- Lennox-Gastaut Syndrome (LGS) is a severe epilepsy syndrome that usually starts when children are 5-7 years old
- Patients are often treated with medication or ketogenic diet first
- Surgery may be a helpful intervention for patients that either a) have a focal lesion or b) are unresponsive to medication and diet changes
- The three main surgeries used to treat LGS are resection, corpus callosotomy, and vagus nerve stimulation
- Resection may be curative. On the other hand, corpus callosotomy and vagus nerve stimulation are palliative (improve but do not typically stop the seizures)
What is Lennox-Gastaut Syndrome?
Lennox-Gastaut Syndrome (LGS) is a severe epilepsy disorder found in children. It usually starts when they are 3-7 years old and lasts through adulthood. There are two main features of LGS. First, patients have multiple types of seizures. Second, they have abnormal brain electrical activity. This is detected by a machine called EEG. In addition, patients often have a decline in their development.
What is the treatment for LGS?
Children with LGS are first treated with medication. Based on multiple research studies, it is unclear which medications work best. A panel of experts have suggested three medications to start with. They recommend either valproic acid, lamotrigine, or rufinamide. There are other medications that may also be effective.
Unfortunately, medications do not always stop the seizures. One alternative is the ketogenic diet. The ketogenic diet is high in fat. This tricks the body to make it think that it is starving. The results of different studies are mixed. Some studies show a large reduction in seizure frequency in up to half of the patients. For many patients, there is no effect.
Some patients with LGS may be considered for surgery. This may be because they did not respond to medications or dietary changes. It may also be due to the cause of their seizures. They can be caused by a focal lesion, which is a specific area of the brain with disease. When a focal lesion is seen on brain imaging, it can be removed by a neurosurgeon. This surgery is called resection. For certain children, resection can cure their seizures. This is why it is important to have brain imaging early.
When no lesion is found on brain imaging, there are other types of surgeries that may help. One cause of severe seizures is when the abnormal electrical activity spreads all across the brain from one side to the other. To stop this from happening, the surgeon can disconnect the two sides of the brain. This procedure is called a corpus callosotomy. Another way to stop the spread is to give the brain electrical stimulations. This procedure is called vagus nerve stimulation.
What is the outcome of the surgery?
In studies on children with LGS that had resective surgery, 50-60% became completely seizure free. Another 15-17% of children very rarely had seizures after surgery. The size of the surgery ranges from the resection of one lobe of the brain to the entire side, or hemisphere. Compared with children who had smaller resections, the children who had an entire hemisphere resected had the best seizure outcomes, with 71% seizure free. Adaptive behavior and social skills were better in children that were seizure free.
Vagus Nerve Stimulation
Vagus nerve stimulation (VNS) is a surgery that involves the implantation of a device in the chest. The device has a wire that is connected to the vagus nerve in the neck. Studies show that about 55% of children improve with VNS. The total number of seizures tends to decrease by about 50%. One type of seizure called atonic seizures, or drop attacks, may be reduced by up to 88%. Because the seizures improve but only very rarely stop with VNS, this procedure is considered palliative rather than curative. The side effects of VNS are rare and tend to improve over time. Children with VNS can continue taking seizure medications.=
The corpus callosum is a structure in the brain that connects the two hemispheres. When this is cut, it is called a corpus callosotomy. This procedure has a similar rate of improving seizures as VNS. It is even more effective than VNS at improving drop attacks. For this reason, it is especially effective for patients who have many drop attacks. A possible side effect of this procedure is disconnection syndrome. This has not been commonly reported for children that have had corpus callosotomy.
Cross, J. H., Auvin, S., Falip, M., Striano, P., & Arzimanoglou, A. (2017). Expert opinion on the management of Lennox–Gastaut syndrome: treatment algorithms and practical considerations. Frontiers in neurology, 8, 505.
Kang, J. W., Eom, S., Hong, W., Kwon, H. E., Park, S., Ko, A., … & Kim, H. D. (2018). Long-term outcome of resective epilepsy surgery in patients with Lennox-Gastaut syndrome. Pediatrics, 142(4).
Lee, Y. J., Kang, H. C., Lee, J. S., Kim, S. H., Kim, D. S., Shim, K. W., … & Kim, H. D. (2010). Resective pediatric epilepsy surgery in Lennox-Gastaut syndrome. Pediatrics, 125(1), e58-e66.