Epileptic syndromes

An epileptic syndrome is a group of signs and symptoms that share a common pathogenesis, prognosis and response to treatment.

The classification of epileptic syndromes comprises 2 major categories -:

• localization-related syndromes
• generalized-onset syndromes

Clinicians ideally classify their patients' seizures by using the classification for seizure types and make a syndrome diagnosis if possible.

Clinical features and prognosis depends a lot on the specific epileptic syndrome but it is not always possible to make a syndrome diagnosis. More often, there is only a description of the type of seizures.

Examples of Epileptic Syndromes in children

Benign epilepsy with Rolandic foci

Onset is between 2 and 12 years and is maximal between 7 and 10 years and stops by 13 years. Attacks are clonic, partially sensori-motor affecting the face, tongue and pharyngeal (of the pharynx) muscles, hand and arm and they occur particularly on waking.

Juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy (JME) occurs in the teen years. In JME, individuals have generalized motor seizures, myoclonic jerks (suddenly drop things) and staring spells that occur upon awakening.

Infantile spasms (West’s syndrome)

Infantile spasms, or West's syndrome, consist of ‘runs’ of tonic spasms occurring every 5-10 seconds. Attacks start in the first year with a peak onset at around 4 months, the outcome being worse with early onset. The commonest spasms are flexion (the bending of limbs). Parents may notice loss of visual and social interaction rather than spasms. West's syndrome is symptomatic of many underlying brain pathology.

A grossly disorganised epileptic electroencephalogram (hypsarrhythmia) is characteristic but not always seen. The mainstays of treatment are corticosteroids and vigabatrin.

A death rate of about 20% and the occurrence of cerebral palsy in 30-50% and cognitive disability in up to 85% should prompt early determination and energetic treatment.

Lennox-Gastaut syndrome

In the Lennox-Gastaut syndrome, multiple seizures occur in the first eight years of life. The seizures include tonic attacks (particularly in sleep), atypical (not conforming to the usual type) absence seizures, atonic and myoclonic attacks and episodes of non-convulsive ‘Status epilepticus’ with long periods of impairment of motor and cognitive function. Half of the children affected have primary developmental delay and all have learning problems after five or more years of the condition. Only up to 10% have a reasonable outcome.

Seizures are often resistant to anti-epileptic drugs, but benzodiazepines, sodium valproate, lamotrigine, corticosteroids and a ketogenic diet (containing minimal amounts of protein and carbohydrate) are regularly used. Occasionally, surgical treatment can be offered for instance to reduce severe drop attacks (that cause sudden falls and head injury).

Sudden unexplained death in epilepsy (SUDEP)

This is a mysterious, rare condition in which individuals with epilepsy die without a clearly defined cause. By definition, (1) death is sudden and unexpected, (2) a clear cause of death is absent, and (3) the individual had epilepsy. They are otherwise in a reasonable state of health at the time of death. Although seizures are suspected to have occurred prior to death, there is no evidence of seizure as the direct cause of death.

Recent studies have suggested that a combination of impaired breathing (apnoea), increased fluid in the lungs (impairing the exchange of oxygen and carbon dioxide) and being face down on the bed all combine to cause death due to impaired respiration.

The risk of SUDEP for someone with epilepsy is about 1 in 3000 per year. This risk is multiplied in those who have frequent seizures and take large doses of many anti-epileptic drugs (AEDs). A major risk factor for SUDEP appears to relate to the severity of the epilepsy, as SUDEP is more common in those with -:

• frequent convulsive seizures
• early age of onset of epilepsy
• long duration of epilepsy
• higher number of anti-epileptic medications and at high doses
• frequent medication changes

Steps to minimize the chances of SUDEP

1. Ensure compliance with medication

2. Supervision of individuals with a high likelihood of tonic-clonic seizures in sleep

3. Basic first aid should be provided during a seizure, including rolling the individual onto one side, checking respiration and avoiding putting any object in their mouth.

4. A family member or carer of children with uncontrolled convulsive seizures should learn cardiopulmonary resuscitation.