How should I assess the physical health risks in a patient with anorexia nervosa?

To assess the physical health risks in a patient diagnosed with anorexia nervosa, start with a comprehensive physical and mental health review at least annually if the patient is not under ongoing specialist treatment. This review should include measurement of weight or BMI (adjusted for age if appropriate), blood pressure, relevant blood tests, and an assessment of daily functioning and risk related to both physical and mental health ¹.

Specifically, assess fluid and electrolyte balance, especially if the patient engages in compensatory behaviours such as vomiting, laxative or diuretic misuse, or excessive exercise, as these increase the risk of electrolyte disturbances and cardiac complications ¹. An ECG should be considered if there are risk factors such as rapid weight loss, severe purging behaviours, bradycardia, hypotension, electrolyte imbalance, or if the patient is on medications that may affect cardiac function ¹ (Friars et al., 2023).

Monitor for signs of cardiovascular instability including bradycardia (heart rate below 40 beats per minute), prolonged QT interval, hypotension, and tachycardia on standing, as these indicate increased medical risk and may necessitate urgent intervention or inpatient care ¹ (Friars et al., 2023). Evaluate muscle strength (e.g., Sit up–Squat–Stand test) and check for hypothermia or other signs of severe malnutrition ¹.

Blood tests should include electrolytes, glucose, and markers of organ function to detect complications such as hypoglycaemia, electrolyte imbalance, or organ failure. Persistent unexplained electrolyte abnormalities warrant investigation for other causes ¹.

In children and young people who have not completed puberty, closely monitor growth and development, including delayed puberty and faltering growth, and consider specialist paediatric advice if concerns arise ¹,².

Assess bone health as anorexia nervosa is a significant risk factor for low bone mineral density and osteoporosis. Consider bone density scanning after 1 year of underweight in children and young people or 2 years in adults, or earlier if there is bone pain or recurrent fractures. Bone density results should be interpreted by a specialist, and treatment options discussed, including the importance of weight restoration as the primary intervention ¹.

Advise patients who vomit to have regular dental and medical reviews and to avoid brushing teeth immediately after vomiting to prevent dental erosion ¹,². Patients misusing laxatives or diuretics should be counselled that these do not reduce calorie absorption and should be gradually stopped ¹,². Excessive exercise should be discouraged ¹,².

Be aware that medically unstable patients can appear deceptively well; therefore, a low threshold for concern and specialist referral is essential. Rapid weight loss (>1 kg/week), severe malnutrition, dehydration, or signs of organ failure require urgent medical care and possible inpatient admission ¹,² (Zipfel et al., 2015).