Clinical Pearls & Morning Reports
Published December 25, 2019
There are two viruses that are associated with profound lymphocytic pleocytosis in the cerebrospinal fluid (CSF): mumps virus and lymphocytic choriomeningitis virus. Read the latest Case Records of the Massachusetts General Hospital here.
Q: What causes of bacterial meningitis commonly manifest with lymphocytic pleocytosis in the CSF?
A: Unlike most other cases of bacterial meningitis, tuberculous meningitis and listeria meningitis commonly manifest with lymphocytic pleocytosis in the CSF. Although a predominance of lymphocytic cells in the CSF can occur early during the clinical course of acute bacterial meningitis, neutrophilic pleocytosis is more common.
Q: What are some of the features of herpes simplex virus (HSV) meningitis?
A: Although HSV infection can cause both meningitis and encephalitis, HSV encephalitis can be fatal and can be manifested by features that are clinically similar to those of acute bacterial meningitis, such as rapid onset and marked severity of headache, fever, and focal neurologic signs. HSV encephalitis is usually associated with frontotemporal signs, including behavior changes, amnesia, aphasia, seizures, and hemiparesis. In patients with HSV encephalitis, MRI characteristically shows signal hyperintensity in the orbitofrontal and temporal lobes.
A: Lymphocytic choriomeningitis virus (LCMV) is a rodent-borne arenavirus. House mice are the natural reservoir, and an estimated 5% of house mice in the United States are infected. The virus can be transmitted to humans by direct contact or by aerosolization of rodent urine or feces. Infection is most common in the winter, when mice are indoors. LCMV infections have been reported in Europe. The infection has an incubation period of approximately 1 to 2 weeks, and most infections are mild and self-limiting. Among patients in whom meningitis develops, the typical manifestation of infection is a biphasic illness characterized by an influenza-like syndrome followed by a convalescent period of several days before the onset of meningismus.
A: The diagnosis can be established by the detection of LCMV nucleic acids in the CSF during the acute stage of illness or by the detection of seroconversion to the virus on the basis of antibody testing during the acute and convalescent stages. The enzyme-linked immunosorbent assay (ELISA) for LCMV is available only at the Centers for Disease Control and Prevention. Serologic testing by means of an immunofluorescence assay that is typically performed at commercial laboratories has a lower sensitivity than ELISA for the detection of LCMV. LCMV nucleic acid testing may detect viral ribosomal nucleic acids in the blood or CSF only during the first 2 weeks after phase 1 symptoms begin. Care for patients with LCMV infection is symptom-oriented, given a lack of established specific therapies.