Epilepsy

  Print full article

Tests

Laboratory and non-laboratory tests are used to diagnose and monitor epilepsy, to determine what kind(s) of seizures the patient is having, to identify underlying conditions such as toxins, infections, drug or alcohol withdrawal, fever (in a child), or diabetes that may be causing seizures, and to distinguish epilepsy from conditions such as fainting or a stroke that may cause some of the same symptoms.

A medical history, input from the patient, and input from family members who have witnessed a patient’s seizures are important parts of the diagnostic process. The patient may remember a strange smell, an aura, and/or sensations that precede a seizure but may not remember what has happened during the seizure itself. Depending upon the signs and frequency of a person’s seizures, it may take some time to determine the proper diagnosis.

Laboratory Tests
Laboratory tests are primarily used to monitor anti-epileptic medications (AEDs) and to rule out other conditions such as diabetes, anaemia, infection, meningitis or encephalitis. Testing may include:

Seizure Evaluation testing:

• FBC (full blood count) – to evaluate red and white blood cells  
• Glucose – may be increased or decreased with diabetes 
• Electrolytes
• Toxicology, alcohol level
• CSF analysis – to check for infection and help diagnose meningitis and encephalitis
• Blood culture – to check for septicaemia, infection in the blood

Non-Laboratory Tests

• Electroencephalogram (EEG) – a primary diagnostic tool for epilepsy; it is used to evaluate the brain’s electrical activity and identify changes in brain wave patterns.

Imaging scans:

• Computerised tomography (CT) – identify brain structure abnormalities and tumors
• Magnetic resonance imaging (MRI) – also identify brain abnormalities
• Positron emission tomography (PET) – radioactive material is used to look at active areas of the brain.
• Single-photon emission computerised tomography (SPECT) – radioactive material is used to identify the region of the brain where seizures originate when it is not clear on other scans.

• Carbamazepine
• Phenytoin
• Valproic acid
• Phenobarbitone

Some workers in the field consider routine AED levels unnecessary (phenytoin being an exception). The dose is adjusted on the basis of seizure control and adverse effects.

There are situations when AED levels are useful: Once an efficacious dose is established it may be helpful to document a serum concentration; AED levels help to determine drug compliance; they are useful in the management of status epilepticus. They may be useful if there is drug interaction. (e.g. Lamotrigine levels can fall with oral contraceptives)
 
 

Last Review Date: June 7, 2017