Influenza A Encephalopathy, Cerebral Vasculopathy, and Posterior Reversible Encephalopathy Syndrome: Combined Occurrence in a 3-Year-Old Child

Severe form of encephalopathy associated with 2009 pandemic influenza A (H1N1) in Japan

“…12 Pre-existing conditions were present in about a half of the patients in some reports, 13,16,18 whereas no pre-existing conditions were seen in several case reports and case series of acute encephalopathy with pH1N1. 14,15,17,[19][20][21][22][23][24] These conflicting data indicate that further studies are necessary to clarify the relationship between pre-existing conditions and acute encephalopathy.…”

“…However, there have been increasing reports of ANE with pH1N1 from North America and Europe. 13,14,16,18,20,22,23,25 This suggests that pH1N1 has a predilection to ANE. At present, hypercytokinemia and hyperpermeability of both the blood-brain barrier and the capillary walls of the brain are considered to be closely related to the pathogenesis of ANE.…”

H1N1 Encephalitis with Malignant Edema and Review of Neurologic Complications from Influenza

“…This subtype has been reported with seasonal influenza but not specifically with H1N1. The MRI imaging appears radiographically identical to PRES caused by more typical causes such as pregnancy or malignant hypertension [30,31]. Vascular caliber changes have been observed in these cases; this is non-specific and can be related to infectious vasculitis or PRES.…”

Posterior reversible encephalopathy syndrome following measles vaccination

“…The possibility of acute disseminated encephalomyelitis (ADEM) was also suspected in this patient, but MRI findings in this patient were typical for PRES, and the interval between measles vaccination and onset was only 8 h. In cases of ADEM, it usually takes 2 days to 4 weeks after vaccination [15]. In fact, there are two similar reports of PRES occurring acutely during influenza A infection [16,17].…”