gms | German Medical Science

60th Annual Meeting of the German Society for Neuropathology and Neuroanatomy (DGNN)

German Society for Neuropathology and Neuroanatomy

26. - 28.08.2015, Berlin

Epilepsy, hippocampal sclerosis and amygdalar atrophy as remote complications of H1N1-influenza-associated encephalopathy in an adult

Meeting Abstract

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  • Shirin Karimi - University Health Network, Pathology, Toronto, Canada
  • Taufik Valiante - University Health Network, Pathology, Toronto, Canada
  • corresponding author presenting/speaker Rasmus Kiehl - University Health Network, Pathology, Toronto, Canada

Deutsche Gesellschaft für Neuropathologie und Neuroanatomie. 60th Annual Meeting of the German Society for Neuropathology and Neuroanatomy (DGNN). Berlin, 26.-28.08.2015. Düsseldorf: German Medical Science GMS Publishing House; 2015. Doc15dgnnP29

doi: 10.3205/15dgnn53, urn:nbn:de:0183-15dgnn536

Published: August 25, 2015

© 2015 Karimi et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.


Outline

Text

A number of clinical cases of H1N1 influenza associated encephalitis (H1N1-IAE) have been reported in the pediatric literature, but very few cases have been described in adults, and none describe neuropathologic features. A wide range of neurological complications were previously reported among survivors of H1N1-IAE, including altered mental status, febrile seizures, ophthalmoparesis, quadriparesis, delayed Parkinsonism, encephalitis lethargica and many more subtle neurologic changes. The neuropathological findings of H1N1-IAE are limited to autopsies from cases of acute fatal encephalopathy. Most of the described neuropathological findings in H1N1-IAE are acute to subacute morphologic changes, including edema, inflammation, necrosis, fibrin thrombi, endothelial injury, hemorrhage, neuronal loss, gliosis, and axonal injury. The patient was an ICU nurse with H1N1-IAE during the H1N1 pneumonia epidemic of 2009, resulting in intractable temporal lobe epilepsy. Imaging revealed atrophy of hippocampus, amygdala and temporal lobe. The patient had an anterior temporal lobectomy and the specimen showed marked hippocampal neuronal loss and reactive gliosis, suggestive of hippocampal sclerosis. Sections from right temporal lobe and amygdala revealed extensive gliosis and some perivascular lymphocytic cuffing. Prior experimental studies in animal models of H1N1-IAE have demonstrated inflammatory reactions and morphologic changes. The clinical, radiological and neuropathological findings in this patient are compatible with hippocampal sclerosis and amygdalar atrophy as remote complications of H1N1-IAE.

Figure 1 [Fig. 1]