NEW YORK--With good management, brain tumor patients at risk for seizures can control their seizures and regain control of their lives, a UCLA neuro-oncologist reassured brain tumor patients during a Cancer Care, Inc. teleconference.
Timothy Cloughesy, MD, director of the Neuro-Oncology Program at UCLA Medical Center, reviewed some important points of seizure control and had some tips for physicians as well.
First and foremost, he said, the patient and physician must recognize that seizures are occurring, and they are not always easy to identify.
The most obvious seizures are the generalized tonic-clonic type in which the person becomes unconscious, shakes, and may have frothing at the mouth or other symptoms, he said.
On the other hand, a simple seizure, one that is very focal, can manifest more subtly--as a strange smell, a sense of rising in the stomach, or a feeling of impending doom. The more common symptoms of focal seizures are twitching, visual changes, or abnormal sensations in the arms or legs.
If a focal seizure spreads to the temporal lobes, it becomes a complex partial seizure, which is also hard to diagnose, Dr. Cloughesy noted. Patients may lose contact with the environment and develop automatic behaviors. They may be able to get up and walk and look like they are doing something appropriate, but actually they are not in control and are unresponsive.
Seizures Are Stereotyped
Something to look for when making a diagnosis, Dr. Cloughesy said, is that seizures are stereotyped. If twitching happens during one seizure, it will occur the next time rather than some other symptom. But symptoms can change during one event if the seizure spreads.
Seizures cannot always be documented by an EEG, Dr. Cloughesy warned, so the physician may have to rely on symptomatology alone. "The physician has to realize that what is going on is actually a seizure and that it is coming from the brain and not from something in the stomach or the nose," he said.
The physician also has to be very astute to make an early diagnosis of a brain tumor based on seizures, he added, stressing the need for magnetic resonance imaging (MRI). "Many times a physician will order a CT scan," he said, and then tell the patient--well, you are having some event, but actually we dont see a tumor or even a lesion there--but when an MRI scan is obtained, the lesion becomes quite clear."
The top part of the brain is most susceptible to seizures, Dr. Cloughesy said, and patients with tumors in that area will likely be given antiseizure agents prophylactically after surgery. Patients with a more mid-line tumor, one that is not out at the cortex, have a decreased risk of seizure and will not usually be treated prophylactically.
People with gliomas have about a 70% chance of having seizures, he said, and are usually given antiseizure agents prophylactically. Generally, patients with meningiomas are not treated unless they actually have seizures.
Individuals with metastatic brain tumors are not thought to be at risk for seizures, unless the metastatic tumor arises from a melanoma or renal cell cancer, in which case prophylactic antiseizure medication is often prescribed, Dr. Cloughesy said.
He urged brain tumor patients who are prone to seizures or taking antiseizure medication to inform their doctor before any surgery requiring general anesthesia. The physician should then make sure that the anticonvulsant the patient is taking can be given intravenously if necessary in the surgical setting. If not, it should be changed to a medication that can be given intravenously.
The serum level of the antiseizure drug must also be carefully monitored before and after surgery, he said, particularly in settings where the patient may develop nausea.
Tumors That Cause Seizures
Even after a tumor that is causing seizures is resected, the antiseizure medicine must be continued for 1 to 2 years, Dr. Cloughesy said. After that, it can be tapered off if there have not been any more seizures.
Patients will also be put on antiseizure medication after resection, even if they have never had a seizure, in order to prevent a reactive seizure. These patients usually remain on the medication for 6 weeks to 6 months.
Conventional radiation for brain tumors does not lead to an increase in seizure frequency and often leads to an improvement in seizure control, especially in the case of low-grade tumors, Dr. Cloughesy said. But stereotactic radiation, because of the high amount of radiation being delivered, does bring increased risk of seizures and necessitates temporarily increasing the antiseizure medication dose.
Chemotherapy, because of the way it interacts with antiseizure medicine, may increase seizure risk by decreasing serum drug levels. Also, if a patient vomits because of the chemotherapy, and does so less than an hour after ingesting anti-seizure medicine, the patient will need to take more of the anticonvulsant, Dr. Cloughesy said.
Although all of the anticonvulsants have similar side effects, people react to each differently, and may do better with one than another, he said.
Side effects can include lethargy, cognitive changes, or even double vision or difficulty in walking and talking. What is important, Dr. Cloughesy cautioned, is that the side effects of an antiseizure medication not be mistaken for the effects of a tumor.
In general, anticonvulsants work better when used as a single agent, because there will be fewer side effects and, therefore, better compliance. However, a newer anticonvulsant, such as gabapentin(Drug information on gabapentin) (Neurontin), is usually added when first-line drugs, such as carbamazepine(Drug information on carbamazepine) (Tegretol and others), phenytoin (Dilantin), valproic acid (Depakene, Depakote), and phenobarbital(Drug information on phenobarbital), do not work. He added that gabapentin needs to be given at a higher dose and can cause sedation.
Once a seizure has started, there are different ways to control it, he said. One way is to take more of the medicine the patient is already using, but that may not work because of the time it takes for the medicine to be absorbed.
In the emergency room, patients can be given an intravenous form of their current medicine if it is available, or intravenous diazepam(Drug information on diazepam) (Valium) or lorazepam(Drug information on lorazepam) (Ativan), Dr. Cloughesy commented.
Diazepam Gel Formulation
If someone has a simple seizure that lasts a couple of minutes and feels that a bigger seizure is coming on, the new diazepam gel formulation delivered rectally is very effective in aborting a larger seizure, Dr. Cloughesy said. "It actually empowers the patient quite a bit. It keeps people from going to the emergency room, when they can control the situation in the confines of their own home."
Oral lorazepam is also valuable, he said. "When it is crushed and placed under the tongue, it actually has fairly good and rapid absorption." Dr. Cloughesy recommends that patients take a crushed form of oral lorazepam in a bag with them when they go out.
"It is just so critical that you have control over your situation," Dr. Cloughesy told his audience. "Seizures can be incredibly frightening and dangerous as you all know, and I hope you have learned that you can take control."