Bulimia Nervosa

Question 1

Define bulimia nervosa

Answer 1

An eating disorder characterised by recurrent episodes of uncontrolled binge eating w/ compensatory weight loss behaviours + overvalued ideas regarding the ‘ideal body shape/weight

N.b. body weight may be normal

Question 2

Epidemiology

Answer 2

• 1-1.5% women
• Young women
• AN seen more in higher socioeconomic classes (but equal distribution in BN)

Risk factors same as anorexia

Question 3

Aetiology + pathophysiology

Answer 3

• Similar aetiology to AN (but role of genetics is unclear in BN)

Psychopathology:

1. Strong cravings lead to binging
2. This leads to guilt + fear of fatness → compensatory behaviours (vomiting, laxatives, excessive exercise, starvation periods)
3. Results in:
   a. Large fluctuations in weight (reinforces the cycle)

Question 4

Co-morbidities

Answer 4

Co-morbidities:

- Depression, anxiety. Deliberate self-harm, substance misuse, emotionally unstable (borderline) personality disorder

Question 5

CFs

Answer 5

Bulimia Patients Fear Obesity

Behaviours to prevent weight gain (compensatory)
- Self-induced vomiting, periods of starvation, drugs (laxatives, appetite suppressants, amphetamines, thyroxine), excessive exercise

Preoccupation w/ eating
- A sense of compulsion (craving) to eat. Regret or shame after binge episode

Fear of fatness
- Self-perception of being too fat

Overeating
- 2 episodes per week (3mths)

Question 6

What are the 2 types of BN?

Answer 6

1. Purging type → pt uses self-induced vomiting (+ other ways to expel food: laxatives) – n.b. purging BN pt’s may use non-purging methods too (but the purging methods are their main compensatory behaviour)
2. Non-purging type → less common. Pt use excessive exercise or fasting after a binge

**purging = compensatory acts such as vomiting and laxatives (not starvation + excessive exercise)

Question 7

Other features BN

Answer 7

Other features: low self-esteem, depression, normal weight, irregular periods, signs of dehydration (low BP, dry mucous membranes, ^ cap refill time, ↓ skin turgor, sunken eyes)

Question 8

Signs of BN

Answer 8

• Similar to AN
• Purging problems:
  o Arrhythmias
  o Cardiac failure + sudden death
  o Electrolyte disturbance (↓ K+, Na+, Cl-, metabolic acidosis [laxatives] or metabolic alkalosis [vomiting])
  o Oesophageal erosions
  o Oesophageal/gastric perforation + Mallory Weiss tears
  o Gastric/duodenal ulcers
  o Pancreatitis
  o Constipation/steatorrhoea
  o Dental erosion
  o Leukopaenia

Question 9

Sign of repeated vomiting

Answer 9

Russell’s sign (calluses on knuckles), bilateral parotid swelling, dental erosion

Question 10

Ix

Answer 10

1. Bloods: FBC, U/Es, amylase, glucose, TFTs, magnesium, calcium, phosphate
2. VBG (metabolic alkalosis due to vomiting)
3. ECG (arrhythmias as a consequence of hypokalaemia → prolonged PR interval, flattened or inverted T waves, prominent U waves after T wave [EASY EXAM Q])

Question 11

Rx

Answer 11

General principles:
• OUTPATIENT (usually) → admission if suicidal, physical problems (electrolyte imbalance), pregnant (risk of spontaneous abortion)…

• COMBINED approach
o Pharmacological → high dose SSRI (fluoxetine) = SSRI of choice
o Psychological → CBT (best evidence), psychoeducation about nutrition, IPT (interpersonal psychotherapu)
• Social: food diary, techniques to avoid bingeing (eating in company), small/regular meals, guided self-help programmes
• Also:
o Risk assessment (suicide)
o Screen for co-morbidities
o Rx complications

Question 12

Hypokalaemia & rx

Answer 12

• Life-threatening problem of excessive vomiting
• K+ = <3.5mmol/L
• Muscle weakness, cardiac arrhythmias (see ECG changes) + renal damage
• ECG changes: prolonged PR interval, flattened or inverted T waves, prominent U waves after T wave
• Rx:
  o Mild: oral replacement K+ rich foods (bananas) ± oral supplements
  o Severe: Hospital admission + IV K+ replacement

Question 13

Anorexia nervosa vs Bulimia nervosa

Answer 13

Anorexia nervosa

• Sig. underweight
• More likely to have endocrine abnormalities
• No strong cravings for food
• Don’t binge eat
• May have compensatory weight loss behaviours (excluding purging)

Bulimia nervosa

• Normal weight/overweight
• Less likely endocrine abnormalities
• Strong cravings for food
• Recurrent episodes of binging
• Compensatory weight loss behaviours

Question 14

Binge eating disorder

Answer 14

recurrent episodes of binge eating w/out compensatory purging behaviour