Eating Disorders Flashcards
What is anorexia nervosa?
A severe psychiatric disorder consisting of self induced starvation, excessive weight loss and distorted body. Typically manifests in adolescence and predominantly affects females
What is the epidemiology of anorexia nervosa?
9 in 1000 females experience anorexia in their lives
Affects women more than men in ratio of 10:1
Peak incidence in early to mid-adolescence
What are the risk factors for anorexia?
- Genetic factors
* Increased risk for first degree relatives. Higher concordance rates in monozygotic vs dizygotic twins
* certain gene polymorphisms are associated with anorexia including those involved in serotonin regulation and energy homeostasis - Biological factors
* Endocrine disturbances such as hypercortisolaemia and alterations in leptin levels have been observed (unclear if causative or consequential)
* Structural and fucntional brain changes including reduced grey matter volume and altered reward system functioning - Psychological factors
* Personality traits such as perfectionism, rigidity, harm avoidance, low self-esteem and OCD tendencies
* Prior exposure to traumatic events or ACEs - Sociocultural factors
* The cultural idealisation of thinness in western societies
* Pressure from peers or family members
* Exposure to media promoting thin ideals
* Participation in activities that emphasise leanness e.g. ballet/gymnastics
What is the pathophysiology of anorexia?
May be genetic, psychological and sociocultural predisposition to onset of anorexia.
Abnormalities in neurotransmitter systems e.g. serotonin and dopamine which are involved in regulating mood and appetite which may contribute to characteristic fear of weight gain and body image distortion.
Anomalies in HPA axis may cause hyperactivity of the stress-response system.
Initial weight loss can then lead to physiological changes that perpetuate the disorder. Changes in neuroendocrine function, metabolism and gut microbiota can exacerbate fear of eating and weight gain.
The predispositional factors and hormonal/neuroendocrine changes interact in a vicious cycle driving disordered eating behaviours. For example starvation induced cognitive impairment may reinforce rigid dietary rules and distorted body image
What is the clinical presentation of anorexia nervosa?
- BMI <17.5 or in those under 18 weight below 85% of predicted in BMI centile charts
- Dieting and/or restrictive eating practices
- Rapid weight loss including use of over exercising, diuretics, laxatives, and self-induced vomiting
- Fear of gaining weight
- Over evaluation of size
- Denial of condition
- Resistance to help or intervention
- Social withdrawal
- Lack of management of pre-existing conditions that involve control of diet e.g. diabetes
Other physical features include:
* Amenorrhoea (3+ months)
* GI sx e.g. constipation, dysphagia, and abdominal pain
* General symptoms e.g. fatigue, dizziness and intolerance of cold
* Delay in secondary sexual characteristics if pre-pubertal
* Bradycardia
* Hypotension
* Enlarged salivary glands
What physiological abnormalities may be found in anorexia nervosa?
- Hypokalaemia
- Low FSH, LH, oestrogens and testosterone
- Raised cortisol and growth hormone
- Impaired glucose tolerance
- Hypercholesterolaemia
- Hypercarotinaemia
- Low T3
What are the diagnostic criteria for anorexia?
Diagnosis is now based on DSM 5 and specific criteria around BMI and amenorrhoea are no longer mentioned:
1. Restriction of energy intake relative to requirements leading to a significantly low body weight in the context of age, sex, developmental trajectory, and physical health
2. Intense fear of gaining weight or becoming fat, even though underweight
3. Disturbance in the way in which one’s body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or denial of the seriousness of the current low body weight
What differentials should be considered for anorexia and what are the similarities and differences when compared with anorexia?
It is important to exclude medical/organic causes of weight loss
- Bulimia nervosa
* Similarities - both conditions involved preoccupation with body weight and shape and abnormal eating behaviours. Patients may engage in restrictive eating and excessive exercise
* Differences - bulimia is characterised by recurrent episodes of binge eating followed by compensatory behaviours such as self induced vomiting, use of laxatives, or diuretics. Patients typically maintain a normal weight or are slightly overweight - Major depressive disorder
* Similarities - weight loss, lack of appetite and general withdrawal from social activities. Both may present with significant mood disturbances and low energy levels
* Differences - weight loss is usually unintentional and not associated with distorted body image. Primary focus is on pervasive depressive mood and loss of interest in activities - Hyperthyroidism
* Similarities - both can lead to significant weight loss, fatigue, and an increase in physical activity levels (restlessness in hyperthyroidism, excessive exercise in AN)
* Differences - Medical condition leads to tachycardia, heat intolerance, tremors. Blood tests will show elevated levels of thyroid hormones - Binge eating disorder/unspecified feeding or eating disorder
What investigations shoud be carried out in anorexia nervosa?
Bloods (to rule out other causes of weight loss and check for electrolyte abnormalities) - FBC, ESR, TFTs, U&Es, glucose, LFTs
ECG - may show bradycardia or prolonged QT interval in severe anorexia
Imaging - dual energy X-ray absorpitometry (DXA) after a year of being underweight in <18 or 2 years in adults to assess bone density
What is the management of under 18s with anorexia nervosa?
Should be referred immediately to an eating disorder service for assessment and treatment.
Anorexia nervosa focussed family therapy (FT-AN):
* First line treatment involves 18-20 sessions over a year involving the family in the patients recovery
* Phase 1 - allows changes in diets and eating regimes in normal context to try and gain weight. Responsibility of control of eating given to parents/carers
* Phase 2 - once weight is restored responsibility given to the patients to manage eating habits
* Phase 3 - planning to prevent relapse and maintain recovery
If FT-AN is not effective or appropriate then individual CBT or adolescent focussed psychotherapy
What is the management of anorexia nervosa in adults?
- Individual eating-disorder-focussed cognitive behavioural therapy (CBT-ED) - 40 sessions over 40 weeks
- Maudsley Anorexia Nervosa Treatment for Adults (MANTRA) - 20 sessions
- Specialist supportive clinical management (SSCM) - 20 or more weekly sessions
What are the criteria for hospital admission with anorexia nervosa?
Urgent admission required if:
* Electrolyte imbalance
* Severe malnutrition
* Severe dehydration
* Organ failure
* Bradycardia/prolonged QT interval
* Very low BMI (below 0.2nd centile) or BMI <13
* Rapid weight loss (more than 1kg per week for more than 2 weeks in a row)
* Need for refeeding
* Inability for parents to provide support needed
* Suicide risk
Admission under the Children Act 1989 or Mental Health Act Section 3 may be needed
Admission should be to a specialist eating disorder unit where safe refeeding can be started to avoid death
What are the complications of anorexia nervosa?
- Cardiovascular - bradycardia, hypotension, prolonged QT. Increased risk of SCD. Mitral valve prolapse can occur
- Endocrine - Amenorrhoea due to hypothalamic dysfunction. Thyroid dysfunction (hypothyroidism). Growth hormone resistance, cortisol excess and insulin resistance
- GI - Gastroparesis, constipation, liver dysfunction. SMA syndrome can develop
- Bone health - Osteopenia or osteoprosis due to low levels of oestrogen
- Haematologic - Leukopenia and thrombocytopenia as a result of malnutrition. Anaemia is common
- Nutritional - deficiences can lead to complications such as pellagra, scurvy, Wernicke’s encephalopathy
- Mental health - comorbid psychiatric conditions such as depression, anxiety, OCD and increased risk of suicide
What is the prognosis with anorexia nervosa?
Has the highest mortality rate among psychiatric disorders. Mortality ratio estimated around 5.86
Most deaths due to complications from severe malnutrition or suicide
Prolonged starvation can result in multi-organ failure
50% of individuals with AN achieve full recovery while around 20-30% remain chronically ill. Remaining patients may have partial recovery but continue to struggle with body image issues or disorderd eating patterns.
Early intervention improves outcomes significantly
What is bulimia nervosa?
An eating disorder characterised by repeated episodes of uncontrolled binge-eating followed by weight loss behaviours to compensate for binges
