seizure, epilepsy

Seizure refers to abrupt, brief impairment of brain function. The human brain is a very complicated organ. It controls all the functions of the body. The manifestation of the disorder depends on the site of abnormality.

It can be in the form of involuntary movements, abnormal sensation, psychic disturbance or abnormality of the autonomic nervous system. There can be more than one abnormality at the same time. Alteration or lack of consciousness is a common occurrence.

Causes: The disorder can be due to many causes like congenital abnormalities of brain, trauma, infection, metabolic disturbance, hypoxia (decreased supply of oxygen to the brain) and bleeding due to abnormal blood vessels or bleeding disorders. Tumors of brain can also cause epilepsy.

The incidence of the problem is higher in newborn babies and young children than in older children.

The disorder is broadly classified as symptomatic (due to identifiable cause) or Idiopathic (no cause can be found).

Symptoms and signs: The disorder is first suspected on the basis of history. Occasionally the manifestation can be subtle and parents may bring a child for some abnormal behavior. Patient may experience a sense of fear for no apparent reason. Abnormal sensation like tingling in some part of body or flashes of light may be experienced by some patients.

Sometimes the only manifestation is blank stare and unresponsiveness for a short period. There may be deviation of eye balls to one side and or stiffness of one or more limbs. Sudden pallor may be noted. Impairment or loss of consciousness is a common feature.

There may be involuntary passage of urine or feces. In some children excessive salivation and drooling may be seen. The body may become limp suddenly and the patient fall down. Often the patient remains in a stake of confusion for some time after an attack of seizure.

In a newborn baby the manifestation can be very vague. There may be sudden pallor, cessation of breathing for a short period (apnea), stiffening of a limb, deviation of eye balls to one side or jerky movements of one or more limbs. Generalized seizure is uncommon in newborn babies.

It is important to rule out known causes before labeling it as idiopathic. Febrile seizures are very common between the ages of 6 months to 6 years. It is diagnosed after ruling out central nervous system infection like meningitis.

The terms status epilepticus is used when an attack lasts for 30 minutes or more. It is also used to describe very frequent attacks without complete recovery for 30 minutes or more. This can be in the form of convulsions (jerky movements of limbs) or in the form of altered mental status.

Status epilepticus is a medical emergency. Without prompt treatment there can be damage to the brain due to hypoxia or swelling of the brain. Even death can occur.

Clinical types: Depending on clinical manifestation the disorder may be classified as focal or generalized. Focal type is confined to only a few parts of the body-one limb, two limbs on one side or face.

Focal type is also known as partial seizure. This is further classified into simple partial and complex partial types.

In simple partial type any part may be involved but there is no aura. Complex partial type is associated with aura in the form of unexplained fear, abdominal discomfort and various hallucinations. It is followed by a brief state of confusion.

Primary generalized type is associated with loss of consciousness. There may be stiffness followed by jerky movements of limbs along with drooling of saliva and involuntary passage of urine or feces. In some patients with generalized seizure there are no convulsive movements of limbs. It may manifest as sudden loss of consciousness with decreased muscle tone.

Investigations: The type of investigation depends on the age of the patient, history and clinical examination. Often investigations are carried out in stages. In a newborn baby without any complication during delivery it may be only necessary to do blood sugar and calcium. If the baby looks ill cerebrospinal fluid analysis and screening for septicemia are required.

Depending on history tests for toxoplasmosis, rubella, cytomegalovirus, herpes virus and syphilis may have to be done. Cranial ultrasound and CT scan are required if congenital malformation or intracranial bleeding is suspected.

Tests for inborn errors of metabolism may be necessary if other tests are negative or if there is strong reason to suspect one (family history of mental retardation, unexplained neonatal death or death of children without apparent cause).

If seizure occurs with fever in a child more than 3 months and below 6 years the most probable diagnosis is febrile seizure. If the child recovers promptly and appears well except for fever no special test may be needed.

However even if there is slight doubt lumber puncture should be performed and CSF analyzed to rule out meningitis which is vary serious and potentially fatal.

Electroencephalogram (EEG) records the electrical activity of the brain. Though it has certain limitations it can be quite useful is confirming the diagnosis of seizure, identifying the type and selecting appropriate medicines. A normal EEG is a child who is strongly suspected of having seizure on the basis of history and/or observation usually indicates good prognosis.

CT (computerized tomography) scan is an imaging technique which can show sections of brain at various levels. This is very useful in detecting bleeding inside the brain, infarction (an area of tissue death) and tumors.

MRI (magnetic resonance imaging) is another imaging technique which helps in diagnosing structural abnormalities of the brain.

SBI!

Seizure and epilepsy