Early cerebellar involvement on diffusion-weighted magnetic resonance images in herpes simplex encephalitis

Abstract

Sirs: Herpes simplex virus (HSV) type 1 is one of the most common causes of sporadic viral encephalitis in adults. The lesions have a characteristic predilection in the brain for the medial temporal and inferior frontal lobes, and occasionally the insular cortex and the cinglulate gyrus [6]. Localization of herpes simplex encephalitis (HSE) in other brain regions is unusual. In this communication we present a patient with HSE caused by HSV type 1 with the extremely rare involvement of the cerebellum which was demonstrated on diffusion-weighted images (DWI) of magnetic resonance imaging (MRI).The patient was a 66-year-old male mechanic who had a past history of cerebral infarction at the age of 61 years. One day at the age of 66 he complained of general fatigue and a fever of 38.2°C. On the next day he experienced nausea and vomited several times. He had an unsteady gait and dysarthria. On the fourth day he neglected to wash his oily hands after working on machinery. On the fifth day he could not work properly. On the sixth day his fever reached 39.5°C. He manifested a generalized seizure on the eighth day, and was admitted to our hospital.On neurological examination, he was stuporous with some primitive responses to noxious stimuli. His score on the Glasgow Coma Scale was 8. Pupillary reactions were normal. Tendon reflexes were normal, and there were no pathological reflexes. There were no definite meningeal signs.On admission, laboratory examination of his blood demonstrated elevated leukocyte count (9300/mm 3 ), γ-globulin fraction (25.1%), and Creactive protein (8.74 mg/dl). Lumbar puncture yielded clear cerebrospinal fluid (CSF) containing 4/mm 3 lymphocytes, 2/mm 3 polymorphonuclear cells, and 15/mm 3 erythrocytes. The initial CSF pressure was high (280 mmH 2 O). Glucose was 101 mg/dl (plasma glucose 185 mg/dl), and protein was 40 mg/ dl, showing normal levels. Polymerase chain reaction assay of the CSF specimen [1] detected DNA of HSV. IgG level against HSV type 1 in the CSF was 3.1 by enzymelinked immunosorbent assay. To compensate for possible leakage of serum antibody into CSF the ratio of serum to CSF albumin concentration was used to calculate a specific anti-HSV type 1 antibody index [3] analogous to the IgG index. The antibody index was 9.6 (normal value < 1.91), indicating specific intrathecal antibody synthesis. An electroencephalogram was abnormal, with periodic lateralized epileptiform discharges predominantly over the left temporal region.MRI (1.5 T) on admission disclosed lesions over the cerebral hemispheres with a marked asymmetry (Fig. 1). The lesions showed high intensity on T2-weighted images (T2WI), fluid attenuated inversion recovery images (FLAIR) and DWI, and low intensity on T1-weighted images (T1WI). The largest lesion was found not only in the medial part but also in the lateral part of the right temporal lobe. The lesion extended into the right insular cortex, inferior frontal lobe, and cingulate gyrus. The putamen was spared. The lesions in the left cerebral hemisphere were much s...

Acute Cerebellitis Caused by Herpes Simplex Virus Type 1

“…One month after the initiation of treatment, MRI findings demonstrated a marked decrease of the diffuse hyperintense signal in both patients. Although involvement of the cerebellum has been reported to occur during the course of HSE [20][21][22][23], we are not aware of any other patient who has manifested HSV-1 acute cerebellitis. Therefore, this is the first report of a definite diagnosis of acute cerebellitis due to HSV.…”

“…Coxiella burnetii and Borrelia burgdorferi have also been reported to cause acute cerebellitis [16][17][18], and a syndrome of unexplained cerebellar degeneration associated with HIV infection has also been described [19]. Although neuroradiological cerebellar involvement has been described in 2 patients with HSE [20,21], and ataxia has been reported in a patient with HSV brainstem encephalitis [22] and in 40% of patients with HSE [23], a primary HSV-1 infection of the cerebellum has not yet been described, to our knowledge.…”

Vancomycin-resistant Enterococcus faecium-associated encephalitis and concurrent cerebellitis

“…Different forms of encephalitis can produce distinctive patterns of neuroimaging abnormalities that provide clues suggestive of particular pathogens, which can guide more definitive tests such as polymerase chain reaction, antibody tests, and brain biopsy [1,2]. Concurrent cerebellitis with encephalitis is unusual and has been reported to occur in association with Japanese encephalitis virus, Influenza A virus, rotavirus, and herpes simplex virus [4][5][6][7]. The association of VRE with encephalitis and concurrent cerebellitis has rarely been documented.…”

“…Infectious causes of acute encephalitis are myriad [1][2][3][4][5][6][7][8]. However, a specific etiology is identified in less than one-third of cases, even if extensive laboratory testing is performed [2].…”

An unusual late complication of intracerebral haematoma in herpes encephalitis after successful acyclovir treatment

“…Atypical restricted lesions have been reported in PCR proven HSVE to be localised posterior in the parietal, occipital lobes and cerebellum without the typical limbic localisation in the insular and inferior frontal regions [13,14]. However, intracerebral haematoma formation is an extremely rare and unusual feature in HSVE with only eight case reports in the world literature, 7 in adults [4][5][6][7][8][9]11] and 1 in an infant [10].…”