What Causes Seizures in Children?
Although seizures have many known causes, for most children, the cause remains unknown. In many of these cases, there is some family history of seizures. The remaining causes include infections such as meningitis, developmental problems such as cerebral palsy, head trauma, and many other less common causes.
About 25% of the children who are thought to have seizures are actually found to have some other disorder after a complete evaluation. These other disorders include fainting, breath-holding spells, night terrors, migraines, and psychiatric disturbances.
The most common type of seizure in children is the febrile seizure, which occurs when an infection associated with a high fever develops.
Other reasons for seizures include:
- Metabolic disorders
- Disordered blood vessels
- Bleeding inside the brain
- Many yet undiscovered problems
A large portion of seizures in childhood can be grouped into the following categories:
- Myoclonic: A seizure characterized by jerking, spasming muscle groups with no loss of consciousness
- Myoclonic absences: A seizure characterized by spasming muscle groups with brief loss of consciousness
- Myoclonic tonic seizures: The seizure includes jerky muscle spasms and motionless spasms that cause rigidity.
- Other seizure disorders in children are not discussed here
Seizure disorders in infancy and early childhood often are caused by a genetic mutation, but a significant percentage of children with seizure disorders don’t readily fit into established disorders and diagnoses – the cause is a mystery. The following are some types of myoclonic seizure disorders in children:
Early infantile epileptic encephalopathies: This includes early myoclonic encephalopathy (EME) and early infantile epileptic encephalopathy (EIEE). These are severe disorders with a grave prognosis.
Causes of early infantile epileptic encephalopathies include brain malformations, inborn errors of metabolism, and neurogenetic disorders.
Myoclonic epilepsy occurring as part of a mixed generalized epilepsy syndrome: This includes:
- Doose syndrome (myoclonic-atonic epilepsy)
- Lennox-Gastaut syndrome
- Dravet syndrome (severe myoclonic epilepsy of infancy)
- Progressive spasticity is frequently seen in older children and adolescents with Dravet syndrome, often associated with the development of crouched gait or walk.
- Causes may include brain malformation and mutations that cause neurons to malfunction, such as SCN1A mutations.
- Other syndromes that feature several kinds of generalized seizures are also included in this classification.
Nonprogressive myoclonic epilepsies: This group of disorders overall has a more favorable prognosis and includes:
- Benign neonatal myoclonic epilepsy,
- Familial myoclonic epilepsy, and
- Autosomal dominant cortical myoclonus and epilepsies.
Nonprogressive myoclonic encephalopathies may also occur, with a worse prognosis. These disorders are usually genetically determined conditions.
Progressive myoclonic epilepsies: In this class of myoclonic epilepsies, seizures occur in the context of an underlying neurodegenerative disorder. Representative diseases include:
- Unverricht-Lundborg disease
- Lafora body disease
- Myoclonic epilepsy with ragged red fibers (MERRF)
- The neuronal ceroid lipofuscinosis, sialidosis, and dentate-rubral-pallidoluysian atrophy (DRPLA).
Seizures in the context of these disorders may be stimulus-sensitive or action-induced.