Elsevier

Pediatric Neurology

Volume 38, Issue 6, June 2008, Pages 439-442
Pediatric Neurology

Case report
Epilepsy Surgery in a Case of Encephalitis: Use of 11C-PK11195 Positron Emission Tomography

https://doi.org/10.1016/j.pediatrneurol.2008.03.001Get rights and content

The positron emission tomography radiotracer 11C-PK11195 selectively binds to the peripheral-type benzodiazepine receptors expressed in activated microglia and can, therefore, detect areas of neuroinflammation. 11C-PK11195 positron emission tomography was used in determining the surgical treatment of a 5-year-old boy with intractable epilepsy due to encephalitis of unknown etiology. After 4 months of treatment in the pediatric intensive care unit for altered consciousness and refractory seizures despite multiple anticonvulsants, including continuous midazolam infusion, 11C-PK11195 positron emission tomography revealed an area of increased uptake in the left temporal-occipital cortex. Because the majority of his seizures at this stage of his illness emanated from the same region, the patient underwent left temporal-occipital cortical resection guided by intraoperative electrocorticography. The surgery resulted in significant recovery, and he could be discharged from the hospital. Focal areas of neuroinflammation may play an important role in seizure pathogenesis in a subset of patients with refractory seizures associated with encephalitis. In such cases, 11C-PK11195 positron emission tomography may highlight the region of maximal inflammation for palliative surgical treatment.

Introduction

Refractory seizures in patients with encephalitis can be very difficult to manage, and probably contribute to further brain injury. Given that some of these children manifest focal features in seizure semiology and on their electroencephalograms, their seizures may be emanating from focal brain regions of inflammation or ischemic injury. Activated microglia in areas of inflammation express many types of receptors, including peripheral-type benzodiazepine receptors [1], [2]. The positron emission tomography radiotracer 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline carboxamide (PK11195) labeled with 11C specifically binds to the peripheral-type benzodiazepine receptor and has been used to image areas of neuroinflammation in various conditions [1], [3], [4].

In the present case, 11C-PK11195 positron emission tomography was used in the evaluation and surgical treatment of a 5-year-old boy with refractory seizures associated with encephalitis of unknown etiology—a novel use of 11C-PK11195 positron emission tomography.

Section snippets

Case Report

The patient was a previously normal 5-year-old right-handed boy who developed intermittent high-grade fever associated with cough of 1-week duration. He was found to have an ear infection with viral pneumonia and was started on azithromycin. Despite this antibiotic, however, he remained febrile and was irritable. On the day of admission, he had a generalized convulsion lasting 5 to 7 minutes, followed by postictal lethargy. He was subsequently taken to the emergency department, where he

Discussion

In patients with intractable epilepsy not responding to treatment, underlying brain inflammation should be considered. The inflammation may be very subtle or undetectable, without any disruption of the blood-brain barrier, as in the present case, in which all investigations—imaging (including computed tomography, magnetic resonance imaging with contrast, magnetic resonance spectroscopy, and [18F]fluorodeoxyglucose positron emission tomography), biochemical, serological, and immunological—were

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