Radiographic studies
•
Head CT is indicated in the acute
setting of new onset seizure. CT is valuable in evaluating for possible head
trauma, subarachnoid hemorrhage and mass lesions. The probability that CT
imaging will be abnormal markedly increases if there is a history of recent
trauma, prior stroke, or a history of malignancy.
•
MRI of the brain is not typically
required on an emergent basis. However, if preliminary testing does not disclose
an etiology for the seizure, MRI of the brain is indicated in all patients. MRI
is the modality of choice to demonstrate arteriovenous malformations, neoplasm,
prior stroke, congenital malformations and
mesial temporal sclerosis (the latter
a common cause of seizures). Imaging should be
performed with gadolinium to demonstrate any vascular abnormality or
neoplasm. In addition, coronal imaging with thin cuts
through the temporal lobes should be performed to increase the yield
of demonstrating a temporal lobe abnormality.
Electroencephahlography (EEG)
EEG is indicated in all new-onset seizure patients. It
is not usually required on a stat basis unless the patient is having ongoing
recurrent seizures. EEG may be able to define the location of the seizure focus.
In some seizure types, the EEG can be diagnostic (e.g., primary generalized
epilepsy).
Who needs to be started on an anticonvulsant and/or
admitted to the hospital?
The decision to initiate anticonvulsant therapy after a single seizure is
problematic. It ultimately depends on the etiology and
whether there is an ongoing risk for recurrent seizures.
Take two examples on the extremes of the spectrum:
The first is a patient with a
normal examination, normal imaging and normal EEG, who had a single seizure
shortly after beginning a new medication known to increase the risk of seizures
[e.g., wellbutrin (bupropion hydrochloride)]. In this case, there is no indication for anticonvulsant
therapy.
The second is a patient with
recent head trauma; a CT scan showing a small left subdural hematoma; an EEG
showing ongoing spike waves in the left hemisphere; and a neurologic examination
showing a subtle right hemiparesis. In this case, there is an ongoing risk for
further seizures and such a patient needs to be treated with anticonvulsants.
Ultimately, it is a complex decision between the patient and the physician
taking into account the likely etiology and the risk of further seizures.
Regarding the need for admission to the hospital, again this decision is
complex. Clearly, any patients with new focal
neurologic deficits, lesions on neuroimaging, any evidence of infection, drug
intoxication or drug withdrawal, or underlying medical problems need to be
admitted. More problematic is the patient with no underlying medical
problems and a normal examination who recovers completely in the emergency room
whose laboratory testing and CT are normal. In general, these patients can
complete their evaluation as an outpatient. However, it is a decision based on
the specifics of the case, made between the physician and the patient.
Important Information For Patients with New-Onset
Seizures
Until their evaluation is complete, all patients with a new onset seizure
must be considered at risk for future seizures. Thus, they must be directed to
modify their behavior so that they would not be a danger to themselves or others
if they had a recurrent seizure. This means that the
physician needs to tell the patient not to drive and document this discussion in
the chart. No exceptions. In additions, patients should not operate
power tools, be on ladders, swim or use a bath alone. Not all contingencies can
be known in advance; patients need to be told to use common sense: don’t
participate in any activity which could harm themselves or others if they were to
lose consciousness secondary to a seizure. |