Age at onset

• ~5 to 40 years (peak ~11-23 years); ~80% have their first GTCS in the second decade of life.

Genetics

• Common genetic generalised epilepsy of complex inheritance.

Seizure semiology

• All patients suffer from GTCS
• Other seizure types do not occur
• Note: Absence and myoclonic seizures are NOT present.

Timing

• Occurs predominantly on awakening or related to the sleep-wake cycle.

Neurological and mental state

• Normal

Seizure-precipitating factors

• Sleep deprivation, fatigue, and excessive alcohol consumption.

Differential diagnosis

• Other generalised epilepsies, such as Juvenile Myoclonic Epilepsy and Juvenile Absence Epilepsy, which share the same propensity to GTCS on awakening, but also include absence seizures and/or myoclonic jerks.
• Genetic Epilepsies with Febrile Seizures Plus.
• Focal epilepsy with exclusion of patients with seizure evolution to bilateral convulsive. Any focal features on history or examination should prompt neuro-imaging.

EEG

• Usually normal background, with generalized 3-5.5 Hz spike-wave or generalised polyspike and wave.

Neuroimaging

• An MRI is not required in every case but should be considered with alerts or if clinical concern for a possible structural lesion exists.
• Neuroimaging should be normal.

Epilepsy with GTCS alone on awakening is probably lifelong with a high incidence of relapse upon withdrawal of treatment.
 

• Avoidance of seizure precipitants.
• Sodium valproate can be considered and is usually an effective drug for males, but in women of child bearing age, teratogenicity is a major concern. Other AEDs that may be useful include: levetiracetam, lamotrigine, and clobazam.
• Sodium valproate has been associated with risks of teratogenicity (i.e. malformations, cognitive impairment, and Autistic Spectrum Disorder). The risk of teratogenicity increases with increasing dosage. It is important clinicians and women of child bearing age are aware of this risk. Ideally, pregnancies in women with epilepsy should be planned and managed by a neurologist. Medication choices should be selected and discussed keeping in mind the safety of mother and foetus.
• Discussion with family
• Safety
• Epilepsy Medical Record
• Drug Handout
• Driving
• Potential of performing baseline educational assessment (through school counsellor)

Resources

• Epilepsy Action (UK) have information for Parents on Generalized Tonic Clonic Seizures

According to the NICE Guideline: Epilepsies in children, young people and adults (April 2022):

• The seizure type(s) and epilepsy syndrome, aetiology, and co-morbidity should be determined.
• If there is diagnostic uncertainty, individuals should be referred to tertiary services soon (within 4 weeks) for further assessment.
• Chapter 5 of the NICE guideline provides information on treating epileptic seizures in children, young people and adults.

The current classification and description of GTCSA can be found in the Position Statement by the ILAE Taskforce: Idiopathic Generalised Epilepsy Syndrome.

• Hirsch E, French J, Scheffer IE, Bogacz A, Alsaadi T, Sperling MR, et al. ILAE definition of the Idiopathic Generalized Epilepsy Syndromes: Position statement by the ILAE Task Force on Nosology and Definitions. Epilepsia. 2022; 63: 1475–1499. https://doi.org/10.1111/epi.17236
• Panayiotopoulos CP. The epilepsies: Seizures, syndromes and management: Based on the ILAE classifications and practice parameter guidelines. Chipping Norton, Oxfordshire: Bladen Medical Publishing; 2005.
• Roger J, Bureau M, Dravet C, Genton P, Tassinari CA, Wolf P, editors. Epileptic syndromes in infancy, childhood and adolescence (4th ed).  Montrouge, France: John Libbey Eurotext Ltd; 2005.