Acute Postviral Encephalopathy

Abstract

The authors report a case of fatal acute encephalopathy following influenza infection, with slightly atypical pathological and imaging findings. A healthy 8-year-old boy with probable recent influenza A/B infection admitted for refractory seizures was placed on phenobarbital coma and later developed hemodynamic instability. Magnetic resonance imaging revealed bilateral cerebral and cerebellar white matter lesions and microhemorrhages. Following his demise, the autopsy revealed a large area of necrosis in the right centrum semiovale with similar lesions in the temporal and cerebellar regions. Microscopically, there was extensive coagulative necrosis, compatible with necrotizing white matter encephalopathy, and neuronal loss suggesting superimposed hypoxic–ischemia. The acute progressive neurologic deterioration was partly reminiscent on acute necrotizing encephalopathy, a condition recently associated with influenza A. In acute necrotizing encephalopathy, typical brain findings are characterized by bilateral thalamic necrosis/petechiae with variable white matter edema. The somewhat atypical findings in our case can relate to superadded cardiovascular collapse and hypoxic–ischemic effects.

A paediatric influenza update 100 years after the Skyros island Spanish flu outbreak

“…Imaging patterns are typical with evidence of bilateral, symmetrical areas of necrosis and haemorrhage in the thalami, the basal ganglia and occasionally the brain stem, and additional diffuse or focal areas of oedema in the cerebral and cerebellar white matter (38). On apparent diffusion coefficient maps, there is a laminar, target or tricolour pattern of involvement of the thalami (39). Overall, in a child with acute encephalopathy and bilateral symmetrical involvement of the thalami, putamen, internal capsule, brainstem, cerebellum and periventricular white matter, the suspicion for ANE should be raised.…”

A Paediatric Death Due to Meningitis-an Autopsy Diagnosis of a Rare Complication of Influenza B Infection

“…However, signs of cerebral herniation were not observed in this case. In acute necrotizing encephalitis, a more severe form of IAE, symmetrical necrosis of the white and grey structures could be seen Mizuguchi et al (1995), characterized by bilateral thalamic necrosis and petechiae with variable white matter oedema Achiriloaie et al (2016). In this case under discussion, softening and liquefaction of periventricular white matter of the cerebrum, corpus callosum and surrounding white matter of the cerebellum were seen.…”

Post–COVID‐19 inflammatory syndrome manifesting as refractory status epilepticus

“…Postviral refractory seizures have been reported in a child with leukoencephalopathy and microhemorrhages on MRI and pathology evidence of necrotizing white matter with superimposed hypoxic‐ischemic injury 5 . Although some patients with COVID‐19 also have leukoencephalopathy and microhemorrhages, this was not the case for our patient 6 .…”