From the Guidelines
Yes, seizures and Todd's paresis can exhibit computed tomography (CT) abnormalities similar to those of a stroke. Todd's paresis, which is temporary weakness following a seizure, can be associated with transient CT changes including focal hypodensity, localized edema, or abnormal contrast enhancement in the affected brain region [ 1 ]. These changes typically resolve within hours to days, unlike stroke changes which often persist. During the acute phase of a seizure, increased metabolic demand and blood flow to the seizure focus can cause CT findings such as subtle hyperdensity or hypodensity. However, these seizure-related changes are generally less defined and less persistent than those seen in ischemic or hemorrhagic strokes.
Key Considerations
- The timing of imaging is crucial, as early CT scans during seizure activity or immediately after Todd's paresis may show abnormalities that can be misinterpreted as stroke [ 1 ].
- Follow-up imaging is often necessary to differentiate between seizure-related changes and true stroke, as management differs significantly between these conditions [ 1 ].
- Seizure in the absence of imaging confirmation of acute ischemia is a relative contraindication for the use of rtPA in acute ischemic stroke [ 1 ].
Clinical Implications
- Physicians should be aware of the potential for seizures and Todd's paresis to mimic stroke on CT scans, and consider alternative diagnoses when evaluating patients with suspected stroke [ 1 ].
- A comprehensive clinical evaluation, including electroencephalography and follow-up imaging, is essential for accurate diagnosis and management of patients with suspected stroke or seizure [ 1 ].
From the Research
Seizures and Todd's Paresis Exhibiting CT Abnormalities Similar to Stroke
- Seizures and Todd's paresis can present with focal neurological deficits, mimicking stroke, and can be distractors in the emergency setting 2.
- CT perfusion can aid in the diagnosis of both stroke mimics and acute ischemic stroke, and can help differentiate between the two conditions 2, 3.
- Todd's paralysis can occur immediately after an epileptic seizure and can present with acute-onset neurological findings, such as paralysis, paresthesia, aphasia, hemianopsia, and an altered state of consciousness, which can be accompanied by cytotoxic edema on diffusion MRI 4.
- Todd's phenomenon can be confused with other conditions, most commonly a stroke, and postictal ocular manifestation may be accompanied by aphasia or hemiplegia, but isolated gaze palsy is rarely reported 5.
- The etiology of Todd's paralysis is associated with cerebral perfusion abnormality after seizures, and the duration of Todd's paralysis can range from minutes to days, depending on the type of seizure or whether the patient has experienced cortical structural damage 6.
Diagnostic Challenges
- Differentiating between Todd's paralysis and acute ischemic stroke can be challenging, especially in individuals without a pre-existing history of epilepsy 6.
- CT angiography and CT perfusion can be useful tools in diagnosing and differentiating between the two conditions, but may not always be conclusive 2, 3.
- Clinical features, such as the presence of seizure activity, and investigation results, such as CT perfusion and MRI, can aid in the diagnosis of Todd's paralysis and differentiation from acute ischemic stroke 2, 4.