By: Nowshin Yeasmin Nishat

Bilateral Tonic-Clonic Seizures

Definition

Bilateral tonic-clonic seizures are generalized seizures in which abnormal electrical activity spreads across both hemispheres of the brain at onset, causing loss of consciousness and strong motor symptoms (Fisher et al., 2017). They were previously called “grand mal” seizures. The seizure occurs in two phases:

• Tonic phase: sudden loss of consciousness, muscle stiffening, body rigidity, and possible fall; breathing may become irregular.
• Clonic phase: rhythmic jerking of the limbs and face due to ongoing abnormal discharges.

After the seizure, a postictal state typically follows, which includes confusion, fatigue, headache, and temporary memory difficulty (Engel, 2013).

How it impacts the brain and the person

Impact on the brain

During a bilateral tonic-clonic seizure, widespread abnormal electrical activity disrupts normal neuron communication across both hemispheres, impairing networks responsible for consciousness, movement, and sensory processing (Berg et al., 2010). In that moment, the brain temporarily loses its ability to regulate awareness and voluntary movement.

The postictal phase, when the person is confused or extremely tired, basically reflects the brain recovering after this intense electrical disturbance (Engel, 2013). If seizures are frequent or not controlled, there can also be longer-term risks related to neurological stability and injury (Kwan & Brodie, 2000).

Impact on the person

Physically, people can get injured from sudden falls during a seizure. Muscle soreness, exhaustion, headaches, and general weakness are also common afterward.

But what stood out to me while reading this topic is that the impact is not only physical. The unpredictability of seizures often creates constant anxiety, especially in public spaces where the person cannot control what happens or how others respond. In many cases, this also leads to stigma or people treating them differently once they know about the condition (Jacoby, 1994).

From a daily life perspective, epilepsy can affect education, work, and mobility. Some people cannot drive, some may miss classes or work, and others may become more dependent on family members for safety and support. So even though it starts as a neurological condition, it clearly spills into social life and identity as well.

Diagnostic tests

• Medical history: A detailed description of seizure episodes from both the patient and witnesses is essential, including duration, movements, loss of consciousness, and recovery pattern (Berg et al., 2010).
• Electroencephalogram (EEG): EEG detects abnormal electrical activity in the brain. In generalized bilateral tonic-clonic seizures, it may show generalized spike-wave or fast activity patterns, although results can sometimes appear normal between seizures (Fisher et al., 2017). Video-EEG is sometimes needed to distinguish generalized onset seizures from focal seizures that spread (Ngayawaan et al., 2022).
• Brain imaging: MRI (preferred) or CT scans help identify structural causes like lesions, tumors, or past injuries that may contribute to seizures (Engel, 2013).
• Blood tests: These are used to rule out metabolic or infectious triggers, such as electrolyte imbalance or drug-related causes.

Treatment options

• Anti-seizure medications (first-line): Drugs like valproate, levetiracetam, and lamotrigine are commonly used to reduce seizure frequency and stabilize brain activity (Kwan & Brodie, 2000). Valproate is often avoided in people who may become pregnant due to teratogenic risks, so alternatives like lamotrigine or levetiracetam are preferred in those cases.
• Lifestyle management: Regular sleep, stress reduction, medication adherence, and avoiding triggers (like missed doses or alcohol misuse) can help improve seizure control.
• Emergency care: During a seizure, the priority is safety, to protect the person from injury, clear the surrounding space, place them on their side if possible, and avoid restraining movements. Emergency help should be called if the seizure lasts more than 5 minutes, repeats without recovery, or causes serious injury.
• Advanced treatments: If seizures remain uncontrolled despite medication, the condition may be classified as drug-resistant epilepsy. In such cases, options like epilepsy surgery, vagus nerve stimulation (VNS), or responsive neurostimulation (RNS) may be considered (Engel, 2013).

Conclusion

Bilateral tonic-clonic seizures are generalized seizures that involve widespread electrical disruption across both hemispheres of the brain, leading to loss of consciousness and strong motor symptoms. While the condition is neurological in origin, its effects extend far beyond the brain, influencing physical safety, emotional stability, and social participation.

From both a medical and social perspective, managing epilepsy is not only about controlling seizures but also about understanding how the condition shapes everyday life, relationships, and identity.

References

Berg, A. T., et al. (2010). Revised terminology and concepts for organization of seizures and epilepsies. Epilepsia.

Engel, J. (2013). Seizures and epilepsy. Oxford University Press.

Fisher, R. S., et al. (2017). Operational classification of seizure types by the ILAE. Epilepsia.

Jacoby, A. (1994). Felt versus enacted stigma: A concept revisited. Social Science & Medicine.

Kwan, P., & Brodie, M. J. (2000). Early identification of refractory epilepsy. New England Journal of Medicine.

Ngayawaan, I. L., et al. (2022). Video-EEG features distinguishing generalized vs focal onset tonic-clonic seizures. Epilepsia.