Epileptic syndromes

Modern Classification of Epilepsy

According to the current guidelines of the International League Against Epilepsy (ILAE), the diagnosis is formulated across three consecutive levels:

1. Seizure type (seizure type).
2. Epilepsy type (epilepsy type).
3. Epilepsy syndrome (epilepsy syndrome).

At each of these stages, the physician must consider the etiological factor. The cause of the disease can be structural, genetic, infectious, metabolic, immune, or unknown.

The baseline classification of seizures depends on the localization of their onset:

• Focal seizures (focal seizures): originate within neuronal networks limited to one cerebral hemisphere (including subcortical structures). They may be localized to a single area or widely distributed. If the discharge spreads to the second hemisphere, it is referred to as a focal to bilateral tonic-clonic seizure.
• Generalised seizures (generalised seizures): pathological activity engages neural networks of both hemispheres ab initio.
• Unknown onset: when the point of origin cannot be determined.

Clinical Characteristics of Seizures

The most crucial evaluation criterion is the level of consciousness during the seizure.

• During focal aware seizures, the patient is fully aware, even if they lose the ability to move or speak.
• Focal impaired awareness seizures imply any alteration in the clarity of perception (formerly referred to as a "complex partial seizure").
• Generalised seizures are accompanied by loss or impairment of consciousness by default.

Based on clinical manifestations, motor (with motor activity) and non-motor variants are distinguished.

• Generalised motor seizures include tonic (sustained muscle spasm) and clonic (non-rhythmic jerking) convulsions. In older literature, they appear as grand mal.
• Generalised non-motor seizures are absences (formerly petit mal).
• The term "aura", which denoted seizure precursors, is no longer used in the new nomenclature. Now, these early sensory, cognitive, or emotional symptoms are considered the actual onset of a focal non-motor seizure.

Features of Seizures in Children

Seizure disorders in infants have their own specific characteristics. In newborns, chaotic clonic jerks predominate, which may begin as simple startles and progress to large-amplitude arm tremors. Intrauterine CNS lesions are usually diffuse, making topical diagnosis difficult, while movement disorders (e.g., hypotonia syndrome) come to the forefront.

Main types of seizures in pediatrics:

• Myoclonic: sudden, arrhythmic muscle jerks. Typical for infants, they often follow a malignant course and lead to profound psychomotor retardation.
• Febrile: triggered by temperatures above 38.5 °C, presenting as classic generalized or focal tonic-clonic seizures.
• Breath-holding spells: occur in excitable children against the background of loud crying. Due to progressive hypoxia, they can progress into true generalized seizures.

Etiology varies with age. In neonates, developmental anomalies, intrauterine infections, withdrawal syndrome, and metabolic disorders (hypoglycemia, hypocalcemia) lead the way. In infants, neuroinfections and severe ARVI take precedence, whereas in older children, true epilepsy, tumors, and intracranial hemorrhages emerge.

Neuroimaging and Principles of Treatment

MRI (MRI) is the gold standard for elective diagnostics. The study is mandatory for all patients except those with genetic generalized or benign rolandic epilepsy. The main goal is to identify a structural anomaly and assess its proximity to functionally critical areas (motor, speech). In emergency cases (trauma, fever, focal deficit), CT (CT) remains the method of choice.

Therapy begins with the selection of antiseizure medications. To abort acute conditions, the following are used:

• Benzodiazepines (diazepam) are first-line drugs for status epilepticus and acute symptomatic seizures (e.g., in ischemic stroke or meningitis).
• Magnesium sulfate is the drug of choice in eclampsia and severe pre-eclampsia, as well as in hypertensive crises.
• Barbiturates (thiopental sodium) are a reserve option for status epilepticus refractory to benzodiazepines.

If focal seizures are drug-resistant, surgical removal of the epileptogenic focus is considered. For children and adolescents with pharmacoresistant forms, early surgery can be a radical (fully curative) method.

Class and exam questions

What else to study on this topic

• MRI patterns in neurodegenerative diseases ("hummingbird" sign, "hot cross bun" sign)
• Prominent neuroimaging modalities: fMRI, PET, SPECT, and microstructural diffusion
• Metabolic imbalances as a cause of neonatal seizures (hypoglycemia, hyperammonemia)
• Muscle hypotonia syndrome in inherited metabolic disorders (sphingolipidoses, glycogenoses)
• Surgical treatment of pharmacoresistant epilepsy: indications and prognoses

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.