Lennox–Gastaut syndrome (LGS) is a complex, rare, and severe childhood-onset epilepsy. It is characterized by multiple and concurrent seizure types, cognitive dysfunction, and slow spike waves on electroencephalogram (EEG). Typically, it presents in children aged 3–5 years and can persist into adulthood. It has been associated with several gene mutations, perinatal injuries, congenital infections, brain tumors/malformations, and genetic disorders such as tuberous sclerosis and West syndrome. The prognosis for LGS is poor with a 5% mortality in childhood and persistent seizures into adulthood (80%–90%).LGS was named for neurologists William G. Lennox (Boston, USA) and Henri Gastaut (Marseille, France), who independently described the condition. The international LGS Awareness Day is  on November 1. Signs and symptoms
The symptoms vary and progress with age and are characterized by a triad of seizures, cognitive dysfunction, and EEG findings. The triad may not fully emerge until 1–2 years after first seizure episode. Seizures
The peak age of onset of seizures is typically between 3 and 5 years of age. The mainstay symptoms are seizures that are frequent – occurring daily and difficult to treat with antiseizure medications. An estimated 30% of patients with infantile spasms (West syndrome) have been reported to progress with LGS.The seizures are most commonly tonic seizures. They occur most frequently during non-REM sleep (90%). They initially last only a few seconds and are activated by sleep. The presentation can be subtle.
It may take 1–2 years after first initial seizure for all criteria for diagnosis to emerge, so LGS should be considered if there are suggestive signs and symptoms without presence of complete triad.To confirm diagnosis, awake and asleep EEG and magnetic resonance imaging (MRI) are performed. MRI is used to detect focal brain lesions. Ruling out other diagnoses
Certain diagnoses must be ruled out before diagnosing LGS. These diagnoses are:
Doose syndrome
Dravet syndrome
pseudo-Lennox Gastaut syndrome (atypical benign partial epilepsy)LGS is more easily distinguished from Doose syndrome by seizure type after the syndrome has progressed. Doose syndrome has more myoclonic seizures and LGS has more tonic seizures. The Doose syndromes is less likely to have cognitive disabilities.Pseudo-Lennox–Gastaut syndrome can be distinguished from LGS because pseudo-LGS has different spike-and-wave patterns on EEG. Treatment
There are several treatment options, including medications, surgery, and diet. Medications
In most patients with LGS, the treatment does not end seizure recurrence. The goals of treatment are to lower frequency and severity of seizures to greatest extent possible. There are no studies using only one medication. Lamotrigine and rufinamide used as add-ons are very effective in reducing overall seizures, but do not stop them.The treatments for LGS has evolved over the years. Various treatments have been shown to have some degree of efficacy. In 1997–1999, lamotrigine was found to be effective and approved by the Food and Drug Administration and Health Canada.