Seizures

Approach to seizures

The approach taken when someone presents with a seizure depends on circumstances:

• Establishing aetiology
• First seizure
• Seizures in epilepsy
• Seizures in pregnancy
• Seizures with intracranial masses
• Seizures after stroke
• Seizures after traumatic brain injury
• Acute recurrent seizures
• Status epilepticus

Estabilishing aetiology

The resources spent attempting to establish the aetiology of a seizure will depend upon patient factors. In someone presenting with a first seizure, it is important to consider aetiology in detail to guide management and ensure potentially important causes of symptomatic seizures such as brain infections or tumours are not missed. On the other hand, a patient with Dravet syndrome with an ongoing stable seizure burden may not require the same level of investigation - though there are always some useful factors to consider such as medication compliance.

Investigations

Blood samples can be useful for identifying abnormalities that:

• Are sufficient in their own right to cause seizures (e.g. hypoglycaemia)
• Raise the possibility of an important underlying diagnosis (e.g. elevated inflammatory markers)
• Support a diagnosis of seizure vs. a differential such as syncope or dissociative attacks

Test	Interpretation
Glucose	Hypoglycaemia can cause seizures

Neuroimaging is often performed in the initial evaulation of a patient presenting with a seizure without a clear cause. In acutely unwell patients, CT scans of the head allow identification of potential bleeds as well as large masses or evidence of trauma. In stable patients, MRI of the brain provides much more information allowing identification of inflammation, masses and structural abnormalities associated with epilepsy.

CSF is not routinely examined after a seizure in the absence of suspicion of a disorder such as CNS infection or autoimmune encephalitis.