Can Todd's paresis (Transient focal neurological deficit) occur without generalized tonic-clonic seizures, but with focal impaired awareness seizures (FIAS)?

From the Guidelines

Yes, Todd's paresis can occur following focal impaired awareness seizures without generalized tonic-clonic seizures. Todd's paresis is a temporary weakness or paralysis that affects a part of the body after a seizure has ended. While it is commonly associated with generalized tonic-clonic seizures, it can also develop after focal seizures, including those with impaired awareness, as noted in the context of seizures and their aftermath 1. The neurological mechanism involves temporary dysfunction in the affected brain region due to post-ictal depression of electrical activity. This post-ictal phenomenon typically resolves within 24-48 hours, though it can occasionally last longer. The location and extent of the weakness correlate with the seizure focus in the brain.

Key points to consider:

• Focal seizures, including focal impaired awareness seizures (FIAS), can lead to Todd's paresis without the need for a generalized tonic-clonic seizure to occur 1.
• The presence of focal features during a seizure is significantly associated with clinically relevant abnormalities on neuroimaging, highlighting the importance of thorough evaluation in such cases 1.
• Patients experiencing unexplained temporary weakness after what seems like a minor seizure event should seek medical evaluation promptly, as this could represent Todd's paresis following a focal seizure and may require adjustment of anti-seizure medications or further diagnostic workup.

Given the most recent and highest quality evidence available, particularly from the 2024 American Heart Association and American Red Cross guidelines for first aid 1, it's clear that Todd's paresis is not exclusively linked to generalized tonic-clonic seizures but can also occur after focal impaired awareness seizures. Therefore, medical evaluation is crucial for anyone experiencing temporary weakness after a seizure, regardless of the seizure type, to ensure appropriate management and to rule out any underlying conditions that may require immediate attention.

From the Research

Todd's Paresis and Seizure Types

• Todd's paresis, also known as Transient focal neurological deficit, is a condition characterized by temporary weakness or paralysis in a part of the body after a seizure 2, 3, 4, 5, 6.
• The condition can occur after various types of seizures, including generalized tonic-clonic seizures (GTCS) and focal impaired awareness seizures (FIAS) 3, 6.

Focal Impaired Awareness Seizures (FIAS) and Todd's Paresis

• While the provided studies primarily discuss Todd's paresis in relation to GTCS, there is evidence to suggest that Todd's paresis can occur after focal seizures, which may include FIAS 3, 6.
• A study published in 2024 describes a patient with left fronto-opercular epilepsy who experienced bilateral Todd's paralysis after seizures that were characterized as focal, with occasional evolution to bilateral tonic or tonic-clonic seizures 6.
• Although this study does not specifically mention FIAS, it demonstrates that Todd's paresis can occur after focal seizures, which may imply that it is possible for Todd's paresis to occur without GTCS, but with FIAS.

Key Factors and Considerations

• The occurrence of Todd's paresis is often associated with underlying structural brain abnormalities, but it can also occur in individuals without such abnormalities 2, 4, 5.
• The duration and severity of Todd's paresis can vary widely, and it may be accompanied by other postictal symptoms such as aphasia, gaze palsy, or sensory loss 4, 5.
• Distinguishing Todd's paresis from other conditions, such as stroke, can be challenging, and further research is needed to improve diagnosis and understanding of the condition 2, 5.