Synopsis
Interpret cardiac, biochemical and skeletal complications of eating disorders, recognise when monitoring or acute correction is needed, and use NICE bone-health recommendations accurately.
- Order ECG according to rapid loss, excessive exercise, purging, bradycardia, hypotension, weakness, electrolyte imbalance, rhythm history, caffeine and prescribed or non-prescribed medication.
- Sinus bradycardia commonly reflects starvation adaptation, but an awake heart rate below 40, symptoms, conduction disease, arrhythmia or prolonged QTc requires urgent assessment.
- Vomiting commonly causes chloride and potassium depletion with metabolic alkalosis; laxative diarrhoea may cause potassium and bicarbonate loss with metabolic acidosis.
- Hyponatraemia may result from water loading, medication or volume disturbance; correction must be cautious and guided by cause, chronicity, symptoms and urine studies.
- NICE recommends oral electrolyte replacement unless absorption is impaired or the disturbance is severe; route and dose depend on level, ECG, renal function and ongoing losses.
- The main way to prevent and treat low bone density in anorexia is reaching and maintaining a healthy weight or BMI for age, not prescribing hormones without nutritional restoration.
- Consider bone-density scanning after 1 year of underweight in children and young people and after 2 years in adults, or earlier for bone pain or recurrent fractures.
- Do not repeat bone-density scans more often than annually unless bone pain or recurrent fractures develop; paediatric results need adjustment for bone size.
Key red flags
Preserved consciousness and a sinus rhythm do not make an awake pulse below 40 safe; MEED recommends physician or paediatric assessment with postural observations, bloods and ECG.
Prolonged QTc, heart block, ventricular ectopy, new T-wave change or syncope requires review of rate correction, electrolytes and prescribed or non-prescribed drugs.
Potassium below 2.5 mmol/L is a MEED red finding and may need initial intravenous correction with ECG monitoring when oral treatment is unsafe or ineffective.
Falling phosphate after nutrition begins may be the earliest refeeding warning and can progress to respiratory, cardiac and neuromuscular failure.
Bone pain, recurrent fracture, loss of height or high-impact exercise in established osteoporosis requires prompt skeletal and activity review.
Investigation priorities
Assess rate, rhythm, conduction, repolarisation and QTc under standard resting conditions.
Management branches
Syncope, palpitations, chest pain, bradycardia, purging or QT-active medication raises concern.
- Obtain ECG, glucose and urgent potassium, magnesium, calcium and renal testing while assessing postural and hydration status.
- Place severe electrolyte disturbance, significant ECG abnormality or symptomatic extreme bradycardia in a monitored setting with senior input.
- Correct the cause, review medication and provide nutrition; do not use pacing or antiarrhythmics reflexively for starvation sinus bradycardia.