Fibrin-fibrinogen degradation products in cerebrospinal fluid.

An increase in low molecular weight fibrin-fibrinogen degradation products (FDP) was demonstrated in cerebrospinal fluid (CSF) from 17 of 18 patients with bacterial or viral meningitis compared with 29 patients without meningitis. The CSF also showed an increase in coagulation proteins of molecular weight less than 90000 (factors VII, IX, and plasminogen) but did not contain fibrinogen (MW 340000) or plasminogen activator. It is concluded that low molecular weight FDP in the CSF in infective meningitis result from leakage through a damaged blood-CSF barrier rather than from local digestion of fibrin deposited on the meninges.