Occasional convulsive seizures, non-convulsive seizures and the
post-ictal state (the time after the visible seizure ends but the patient is still
not back to normal) can have residual focal numbness or weakness that last
minutes to hours or more after the event—unlike strokes these are not
associated with demonstrable brain circulatory problems. This post-ictal
phenomenon is referred to as a Todd’s
Paralysis which can mimic strokes causing the patient to worry, “Am I
having a stroke?” However, unlike most strokes, these worrisome symptoms soon
dissipate. \
Transient ischemic attacks (TIAs) can cause these same symptoms. We use
the term Todd’s Paralysis when the
focal symptoms are due to seizures. TIAs are associated with brain circulation
interruption and often predict a future stroke. These TIA symptoms can last
minutes up to 24 hours and then disappear. But, if these focal symptoms occur
and then disappear after a seizure we diagnose a “post-ictal phenomenon” or Todd’s Paralysis; this is not a stroke.
How do the patient and the doctor differentiate the post-ictal focal numbness/weakness
symptoms associated with an epileptic seizure from a true brain circulatory
interruption causing a TIA or a stroke? The bedside medical evaluation sometimes
leads to uncertainty. Often, rapidly obtaining an electroencephalogram (EEG) to
diagnose seizures is not possible. Then how do we make an accurate diagnosis?
We obtain a brain CT or MRI scan.
Fortunately, the CT scan is readily available and easy to do
in Western countries. The radiologist performs a CT scan and then can inject a
dye-like substance into a vein. The brain CT picture is again examined for
perfusion or circulatory changes highlighted by the dye; it can differentiate
seizure from TIA/stroke in those patients with symptoms suggestive of stroke
with focal numbness and/or weakness and/or speech problems. Loss of
consciousness is usually not associated with stroke or TIA.
No focal increased flow or perfusion in the brain cortex is
seen if it’s a post-ictal state affecting one side of the face/body called “lateralizing
signs.” This is how doctors can make this crucial diagnosis and reassure the
patient no stroke happened.
The younger the patient with post-ictal lateralizing focal
symptoms/signs that is not in the typical older-adult stroke population, the
more reassured everyone can be that a permanent stroke is not occurring. A past
history of Todd’s Paralysis,
especially in younger people with epilepsy is also reassuring against stroke.
Migraine sometimes occurs without headache and it is another
condition that can mimic clinical presentation of TIA / stroke. Brain scans are
usually normal in migraine, abnormal in stroke. And migraine is a repetitive
clinical situation which makes differentiating Todd’s Paralysis from TIAs and Stroke, easier. Recurrent migraine usually
occurs at younger ages than stroke, too.
Lance
Fogan, M.D. is Clinical Professor of Neurology at the
David
Geffen School of Medicine at UCLA. “DINGS” is his first novel. It is a mother’s
dramatic story that teaches epilepsy,
now available in eBook, audiobook and soft cover editions.
