Aims: To clarify the status of the coagulation system in children with community-acquired pneumonia.
Methods: Coagulation activation markers (prothrombin fragment F1 + 2, thrombin–antithrombin complexes, D-dimer), the natural anticoagulants (antithrombin, protein C and S) and tissue factor were measured in 28 consecutive children with pneumonia on admission to the hospital. Patients were divided into those with either bacterial-type pneumonia (at least two of the following three criteria: plasma C-reactive protein (CRP) >80 mg/L, white blood cell count >15 × 109/L and alveolar infiltrates on the chest radiograph) or viral-type pneumonia.
Results: The majority of the patients (79%) showed elevation of at least one of the three coagulation activation markers. Plasma CRP concentration correlated with F1 + 2 (R = 0.44, p < 0.05) and D-dimer (R = 0.71, p < 0.0001). Patients with bacterial-type pneumonia (n = 17) had higher D-dimer levels (p < 0.05) and lower levels of antithrombin (p = 0.005) and protein C (p = 0.08) than the patients with viral-type pneumonia.
Conclusions: Children with community-acquired bacterial-type pneumonia show distinctive changes in their coagulation system. The finding of coagulation system activation and depressed function of natural anticoagulants in uncomplicated pneumonia helps to understand the rapid and unpredictable changes observed in the coagulation status in patients with more severe forms of disease.