Eating disorders Flashcards
Aetiology of eating disorders
Genetics (less in bulimia)
Psychological theories - perfectionism and low self-esteem are RFs for AN and BN; successful weight loss enhances sense of achievement, autonomy and perfectionism
Sociocultural - pressures to be thin and promoting of dieting; high risk groups (models, athletes, dancers)
Personal history - Hx obesity (BN), Hx AN (BN), child abuse
FHx - parental overprotection and family enmeshment; disturbed fam dynamics, parental weight concern, high parental expectation; FHx of obesity, depression, substance misuse
Anorexia Nervosa
Disorder characterised by deliberate weight loss, induced and sustained by the pt
Mostly in adolescent girls and young women but can affect others
Psychopath: dread of fatness/flabby body contour persists as an intrusive overvalues idea; pt imposes a low weight threshold on themselves
Undernutrition of varying severity with secondary endocrine and metabolic changes and disturbances of bodily function
Sx include restricted dietary choice, excessive exercise, induced vomiting and purgation and use of appetite suppressant and diuretics
Main 4 diagnostic features of anorexia nervosa
BMI <17.5 (or weight 15% less than expected)
Deliberate weight loss; extra-ordinary extents, restrict calorie intake, may use laxatives, vomiting, excessive exercise. Appetite suppressants, thyroxine, diuretics and stimulants may be used; diabetics may skip insulin to prevent fat deposition
Distorted body image: preoccupied with body shape and dread of weight gain, overvalued idea that they are fat despite being very thin
Endocrine dysfunction: hypothalamo-pituitary-gonadal axis affected -> amenorrhoea/impotence; loss of libido; if pre-pubescent, may cause delay/arrest of menarche or breast development
Physical complications of AN
Lethargy and cold intolerance
Pancytopenia in severe anorexia due to bone marrow hypoplasia
Infections resulting from reduced immunity
Cardiovascular: sudden death; bradycardia, hypotension (postural), arrhythmia (due to hypokalaemia), mitral valve dysfunction and cardiac failure
GI: constipation, abdo pain, ulcers, oesophageal tears, gastric rupture due to vomiting, nutritional hepatitis (low serum protein, raised bilirubin, LDH and ALP); delayed gastric emptying->feels bloated even after eating small amounts
Reproductive: amenorrhoea is a Dx criterion in women, infertility (atrophy of ovaries and testes), loss of libido, loss of morning erections in men
MSK: osteoporosis (leading to fractures and proximal myopathy
Neuro: peripheral neuropathy, delirium and convulsions
Other: lanugo hair (attempt to keep body warm), swollen salivary glands after bingeing, atypical dental wear e.g. erosion
Investigations
Assessment tools: SCOFF screening tool
Height, weight, BMI
Squat test: squat and rise without using arms (tests proximal myopathy)
Bloods: ESR (is normal or low in AN) and TFTs - to exclude organic causes hypothyroidism, chronic inflam disease; FBC, U&E, phosphate, albumin, LFT, creatine kinase, glucose - to evaluate nutritional state and risk
ECG - bradycardia, arrhythmias, prolonged QT interval
DEXA to assess bone density (if indicated)
Physical abnormalities in AN:
- Hypokalaemia - and associated ECG abnormalities
- Low LH, low FSH, low oestrogens, low testosterone
- Raised cortisol and GH
- Impaired glucose tolerance
- Hypercholesterolaemia
- Hypercaritonaemia
- Low T3
- Gs and Cs are raised (GH, glucose, salivary glands, cortisol, cholesterol, caritonaemia)
MARSIPAN checklist
Management of AN
Engagement
Psycho-education - advise on nutrition and health
Treat comorbid psych illness - depression, OCD, substance misuse
Nutritional management and weight restoration - realistic weekly weight gain target and set eating plan
Psychotherapies - motivational interviewing (engaging for insight), family therapy (best response in short Hx AN), interpersonal therapy (best for pts with longer onset/duration illness), CBT
Medical Tx - particularly important if there are physical complications, rapid weight loss or BMI <13.5
Inpatient Tx - if BMI <13 or extremely rapid weight loss, serious phys complications, high suicide risk; MHA may be needed for compulsory feeding
Medication should not be offered as sole Tx, but anti-depressant (fluoxitine) may be useful
Referrals pathway according to severity of AN
Mild: BMI >17, no additional co-morbidity
- Monitor/advice/support for 8 weeks, recommend support from BEAT; failure to respond = routine referral to community eating disorder service (CEDS)
Moderate: BMI 15-17, no evidence of system failure
- Routine referral to CEDS
Severe: BMI <15, rapid weight loss, evidence of system failure
- Urgent referral to CEDS
NICE Psychological treatment options for AN
Individual eating disorder focused CBT (CBT-ED)
- Aim to reduce risk of physical health and other Sx
- Encourage reaching a healthy body weight
- Cover nutrition, cognitive restructuring, mood regulation, social skills, body image concern, self-esteem and relapse prevention
- Include self-monitoring of dietary intake and associated thoughts and feelings
Maudsley Anorexia Nervosa Treatment for Adults (MANTRA)
- Workbook to encourage pt to develop a non-anorexic identity
Specialist supportive clinical management (SSCM)
- Aim to recognise link between Sx and abnormal eating behaviour
If above not accepted/effective: eating-disorder-focused psychodynamic therapy (FPT)
In children and young people:
AN-focussed family therapy (FT-AN)
- Emphasises role of fam in helping recovery
- Temporary role of parent/carer in early Tx to manage eating
- Relapse prevention
Other options: CBT-ED, adolescent focused psychotherapy for AN (AFP-AN)
Markers of need for urgent inpatient medical treatment
High-risk pts with nutritional decompensation
BMI <13
Weight loss >1kg/week
Purpuric rash
Cold peripheries
Core body temp <34.5
Hypotension (<80/50mmHg)
Bradycardia (<40bpm) with prolonged QT interval on ECG
Inability to stand from squatting without using arms for leverage
Electrolyte imbalance (K+ <2.5, Na+ <130, phosphate <0.5)
Refeeding syndrome; when, cause, prevention, management
Complication as a result of fluid and electrolyte shifts during aggressive nutritional rehabilitation of malnourished patients
Characterised by electrolyte imbalance (low phosphate, potassium and magnesium)
Caused by sudden intracellular movement of electrolytes due to switch from fat to carbohydrate metabolism and associated increased secretion of insulin
Prevention - avoid rapid increases in daily caloric intake; close monitoring esp during early stages
Management - Reduce nutritional support; aggressively correct hypophosphatemia, hypokalaemia and hypomagnesemia
Biochemistry and clinical features of refeeding syndrome
Biochem: Low phosphate - malnourished pts have low phosphate stores, nutritional replenishment incl. carbs -> insulin release -> triggers cellular uptake of phosphate (and K and Mg) -> decreased serum levels Low magnesium Low potassum Low thiamine Salt and water retention
Clinical features: Fatigue Weakness Confusion High blood pressure Peripheral oedema Rhabdomyolysis Seizures Arrhythmia Congestive heart failure
Bulimia Nervosa
Syndrome characterised by repeated bouts of overeating and excessive preoccupation with the control of body with, leading to pattern of overeating followed by vomiting or use of purgatives
Shares many psychological fetaures with AN, including overconcern with body shape and weight
Repeated vomiting likely to cause disturbance of body electrolytes and physical complications
Often Hx of AN (months-years)
Four key features in BN and physical Sx
Binge eating - Repeated bouts of overeating (hallmark); experience irresistible cravings for food and lose control; sense of desperate urgency and compulsion; often triggered by distress
Purging - Binge causes feelings of shame and guilt leading to measures to undo the damage (e.g. vomiting, using laxatives or diuretics)
Body image distortion - Pts feel fat and are pre-occupied by shape and weight; often hate their body
BMI >17.5 - Usually normal or slightly increased weight; periods usually present
Pts usually secretive about binge-/purge behaviour Weight is normal, so phys Sx tend to be 2ndard to vom/purging - Arrhythmias (hypokalaemia) - Convulsions (hyponatraemia) - Dehydration - Enlarged parotid glands - Dental caries - Mallory-Weiss tear - Osteoporosis - Russell's sign (calluses on knuckles)
Investigations for BN
Same as AN
Particularly assess electrolytes and ECG
May have hypochloraemic metabolic alkalosis and hypokalaemia due to vomiting and loss of HCl from stomach
ECG may show signs of hypokalaemia: tall P waves, flattened T waves
Referral pathways for BN
Mild
- Recommend self-help, recommend BEAT, monitor/advice/support for 3 months, routine referral to CEDS if no improvement/deterioration
Moderate: frequent binging and purging (>2/week), no significant electrolyte abnormality, some medical consequences e.g. chest pain
- Monitor/advice/support for 8 weeks, recommend self-help, consider SSRI, routine referral to CEDS if failure to response
Severe: daily purging with significant electrolyte imbalance, comorbidity
- Urgent referral to CEDS
