Acute necrotizing encephalopathy of childhood. Diagnostic and treatment challenges in COVID-19 pandemic

Acute necrotizing encephalopathy of childhood (ANEC) can occur in previously healthy children during a respiratory infection with fever and can manifest by epileptic seizures. Magnetic resonance imaging (MRI) typically shows bilateral lesions of the brainstem, cerebellum, thalamuses, basal neclei, and hemispheral white matter. We describe three clinical cases with an initial diagnosis of ANEC. In the first case, a 12-year old patient developed headache, leg weakness and high blood pressure during treatment of hepatitis C virus infection with PEG-interferon alfa2b. Later on she had myoclonic seizures with subsequent epileptic status, tetraparesis, confusion, and hyperthermia. Her clinical chemistry parameters showed a non-significant increase in liver enzymes levels. Cerebrospinal fluid was remarkable for increased protein level. The patient's brain MRI showed typical for ANEC bilateral thalamic lesions. The second case manifested with myoclonic seizures and subsequent epileptic status in a 17-months' old patient with a respiratory infection (vomiting, rhinitis, fever, and hyperthermia). His brain MRI showed bilateral lesions in the brainstem (dorsal part of the pons), thalamus, subcortical nuclei, white matter of the cerebral hemispheres, as well as lesions in the left hippocampus. The patient had increased urine levels of malic, 2-hydroxyisovalerianic, 3-hydroxy-isovalerianic, N-acetylaspartic, 3-hydroxybutyric, and lactic acids and increased blood levels of alanine, glutamic acid, glycine, and ornithine. By the time of the study, no hereditary metabolic disease was identified. In the third case, a 3-year old patient with a respiratory infection with vomiting and fever developed left-sided hemiparesis after she had fallen out of bed. The brain MRI revealed acute ischemic damage. Her cerebrospinal fluid was remarkable for a decreased protein level. Currently, ANEC is a diagnosis of exclusion. In the third patient, ANEC was obviously misdiagnosed. It is necessary to clarify the diagnostic criteria for the syndrome and to develop a management protocol for patients with ANEC