A concussion, a mild form of traumatic brain injury (TBI), can cause a worsening of pre-existing epilepsy. This head trauma introduces a sudden, temporary disruption to the brain’s normal function, altering the delicate balance of electrical activity. For someone with epilepsy, this disruption can destabilize the condition, leading to an increase in seizure frequency or severity. This article explains the biological reasons behind this relationship and provides guidance on recognizing warning signs and adjusting long-term management.
Defining Concussion and Existing Epilepsy
A concussion is defined as a transient functional disturbance of the brain caused by a direct blow, jolt, or forceful movement to the head or body. Although categorized as a mild TBI, it involves the brain moving within the skull, causing a brief alteration in brain chemistry and cellular function. This injury temporarily changes how brain cells communicate, resulting in symptoms like confusion, headache, and dizziness.
Epilepsy is a chronic neurological condition characterized by recurrent, unprovoked seizures arising from abnormal, excessive electrical discharges. The epileptic brain is already predisposed to these electrical storms due to underlying issues like scar tissue or genetic factors. When a new trauma, such as a concussion, is introduced, it compounds this existing vulnerability. Even a mild TBI can destabilize an already controlled seizure disorder.
Neurological Mechanisms of Increased Seizure Activity
The mechanical force of a concussion initiates a cascade of biological changes that increase the brain’s excitability. A primary mechanism is the massive, uncontrolled release of excitatory neurotransmitters, particularly glutamate. This flood of chemical messengers overstimulates neurons, causing a temporary state of hyper-excitability within the brain’s circuits.
This surge of activity is followed by acute neuroinflammation, where the brain’s immune cells, called glial cells, respond to the injury. The inflammatory response can alter the function of existing neuronal networks. Specifically, this inflammation can disrupt the blood-brain barrier, which normally shields the brain, further increasing brain dysfunction and the risk of abnormal electrical activity.
The overall effect of the trauma is a shift in the balance between excitatory and inhibitory signals. Inhibitory neurotransmitters like GABA act as a brake on electrical activity, preventing runaway firing. A concussion can impair the function of GABA receptors, reducing the brain’s ability to suppress electrical overactivity. This combination of increased excitation and decreased inhibition lowers the seizure threshold, meaning the brain is more easily triggered into a seizure.
Immediate Post-Concussion Red Flags
Following a head injury in a person with epilepsy, certain signs require immediate emergency medical evaluation, as they may indicate a severe complication or a dangerous change in seizure pattern. The appearance of any new seizure or a cluster of seizures within 24 hours of the concussion is a significant concern. A seizure that is significantly longer than the person’s usual episodes or one that lasts more than five minutes (status epilepticus) demands emergency intervention.
Other acute symptoms that should prompt an immediate trip to the emergency room include signs of increased intracranial pressure or severe brain injury. These signs manifest as repeated, forceful vomiting or nausea, a headache that progressively worsens, or any new focal neurological deficits, such as weakness or numbness in the limbs. A prolonged loss of consciousness, slurred speech, profound confusion, or an inability to wake up are also critical warning signs.
Adjusting Treatment and Long-Term Monitoring
After the acute phase of a concussion, management involves reassessing the existing treatment plan for epilepsy. The treating neurologist will review the efficacy of the patient’s current anti-epileptic drugs (AEDs) to determine if a dosage adjustment is necessary to compensate for the lowered seizure threshold. The physical and chemical changes caused by the trauma may alter how the patient metabolizes or responds to their medication, sometimes requiring a temporary increase in dosage or a switch to a different drug.
Follow-up testing monitors for lasting structural or electrical changes in the brain. An electroencephalogram (EEG) can detect abnormal brain wave activity that indicates an increased risk of future seizures, providing objective data for adjusting the treatment plan. Imaging studies like an MRI may be used to rule out small bleeds or contusions contributing to the heightened seizure activity.
Beyond medication, long-term management focuses on lifestyle modifications to support brain health and minimize seizure triggers. Sleep deprivation is a powerful seizure trigger, and concussions often disrupt sleep patterns, making strict adherence to sleep hygiene especially important. Managing stress and gradually returning to normal activities under medical supervision are important steps.