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Eating disorders
Anorexia nervosa is restricted eating with a significantly low weight, fear of weight gain and a disturbed body image; bulimia is binge eating with compensatory behaviour at a normal weight; the great medical danger at the start of renourishment is refeeding syndrome with a fall in phosphate.
Why it matters in the exam
Exam questions present a girl or young woman with weight loss, bradycardia, hypotension, hypothermia and fine body hair (lanugo), and ask about the diagnosis, the complications and the decision to admit. Know that amenorrhoea is no longer required for the diagnosis of anorexia. Questions also test the laboratory findings: hypokalaemia and metabolic alkalosis from vomiting, low T3 with a normal TSH, low LH and FSH, and on bone density — osteopenia.
In bulimia the weight is usually normal, with binge eating and compensatory behaviour at least once a week for 3 months. Physical signs: enlarged salivary glands, dental enamel erosion and calluses on the back of the hand (Russell sign). Bulimia is treated with CBT and fluoxetine, and bupropion is forbidden because of the seizure risk. In anorexia the treatment is gradual nutritional rehabilitation, and in adolescents family-based treatment (FBT). Eating disorders have the highest mortality of the mental disorders, partly from arrhythmias and partly from suicide. Binge eating disorder is binge eating without compensatory behaviour.
Key points
- Anorexia: restriction, low weight, fear of gain, distorted body image; amenorrhoea not required.
- Bulimia: binge eating and compensation once a week for 3 months, normal weight.
- Refeeding: monitor phosphate and electrolytes.
- Bulimia: CBT and fluoxetine; bupropion forbidden.
- Admission: heart rate below 50, potassium below 3, BMI below 15, arrhythmia.
Summary table
| Disorder | Definition | Findings | Treatment |
|---|---|---|---|
| Anorexia nervosa | Restriction, significantly low weight (BMI below 18.5), fear of weight gain, disturbed body image | Bradycardia, hypotension, hypothermia, lanugo, osteopenia; amenorrhoea not required | Nutritional rehabilitation, family-based treatment in adolescents, psychotherapy |
| Severity of anorexia | BMI below 15 = extreme | — | Consider admission |
| Bulimia nervosa | Binge eating and compensatory behaviour, at least once a week, 3 months; normal weight | Enlarged salivary glands, dental erosion, Russell sign, hypokalaemia and alkalosis | CBT and fluoxetine; bupropion forbidden |
| Binge eating disorder | Binge eating without compensatory behaviour, at least once a week, 3 months | Often overweight | CBT; lisdexamfetamine |
| Refeeding syndrome | In the first days of renourishment | Low phosphate, potassium and magnesium; heart failure and arrhythmias | Gradual feeding and monitoring of phosphate and electrolytes |
| Indications for admission | Heart rate below 50, BP below 90/45, potassium below 3, BMI below 15, syncope or arrhythmia | — | Admission for medical stabilisation |
A free exam question
?איזה סימן מאפיין הרעלת סטימולנטים (the question as examined, in Hebrew)
- א. שינויים בלחץ דם
- ב. מיוזיס
- ג. עליה במשקל
- ד. התחזקות שרירים
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Sources
- DSM-5-TR, American Psychiatric Association, 2022 — Feeding and Eating Disorders
- APA Practice Guideline for the Treatment of Patients With Eating Disorders, 4th edition (2023) — Assessment and treatment
- NICE guideline NG69, 2017, updated 2020 — Eating disorders: recognition and treatment
- Kaplan and Sadock's Synopsis of Psychiatry, 12th edition (2021) — Feeding and Eating Disorders
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.