Eating disorders are associated with a high degree of morbidity, and occasionally – mortality. They most commonly present in adolescent females. About 1 in 20 young females who pursue a ‘diet’ to lose weight will progress to a diagnosable eating disorder.
Eating disorders are typically characterised by abnormal eating behaviours, maladaptive weight loss behaviours, and distorted beliefs about body image, normal weight and norma body shape.
The SCOFF questionnaire can be used as a screening tool for eating disorders:
- S – Do you make yourself SICK because you feel uncomfortably full?
- C – Do you worry you have lost CONTROL over how much you eat
- O – Have you recently lost more than ONE STONE (6kgs) in a three month period
- F – Do you believe yourself to be FAT when other say you are thin?
- F – Would you say FOOD dominates your life?
Answering “Yes” to two or more questions has a high sensitivity for bulimia nervosa.
It is also important to consider other disorders, both organic and psychiatric:
- Stress / anxiety / depression – probably the number one cause. Is often temporary. May be a history of similar episodes earlier in life. Caused by reduced appetite.
- Malignancy – in some cancers (including stomach, pancreatic, lymphoma, and other bowel cancers) weight loss may be the only symptom. This is often the cause of multiple factors – including decreased appetite (“anorexia”) and increased metabolism
- Chronic Infection – consider TB, HIV, infective endocarditis and brucellosis – particularly in at-risk populations
- Other gastrointestinal causes – e.g. coeliac disease, peptic ulcer disease, other causes of malabsorption
- Metabolic Causes
- Medications – including NSAIDs, antihypertensives, digoxin and theophylline
- Drug and Alcohol Dependency
- How much weight lost and over what period?
- Changes to diet?
- What is your appetite like?
- Have clothes become more loose?
- How is general health?
- Do you feel anxious, stressed or depressed?
- Consider a screening tool, such as DASS
- Questions about metabolic disorders
- Do you often feel thirsty?
- Do you pass a lot of urine?
- Do you get hot and sweaty easily or frequently?
- Do you get irritable or have tremors?
- Questions about other causes
- Weight loss itself in any history if a red flag (for malignancy or infectious disease)
- Rapid weight loss
- Erosion of dental surfaces
- Weakness and malaise in young females – consider eating disorder and hypokalaemia
- Weight, height and BMI
- Check teeth for acid damage
- Consider abdominal examination +/- PR as indicated from history
- Check reflexes and examine thyroid gland. Consider full examination for signs of hyperthyroidism
- Blood tests – FBC, U+Es, ESR, CRP, TFTs, LFTs, random blood sugar
- Faecal occult blood
- If indicated, consider other tests including:
- HIV serology
- Endoscopy (upper and / or lower bowel)
- USS or CT abdomen
- specific tumour markers – e.g. CEA, ca-125
- 1/3 of patients make a complete recovery
- 1/3 make only partial recovery and have many relapses
- Anorexia nervosa has a mortality rate of 10-25%. This can be from suicide, pneumonia or hypokaleamia (leading to arrhythmias)
Epidemiology and Aetiology
- Affects 1% of the population
- Most commonly affects girls (10:1)
- Bimodal age of onset
- Age 13-14
- Age 17-18
- Incidence is rising in boys
- Typically affects intelligent, diligent and highly motivated individuals
- Patients usually have poor insight
- Associated with amenorrhoea
- Can cause dry scaly skin, alopecia and increased body hair
- Overestimation of actual weight and body size – the discrepancy between actual and perceived weight increases as weight reduces.
- Often the patient will deny any weight loss, and disagree that she is too thin.
- Phobia of normal body size and weight
- Methods of reducing weight:
- Restricting calorie intake
- Use of laxatives
- Use of diuretics
- Very low body weigh – There is a ‘critical weight’ (usually around 48Kg) below which amenorrhoea will occur. If the patient is not completely through puberty, they may regress to a pre-pubertal state
- The control of weight may give the patients a sense of power – puberty can be a difficult time of maturity, when many patients feel they are ‘losing control’ of their local environment. Anorexia gives control over weight which may be comforting
- Obsession and pre-occupation with food and cooking – many patients take up cooking as a hobby, although never eat any of their own food
- Low metabolic rate
- Cold peripheries
- Vitamin deficiencies & electrolyte disturbances
- Lanugo hair – fine downy hair that may appear on the body
- Skin changes
- Falsely low T3 level – giving appearance of hypothyroidism
- Low plasma proteins
- Ankle oedema
- ↓LH and ↓FSH
- Associated with:
- Treat the psychological disorder
- Encourage weight gain
- Alter behaviours that lead to the development of anorexia
- Only a small percentage of patients will continue to lose weight after admission. In these cases, tube feeding may be used.
- On admission, the patient is usually fed 2000 calories per day. This is not usually in big meals, as these can cause difficulties.
- Once a normal weight has been achieved, a more psychotherapeutic level of care is adopted. Signs that indicate a good prognosis include:
- Good relationship with the parents
- Ability to discuss previous suppressed emotional difficulties – usually around pressures of adolescence, growing up and relationships.
- More common than anorexia
- More common in girls
- Prevalence is increasing
- Typically affects older teenagers than anorexia
- Typically occurs 3-4 days after eating beings
- The result of a change in metabolism, from metabolising fats to metabolising carbohydrates
- Protein is a particular aetiological factor (e.g. in meat, milk and cheese)
- There are severe electrolyte disturbances, typically thymine and phosphate deficiencies, and there may also be hypoglycaemia, and low potassium and glucose.
- Lack of phosphate can lead to muscle weakness, which can result in diaphragmatic insufficiency.
- These deficiencies occur because there is a massive cellular uptake of electrolytes and thus serum levels fall.
Treatment and prevention
- Typically thiamine and vitamin B complex supplements are given when feeding resumes in anorexia.
- Biochemistry should be closely monitored, and any abnormalities in potassium, magnesium and phosphate should be corrected