Background Enterovirus 71 infection causes hand-foot-and-mouth disease in young children, which is characterized by several days of fever and vomiting, ulcerative lesions in the oral mucosa, and vesicles on the backs of the hands and feet. The initial illness resolves but is sometimes followed by aseptic meningitis, encephalomyelitis, or even acute flaccid paralysis similar to paralytic poliomyelitis. Methods We describe the neurologic complications associated with the enterovirus 71 epidemic that occurred in Taiwan in 1998. At three major hospitals we identified 41 children with culture-confirmed enterovirus 71 infection and acute neurologic manifestations. Magnetic resonance imaging (MRI) was performed in 4 patients with acute flaccid paralysis and 24 with rhombencephalitis. Results The mean age of the patients was 2.5 years (range, 3 months to 8.2 years). Twenty-eight patients had hand-foot-and-mouth disease (68 percent), and six had herpangina (15 percent). The other seven patients had no skin or muco...

https://www.nejm.org/doi/pdf/10.1056/NEJM199909233411302

Neurologic complications in children with enterovirus 71 infection.

During the winter of 1998-1999, there was an outbreak of encephalitis/encephalopathy in Japan that appeared to be associated with influenza. We conducted a national survey of the prevalence and clinical features of disease and the associated outcomes and prognostic factors related to this outbreak. A total of 202 cases were analyzed, of which 148 were diagnosed as influenza-associated encephalitis/encephalopathy on the basis of virologic analysis. Of the 148 cases studied, 130 (87.8%) were type A influenza and 17 were type B. Encephalitis/ encephalopathy developed mainly in children age <5 years, either on the day that influenza signs appeared or on the next day. The major signs included altered consciousness or loss of consciousness, convulsions, cough, and vomiting. In many patients, multiple-organ failure developed, and rates of mortality (31.8%) and disability (27.7%) were high. Thrombocytopenia and severely elevated transaminase levels were factors associated with a poor prognosis. Thus, influenza-associated encephalitislencephalopathy progressed rapidly and was associated with poor outcomes.

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Encephalitis and Encephalopathy Associated with an Influenza Epidemic in Japan

The clinical, radiological and pathological features of acute necrotizing encephalopathy of childhood, a disease entity established recently, are described. This disease predominantly affects infants and young children living in Japan and Taiwan, and manifests itself as acute encephalopathy following viral infections. The hallmark of this encephalopathy is multifocal, symmetric brain lesions affecting the bilateral thalamus, brainstem tegmentum, cerebral periventricular white matter and cerebellar medulla, which can be visualized by computed tomography and magnetic resonance imaging. Both the gray and white matter are involved, with neuropathological evidence of local breakdown of the blood-brain barrier (dysoria). The prognosis was poor in the 1980s, but has improved recently. A characteristic combination of focal neurologic signs is often recognized as the sequelae. Its distinction from clinically similar conditions, such as the Reye syndrome, and from pathologically related conditions, such as the Leigh and Wernicke encephalopathies, is also discussed.

Acute necrotizing encephalopathy of childhood: a novel form of acute encephalopathy prevalent in Japan and Taiwan

Background Eastern equine encephalitis occurs principally along the east and Gulf coasts of the United States. Recognition of the neuroradiographic manifestations of eastern equine encephalitis could hasten the diagnosis of the illness and speed the response to index cases. Methods We reviewed all cases of eastern equine encephalitis reported in the United States between 1988 and 1994. The records of 36 patients were studied, along with 57 computed tomographic (CT) scans and 23 magnetic resonance imaging (MRI) scans from 33 patients. Results The mortality rate was 36 percent, and 35 percent of the survivors were moderately or severely disabled. Neuroradiographic abnormalities were common and best visualized by MRI. Among the patients for whom MRI scans were available, the results were abnormal for all eight comatose patients as well as for all three noncomatose patients who subsequently became comatose. The CT results were abnormal in 21 of 32 patients with readable scans. The abnormal findings included f...

https://www.nejm.org/doi/pdf/10.1056/NEJM199706263362604

Clinical and Neuroradiographic Manifestations of Eastern Equine Encephalitis

Influenza virus and CNS manifestations

Two cases of influenza A encephalitis seen during an outbreak of influenza types A/England/427/88 (H3N2) and A/Taiwan/1/86 (H1N1) in December 1989 are described. In both children the encephalitis developed within three days of the respiratory symptoms and both became comatose within 48 hours. Virological studies showed that the patients had had a recent influenza A infection. Symmetrical localised hypodense lesions within the thalami and pons were demonstrated in both cases on computed tomography of the brain and striking findings in the pons in one case on magnetic resonance imaging. Influenza A encephalitis is not easy to recognise clinically and serological confirmation can only be made after 10 days. Imaging may provide evidence in the acute stage to support a diagnosis of influenza encephalitis during influenza outbreaks.

https://adc.bmj.com/content/archdischild/66/6/702.full.pdf

S M Protheroe

Papers

Imaging in influenza A encephalitis.