Todd's paresis (or postictal paresis/paralysis, "after seizure") is focal weakness in a part or all of the body after a

seizure A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, o ...

. This weakness typically affects the limbs and is localized to either the left or right side of the body. It usually subsides completely within 48 hours. Todd's paresis may also affect

speech Speech is the use of the human voice as a medium for language. Spoken language combines vowel and consonant sounds to form units of meaning like words, which belong to a language's lexicon. There are many different intentional speech acts, suc ...

, eye position (gaze), or

vision Vision, Visions, or The Vision may refer to: Perception Optical perception * Visual perception, the sense of sight * Visual system, the physical mechanism of eyesight * Computer vision, a field dealing with how computers can be made to gain und ...

. The condition is named after

Robert Bentley Todd Robert Bentley Todd (9 April 1809 – 30 January 1860) was an Irish-born physician who is best known for describing the condition postictal paralysis in his Lumleian Lectures in 1849 now known as Todd's palsy. Early life The son of physici ...

(1809–1860), an Irish-born

London London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Wester ...

physiologist Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a subdiscipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out chemical and ...

who first described the phenomenon in 1849. It may occur in up to 13% of seizure cases. It is most common after a focal motor seizure affecting one limb or one side of the body. The generally postulated cause is the exhaustion of the

primary motor cortex The primary motor cortex ( Brodmann area 4) is a brain region that in humans is located in the dorsal portion of the frontal lobe. It is the primary region of the motor system and works in association with other motor areas including premotor c ...

, although no conclusive evidence is available to support this.

Presentation

The classic presentation of Todd's paresis is a transient weakness of a hand, arm, or leg after

focal seizure Focal seizures are seizures that originate within brain networks limited to one hemisphere of the brain. In most cases, each seizure type has a consistent site of onset and characteristic patterns of spread, although some individuals experience mo ...

activity within that limb. The weakness may range in severity from mild to complete paralysis. When seizures affect areas other than the

motor cortex The motor cortex is the region of the cerebral cortex involved in the planning, motor control, control, and execution of voluntary movements. The motor cortex is an area of the frontal lobe located in the posterior precentral gyrus immediately ...

, other transient neurological deficits can take place. These include sensory changes if the

sensory cortex The sensory cortex can refer sometimes to the primary somatosensory cortex, or it can be used as a term for the primary and secondary cortices of the different senses (two cortices each, on left and right hemisphere): the visual cortex on the occ ...

is involved by the seizure, visual field defects if the

occipital lobe The occipital lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The name derives from its position at the back of the head, from the Latin , 'behind', and , 'head'. The occipital lobe is the ...

is involved, and

aphasia Aphasia, also known as dysphasia, is an impairment in a person's ability to comprehend or formulate language because of dysfunction in specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine, but aph ...

if speech, comprehension or conducting fibers are involved. Postictal paresis (PP), although familiar to neurologists, has not been well-studied. One retrospective observational study evaluated 328 selected patients from ages 16 to 57 years who had prolonged video-electroencephalogram (EEG) monitoring for medically intractable epilepsy and focal seizure onset; those with nonepileptic seizures,

status epilepticus Status epilepticus (SE), or status seizure, is a medical condition with abnormally prolonged seizures. It can have long-term consequences, manifesting as a single seizure lasting more than a defined time (time point 1), or 2 or more seizures over ...

, and Lennox-Gastaut syndrome were excluded. The following observations were made: * PP occurred in 44 patients (13.4 percent) * PP was always unilateral and always contralateral to the seizure focus * The mean duration of PP was 174 seconds (range 11 seconds to 22 minutes) Of all seizures followed by PP, the following features were noted: * Obvious ictal motor activity was seen in 78 percent (Todd's paresis is more common after any

clonic Clonus is a set of involuntary and rhythmic muscular contractions and relaxations. Clonus is a sign of certain neurological conditions, particularly associated with upper motor neuron lesions involving descending motor pathways, and in many cas ...

seizure activity) * Very slight ictal motor activity was seen in 10 percent * No ictal motor activity was seen in nearly 10 percent * The most common ictal lateralizing sign was unilateral clonic activity in 56 percent * Ictal dystonic posturing occurred in 48 percent * Ictal limb immobility occurred in 25 percent The results of this study are valuable because few other data exist on the frequency, duration, and seizure characteristics associated with PP. However, the study is likely biased by the inclusion only of patients with medically intractable seizures who had undergone video-EEG monitoring, and the results may not extrapolate to a general epilepsy population. Other post-ictal neurological findings that do not involve activity of the area affected by the seizure have been described. They are thought to be caused by a different mechanism than Todd's paresis, and including paralysis of the contralateral limb, and rare genetic causes of hemiplegia and seizures.

Causes

The cause of Todd's paresis has been attributed to the affected cortex being ‘exhausted’ or silenced due to increased inhibition, but these conjectures are not supported. It has been observed that the impairments that follow seizures are similar to those that follow strokes, where for a period of time blood flow to certain areas of the brain is restricted and these areas are starved of oxygen.

Diagnosis

One of the main challenges with Todd's paresis is distinguishing it from a stroke. This is made harder because some strokes can cause focal seizures during the early stage. In such cases, Todd's paresis might make the neurological damage seem worse due to the stroke itself, leading to incorrect decisions about urgent stroke treatments like thrombolysis. Therefore, having a seizure during a stroke is generally considered a reason to be cautious about using thrombolytic therapy, especially if there's no clear evidence of a blocked blood vessel in the brain using imaging techniques. An infant with Todd's paresis does not necessarily preclude the diagnosis of a febrile convulsion. This view is as a result of a recent study that showed the incidence of Todd's paresis to be in 0.4% of infants that have been diagnosed with a febrile convulsion.

Treatment

There is no treatment for Todd's paralysis. Individuals must rest as comfortably as possible until the paralysis disappears.

Prognosis

An occurrence of Todd's paralysis indicates that a seizure has occurred. The prognosis for the patient depends upon the effects of the seizure, not the occurrence of the paralysis.

References

External links

{{DEFAULTSORT:Todd's Paresis Cerebral palsy and other paralytic syndromes