Todd's paralysis is a brief period of paralysis that occurs in the aftermath of a seizure.
The period of time directly following a seizure is called the "postictal state." During this time period, the individual's brain is still recovering from the major changes brought on by the seizure. Drowsiness and confusion are very common symptoms of the postictal state. In some cases, the symptoms are even more pronounced and dramatic, and may even involve severe weakness or paralysis of a limb or one side of the body (hemiparesis), odd sensations such as numbness, or pronounced vision changes or blindness.
Todd's paralysis usually strikes individuals who have epilepsy (recurrent seizures), although it may occur after any seizure.
Causes and symptoms
A seizure is an episode of abnormal electrical activity in a particular part of the brain. There are many kinds of seizures, and they may affect any specific part of the brain, or may spread to affect a wider distribution of the brain. The behavior of an individual suffering from a seizure may range from a simple, brief staring episode to complete loss of consciousness, with involuntary jerking of the muscles. The aftermath of a seizure is referred to as the postictal state. During the postictal period, although the seizure itself has ended, the brain is still recovering from the abnormal electrical discharges that precipitated the seizure activity. During this time period, the individual may be drowsy, less responsive than normal, or confused. Todd's paralysis is thought to occur due to depressed activity in the area of the brain that underwent the seizure.
The symptoms of Todd's paralysis depend on the area of the brain where the seizure took place. For example, if the seizure occurred in the motor cortex (that part of the brain responsible for purposeful movement of the muscles), Todd's paralysis may result in hemiparesis, an inability to move the muscles of one-half of the body. Because the occipital lobe (the lower back part of the brain) is responsible for vision, an occipital lobe seizure may result in visual change or outright blindness during the postictal phase. In fact, tracking the specific symptoms of Todd's paralysis may actually help the physician diagnose the specific area of the brain in which an individual's seizures are occurring.
The symptoms of Todd's paralysis are often gone within minutes or hours of their onset. In some, more rare cases, the symptoms may last as long as 48 hours. Ultimately, however, full function is restored.
Diagnosis of Todd's paralysis is crucial, because the symptoms can closely resemble those of a stroke (injury to the brain due to oxygen deprivation after bleeding or a blockage of an artery). It is important to distinguish between Todd's paralysis and a stroke, because the treatments are quite different.
Generally, Todd's paralysis can be easily diagnosed when it occurs in the aftermath of a documented seizure. The quick resolution of symptoms is another clue pointing to Todd's paralysis. When the diagnosis is unclear, however, tests may be run, including an electroencephalogram or EEG (a test that records information about the brain's electrical activity) or MRI. In the case of a seizure, the EEG may be abnormal; in the event of a stroke, the MRI may show an area of damage.
There is no specific treatment necessary for Todd's paralysis. The symptoms should fully resolve within minutes to hours or days.
Recovery and rehabilitation
Because of the quick and complete resolution of symptoms of Todd's paralysis, no rehabilitation is necessary.
The prognosis of Todd's paralysis is excellent, with full recovery to be anticipated.
Pedley, Timothy A. "The Epilepsies." Cecil Textbook of Internal Medicine, edited by Lee Goldman, et al. Philadelphia: W.B. Saunders Company, 2000.
Pollack, Charles V., and Emily S. Pollack. "Seizures." Rosen's Emergency Medicine: Concepts and Clinical Practice, 5th ed., edited by Lee Goldman, et al. St. Louis: Mosby, Inc., 2002.
Binder, D.K. "A history of Todd and his paralysis." Neurosurgery 54 (2) (February 2004) 486–487.
Iriarte, J. "Ictal paralysis mimicking Todd's phenomenon" Neurology 59 (3) (August 2002) 464–465.
Kellinghaus, Christoph; Kotagal, Prakash" Lateralizing value of Todd's palsy in patients with epilepsy" Neurology 62 (2) (January 27, 2004) 289–291.
Urrestarazu, E. "Postictal paralysis during video-EEG monitoring studies" Review of Neurology 35 (5) (September 1, 2002) 486–487.
National Institute of Neurological Disorders and Stroke (NINDS). Todd's Paralysis Fact Sheet. Bethesda, MD: NINDS, 2003. <http://www.ninds.nih.gov>.
Rosalyn Carson-DeWitt, MD