Creatine kinase isoenzyme BB in cerebrospinal fluid from patients with meningitis and encephalitis.

High CK BB isoenzyme activity has been demonstrated in the CSF of many patients with various neurologic disorders and is considered to reflect brain tissue damage [1, 2]. Increased CK BB activity in the CSF has been described in a patient with fatal pneumonococcal meningitis [3] and also in two patients with viral encephalitis [1]. Since routine laboratory tests are of limited value for assessing the prognosis of patients with CNS infections, the present investigation was undertaken to study the possibility of early detection of brain tissue damage in such patients by determining the CK BB activity in the CSF. The CK BB activity in the control subjects was less than or equal to 10 nkat/liter, which is in accordance with a previous study based on bioluminescence assay [2]. Six of the seven patients with neurologic complications in the present study had marked increases of the CK BB activity. In the patient with brain death due to HSV infection, serial measurements of the CK BB activity in the CSF have shown a maximal fourfold increase from the value of 45 nkat/liter found on admission. In one of the patients with purulent meningitis who developed a slight hydrocephalus, the CK BB activity was normal, but no focal brain damage was found by computed tomography in this case. The results indicate that increased CK BB activity in the CSF is related to the clinical outcome of patients with infections of the CNS. Thus, the determination of the CK BB activity seems to be useful for assessing the prognosis of patients with bacterial and viral meningitis and encephalitis.