Although brain lesions are common in people with TSC, their effects vary greatly. Some people with TSC-related brain abnormalities experience few or no debilitating neurological complications for the duration of their lives. However, because of the possible connection between cortical tubers and epileptic seizures, and because SEGAs are potentially life threatening, it is important for people with TSC to undergo regular brain imaging and examinations by a neurologist who specializes in the disorder.
Upon diagnosis, physicians and imaging specialists use computed tomography (CT) scans or magnetic resonance imaging (MRI) to identify any and all brain lesions. This initial examination establishes a baseline against which all future examinations can be compared. In most cases, brain imaging for TSC should be repeated every one to three years through childhood and adolescence. Specialists recommend more frequent examinations for individuals with SEGAs. If a SEGA is present, examinations as frequently as every three to six months may be necessary to carefully monitor the tumor for further growth and/or obstruction. This is especially true during childhood and adolescence, when SEGAs are most likely to grow. For reasons that remain unclear, SEGAs lose their propensity for growth during late adolescence.
Doctors may also use an electroencephalogram (EEG) examination to assess the electrical activity in the brain if there is a concern that an individual is experiencing seizures. Individuals with TSC should be aware of the ongoing risk of seizures and discuss with their physician any concerning sensations or behaviors they may have.
Surgical intervention for brain abnormalities is usually not necessary. However, large, progressive SEGAs that obstruct the flow of cerebrospinal fluid and increase intracranial pressure present a neurosurgical emergency and must be removed. Surgery typically provides a permanent solution to this serious medical condition—but not always. As told in Michael's family story, SEGAs can regrow following successful surgery and sometimes need to be removed again. Also, in cases involving SEGAs that are particularly large or otherwise difficult to remove, the flow of cerebrospinal fluid may remain obstructed following surgery. In such cases, neurosurgeons place a section of tubing, called a shunt, into the obstructed section, so that fluid can flow freely and pressure does not build up.
People who suffer from intractable seizures may also be treated surgically, provided the source of the seizures is localized to a specific region of the cerebral cortex, usually a cortical tuber. Neurosurgeons have successfully reduced or eliminated seizures in some people by removing such tubers. However, it is not always possible to determine which tuber or part of the brain might be responsible for seizures.
It is important to remember:
- There are three types of benign brain findings associated with TSC: cortical tubers, subependymal nodules (SENs), and subependymal giant cell astrocytomas (SEGAs).
- Cortical tubers are typically found in the cerebral cortex, the brain's outermost layer, and may be associated with seizures, learning difficulties, and behavioral problems. They are present at birth and are not thought to grow.
- SENs and SEGAs are typically found along the walls (subependymal lining) of cavities (ventricles) deep inside the brain. If they grow large enough, they can obstruct the flow of cerebrospinal fluid through these cavities.
- TSC specialists recommend brain imaging every one to three years during childhood and adolescence, and more often for people with progressive SEGAs. SEGAs lose their propensity for growth during late adolescence for reasons that remain unclear.
- It is important to find a neurologist who is familiar with TSC-related brain abnormalities and their neurological consequences.
A neurologist is a physician who specializes in disorders of the nervous system. A neurologist who treats people with TSC is trained to recognize the neurological symptoms and brain abnormalities characteristic of the disorder.
A neurosurgeon is a physician who specializes in performing surgery on the central nervous system, including the brain. A neurosurgeon who treats people with TSC is trained in the identification and removal of SEGAs. A neurosurgeon who specializes in epilepsy surgery is trained in the removal of specific regions of the cerebral cortex identified as the primary location of seizure activity. A neurosurgeon may also be trained to implant a vagus nerve stimulator (VNS) to help control seizures.
A radiologist is a medical professional who creates and interprets images, including x-rays, ultrasounds, MRIs, and CT scans. A neuroradiologist is trained to recognize abnormalities of the nervous system, including the brain findings associated with TSC.
You can find a list of on-staff physicians on the Herscot Center for Children and Adults with TSC Web site.