Lymphocytic choriomeningitis virus: an underrecognized cause of neurologic disease in the fetus, child, and adult

Abstract

Lymphocytic choriomeningitis virus (LCMV) is an important cause of neurologic disease in humans. Carried and secreted principally by wild mice, LCMV covers a large geographic range and infects great numbers of people. Humans acquire LCMV disease when they come into contact with the secretions of infected mice. Because it has a strong neurotropism, the clinical signs and symptoms of LCMV infection are mostly neurologic. When the virus is acquired postnatally by children or adults, the clinical manifestations are usually those of aseptic meningitis. Most people who acquire LCMV infection during childhood or adulthood are moderately symptomatic for several weeks, but have a full recovery. A much more severe disease ensues when the infection occurs prenatally. LCMV can infect the fetal brain and retina, where it leads to substantial injury and permanent dysfunction. The possibility of LCMV infection should be considered in all babies with evidence of congenital infection, especially those with prominent neurologic signs, such as microencephaly, periventricular calcifications, and hydrocephalus.

Figure 1

Pathologic changes commonly observed in congenital LCMV infection. Shown here are head CT scans from a normal child (A) and from two children with congenital LCMV infection (B and C). B. The most common abnormalities in congenital LCMV infection include periventricular calcifications (arrows) and ventriculomegaly (V), often due either to non-communicating hydrocephalus or to cerebral atrophy. C. Some patients with congenital LCMV infection have regions of encephalomalacia (*), reflecting focal tissue destruction. In addition to massive encephalomalacia, this patient has periventricular calcifications (arrow).

Figure 2

Neuroimaging studies reveal neuropathology induced by congenital LCMV infection. Shown here are MRI scans from normal children (left column) and children with congenital LCMV infection (right column). A. In the midsagittal plane of a normal child, the cerebellum (arrow) is large and fills the posterior fossa. B. In congenital LCMV infection, the virus can impair cerebellar growth and lead to cerebellar hypoplasia (arrow). C. In the horizontal plane of a normal child, the cerebral cortex is folded into a complex set of gyri and sulci (arrow). D. In congenital LCMV infection, the cerebral cortex is often featureless and smooth, lacking normal gyri and sulci, and reflecting a neuronal migration disturbance (arrows). This patient also has periventricular calcifications (arrowheads) and ventriculomegaly.

Figure 3

Vision loss due to retinal pathology is a common feature of congenital LCMV infection. Shown here are fundal photographs from the right eye (A) and left eye (B) of a child with congenital LCMV infection. In the right eye (A), there is a large chorioretinal scar (black arrows) that surrounds the optic disk and includes the macula. Abnormal pigmentation (white arrows) abuts the chorioretinal scar in a variety of places. In the left eye (B), a chorioretinal scar (black arrow) lies inferonasal to the optic disk, and a region of abnormal pigmentation (white arrows) lies nasal to chorioretinal scar.