A prospective study of magnetic resonance imaging patterns of central nervous system infections in pediatric age group and young adults and their clinico-biochemical correlation

Abstract

Background:Infections of the central nervous system (CNS) are common and routinely encountered. Our aim was to evaluate the neuroimaging features of the various infections of the CNS so as to differentiate them from tumoral, vascular, and other entities that warrant a different line of therapy.Aims:Our aim was to analyze the biochemical and magnetic resonance imaging (MRI) features in CNS infections.Settings and Design:This was a longitudinal, prospective study over a period of 1½ years.Subjects and Methods:We studied cerebrospinal fluid (CSF) findings and MRI patterns in 27 patients of 0–20 years age group with clinical features of CNS infections. MRI was performed on MAGNETOM Avanto 18 Channel 1.5 Tesla MR machine by Siemens India Ltd. The MRI protocol consisted of diffusion-weighted and apparent diffusion coefficient imaging, turbo spin echo T2-weighted, spin echo T1-weighted, fluid-attenuated inversion recovery (FLAIR), and gradient-echo in axial, FLAIR in coronal, and T2-weighted in sagittal plane. Contrast-enhanced T1-weighted sequence and MR spectroscopy were done whenever indicated.Results and Conclusions:We found that most of the children belong to 1–10 years age group. Fungal infections were uncommon, mean CSF adenosine deaminase values specific for tuberculosis and mean CSF glucose-lowered in pyogenic. Hemorrhagic involvement of thalamus with/without basal ganglia and brainstem involvement may indicate Japanese encephalitis or dengue encephalitis. Diffusion restriction or hemorrhage in not expected in the brainstem afflicted lesions of rabies. Congenital cytomegalovirus can cause cortical malformations. T1 hyperintensities with diffusion restriction may represent viral encephalitis. Lesions of acute disseminated encephalomyelitis (ADEM) may mimic viral encephalitis. Leptomeningeal enhancement is predominant in pyogenic meningitis. Basilar meningitis in the presence of tuberculomas is highly sensitive and specific for tuberculosis.

Microglia and CNS Interleukin-1: Beyond Immunological Concepts

“…Initially, post-infectious neurological dysfunction was thought as a consequence of permanent damage caused by the invading pathogens and the specific immune responses to the pathogen ( 84 ). However, patients who survived CNS infection sometimes show deficits implicating brain regions beyond the foci of the initial infection ( 85 ) and animal studies show chronic neuroinflammation may persist after the acute infectious pathogens have been eradicated ( 86 ). Thus, off-target inflammatory activity may contribute to post-infectious neuropathology.…”

Infectious immunity in the central nervous system and brain function

“…Animal models of neuroinfectious diseases support the idea that CNS injury mediated by pathogens or lymphocytes underlies permanent loss of motor and cognitive function 8 . Explanations for the focality of neurological symptoms in patients thus rely on the CNS regions acutely infected, as determined on the basis of initial MRI results 9 . However, neurological dysfunction in patients that survive CNS infections is not always consistent with prior neuroimaging findings 10 , and rodent models of neuroinfectious diseases do not always show extensive brain damage in survivors 11 .…”

Paediatric Virology: A rapidly increasing educational challenge

“…With some agents, such as reactivated latent herpes simplex virus 1 (HSV-1) in older children, imaging is so specific that it may be diagnostic: foci of haemorrhage and dystrophic calcification acquiring a gyriform pattern are observed both on computed tomography (CT) and MRI with a predilection for the temporal lobes ( 54 ). Additionally, recent studies support that in children with other causes of viral encephalitis, neuroimaging features may suggest the pathogens ( 55 ). In the presence of arterial ischaemic stroke in children, post-varicella infection vasculitis should be considered ( 56 ) ( Fig.…”

“…However, as a rule of thumb, the later the diagnosis of congenital infections is made, the more difficult it is to identify the agent and the imaging findings may become non-specific and less conspicuous, as incomplete white matter myelination may interfere with the pathology ( 54 ). In neonatal brain infections, magnetic resonance imaging (MRI) is the modality of choice even in an emergency setting ( 55 ). It accurately demonstrates focal lesions, usually associated with deep venous infarcts, diffuse white matter oedema and/or findings of meningitis.…”