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MR and CT imaging patterns in post-varicella encephalitis
C F Darling1, M B Larsen, S E Byrd
1Division of Neuroimaging, Children's Memorial Center, Northwestern University Medical School, Chicago, IL 60614, USA.
Insights
Post-varicella encephalitis can cause distinct brain imaging patterns, particularly affecting the basal ganglia or diffuse cerebral areas. Recognizing these computed tomography (CT) and magnetic resonance (MR) findings aids in differentiating it from other neurological conditions.
Area of Science:
- Neurology
- Radiology
- Pediatrics
Background:
- Post-varicella encephalitis is a rare neurological complication following varicella (chickenpox) infection.
- Understanding its neuroimaging patterns is crucial for accurate diagnosis and management.
Observation:
- A retrospective review of four children (ages 2-11) with post-varicella encephalitis was conducted.
- Clinical data and neuroimaging (CT and MR) findings were analyzed.
Findings:
- Two distinct patterns of cerebral involvement were identified on CT and MR imaging.
- Pattern 1: Bilateral, symmetric basal ganglia lesions (hypodense on CT, low T1/high T2 signal on MR), often associated with parkinsonian symptoms.
- Pattern 2: Diffuse, multiple gray and white matter lesions, with some enhancement, in a child without gait disturbances.
Implications:
- Neuroimaging findings in post-varicella encephalitis can be characteristic, aiding differentiation from other etiologies like trauma, anoxia, metabolic, or demyelinating diseases.
- CT and MR imaging play a vital role in diagnosing post-varicella encephalitis when combined with clinical presentation and varicella history.
Abstract:
The aim of the investigation was to determine the patterns of cerebral involvement on computed tomography (CT) and magnetic resonance (MR) imaging in post-varicella encephalitis. Four children between the ages of 2 and 11 years presented over a 5-year period with a diagnosis of post-varicella encephalitis. Their imaging studies and clinical data were reviewed retrospectively. The medical histories of all four children were noncontributory except for recent bouts of chickenpox 1 week to 3 months prior to hospitalization. Three children presented with parkinsonian manifestations. Bilateral, symmetric hypodense, nonenhancing basal ganglia lesions were found on CT. These areas showed nonenhancing low signal intensity on T1-weighted images and high signal intensity on T2-weighted images on MR. One child presented with diffuse, multiple gray and white matter lesions of similar imaging characteristics; some lesions, however, did enhance. This child had no gait disturbances. Post-varicella encephalitis can produce two patterns of dramatic CT and MR findings. With an appropriate history and clinical findings, varicella as a cause of bilateral basal ganglia or diffuse cerebral lesions can be differentiated from other possible etiologies which include trauma, anoxia, metabolic disorders and demyelinating diseases.