What is Todd Paresis?
Todd paresis is a condition that causes weakness or even complete loss of movement in parts of the body after a seizure. Often, it may affect a single limb or half the body, but symptoms can vary widely. You might also hear it referred to as Todd paralysis or Todd palsy. However, the condition isn’t just about motor function – it actually extends to other areas, including language, eye movement, sensations, consciousness, and vision.
The syndrome was first observed by an Irish doctor and physiologist named Robert Bentley Todd in 1849. Since then, many others have contributed to further research and understanding of this phenomenon. Despite Todd paresis being frequently observed by neurologists, there isn’t a huge amount of research on it.
What Causes Todd Paresis?
Todd paresis is a condition that occurs after a seizure. After a seizure, there’s a period where the brain is recovering, which is referred to as the postictal syndrome. Not every seizure results in this syndrome, or it might not always be noticeable, like in the case of certain types of seizures like absence seizures, myoclonic seizures, or in simple terms, seizures that only affect a specific region of the brain.
An interesting fact about Todd paresis is that its symptoms can help locate where in the brain the preceding seizure occurred. This is especially useful if the seizure wasn’t observed, because most seizures last less than five minutes.
The generally accepted explanation for Todd paresis is that it’s a result of exhaustion of a part of the brain after a seizure. This could happen due to a few reasons. One is that during a seizure, the brain cells in a certain area may become overactive, which tires them out. A second reason is that the blood flow to that part of the brain might decrease due to changes in blood vessel size, denying the brain cells there of the oxygen they need to function.
Risk Factors and Frequency for Todd Paresis
About 13% of all seizures result in a condition called Todd paresis, which can appear in various forms. It does not favor any gender, age, or race.
- About 90% of people who experience post-seizure paralysis show noticeable jerking movements during the seizure.
- Only 10% of these patients do not have any motor activity during the seizure.
- In over half of the patients (56%), one-sided jerking movements are the most common sign of upcoming post-seizure paralysis.
Signs and Symptoms of Todd Paresis
People suffering from this condition often experience weakness in a limb on the opposite side of the body where a seizure has happened. The weakness can range from mild to total paralysis. However, the condition doesn’t just restrict to limb weakness, and can include symptoms such as confusion, memory loss, alternation in consciousness, speech difficulties, agitation, psychosis, abnormal eye movements, numbness, and visual disturbances.
It’s important to note that this condition can be caused by specific seizures that start in one part of the brain, or seizures that start in one part and then affect the entire brain. The first scenario involves a seizure that begins with twitching in a limb, spreads to half of the body, and then becomes more generalized. This is also known as a Jacksonian march. However, in a pure focal seizure, the twitching stays in the initial area and doesn’t spread to the rest of the body.
Memory loss and confusion are more common after generalized seizures. However, these symptoms can also occur from repeated partial seizures. In particular, difficulty with speech can occur if seizures are happening in the left side of the brain.
Symptoms of this condition can last anywhere from a few minutes to several days, but most people will see a complete recovery within 36 hours. On average, full recovery takes around 15 hours.
If someone was present during the seizure, it’s helpful to ask if they noticed any specific activity before the seizure. However, it can often be hard for people to recall, especially if it was their first time witnessing a seizure.
Testing for Todd Paresis
When someone experiences alarming symptoms like agitation, psychosis, or altered consciousness, it may be due to a condition known as Todd paresis. Recognizing this condition can help avoid unnecessary medical tests and treatments.
Todd paresis doesn’t have specific laboratory tests that can confirm its diagnosis, which means doctors must rely on other methods. In particular, scans and imaging become quite important.
For example, computed tomography (CT) scans, which provide detailed images of the brain, might reveal anomalies. This essentially means that some parts of the brain could look a bit different, specifically underperfused (not getting enough blood flow) but these anomalies are inconsistent and not always identifiable, so they can’t be used as a definitive diagnosis tool.
CT angiography, an imaging test that looks at the blood vessels, usually doesn’t show anything unusual in cases of Todd paresis. However, this scan can be a useful tool to help rule out stroke in which a major artery could be seen as blocked.
Brain magnetic resonance imaging (MRI), which provides detailed pictures of the brain’s structure, can show findings consistent with a seizure, like an increased bright signal on a certain type of image called T2 at the site of the seizure activity. This brightness is due to swelling in that part of the brain. But, these findings are not specific to Todd paresis, as they are actually caused by the devastating seizure.
An electroencephalogram (EEG), which records the electrical activity of the brain, might show a slowing down of the brain’s electrical activity. In rare instances, all activity might cease temporarily. While the brain recovers, the normal activity is restored, though the signals may be weaker. Even after the EEG shows improved activity, behavioral dysfunction can still persist for several days! Hence, an EEG can help differentiate Todd paresis from other conditions that involve prolonged seizures.
Treatment Options for Todd Paresis
Generally, the treatment of this condition doesn’t involve any specific interventions because it typically gets better on its own. The most crucial part is for the doctor to accurately recognize and diagnose the condition to avoid unnecessary medical procedures. Some patients might need a medical procedure called orotracheal intubation, which involves inserting a tube through the mouth into the windpipe, but this is only necessary for those who can’t protect their own airways.
Patients suffering from this condition don’t usually need immediate doses of antiepileptic medication for treatment; however, they should continue taking their regular prescribed medicines. For those who have low levels of their antiepileptic medication in their bodies, doctors should adjust and optimize their doses, to prevent them from having further seizure episodes.
What else can Todd Paresis be?
There are several conditions which could potentially be confused with status epilepticus. Here are the key ones to consider:
- Non-convulsive status epilepticus: This usually happens after an extended seizure. While there may be slight twitching or shaking, there is no significant improvement. An EEG test will show seizure activity.
- Stroke: A stroke can be identified using a variety of scans, including CT angiography, brain MRI, magnetic resonance angiography, or a head CT scan. However, care has to be taken with interpreting the results of a perfusion CT scan, as both an epileptic seizure and a stroke can result in reduced blood flow.
- Hemiplegic migraine: This is a rare, heritable form of migraine. The patient typically exhibits severe headache, weakness, lack of coordination, and even paralysis, usually on one side of the body.
Other conditions that might be confused with status epilepticus include:
- Hemiconvulsion (Hemiplegia epilepsy syndrome): This is a disorder usually seen in infants or young children (mostly under 4 years old). It’s characterized by extended seizures during a fever, resulting in brain shrinkage and limp paralysis on one side of the body. Over time, this may also result in recurring targeted seizures.
- Hypoglycemia: Known as low blood sugar, this condition can present symptoms similar to a stroke.
- Psychogenic non-epileptic seizure: This can vary in severity and does not follow a specific pattern. Patients often appear unresponsive, recover quickly, and may also seem weak after an incident. They will often ask what happened, blink their eyes, and appear disoriented.
What to expect with Todd Paresis
The outlook for this condition is very good. The weakness that comes after the condition resolves on its own and doesn’t need any treatment.
Possible Complications When Diagnosed with Todd Paresis
Paresis usually resolves on its own, so complications are not usually an issue. However, sometimes if the condition is not correctly diagnosed, patients may undergo unneeded procedures.
Common Experiences:
- Paresis is often self-limiting
- No complications are usually expected
- Possibility of unnecessary procedures if diagnosis is incorrect
Preventing Todd Paresis
If you’ve had Todd paresis (a temporary period of weakness or paralysis) before, it’s crucial to let your healthcare team know. It’s important to understand that Todd paresis usually resolves on its own, and doesn’t need extra tests. The symptoms can vary in duration, lasting from a few minutes to a few days. However, for most people, the symptoms completely disappear within a day and a half.
