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"Symptomatic" infection-associated acute encephalopathy in children with underlying neurological disorders
Yoshimichi Hirayama1, Yoshiaki Saito2, Yoshihiro Maegaki2
1Division of Child Neurology, Department of Brain and Neurosciences, Faculty of Medicine, Tottori University, Yonago, Japan; Department of Pediatrics, Naha City Hospital, Naha, Japan.
Insights
Children with acute encephalopathy (AE) often have underlying neurological disorders. Hemiconvulsion-hemiplegia syndrome (HH), hemorrhagic shock and encephalopathy syndrome (HSES), and acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) are common AE subtypes in these children.
Area of Science:
- Pediatric Neurology
- Neuroinflammation
- Epileptology
Background:
- Acute encephalopathy (AE) development is multifactorial, influenced by viral agents, age, and genetic factors.
- Children with pre-existing neurological conditions are also susceptible to AE.
- Understanding these risk factors is crucial for early diagnosis and management.
Purpose of the Study:
- To investigate the prevalence and characteristics of underlying neurological disorders in children with AE.
- To identify specific AE subtypes associated with pre-existing neurological conditions.
- To explore potential distinct pathomechanisms in different AE subgroups.
Main Methods:
- Retrospective review of 55 children diagnosed with AE between 1988 and 2013.
- Classification of AE into eight distinct subtypes.
- Analysis of the frequency of underlying neurological disorders within each AE subtype.
Main Results:
- 14% of AE cases (25.4%) had prior neurological conditions, including perinatal insults and genetic syndromes/brain malformations.
- Underlying conditions were more prevalent in acute encephalopathy with biphasic seizures and late reduced diffusion (AESD), hemiconvulsion-hemiplegia syndrome (HH), and hemorrhagic shock and encephalopathy syndrome (HSES).
- A history of epilepsy or febrile seizures was common in HH but rare in other AE types.
Conclusions:
- HH, HSES, and AESD frequently occur in children with pre-existing neurological conditions and heightened neuronal excitability.
- These AE subgroups may possess unique pathomechanisms compared to AE driven by cytokine storms.
- Further research into these distinct pathways is warranted.
Background:
Development of infection-associated acute encephalopathy (AE) is precipitated by several factors, including viral agents, age, and genetic polymorphisms. In addition, children with prior underlying neurological disorders can also present with AE.
Method:
We reviewed 55 children with AE who were referred to hospitals participating in the Status Epilepticus Study Group from 1988 to 2013. AE was classified into eight subtypes: acute encephalopathy with biphasic seizures and late reduced diffusion (AESD); hemiconvulsion-hemiplegia syndrome (HH); acute necrotizing encephalopathy; hemorrhagic shock and encephalopathy syndrome (HSES); clinically mild encephalitis/encephalopathy with a reversible splenial lesion; acute encephalitis with refractory, repetitive partial seizures; Reye-like syndrome; and unclassified.
Result:
Of the 55 AE cases, 14 (25.4%) had underlying neurological disorders, including perinatal insults (n=6) and genetic syndrome and/or brain malformations (n=8). These preceding morbidities were relatively common in AESD (6/18, 33.3%), HH (3/9, 33.3%), and HSES (3/6, 50.0%). History of epilepsy or febrile seizures were frequent in HH cases (4/9, 44.4%), whereas they were rare in other AE subtypes.
Conclusion:
Among the AE subgroups, HH, HSES, and AESD frequently emerged in preceding etiologies with augmented neuronal excitability. These subgroups may have distinct pathomechanism from the "cytokine storm" mediated AEs during childhood.
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