From the Guidelines
Todd's paralysis is a temporary neurological condition characterized by weakness or paralysis in a part of the body, typically lasting from minutes to hours before completely resolving, often occurring after a seizure and mimicking stroke symptoms but not caused by vascular problems. It most commonly affects one side of the body (hemiparesis) and usually follows a focal seizure or a generalized seizure with a focal onset. The paralysis results from the brain's exhaustion after the intense electrical activity of a seizure, particularly in the motor cortex, as noted in studies on seizure recurrence and outcomes 1. This phenomenon is named after Robert Bentley Todd, a 19th-century physician who first described it. According to a prospective cohort study, Todd’s paralysis did predict recurrence of seizures, with a significant increase in risk 1. No specific treatment is needed for Todd's paralysis itself as it resolves spontaneously, but the underlying seizure disorder should be addressed with appropriate antiepileptic medications prescribed by a neurologist. If someone experiences Todd's paralysis for the first time, they should seek immediate medical attention to rule out a stroke, as the symptoms can be very similar, and diagnostic tools such as magnetic resonance diffusion and perfusion-weighted images or angiography may be necessary to differentiate between the two conditions 1. Recurrent episodes should be reported to the treating physician to potentially adjust seizure management. Key points to consider include:
- The temporary nature of Todd's paralysis, which resolves on its own
- The importance of distinguishing Todd's paralysis from a stroke, given their similar symptoms
- The need for medical evaluation to rule out stroke and to manage the underlying seizure disorder
- The role of antiepileptic medications in managing seizures and potentially reducing the risk of recurrence.
From the Research
Definition and Characteristics of Todd's Paralysis
- Todd's paralysis (TP) is a relatively uncommon condition that occurs immediately after an epileptic seizure, presenting with acute-onset neurological findings such as paralysis, paresthesia, aphasia, hemianopsia, and an altered state of consciousness 2.
- It is a heterogeneous clinical syndrome that may be accompanied by cytotoxic edema on diffusion MRI 2.
- Todd's paralysis is characterized by temporary limb weakness or hemiplegia, typically occurring following a seizure, without enduring consequences 3.
Diagnosis and Differentiation from Acute Stroke
- TP may mimic acute stroke even in the presence of an acute brain lesion in the brain MRI, making differentiation necessary as each has completely different treatment and etiology 2.
- Factors that may help clinicians distinguish Todd's paralysis from other clinical indications include:
- Todd's paralysis is commonly observed after partial seizures or generalized tonic-clonic seizures 3.
- The incidence of Todd's paralysis is greater if the epilepsy is associated with old age or stroke history 3.
- 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 3.
- The etiology of Todd's paralysis is associated with cerebral perfusion abnormality after seizures 3.
- Advanced imaging such as cerebral CT and MRI with angiography is recommended to differentiate Todd's paralysis from stroke 4.
Clinical Features and Risk Factors
- Patients with Todd's paralysis were significantly older, more likely to have convulsive status epilepticus, and had a longer duration of convulsion than patients without TP 5.
- Remote etiologies, including old stroke, were identified as independent significant risk factors for TP compared with seizures with cryptogenic etiology 5.
- The positive likelihood ratio of TP seizures was 11.2 for remote seizure etiologies 5.
- Todd's paralysis can also occur due to hyperperfusion syndrome after carotid endarterectomy, mimicking postoperative stroke 6.