Pediatric epilepsy at Mayo Clinic: Managing seizures and related comorbidities
More than 300,000 U.S. children younger than 15 years have epilepsy. More than 90,000 of them have intractable seizures. For children with epilepsy, seizures are often only one of the concerns. One in 4 children with epilepsy has some degree of intellectual disability. For children with intractable seizures, the frequency rises to 1 in 2 and the impairments tend to be more severe.
Elaine C. Wirrell, M.D., a pediatric neurologist specializing in epilepsy at Mayo Clinic in Rochester, Minn., notes that children with epilepsy are also at increased risk of mood disorders, depression and anxiety. "The best way to manage the risk of associated comorbidities is to treat the seizures themselves," she says, "but it is important to address seizures within the context of potential emotional and intellectual deficits."
Nicholas M. Wetjen, M.D., a Mayo pediatric neurosurgeon, agrees. "Our goal is always to treat the epilepsy, but the surgical service here is very attentive to quality of life." When the seizure focus is in eloquent cortex, Dr. Wetjen does his best to help parents weigh the benefit of seizure reduction against surgically induced deficits. He is aided in that effort by the pediatric neurology epilepsy specialists on the team, which, in addition to Dr. Wirrell, includes Katherine C. Nickels, M.D., Lily C. Wong-Kisiel, M.D., and Lori M. Cain, R.N.
Beyond seizures: Comorbidities associated with epilepsy
Children with controlled seizures may appear normal, but they still have cognitive issues. For example, simply living with a chronic disease can generate anxiety, interfere with attention and create social problems.
In a review article published in the June 2009 issue of the Journal of Child Neurology, Dr. Wirrell and co-author L.D. Hamiwka, M.D., of Ohio State University College of Medicine, state that comorbidities associated with pediatric epilepsy can impact not only the child, but also families. Impairments in social, emotional or intellectual processing and development have been found to vary with age of seizure onset, intractability and anatomical locus of seizure focus. The earlier the age of onset, the greater the risk to the developing brain.
Edythe Strand, Ph.D., chair of the Division of Speech Language Pathology at Mayo Clinic in Minnesota, notes that seizures may affect areas of the brain important to language development and that language dysfunction can impede learning and inhibit social interaction during development.
For example, Landau-Kleffner syndrome is a well-recognized disorder characterized by a sudden or gradual regression of language processing in conjunction with the onset of clinical or electrographic seizures. Sometimes, the first indication of a receptive language problem is difficulty recognizing familiar noises. Expressive speech and language can also be markedly impaired, especially when the syndrome appears during critical periods of speech acquisition.
Michael J. Zaccariello, Ph.D., L.P., one of the neuropsychologists on the Mayo team, explains that neuropsychological assessment provides a snapshot of where on a scale of normal behavior a child is functioning relative to cognitive, behavioral and emotional processing within the context of a complex neurological condition. As he says, "We integrate the medical, cognitive and psychosocial data for the family. Our goal is to help families, teachers, students, school administrators and paraprofessionals understand how the child's epilepsy is impacting performance. We provide systematic recommendations on how to address weaknesses and maximize strengths."
Dr. Nickels adds that armed with the results of cognitive testing, families feel "not only informed, but empowered." She notes that when a child's seizures are controlled by medication, families can mistakenly blame continued disabilities on anti-epileptic medications. Although seizure frequency and severity play a role in the duration of behavioral and intellectual deficits, it is the underlying neuropathology and not the seizures themselves that affects development. Among the biological factors that can impact emotional and cognitive function are structural brain abnormalities, irregularities in neurotransmitter pathways, and general or localized brain atrophy.
Interventions for intractable seizures surgery
At Mayo Clinic, the surgical work-up can be done in one to two weeks. It includes state-of-the-art functional brain mapping and studies to determine the locus, frequency, severity and duration of seizures and whether other medical conditions coexist with the seizures.
In-patient pediatric EEG monitoring
Pediatric surgical candidates undergo EEG monitoring in Mayo Eugenio Litta Children's Hospital, the 85-bed pediatric facility located within Mayo Clinic Hospital, Saint Marys Campus in Rochester. Five pediatric rooms, as well as the pediatric intensive care unit, are hardwired with ceiling cameras for behavioral observation and continuous EEG monitoring via external or intracranial EEG leads. In-patient EEG video monitoring helps minimize risks associated with medication withdrawal, a process that is often required to record seizures. Monitoring may take from 24 hours to several days.
Dr. Wirrell also notes that unlike many centers, "Mayo not only records the EEG, but also has technicians monitoring the patient every second of the day or night. So, if the patient or family member is sleeping or the seizure is subtle, our technologists are still able to pick it up." Continuous 24/7 monitoring by trained, on-site technicians increases safety and can reduce the length of stay on the unit.
The EEG video monitoring unit is designed so that an adult family member can stay with the child at all times. Although children are restricted to their room, they are free to move about within the room. The unit's rooms are equipped with the latest technology, including interactive computer games. Child-life specialists visit several times a day with crafts, toys, games and videos and also work with children and families to help them through procedures that may be uncomfortable or are unfamiliar.
Localizing seizure focus through SISCOM
SISCOM stands for subtraction ictal single-photon emission computerized tomography (SPECT) coregistered to MRI. Pioneered by Mayo, it fuses the MRI image with the SPECT image, an innovation particularly useful in seizure localization.
Dr. Wong-Kisiel has a particular interest in the application of SISCOM to children with multifocal or indeterminate focal MRI or EEG findings. A SISCOM study involves a radioactive tracer that is injected by technologists as soon as possible during a seizure. Unlike adults, children are often unable to verbalize when they are having a seizure, so continuous EEG monitoring and observation are critical.
The ketogenic diet — a high-fat, low-carbohydrate diet that mimics the fasting state and stimulates the ketogenic metabolism pathway — was first used in the 1920s at Mayo Clinic. It has since been discovered to improve seizure control in children with intractable epilepsy. More than 100 Mayo Clinic pediatric epilepsy patients are currently on the diet.
Children who are candidates for the diet begin it during a three- or four-day stay in Mayo's pediatric hospital so their parents can learn to manage the diet and a child's response can be monitored before the child is discharged. Dr. Nickels explains that although the diet is rigorous, families seem to adapt quickly. Mayo dietitians have designed more than 100 menus for families to download and are willing to create specific recipes on request.
Having the time it takes
Epilepsy is a group of disorders, and differential diagnosis requires, first and foremost, a lengthy, detailed history and clinical assessment. At Mayo, the evaluation may extend to include metabolic tests and evaluations by autoimmune neurology, genetics and other subspecialty services.
As Dr. Zaccariello states, the clinical evaluation is comprehensive, and families can feel overwhelmed. He feels fortunate that Mayo allows him as much time as necessary to explain, interpret and guide patients through the process. Those feelings are echoed by his fellow team members, who point out that there is always enough time for data from all subspecialties to be reviewed at the epilepsy team conference, to arrive at an agreed-upon treatment strategy. At Mayo, treatment of pediatric epilepsy means finding the best method of seizure control, as well as addressing related cognitive and psychosocial impairments.