Hypophosphatemia is a serum phosphate concentration < 2.5 mg/dL (0.81 mmol/L). Mild hypophosphatemia is somewhat common and usually isn’t a cause for concern however severe hypophosphatemia can be life-threatening and requires medical treatment. The UK Medicines Information group have provided excellent guidance on how to replace phosphate.
Clinical features
- Generally asymptomatic if mild
- Can cause many systemic features
- CNS & MSK: weakness/myalgia, lethargy, confusion, seizures
- Cardiorespiratory failure
- Rickets/Osteomalacia if chronic
Causes
- Malabsorption
- D&V
- Refeeding syndrome
- Chronic alcohol use
Investigations
- Check the calcium, U&Es, renal function
Treatment
- Use local guidelines or consider the information above
- Typically oral replacement for a mild deficiency (e.g. phosphate Sandoz) & IV therapies if moderate or severe
- PO therapy risks diarrhoea
- IV therapy via phosphate polyfusor has a large amount of potassium. Be careful of this contraindication in patients with hyperkalaemia
References & further reading
- Katzel, J.A., Vucuscu, R., Garcia, R., 2013. Wards 101 pocket clinician’s survival guide. Börm Bruckmeier Publishing.
- Lewis III, J. L., 2018. Hypophosphatemia. MSD Manual Professional Version.
- Mozingo, D.W. and Mason Jr, A.D., 2018. Hypophosphatemia. In Total Burn Care (pp. 280-286). Elsevier.
By Dr Shoaib Hussain
Edited by Pratyush Pradeep
