Duration of Todd's Paralysis
Todd's paralysis typically lasts from minutes to hours, but in some cases can persist for up to 36 hours, depending on the type of seizure and whether the patient has experienced cortical structural damage. 1, 2
Clinical Characteristics
Todd's paralysis is a neurological abnormality characterized by temporary limb weakness or hemiplegia that occurs following a seizure. Key features include:
- Occurs in approximately 6-13% of seizures 2
- Most commonly observed after partial seizures or generalized tonic-clonic seizures 1
- Higher incidence in patients with:
- Can present with various neurological deficits:
- Paralysis (most common)
- Paresthesia
- Aphasia
- Hemianopsia
- Altered consciousness 4
Duration Factors
The duration of Todd's paralysis varies based on several factors:
- Typical duration range: Minutes to hours 1, 2
- Maximum reported duration: Up to 36 hours 2
- Influencing factors:
Pathophysiology
The etiology of Todd's paralysis is primarily associated with cerebral perfusion abnormalities that occur after seizures 1. This can be accompanied by:
- Cytotoxic edema visible on diffusion-weighted MRI 4
- Transient metabolic changes in the affected brain regions
Differential Diagnosis
Todd's paralysis is an important stroke mimic that requires careful differentiation from acute ischemic stroke:
- Both conditions can present with acute focal neurological deficits
- Todd's paralysis resolves spontaneously, unlike stroke
- Advanced imaging (CT and MRI with angiography) is recommended to differentiate between the conditions 2
- Resolution of symptoms and normalization of imaging findings over time support Todd's paralysis diagnosis 4
Clinical Implications
Understanding the typical duration of Todd's paralysis has important clinical implications:
- Persistent deficits beyond 36 hours should prompt investigation for alternative diagnoses
- The presence of Todd's paralysis strongly suggests underlying structural lesions in the central nervous system (likelihood ratio of 11.2 for remote seizure etiologies) 3
- Recognition of Todd's paralysis can prevent misdiagnosis of acute stroke and inappropriate treatment 3
Unusual Presentations
In rare cases, Todd's paralysis may present with bilateral symptoms. A recent case report described bilateral postictal paresis in a patient with left fronto-opercular epilepsy, highlighting the potential for atypical presentations 5.