|
|
|
TODD'S PARALYSIS |
Definition:
A temporary weakness or paralysis (typically
minutes to hours, rarely days) that occurs in a limb or limbs following a focal
or focal-to-generalized seizure.
This phenomenon was first described by an English physician, Robert B Todd
(1809 - 1860) (portrait above) who observed the following:
Patients with seizures that
began with focal twitching in one body part would then spread over one side of
the body (i.e., Jacksonian march) before going on to a generalized tonic clonic
seizure. After the seizure, muscles in the limb or the side of the body where
the seizure first began would be flaccid and weak. |
As seizures are a hyperexcitatory state of neurons, the post-ictal
state is a depressed state of neuronal function (the neurons have been
metabolically stressed and need time to recover). In a generalized seizure, the
post-ictal state is also generalized: patients have generalized weakness and a
depressed level of alertness.
However, in a focal-onset seizure, presumably the neurons in the focus are
the ones most hyperexcitable, and accordingly, in the post-ictal state, the ones
most likely to take a greater period of time to recover. In the case of a
seizure that originates in the motor cortex, a post-ictal paralysis of the
contralateral limb occurs following a seizure. |
Although the term Todd’s paralysis was initially used to described hemiparesis
after a seizure, there can be other types of post-ictal deficits - it simply
depends on whether the seizure had a focal onset and the location of the focus.
For example, if the focus is in the primary language area, a patient can have a
post-ictal aphasia. Likewise, a focus in the occipital lobe may leave the
patient with a post-ictal visual field abnormality.
|
Thus, examining a seizure patient in the immediate
post-ictal period is important. Any focal neurologic finding strongly
suggest a focal onset. Importantly, in the
post-ictal period, it is often not possible to determine if a focal neurologic
deficit represents a new neurologic process (e.g., stroke, tumor, etc.) as
opposed to a post-ictal deficit. Basically, time will tell. |
|
|
|