epilepsy

epilepsy
Name	Epilepsy
Synonyms	Seizure disorder
Caption	An electroencephalogram showing generalized spike-and-wave activity during a seizure.
Field	Neurology
Symptoms	Recurrent, unprovoked seizures
Complications	Status epilepticus, Sudden unexpected death in epilepsy
Onset	Any age, most common in childhood and old age
Duration	Often lifelong
Types	Focal, generalized, unknown onset
Causes	Brain injury, stroke, brain tumor, infections of the brain, genetic mutations
Risks	Febrile seizures, family history
Diagnosis	Based on symptoms, EEG, neuroimaging (e.g., MRI)
Differential	Syncope, psychogenic non-epileptic seizures, transient ischemic attack
Prevention	Head injury prevention, prenatal care
Treatment	Antiseizure medications, epilepsy surgery, neurostimulation, ketogenic diet
Medication	Levetiracetam, lamotrigine, valproate, carbamazepine
Prognosis	Variable; ~70% controllable with medication
Frequency	~50 million people worldwide
Deaths	Increased risk of premature death

epilepsy. It is a chronic neurological disorder characterized by recurrent, unprovoked seizures. These episodes result from excessive and abnormal electrical activity in the cerebral cortex of the brain. The condition has been recognized throughout history, with descriptions found in ancient Babylonian texts and the works of Hippocrates.

Signs and symptoms

The primary symptom is the seizure itself, which can manifest in numerous ways depending on the brain region involved. Focal seizures may involve altered consciousness, unusual movements of a body part, or sensory phenomena like auras. Generalized seizures, such as tonic-clonic seizures, involve loss of consciousness and convulsions. Other types include absence seizures, which present as brief lapses in awareness. Associated conditions often include depression, anxiety disorders, and migraine.

Causes

Causes are broadly categorized as genetic, structural, metabolic, immune, or infectious. Common structural causes include cerebral palsy, traumatic brain injury, stroke, and brain tumors such as meningioma or glioma. Infectious etiologies involve neurocysticercosis, cerebral malaria, and HIV/AIDS. Genetic forms can result from mutations in genes like SCN1A, associated with Dravet syndrome. In many cases, particularly in idiopathic generalized epilepsies, the exact cause remains unknown.

Mechanism

Normally, brain function is maintained by a balance between excitatory (e.g., glutamate) and inhibitory (e.g., GABA) signals. The disorder involves a shift toward hyperexcitability, which can arise from defects in ion channels, alterations in synaptic plasticity, or impaired function of astrocytes. This leads to the hypersynchronous neuronal放电 that characterizes a seizure. The kindling model describes how repeated sub-threshold stimuli can lower seizure threshold over time.

Diagnosis

Diagnosis is primarily clinical, based on a detailed description of the events. The International League Against Epilepsy provides classification guidelines. Key diagnostic tools include the electroencephalogram to detect abnormal brain waves. Neuroimaging, particularly magnetic resonance imaging, is used to identify structural lesions. In difficult cases, long-term monitoring in an epilepsy monitoring unit may be employed. Differential diagnosis must rule out syncope, panic attacks, and psychogenic non-epileptic seizures.

Treatment

First-line treatment involves antiseizure medications such as levetiracetam, lamotrigine, or valproate. For drug-resistant cases, considered for about one-third of patients, options include epilepsy surgery like anterior temporal lobectomy or lesionectomy. Neurostimulation devices, including the vagus nerve stimulator and responsive neurostimulation system, are also used. Dietary therapies like the ketogenic diet or modified Atkins diet can be effective, especially for children. In emergencies, status epilepticus is treated with benzodiazepines like lorazepam.

Prognosis

With appropriate treatment, approximately 70% of individuals achieve seizure freedom, often with the first or second medication. However, prognosis varies widely based on the underlying epilepsy syndrome; for instance, childhood absence epilepsy often resolves, while Lennox-Gastaut syndrome carries a poor prognosis. Risks include physical injury from seizures, sudden unexpected death in epilepsy, and significant psychosocial burdens affecting education, employment, and driving privileges as regulated by laws like those from the DVLA.

Epidemiology

It affects an estimated 50 million people globally, making it one of the most common neurological diseases. Incidence is highest in early childhood and again in older age groups, following a U-shaped curve. Prevalence is higher in low- and middle-income countries, partly due to increased rates of neurocysticercosis and perinatal complications. Notable individuals historically diagnosed include Fyodor Dostoevsky, Julius Caesar, and Vincent van Gogh. Major advocacy and research organizations include the Epilepsy Foundation and the American Epilepsy Society.

Category:Neurological disorders Category:Epilepsy