WHAT IS EPILEPSY?

Epilepsy is a neurological condition caused by sudden changes of the electrical stability in the brain. Epilepsy is defined as recurrent unprovoked seizures. A single seizure is not epilepsy. Epilepsy is one of the most common neurological disorders affecting over 65 million people worldwide of which 3.4 million are in the United States.

WHAT IS A SEIZURE?

A seizure is a sudden surge of electrical neuron activity in the brain. Seizures generally last from a few seconds to a few minutes, and can temporarily affect a person’s consciousness, awareness, and physical abilities. Anyone can have a seizure and often the cause is unknown.

Epilepsy Facts

Types of epilepsy

The most recent classification model is the 2017 classification of seizures and epilepsies by the international league against epilepsy (ILAE), It helps patients, and their caregivers in easily understanding seizures that have both focal and generalized onset and include missing seizures. The revised epilepsy classification is a multi-level classification and is classified into four main types 1) focal, 2) generalized, 3) combined generalized and focal, and 4) unknown epilepsies.

Focal epilepsy: Focal epilepsy includes seizures involving one hemisphere of the brain and acts unifocal and multifocal disorders. Focal epileptiform discharges can be seen in interictal EEG. Focal epilepsy includes epileptic disorders such as focal aware seizures, focal impaired awareness seizures, etc.
Generalized epilepsy: Generalized spike-wave activity on EEG can be observed in patients with generalized epilepsy. Different types of seizures, including absence, myoclonic, atonic, tonic, and tonic-clonic seizures, may be seen in patients with generalized epilepsies.
Combined generalized and focal epilepsy: This is a new group of epilepsy wherein patients experience both generalized and focal seizures. Both generalized spike-wave and focal epileptiform discharges may be seen in interictal EEG. This condition commonly occurs in infants or children with severe epilepsies.
Unknown epilepsy: When there is no access to EEG or when EEG studies are uninformative, it cannot determine the type of focal or generalized epilepsy. Hence, it is termed as unknown epilepsy.

Epilepsy symptoms

Although epilepsy symptoms mainly consist of the generalized occurrence of seizures, there are several factors that differentiate epilepsy and seizure disorder. Epileptic seizures vary from person to person. Anyhow, it is quite common for an aura to manifest before the initiation of a seizure. Aura includes symptoms such as:

Abnormal smells
Fear sensation
Increased epigastric sensation and
Paraesthesia’s (abnormal sensation of the skin that can feel like tingling, numbness, burning or pricking)

The following are seen in the postictal state (a state that follows generalized onset seizures, which last from minutes to hours).

Headache
Confusion
Deep sleep, and
Muscle soreness
Todd's paralysis (a transient neurologic deficit, usually weakness, of the limb opposite to the seizure focus)

Focal aware seizure symptoms: motor, sensory, or psychomotor symptoms can be seen.

Focal impaired awareness seizures; Oral automatisms (involuntary chewing or lip-smacking); limb automatisms (e.g., automatic purposeless movements of the hands), irrelevant sounds

Head and eye deviation, usually in a direction opposite to the seizure focus.
Bicycling or pedalling movements of the legs.

Motor symptoms can go away after 1 to 2 minutes, but confusion and disorientation may still occur for 1 or 2 minutes. Postictal amnesia (loss of memory) is common. Left temporal lobe seizures may cause verbal memory changes; right temporal lobe seizures may cause visual-spatial memory abnormalities.

Generalized seizures symptoms: Patients may or may not lose consciousness, and Motor function is abnormal.
Typical absence seizures symptoms: 0- to 30-second loss of consciousness with eyelid fluttering is seen. Axial muscle tone may or may not be lost.
Atypical absence seizures symptoms: Jerking or automatic movements are more Prolonged, and the loss of awareness is less complete.
Myoclonic absence seizures symptoms: Typically, these seizures last 10 to 60 seconds with rhythmic jerking of arms and shoulders (3 times/second). Impairment of consciousness may not be obvious.
Eyelid Myoclonia: The patient shows myoclonic jerks of the eyelids and upward eye deviation.
Atonic seizure symptoms: Include a brief, complete loss of muscle tone and consciousness.
Clonic seizure symptoms: The sustained rhythmic jerking occurs in the body's limbs on both sides and often in the head, neck, face, and trunk.
Myoclonic seizure symptoms: Brief, lightning-like jerks of a limb, several limbs, or the trunk, which may be repetitive, leading to a tonic-clonic seizure.
Myoclonic-atonic seizure symptoms: The jerking of extremities or trunk briefly, then goes limp (drop attack).
Absence seizure symptoms: Formerly known as petit mal. People with absence seizures stare unresponsiveness to external verbal stimuli, and sometimes they may have eye blinking or head nodding symptoms.
Generalized Tonic Clonic (GTC) seizure symptoms: GTC seizure, formally known as grand mal, involves bilateral symmetric convulsive movements (stiffening and then jerking) of all limbs with impaired consciousness.
Febrile seizure symptoms: Uncontrollable shaking, loss of consciousness, eye-rolling, and stiff limbs
Tonic-clonic symptoms: Jerks, body stiffening, shakes, and loss of consciousness.

Epilepsy causes

The most important causes of epilepsy are the imbalance of neurotransmitters, tumours, strokes, brain damage from illness or injury, complications related to genetics, metabolism, and autoimmune issues.

In 1989, based on the etiology, the ILAE divided epilepsy into three groups. They are idiopathic, cryptogenic, and acquired.

Idiopathic: Nearly 40% of the epilepsies in the world are idiopathic epilepsies. It is devoid of neurological signs and onset in childhood. Juvenile myoclonic epilepsy and Childhood absence epilepsy are some examples of idiopathic epilepsy.
Cryptogenic epilepsies are likely to have a cause which can be difficult to identify. These days the term cryptogenic is discouraged as it conveys unclear implications. It is replaced with symptomatic epilepsies that include underlying conditions such as ischemic stroke, infections in the central nervous system, brain injury, prolonged symptomatic seizures intracerebral hemorrhage, and neurodegenerative diseases.
Acquired epilepsy: These epilepsies may occur due to identifiable structural abrasions of the person’s brain, and may include structural brain abnormalities, which indicates presence of underlying disease or condition. It also involves congenital (a condition that exists at birth) and developmental disorders linked with cerebral pathological changes. The following are the other causes of acquired epilepsy:
Cerebral tumours (a cancerous or non-cancerous mass or growth of abnormal cells in the brain)
Cerebral trauma
Cerebral infection
Hippocampal sclerosis (loss of neurons and reactive astrocytosis and gliosis in hippocampus)
Cerebrovascular disorders
Cerebral immunological disorders
Perinatal (the period when you become pregnant and up to a year after giving birth) and infantile.

Some conditions may be considered as acquired epilepsies including open-head surgery, viral meningitis, meningioma, cavernous haemangioma, and cerebral infarction

Epilepsy risk factors

Epilepsy may develop because of various conditions that disrupt normal brain activity. Risk factors for epilepsy in adults include:

Brain tumours
Head trauma
Alcoholism or alcohol withdrawal
Central nervous system (CNS) conditions, such as:
Neurocysticercosis (a parasitic infection that causes cysts in the brain and spinal cord)
Strokes, both embolic and haemorrhagic,
CNS malignancies (cancer)
Cerebral palsy (a group of neurological disorders that cause permanent movement and muscle issues)
Brain inflammation or swelling
Abnormal blood vessel formation (arteriovenous malformations) or bleeding in the brain.
Infections such as meningitis, viral encephalitis, and HIV-related infections
Alzheimer's disease, and other neurodegenerative conditions.
Premature birth or low birth weight
Heart attacks and other conditions which reduce oxygen levels in the brain
Family history of epilepsy or fever-related seizures

Understanding Epilepsy

The Understanding Epilepsy chart examines the causes and symptoms of this condition. Brain anatomy is represented through several images, including views showing the lobes and the functional areas of the brain. Both generalized and partial seizures are described, as are motor neurons and the synaptic cleft.