Chronic Granulomatous Herpes Simplex Virus Encephalitis: A Distinct but Rare Disease
Heather Yong1, Cailey Turner2, Ronak Kapadia1, Taj Jadavji2, Luis Murguia Favela2
1Clinical Neurosciences, 2Pediatric Infectious Disease, Alberta Health Services
Background:
Chronic granulomatous herpes simplex encephalitis (CG-HSVE) is a rare complication following primary herpes simplex virus (HSV) encephalitis. Herein, we highlight the extensive diagnostic workup leading to the identification of CG-HSVE, and the unique treatment approach implemented.
Results:
Herein, we present a 13-month-old female with intractable seizures and progressive neurologic decline five months after an initial HSV encephalitis diagnosis (confirmed by PCR) and adequate prophylactic oral acyclovir treatment. Imaging demonstrated a unique and striking pattern of confluent parieto-occipital lesions with irregular nodular/gyriform enhancement and vasogenic edema. Extensive investigations culminating in a brain biopsy demonstrated chronic granulomatous encephalitis (with discrete well-formed necrotizing/non-necrotizing granulomas). HSV-1 DNA was identified in parenchymal tissue without viral inclusions or immunoreactive antigens. She was treated with acyclovir, high dose corticosteroids, intravenous immunoglobulin, and mycophenolate mofetil, resulting in marked clinical and radiologic improvement.
Conclusions:
CG-HSVE remains a rare entity primarily presenting in the pediatric population– with only fifteen reported cases in the literature; this leads to delays in identification and variable management amongst studies. It is characterized by progressive neurological and radiographic deterioration, intractable seizures, and a characteristic MRI. In all cases, including our own, histopathology was necessary to reach a CG-HSVE diagnosis. Prognosis is variable ranging from good recovery to fatality (in four of the fifteen patients). Earlier identification and treatment are necessary given the significantly variable prognosis of this disease. CG-HSVE pathophysiology is not well understood, possibly mediated by type I interferons and inflammasome activation. Given this uncertain we argue that a two-pronged treatment approach aimed at treating both chronic HSV infection and post-infectious granulomatous inflammation is warranted.
Generative AI Usage
No, did not use generative AI in the drafting or editing in this abstract.
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