Transient hypophosphataemia associated with acute infectious disease in paediatric patients.

The aim of this study was to investigate the prevalence of hypophosphataemia in children with acute infection and the relationship between serum phosphate and C-reactive protein (CRP) concentration. Serum phosphate and CRP levels were measured on admission in 238 patients (aged 1 month to 14 y) with: pneumonia (n = 51), upper respiratory tract-related bacterial infection (n = 70), urinary tract infection (n = 50) and viral infection (n = 67). Patients were classified according to CRP value (0-50, 51-100, 101-150, > or = 151 mg/l) and type of infection. The prevalence of hypophosphataemia was calculated for each group. 30 children with hypophosphataemia on admission had serial measurements of serum phosphate and CRP levels. A significant negative correlation between serum phosphate and CRP levels was found (r = -0.41, p < 0.0001). Patients with CRP > or = 151 mg/l on admission had a lower mean serum phosphate value than those with CRP < or = 50 mg/l (1.17 vs 1.50 mmol/l, p < 0.0001). The overall prevalence of hypophosphataemia for patients with pneumonia, upper respiratory tract bacterial infection, urinary tract and viral infections was 45%, 35.7%, 18% and 4.4%, respectively. Hypophosphataemia occurred during the phase of rising of CRP level and resolved soon after CRP reached a plateau. In conclusion, hypophosphataemia is a relatively frequent but transient phenomenon in children with acute infectious disease. It is associated with an increase in CRP concentration and resolves before the normalization of CRP levels.