Subcortical type cognitive impairment in herpes zoster encephalitis

Abstract

Nine immunocompetent patients with acute herpes zoster encephalitis (HZE) were studied with the help of neurological investigations. All patients were treated with acyclovir. Neuropsychological performance was compared with that of a group of 16 healthy controls. Computed tomography of the head showed infarct-like hypodense lesions in two patients, involving the internal capsule in one case and the temporoparietal cortex and white matter in another. Hypoperfusion shown by single photon emission computed tomography, mostly involving the frontal areas bilaterally, was seen in six of the seven patients examined. Hyperperfusion as seen in herpes simplex encephalitis was not encountered. One patient remained mildly demented, but all the other patients recovered relatively well. Neuropsychological examination after acyclovir treatment showed a decline in memory and speed of cognitive processes, without circumscribed neuropsychological deficits. Six of the nine patients showed behavioural disinhibition, and mood changes were also observed. Memory impairment in HZE was not as global or as severe as is described after encephalitis due to herpes simplex virus. In HZE both the brain perfusion pattern and the neuropsychological test profile showed features compatible with subcortical dysfunction.

Good cognitive outcome of patients with herpes zoster encephalitis: a follow-up study

“…Our findings are in contrast to those of the only previous neuropsychological study investigating sequelae after acute HZE by Hokkanen et al [6]. They described a subcortical impairment involving forgetfulness, slowing of thought processes, emotional and personality related changes and impaired cognitive ability in 9 immunocompetent patients.…”

Mild cognitive impairment after viral meningitis in adults

“…However, the mild disturbances found in our patients correspond to the normal findings on CT or MRI. More severe cognitive decline has been found to be associated with larger brain lesions with morphological changes predominantly located within the frontal and temporal lobes, or in the subcortical white matter [8,14]. However, these findings were derived from patients suffering from herpes viruses, which are known to cause localised and maybe circumscript brain damage, whereas lesion patterns in other viral infections of the CNS might be more diffuse.…”

“…Most often, follow-up examinations were performed in the short-term period after discharge. In the survivors, predominantly symptoms concerning amnesia, especially impairment of verbal memory functions were found [2,[14][15][16]. The combination of decline in memory and speed of cognitive processes as well as mood changes in varicella zoster virus encephalitis was suggested to be compatible with subcortical dysfunctions [14].…”

“…In the survivors, predominantly symptoms concerning amnesia, especially impairment of verbal memory functions were found [2,[14][15][16]. The combination of decline in memory and speed of cognitive processes as well as mood changes in varicella zoster virus encephalitis was suggested to be compatible with subcortical dysfunctions [14]. Subcortical type cognitive impairment due to central nervous system infection was also described in patients after coxsackie virus encephalitis [26], in human immunodeficiency virus infection [23], and, more recently, as long-term sequelae after bacterial meningitis [21].…”

“…However, these findings were derived from patients suffering from herpes viruses, which are known to cause localised and maybe circumscript brain damage, whereas lesion patterns in other viral infections of the CNS might be more diffuse. Correspondingly, perivascular inflammation and small vessel disease like lesions, inflammation-induced demyelination, or concomitant virus-induced neuronal damage should be discussed as potential sources of cognitive impairment in viral meningitis [14,22].…”