Epilepsy Diagnosis

How is Epilepsy Diagnosis done?

For Epilepsy Diagnosis, the doctor would review symptoms and do certain tests. He would establish whether the event was a seizure or not. He would rule out other causes that can cause seizure. In case of epilepsy he would try to conform the cause and direct management further.

The doctor would evaluate a person for epilepsy and seizure in the following sequences:

1. Clinical History For Epilepsy Diagnosis:

The doctor would take the clinical history particularly taking care of the following things for Epilepsy Diagnosis:

• Eyewitness observation

• Patient conditions just before the onset of seizure including history of any medicine recently started or stopped, drug or alcohol use, details about sleep or its deficiency, history of fever, recent headache, or focal neurologic symptoms.

• Presence of an aura or any feeling of perceived warning such as apparent change in odor, visualization of flashes of lights, nausea, or déjà vu.

• Onset and type of seizure activity: to differentiate a seizure in to following types such focal seizure without impairment of consciousness or awareness, focal seizure with impairment of consciousness or awareness or Generalized seizure.

2. Physical examination For Epilepsy Diagnosis

A doctor would perform a general physical examination and a focused neurological examination to assess the behavior, awareness, mental functioning, motor ability.

In a person with epilepsy often there would be no abnormalities detected on physical examination.

3. Blood tests for Epilepsy Diagnosis:

Basic laboratory tests would be done in routine cases of epilepsy, with additional tests done based on individuals presentation and physical examination results. These are to rule check for infection or metabolic or toxic causes.

American College of Emergency Physicians has recommended minimal routine laboratory tests as follows:

▪ Blood glucose and serum sodium: are done in all patients experiencing seizure for the first time in whom the condition has returned to normal baseline after seizure episode.

▪ Serum calcium, magnesium, and phosphate

▪ Pregnancy test: is done in all women of childbearing age

▪ Lumbar puncture: is done to examine cerebrospinal fluid (CSF) in patients presenting with fever (or with other signs and symptoms of central nervous system infection) or immunocompromised state. This has to be performed only after MRI or CT brain. 4041

CBC: elevated or decreased WBC count could suggest infection.

Additional laboratory tests would be recommended depending upon the clinical picture, such as in suspected cases of metabolic derangements or intoxication.

American Academy of Neurology guidelines has recommend EEG and imaging tests to be done routinely in all suspected cases of unprovoked seizure.

4. Electroencephalogram (EEG):

Electroencephalogram (EEG) is a mandatory test done in the evaluation of epilepsy and Epilepsy Diagnosis. This test is done to record electrical activity of the brain by attaching multiple small electrodes on the scalp.

It is an easy and inexpensive test that can show abnormal electrical activity resulting into seizure.

It has following role in Epilepsy Diagnosis and management:

▪ To conform the diagnosis

▪ To describe the type of seizure

▪ To determine the risk of recurrent seizures

▪ To plan and guide medical treatment

The test may be done in a hospital or neurologist’s clinic. The test usually takes about an hour. During the test the doctor might also record the persons activity along with electrical impulses which is called as video EEG.

In adults a normal EEG shows predominantly alpha and beta waves with symmetry on both halves of brain 44.

An abnormal EEG would show difference in pattern of electrical activity in two sides of the brain with abrupt bursts of electrical activity or slowing.

The type of epilepsy is determined by the location, onset and pattern of abnormal electrical activity.

First EEG findings in interictal period are normal in about 50% of the epileptics. However, these patients reveal abnormal findings on subsequent EEGs.

Know more about EEG

5. Imaging tests In Epilepsy Diagnosis:

MRI and CT scan are two imaging tests performed usually in evaluation of epilepsy.

• They are done to look for any structural causes of epilepsy such as cysticercosis, tuberculoma, stroke, brain tumor, meningitis and others.

• These tests shows positive findings in 10% cases of epilepsy.

• May play role in suggesting risk of seizure recurrence.

• In case of emergency, usually is CT scan is preferred especially in case of abnormal neurological examination or focal onset seizure.40

• In non emergency situation MRI with or without contrast is better than CT.

Other less commonly used imaging tests could be:

Functional MRI (fMRI)

Positron emission tomography (PET)

Single-photon emission computerized tomography (SPECT)

There are some newer and additional techniques that can be used to pinpoint where in the brain seizures start:

• Statistical parametric mapping (SPM): Compares area of the brain with increased metabolism during seizures to normal brains.

• Curry analysis: projects EEG data onto MRI of the brain to show abnormality.

• Magnetoencephalography (MEG): uses the magnetic fields produced by brain to identify abnormal areas of seizure onset.

Establishing the accurate diagnosis of the type seizure and knowing from where the seizures begin gives the best chance for obtaining an effective treatment.