A study on viral CNS inflammation beyond herpes encephalitis

Abstract

The early diagnosis of herpes simplex virus encephalitis (HSVE) enables induction of antiviral therapy in this potentially life-threatening disease. The study aimed to determine clinical findings including cerebrospinal fluid (CSF) data and MRI imaging in HSVE patients and to identify features distinguishing HSVE from encephalitis of other viral etiologies. We retrospectively reviewed consecutive patients who were diagnosed with viral encephalitis between 2000 and 2014 at the University Hospital Halle. Forty-nine patients with viral encephalitis were identified. A viral etiology could be confirmed by PCR or antibody testing in 22/49 (44.9 %) of patients (15 (30.6 %) HSV, 5 (10.2 %) VZV, 2 (4.1 %) EBV). In HSVE, typical findings were focal slowing in electroencephalophy (EEG) (80 %, p = 0.021) and presence of cortical (86.7 %, p = 0.030) lesions in MRI. Restricted diffusion was particularly helpful in detection of early signal abnormalities in HSVE (p = 0.014). In 27/49 (55.1 %) of patients, no causative agent could be elucidated. In these patients, 15/27 (55.6 %) experienced a rather "benign" disease course with no MRI pathology despite initially HSVE mimicking clinical picture. However, CSF was significantly different showing a higher amount of granulocytes and activated lymphocytes. The remaining 12/27 (44.4 %) patients developed MRI changes consistent with encephalitis, in 4 of these patients, disease course was fatal. Beside PCR-based serology as standard procedure, MRI including diffusion-weighted images and EEG represent additional tools in early HSVE diagnosis. CSF cytology might be particularly supportive in differentiating likely benign forms of encephalitis.

Evaluation of high resolution computed tomography findings of cystic fibrosis

“…Diffusion weighted imaging (DWI) is used extensively to measure water proton diffusion and image inflammation in the brain or abdomen [63,64]. However, application of DWI for pulmonary imaging can allow for qualitative analysis of the signal intensity of lung defects and can give localised quantitative information about lung inflammation.…”

CSF in acute and chronic infectious diseases

“…This should be performed before the LP. Initially computed tomography is used frequently but most important is the more sensitive magnetic resonance imaging and this should be the imaging study of choice in suspected viral encephalitis (Jordan et al, 2016;Piquet and Cho, 2016;Koeller and Shih, 2017).…”

Can we forecast poor outcome in herpes simplex and varicella zoster encephalitis? A narrative review

“…From the largest MRI studies that focused on HSV encephalitis we can conclude that more extensive FLAIR lesions (>3 brain lobes affected) on the MRI acquired on admission are associated with higher mortality and morbidity ( 47 , 48 ). On the other hand, VZV encephalitis may well be diagnosed despite normal MRI brain scans ( 55 ); this may explain why we found no study evaluating the prognostic value of MRI in VZV encephalitis.…”

“…In contrast, other studies showed no association between MRI findings and outcome (40,55). The studies by Kim et al (40) and Jordan et al (55) both included a retrospective analysis, of 25 and 15 patients, respectively. In the study by Kim et al (40) there was a surprisingly low number of abnormal MRI (64% FLAIR and 59% diffusionweighted imaging (DWI)) compared to larger studies (32,48).…”

“…Singh et al also showed that restricted diffusion on MRI was associated with poor outcome (mRS ≥3) in elderly people (median age 66 years) at hospital discharge as well as 6-12 months later (41). In contrast, other studies showed no association between MRI findings and outcome (40,55). The studies by Kim et al (40) and Jordan et al (55) both included a retrospective analysis, of 25 and 15 patients, respectively.…”