Serial neuroimages of acute necrotizing encephalopathy associated with human herpesvirus 6 infection

Acute disseminated demyelination due to primary human herpesvirus-6 infection

“…Deep grey matter involvement in ADEM is not rare [4] with frequent thalamic involvement. Although there have been a few case reports of abnormal MR neuroimaging in HHV-6 encephalopathy [16,22], white matter lesions caused by HHV-6 have not been previously reported.…”

Review part 2: Human herpesvirus‐6 in central nervous system diseases

“…In pediatric patients, there have been many reports of exanthem subitum associated with neurological complications such as meningoencephalitis [Irving et al, 1990; Ishiguro et al, 1990; Asano et al, 1992; Inagaki et al, 1992; Sato et al, 1992; Yoshikawa et al, 1992; Sloots et al, 1993; Suga et al, 1993; Tan et al, 1993; Itokazu et al, 1994; Jones et al, 1994; Oki et al, 1995; Yanagihara et al, 1995; Fujiwara et al, 1996]. More recently, several reports of HHV‐6 associated encephalitis of non‐immunocompromised children [Kamei et al, 1997; Kimura and Nezu, 1998; Crawford et al, 2007, 2009; Nagasawa et al, 2007; Yoshinari et al, 2007] and adults [Birnbaum et al, 2005; Isaacson et al, 2005] in the absence of classical roseola have been described.…”

“…The clinical features and laboratory diagnosis of HHV‐6 encephalitis has led to a diverse neuroradiographic subset of disease characteristics in both immunocompetent and immunocompromised patients as shown in Table I. Initial case reports on pediatric patients with CNS complications of exanthem subitum revealed computerized tomography (CT) findings of cerebral edema and hypodensities in the cortex, thalami, cerebellum, and brainstem [Irving et al, 1990; Ishiguro et al, 1990; Asano et al, 1992; Inagaki et al, 1992; Sato et al, 1992; Yoshikawa et al, 1992; Sloots et al, 1993; Suga et al, 1993; Tan et al, 1993; Itokazu et al, 1994; Jones et al, 1994; Oki et al, 1995; Yanagihara et al, 1995; Fujiwara et al, 1996]. Larger case series in pediatric immunocompetent patients diagnosed with HHV‐6 encephalitis using MRI, revealed signal abnormalities [Kamei et al, 1997; Kimura and Nezu, 1998; Crawford et al, 2007, 2009; Nagasawa et al, 2007; Yoshinari et al, 2007] of the frontal/temporal‐parietal‐occipital lobes, cerebellum, brainstem, and deep gray nuclei (Table I).…”

Absence of associations between influenza-associated encephalopathy and human herpesvirus 6 or human herpesvirus 7

“…8,21 Elevated serum transaminases and lactate dehydrogenase, vascular damage throughout the body and rapid progression to multiorgan failure suggest that hypercytokinemia and injury to blood vessels or vascular endothelia play important roles in the pathogenesis of influenza-associated encephalopathy. 23 The distribution of the lesions was consistent with acute necrotizing encephalopathy, which is occasionally seen in patients with influenza-associated encephalopathy. 22 Central nervous system manifestations, such as bulging fontanels and febrile convulsions, are occasionally seen in HHV-6 and HHV-7 infections, and several cases of encephalopathy associated with HHV-6 or HHV-7 have been reported.…”