Bulimia Nervosa Flashcards
What is bulimia nervose (BN)?
Bulimia nervosa (BN) is an eating disorder characterized by repeated episodes of uncontrolled binge eating followed by compensatory weight loss behaviours and overvalued ideas regarding ‘ideal body shape/weight’.
Briefly describe the pathophysiology and aetiology of BN
The aetiology of BN is very similar to AN, but whereas there is a clear genetic component in AN, the role of genetics in BN is unclear.
When patients with BN binge due to strong cravings, they tend to feel guilty and as a result undergo compensatory behaviours such as vomiting, using laxatives, exercising excessively and alternating with periods of starvation.
This may result in large fluctuations in weight, which reinforce the compensatory weight loss behaviour, setting up a vicious cycle
Who is commonly affected by BN?
BN typically occurs in young women.
The estimated prevalence in women aged 15– 40 is 1– 2%.
How does socioeconomic class affect BN?
Whereas AN is thought to be more prevalent in higher socioeconomic classes, BN has equal socioeconomic class distribution.
What are the predisposing factors of BN?
Note: biological, psychological and social
Biological
- Female sex
- Family history of eating disorder, mood disorder, substance misuse or alcohol abuse
- Early onset of puberty
- Type 1 diabetes
- Childhood obesity
Psychological
- Physical or sexual abuse as a child
- Childhood bullying
- Parental obesity
- Pre-morbid mental health disorder
- Preoccupation with slimness
- Parents with high expectations
- Low self-esteem
Social
- Living in a developed country
- Profession (e.g. actors, dancers, models and athletes)
- Difficulty resolving conflicts
What are the precipitating factors of BN?
Note: biological, psychological and social
Biological
- Early onset of puberty/ menarche
Psychological
- Perceived pressure to be thin may come from culture (e.g. Western society, media and profession)
- Criticism regarding body weight or shape
Social
- Environmental stressors
- Family dieting
What are the perpetuating factors of BN?
Note: biological, psychological and social
Biological
- Co-morbid mental health problems
Psychological
- Low self-esteem, perfectionism
- Obsessional personality
Social
- Environmental stressors
What other psychiatric conditions are co-morbid with BN?
BN commonly co-exists with the following psychiatric disorders and it is hence important to screen for them:
- Depression
- Anxiety
- Deliberate self-harm
- Substance misuse
- Emotionally unstable (borderline) personality disorder
Briefly describe the ICD-10 Criteria for diagnosing BN
Note: Bulimia Patients Fear Obesity
- Behaviours to prevent weight gain (compensatory): compensatory weight loss behaviours include: self-induced vomiting, alternating periods of starvation drugs (laxatives, diuretics, appetite suppressants, amphetamines, and thyroxine) and excessive exercise.
- Preoccupation with eating: a sense of compulsion (craving) to eat which leads to bingeing. There is typically regret or shame after an episode.
- Fear of fatness: including a self-perception of being too fat.
- Overeating: at least two episodes per week over a period of 3 months.
How may diabetics present with BN?
Diabetics may omit or reduce insulin dose.
Other than those stated in the ICD-10 Criteria, what are the other features of BN?
- Normal weight
- Usually the potential for weight gain from bingeing is counteracted by the weight loss/purging behaviours.
- Depression and low self-esteem
- Irregular periods
- Signs of dehydration
- ↓ blood pressure, dry mucous membranes, ↑ capillary refill time, ↓ skin turgor and sunken eyes
- Consequences of repeated vomiting and hypokalaemia
What are the 2 subtypes of BN?
There are two subtypes of BN:
- Purging type: the patient uses self-induced vomiting and other ways of expelling food from the body, e.g. use of laxatives, diuretics and enemas.
- Non-purging type: much less common. Patients use excessive exercise or fasting after a binge. Purging-type bulimics may also exercise and fast but this is not the main form of weight control for them.
Note: the ICD-10 does not differentiate between the two types
Briefly differentiate between BN and anorexia nervosa
Anorexia nervosa
- Amenorrhoea
- No friends (socially isolated)
- Obvious weight loss
- Restriction of food intake
- Emaciated
- Xerostomia (dry mouth)
- Irrational fear of fatness
- A bnormal hair growth (lanugo hair)
Bulimia nervosa
- Binge eating
- Use of drugs to prevent weight gain
- Low potassium
- Irregular periods
- Mood disturbances
- Irrational fear of fatness
- Alternating periods of starvation
Briefly describe hypokalaemia in BN and how it’s treated
A potentially life-threatening complication of excessive vomiting.
Low potassium (<3.5 mmol/L) can result in muscle weakness, cardiac arrhythmias and renal damage.
Mild hypokalaemia requires oral replacement with potassium-rich foods (e.g. bananas) and/or oral supplements (Sando-K). Severe hypokalaemia requires hospitalization and intravenous potassium replacement.
Briefly describe the MSE of BN
Appearance and behaviour: may have appearance and behaviour consistent with depression or anxiety. Signs include likely normal weight, parotid swelling, Russell’s sign and sunken eyes (dehydration).
Speech: slow or normal.
Mood: low.
Thought: preoccupation with body size and shape, preoccupation with eating and guilt.
Perception: normal.
Cognition: either normal or poor.
Insight: usually has good insight.
What is shown in the images A, B and C?
Complications of repeated vomiting.
A= Russell’s sign
B= Bilateral parotid swelling
C= Dental erosion
