Teach families how to ventilate emotion, set limits, resolve arguments and
solve problems more effectively; increase parents’ understanding of the
difficulties of the affected child; avoid a view of the world where success or
failure is measured in terms of weight, food and self-control
