Summary

Eating disorders are serious mental health conditions characterised by abnormal eating behaviours, distorted body image, and significant physical and psychological consequences. The main types are Anorexia Nervosa (AN) – Restriction, Low BMI, Fear of weight gain; Bulimia Nervosa (BN) – Binge-Purge cycles; and Binge Eating Disorder (BED) – Bingeing without compensatory behaviours. Other categories include OSFED (Other Specified Feeding or Eating Disorder) and ARFID (Avoidant/Restrictive Food Intake Disorder). Anorexia Nervosa has the highest mortality rate of any psychiatric disorder (~10%). Medical complications include electrolyte disturbances (Hypokalaemia, Hyponatraemia), cardiac arrhythmias, osteoporosis, and Refeeding Syndrome (Phosphate depletion during nutritional rehabilitation – Can be fatal). Management involves a multidisciplinary approach: Psychological therapies (CBT-ED, MANTRA, SSCM), nutritional rehabilitation, and monitoring for medical complications. NICE NG69 provides comprehensive guidance.

Key Facts

• Anorexia Nervosa (AN): Restriction, Low BMI (<17.5), Intense fear of weight gain, Distorted body image.
• Bulimia Nervosa (BN): Recurrent binge eating + Compensatory behaviours (Purging, Laxatives, Exercise). Normal/Overweight BMI.
• Binge Eating Disorder (BED): Bingeing without compensatory behaviours. Often obese.
• Mortality: AN = Highest mortality of psychiatric disorders (~10%).
• Refeeding Syndrome: Risk in severely malnourished. Monitor Phosphate.
• Treatment: CBT-ED (BN, BED). MANTRA, CBT-ED, SSCM (AN). Fluoxetine (BN).

Clinical Pearls

"Anorexia Kills": Highest mortality of any psychiatric disorder. Physical monitoring is essential.

"Hypokalaemia in a Young Woman = Consider Bulimia": Purging (Vomiting, Laxatives) causes electrolyte disturbance.

"Refeeding Syndrome – Check Phosphate": When refeeding, phosphate drops rapidly. Can cause cardiac arrest.

"BMI Alone Doesn't Tell the Story": Rate of weight loss, medical complications, and psychological state are equally important.

Why This Matters Clinically

Eating disorders are common, serious, and often hidden. Early recognition and appropriate referral saves lives.

Anorexia Nervosa (AN)

Bulimia Nervosa (BN)

Binge Eating Disorder (BED)

Other Specified Feeding or Eating Disorder (OSFED)

• Does not meet full criteria for AN, BN, or BED but clinically significant.
• E.g., Atypical AN (Normal weight AN), Subthreshold BN/BED.

Avoidant/Restrictive Food Intake Disorder (ARFID)

• Avoidance/Restriction of food intake.
• NOT due to body image concerns.
• Leads to nutritional deficiency, Weight loss, Psychosocial impairment.
• E.g., Sensory sensitivity, Fear of choking.

Mortality Causes (AN)

1. Sudden Cardiac Death (Arrhythmias).
2. Suicide.
3. Infection.

Key Guidelines

Scenario 1:

• Stem: A 17-year-old girl presents with 6 months of weight loss, BMI 15.5, and fear of weight gain. She restricts her food intake. What is the diagnosis and first-line treatment?
• Answer: Anorexia Nervosa (Restricting Type). First-line treatment: Family-based treatment (FBT) for adolescents. (Adults: MANTRA, CBT-ED, or SSCM).

Scenario 2:

• Stem: A young woman with Bulimia Nervosa is found to have Hypokalaemia and QTc prolongation. What is the cause?
• Answer: Electrolyte disturbance from Purging (Vomiting/Laxatives). Risk of cardiac arrhythmias.

Scenario 3:

• Stem: What is the key electrolyte to monitor when refeeding a malnourished patient?
• Answer: Phosphate. Refeeding syndrome causes severe Hypophosphataemia.

What are Eating Disorders?

Eating disorders are serious mental health conditions where people have an unhealthy relationship with food and their body. They include:

• Anorexia: Extreme restriction of food. Very low weight.
• Bulimia: Binge eating followed by purging (vomiting, laxatives).
• Binge Eating Disorder: Eating large amounts without purging.

Why are they serious?

Eating disorders can cause serious health problems: Heart problems, Weak bones, Kidney damage, and can be fatal. Anorexia has the highest death rate of any mental illness.

How are they treated?

• Psychological therapy: Talking therapies like CBT.
• Nutritional support: Helping to restore healthy eating.
• Medical monitoring: Checking heart, blood tests.
• Sometimes medication: Especially for Bulimia.

Key Counselling Points

1. Recovery is Possible: "With the right treatment, many people make a full recovery."
2. Seek Help Early: "The sooner treatment starts, the better the outcome."
3. Support is Available: "Organisations like BEAT (UK) offer help for patients and families."

• Sir William Gull (1868): First described Anorexia Nervosa ("Apepsia Hysterica").
• Gerald Russell (1979): Described Bulimia Nervosa as a distinct entity.
• Binge Eating Disorder: Added to DSM-5 (2013).