Summary

Up to 20% of hospitalised patients may have low serum phosphate concentrations. In certain groups, such as patients with chronic alcohol overconsumption, severe trauma or sepsis, the prevalence may be 30%–50%. Profound hypophosphataemia is less common, but may lead to severe physiological disturbances. In rare cases, hypophosphataemia is caused by phosphaturic substances excreted from a tumour. Osteomalacia with chronic bone pain and fractures, as well as muscle weakness, is common in such patients. The tumours are often small and difficult to detect. Studies suggest that fibroblast growth factor 23 is a reliable marker for detection of these tumours. Persistent hypophosphatemia unresponsive to supplements should raise clinical alertness. With complete resection of the neoplasm, the symptoms rapidly reverse. If the tumour cannot be removed, treatment relies on supplementation with phosphate and active vitamin D compounds. We present a case report of a patient with severe hypophosphataemia, osteomalacia, dysphagia and malnutrition.