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    Epilepsy

    Lennox-Gastaut Syndrome (LGS)

    |7 min read
    D

    Dovy Paukstys

    Founder, Komori Care

    Abstract photograph for the Lennox-Gastaut Syndrome (LGS) explainer
    Photo by Lorem Picsum on Unsplash

    Lennox-Gastaut Syndrome (LGS)

    By Dovy Paukstys, Founder, Komori Care

    This article is educational and is not medical advice. It does not diagnose, treat, prevent, or cure any condition. Komori is not a medical device, is not FDA-cleared, does not detect seizures, and is not intended for people with epilepsy. Talk with a neurologist or epileptologist about personal medical decisions. Households living with epilepsy should use clinically validated seizure-detection devices as directed by their care team.

    Families usually get this label after months of seizures that will not settle. Then they google it and hit a wall of EEG jargon.

    I'm not a neurologist. I don't have epilepsy. I read the ILAE pages, NINDS, MedlinePlus Genetics, and the LGS Foundation so this hub uses the same words a clinician uses.

    LGS is a specific syndrome. It is not a catch-all for "severe childhood epilepsy."

    What the name actually means

    NINDS calls Lennox-Gastaut syndrome a severe form of epilepsy. Seizures start in early childhood, usually before age 4.

    ILAE puts it in a harder bucket: a developmental and epileptic encephalopathy. The cause can slow development. The seizures can slow it more. Both. That's the point of the name.

    Three things travel together on the ILAE site. Multiple seizure types that resist medicine, especially tonic seizures in sleep. Cognitive and behavioral problems, which may not be there on day one. And two EEG patterns: slow spike-and-wave, plus generalized paroxysmal fast activity.

    The LGS Foundation adds a fourth core feature: developmental delay or intellectual disability. Not required at diagnosis. Nearly everyone with LGS has delay within five years of seizure onset, they say.

    Nobody is born with LGS. The Foundation is blunt about that. It develops. Often from an earlier epilepsy.

    When it shows up

    ILAE puts onset between 18 months and 8 years. Peak 3 to 5. Second decade is rare. Slightly more boys.

    LGS is rarely the first label. ILAE says it evolves from a prior syndrome or cause. About 10 to 30 percent come from infantile epileptic spasms syndrome or early-infantile DEE. The Foundation says the same thing: often from infantile spasms or West syndrome, and it can be hard to name before about two and a half because the pieces take time to land.

    It sticks. ILAE says the syndrome persists into adulthood in nearly all cases. Atonic seizures get less common later. The epilepsy itself does not clock out at puberty.

    What the seizures look like

    NINDS lists tonic stiffening with upward eyes and changed breathing. Atypical staring spells. Atonic drops. Myoclonic jerks. Generalized tonic-clonic seizures.

    ILAE is pickier. Tonic seizures are required. Plus at least one other type: atypical absence, atonic, myoclonic, focal impaired awareness, generalized tonic-clonic, epileptic spasms, or nonconvulsive status.

    The Foundation says tonic seizures are the most common and the easiest to miss. They like sleep. Neck or arm stiffening with the eyes rolling up can look like nothing on a hallway check and look obvious on overnight video-EEG. Atonic seizures can be a head nod in a chair or a slam to the floor.

    MedlinePlus Genetics has a number I will not turn into a household forecast. More than two-thirds of people with LGS have status epilepticus or clustered seizures. Each event is often short. The problem is the pile-up.

    The EEG is not optional

    ILAE will not diagnose LGS without an EEG. Mandatory findings: generalized slow spike-and-wave under 2.5 Hz, and generalized paroxysmal fast activity in sleep. Old EEGs count. In a place without much equipment, they still want at least slow spike-and-wave while awake.

    MRI is not required to name the syndrome. It's usually done to hunt a cause. Ictal EEG is not required either, unless Doose syndrome is on the table. Then they want a closer look.

    Causes. A lot of them.

    NINDS lists brain malformations, tuberous sclerosis, lack of oxygen around birth, severe head injury, brain infection, and inherited genetic, degenerative, or metabolic conditions. No cause in 30 to 35 percent.

    ILAE says structural brain abnormalities are in the majority. When they find a gene change without a structural lesion, it's usually de novo. Family history of seizures is not expected.

    MedlinePlus Genetics says most cases are sporadic. When a gene change is found, it usually happened at random. They also say 3 to 30 percent of people with LGS have a family history of some epilepsy. Inherited factors can still matter in a minority. I'm not going to pretend those ranges are tidy.

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    How common. Two different math problems.

    MedlinePlus Genetics: 1 to 2 per million people worldwide. 3 to 4 percent of childhood epilepsy. 1 to 2 percent of adult epilepsy. More males.

    LGS Foundation: about one person in 2,000. About 50,000 people in the US. About 1 million worldwide.

    Those are not the same math. I'm not mashing them into one number. Different sources, different methods. A clinician can tell you which figure they use. A blog cannot.

    Outlook is hard. Say that out loud.

    NINDS: no cure. Complete recovery, including seizure freedom, is very rare. Prognosis varies.

    ILAE: most kids already have developmental impairment. More stagnation or regression can show up when LGS arrives. More than 90 percent end up with moderate to severe intellectual impairment.

    The Foundation: more than 85 percent of children with LGS still have seizures as adults. More than 90 percent have significant intellectual disabilities. MedlinePlus Genetics says a small share of adults live independently. Most people need help with daily life.

    MedlinePlus Genetics and the Foundation both say a higher risk of death than peers. Falls, aspiration pneumonia, poorly controlled seizures, SUDEP. That's a risk statement from those pages. It is not a claim that a consumer camera, wearable, or wellness gadget detects seizures or prevents SUDEP. It doesn't.

    Treatment, without a shopping list

    I'm not ranking drugs. I'm not giving doses.

    NINDS says LGS is very hard to treat. Combinations get used. They name valproate as a medicine often treated as first-line for mixed seizure types, and they list other anticonvulsants clinicians may try. FDA approved cannabidiol (Epidiolex) for LGS-associated seizures in people 2 and older.

    NINDS also lists the ketogenic diet, vagus nerve stimulation, and surgery, typically corpus callosotomy. Which of those belongs to one person is a neurologist question.

    Nearby names that are not LGS

    Infantile spasms / IESS. Early-infantile DEE / Ohtahara. Doose / EMAtS. ILAE keeps those separate. Tonic seizures plus slow spike-and-wave plus sleep fast activity pull toward LGS. Myoclonic-atonic drops with 2 to 6 Hz spike-wave and a normal MRI pull toward Doose.

    Named genetic DEEs that later look like LGS: Rare Epilepsy Long Tail.

    What this page cannot do

    It cannot diagnose your kid. ILAE's criteria need seizure types, EEG, age, and course that only a clinician can put together.

    Households living with epilepsy should use clinically validated seizure-detection devices as directed by their care team. Consumer wellness products do not detect LGS. They do not detect seizures. They do not prevent SUDEP.

    NINDS points families to the LGS Foundation, the Epilepsy Foundation, and ClinicalTrials.gov. That's the right stack.

    FAQ

    What is Lennox-Gastaut syndrome?

    A severe childhood-onset epilepsy. ILAE classifies it as a developmental and epileptic encephalopathy. Working definition: multiple drug-resistant seizure types (tonic seizures required), cognitive and behavioral impairment, and EEG with slow spike-and-wave plus generalized paroxysmal fast activity in sleep.

    Can a child have LGS at the first seizure?

    Usually no. ILAE says it's rarely present at initial onset. The LGS Foundation says nobody is born with it. Features accumulate, often in the preschool years.

    Does LGS go away in adulthood?

    ILAE says it persists into adulthood in nearly all cases. NINDS says complete recovery is very rare. Seizure types can change. Atonic seizures get less frequent later. The syndrome does not vanish.

    Who diagnoses LGS?

    A physician. Usually a pediatric neurologist or epileptologist. EEG is required. MRI and genetic testing look for a cause. No website, app, or consumer monitor can make this call.

    Sources

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