LP, a 15-year-old high school athlete, was suffering from weekly partial onset seizures. She had had a resection of a choroid plexus papilloma at 18 months of age, and had required a ventriculoperitoneal shunt. She had then been involved in a motor vehicle accident at 8 years of age, which resulted in a loss of consciousness and facial contusions.
LP began having generalized tonic-clonic seizures at age 13; she had had three of these by the time she was 15. She also began having weekly partial onset seizures triggered by sleep deprivation. Typically, these began with vertigo followed by leftward eye deviation, head turn to the left and left hand shaking, with some retained consciousness. Once a month, however, these seizures would progress to a loss of consciousness.
The patient had tried a number of anti-seizure medications. All of these were well tolerated, but failed to control her seizures, either as monotherapy or in combination. Her physician contacted Mitchel Berger, M.D., chair of Neurological Surgery at UCSF, who had performed her original surgery. He referred her to the UCSF Epilepsy Center for further management.
Upon examination by UCSF epileptologist Heidi Kirsch, M.D., and other members of the epilepsy team, LP was found to have an incomplete left visual field cut and mild clumsiness of the left hand. An MRI showed a large area of cystic encephalomalacia in the right posterior quadrant. Long-term video EEG monitoring revealed seizure onset from the posterior right temporal region, as well as bursts and runs of polyspike and slow wave discharges from both the right frontocentral and right posterior temporal regions. Magnetoencephalography (MEG) revealed spikes in these same regions and fortuitously captured a seizure. Dipoles were fit to the spikes and to the seizure onset. On magnetic source imaging (MSI)—a technique fusing MEG and MRI data—these mapped to the rim of the cystic encephalomalacia, including deep sources.
After review of all clinical data at the monthly epilepsy surgery case conference, a decision was made to implant subdural electrodes over the right hemisphere to better define the seizure onset and to map the functional cortex (primarily motor and sensory regions, as a Wada test had determined that her language cortex was confined to the left hemisphere). The electrodes were placed by Nalin Gupta, M.D., Ph.D., chief of UCSF Pediatric Neurological Surgery.
LP then spent a week in UCSF's inpatient video EEG telemetry suite, where she had four typical seizures as well as nine subclinical seizures. Kirsch and team found that the seizures began anterior and superior to the mouth of the old resection cavity, but their exact propagation pattern could not be clearly detected, and was presumed to involve sources deep within the cavity, including the dipoles indicated on MSI.
Sensory and motor mapping was also accomplished during this week, and one of the electrodes involved in seizure onset was found to be over the hand sensory cortex. The team discussed with the patient and her family the fact that resection of the seizure focus would cause worsening of her visual field cut and might also cause some sensory loss in her left hand; they elected to proceed.
At the end of the week, LP returned to the operating room, where Gupta removed the electrodes. This was done with the patient asleep, using an anesthetic plan that allowed for intraoperative electrocorticography by Kirsch, which showed active epileptiform activity broadly over the right parietal, temporal and occipital regions. Gupta performed a resection of the parietal cortex posterior to LP's primary sensory gyrus, all of the occipital lobe except for the medial portion, and the superior, middle and inferior temporal gyri posteriorly, as well as disconnection of the anterior temporal tip with resection of the amygdala and hippocampus. Subsequent electrocorticography showed no further epileptiform activity.
Following surgery, the patient was seizure-free initially. As her medications were tapered, she began suffering rare simple partial seizures, so she remains on a single anti-seizure medication. She is now being seen by her local neurologist and visits UCSF about once a year. She reports feeling "more awake" and having improved concentration, and her academic grade-point average has risen from 3.1 to 4.0. She now has her driver's license, since her peripheral vision was tested and found to be sufficient. She has continued to be active athletically on the varsity soccer team, and has begun rock and ice climbing—two activities she says she couldn't have undertaken prior to her surgery. In addition, she has enrolled in college and has become active in community service. She is considering a career in criminology.
For more information, contact Heidi Kirsch, M.D., at (415) 353-2437 or Nalin Gupta, M.D., Ph.D., at (415) 353-2383.
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