From the Research
During a tonic-clonic seizure, pupils are typically nonreactive to light. This means that when a light is shined into the eye, the pupils do not constrict as they normally would. This pupillary nonreactivity occurs because the seizure activity disrupts normal brain function, including the neural pathways that control pupillary response. The autonomic nervous system, which regulates pupil size, is temporarily overwhelmed by the abnormal electrical activity in the brain during the seizure. This pupillary finding is one of several clinical signs that healthcare providers look for when evaluating a patient experiencing a seizure. Other common signs during a tonic-clonic seizure include loss of consciousness, muscle rigidity followed by rhythmic jerking movements, and often urinary incontinence. After the seizure ends (postictal phase), pupillary reactivity typically returns gradually as normal brain function resumes. This pupillary nonreactivity should not be confused with fixed, dilated pupils, which can indicate more serious neurological conditions requiring immediate medical attention.
Some studies have investigated the effects of seizures on brain function and pupil response, but none of the provided studies directly address pupil reactivity during a tonic-clonic seizure 1, 2, 3, 4, 5. However, based on general medical knowledge, it is known that seizure activity can disrupt normal brain function, including the neural pathways that control pupillary response. Therefore, it is reasonable to conclude that pupils are typically nonreactive to light during a tonic-clonic seizure.
In terms of treatment, several antiepileptic drugs have been shown to be effective in controlling generalized tonic-clonic seizures, including lamotrigine, levetiracetam, perampanel, and topiramate 4. However, the choice of treatment depends on various factors, including the underlying cause of the seizures, the patient's medical history, and the potential side effects of the medication. It is essential to consult with a healthcare provider to determine the best course of treatment for a patient experiencing tonic-clonic seizures.
Key points to consider when evaluating a patient with a tonic-clonic seizure include:
- Pupillary nonreactivity to light
- Loss of consciousness
- Muscle rigidity followed by rhythmic jerking movements
- Urinary incontinence
- Postictal phase with gradual return of normal brain function It is crucial to distinguish between pupillary nonreactivity and fixed, dilated pupils, which can indicate more serious neurological conditions requiring immediate medical attention.