A brain bleed, also known as an intracranial hemorrhage, occurs when blood escapes from a vessel within the skull, accumulating inside the brain tissue or in the spaces surrounding it. This event can disrupt normal brain function, and yes, brain bleeds can cause seizures. A seizure is a sudden, uncontrolled electrical disturbance in the brain, which can lead to changes in behavior, movements, feelings, or states of consciousness. The relationship between a brain bleed and the occurrence of seizures is complex, influenced by various factors that determine the likelihood and characteristics of seizure activity.
How Brain Bleeds Lead to Seizures
When blood leaks into the brain, it acts as an irritant to the brain tissue, initiating biological responses that can lead to seizures. The presence of blood triggers an inflammatory response, where the body’s immune system attempts to clean up the extravasated blood. This inflammation can cause swelling, known as edema, around the site of the bleed, increasing pressure within the skull and disrupting normal neuronal activity.
Blood components themselves are neurotoxic, meaning they are harmful to brain cells. For example, hemoglobin, a protein in red blood cells, breaks down into substances like hemin and free iron, which can generate reactive oxygen species and contribute to oxidative stress. These toxic byproducts can directly damage neurons and interfere with their electrical signaling, lowering the brain’s seizure threshold. Additionally, disruption of the blood-brain barrier can allow more irritating components to enter the brain tissue.
Over time, the brain’s healing process can lead to the formation of scar tissue, a process called gliosis, involving reactive astrocytes and microglia. This glial scarring can alter the normal electrical pathways in the brain, creating areas of hyperexcitability where neurons are more prone to firing abnormally. Such changes contribute to an environment where seizures are more likely to occur, potentially even long after the initial bleeding event has resolved.
Different Brain Bleeds, Different Risks
The type of brain bleed significantly influences the risk and characteristics of seizure development. Intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH), and subdural hematomas (SDH) generally carry a higher risk of seizures due to their direct impact or widespread irritation of brain tissue. Epidural hematomas (EDH) are typically associated with a lower risk, though any intracranial bleeding can potentially lead to seizures.
Factors Affecting Seizure Occurrence
Beyond the type of bleed, several factors contribute to seizure occurrence. These include the bleed’s location, particularly in the brain’s outer surface or specific lobes, and its size. The presence of multiple bleeds or intraventricular hemorrhage also increases risk. Patient age and pre-existing medical conditions, such as a history of seizures or stroke, are also influential. Complications like hydrocephalus can further contribute to seizure development.
Addressing Seizures After a Brain Bleed
Prompt diagnosis and management are crucial when seizures occur after a brain bleed. This involves clinical observation, EEG monitoring, and imaging studies. Medical interventions typically include anti-seizure medications to control activity and reduce recurrence. Treatment is individualized, focusing on stabilizing brain electrical activity and preventing further injury.
Different Brain Bleeds, Different Risks
An intracerebral hemorrhage (ICH) involves bleeding directly into the brain’s tissue, often occurring in areas like the cerebral cortex. This direct invasion and irritation of brain cells by blood makes ICH a high-risk factor for seizures, with studies showing incidence rates between 6% and 15% in the first 72 hours, potentially reaching 30% when subclinical seizures are detected by continuous electroencephalogram. This direct structural damage and irritation to cortical networks increases the propensity for abnormal electrical activity.
A subarachnoid hemorrhage (SAH) involves bleeding into the subarachnoid space, the area between the brain and the surrounding membranes. While not directly within the brain tissue, the blood in this space can irritate the brain’s surface and lead to inflammation. Seizures occur in up to 20% of SAH patients, often within 24 hours of the bleeding event. Risk factors for seizures after SAH include the location of the aneurysm, the thickness of the blood clot, and the presence of an associated intracerebral hematoma.
Subdural hematomas (SDH) result from bleeding between the dura mater and the arachnoid mater, typically caused by head injuries. These hematomas can exert pressure on the brain, leading to irritation and an increased risk of seizures. Seizures are a common complication after acute SDH evacuation, with rates ranging from 6% to 25% in various studies. The severity of the injury and the need for craniotomy can significantly increase this risk.
In contrast, an epidural hematoma (EDH) involves bleeding between the skull and the dura mater, the outermost protective membrane of the brain. While EDHs are serious and require immediate medical attention, they are generally associated with a lower risk of seizures compared to ICH or SAH, as the blood collection is often outside the immediate brain surface. However, seizures can still occur as a complication, sometimes even up to two years after the injury, due to the pressure and irritation exerted on the brain.
Factors Affecting Seizure Occurrence
The location of the hemorrhage within the brain is a significant determinant; bleeds in the cerebral cortex, particularly in the frontal or temporal lobes, carry a higher risk of triggering seizures. This is because these outer brain regions are more electrically active and sensitive to irritation. Conversely, bleeds in deeper brain structures, such as the basal ganglia or thalamus, may pose a lower immediate seizure risk.
The size and volume of the brain bleed also correlate with seizure risk; larger hematomas are more likely to induce seizures due to more extensive tissue disruption and irritation. Additionally, if the bleeding extends into the brain’s ventricles, known as intraventricular hemorrhage, the risk of seizures can increase. The presence of multiple bleeds further elevates the overall susceptibility to seizure activity.
A patient’s age influences seizure risk, with both children and older adults exhibiting a higher predisposition. Younger age, especially in cases of intracerebral hemorrhage, is associated with an increased risk of late seizures. Pre-existing medical conditions also play a role; individuals with a history of prior seizures, stroke, brain tumors, or even a history of alcohol abuse may have a lower seizure threshold following a brain bleed. Furthermore, complications such as hydrocephalus, which is an accumulation of cerebrospinal fluid, can increase intracranial pressure and brain irritation, potentially leading to seizures.
Addressing Seizures After a Brain Bleed
Clinical observation for seizure symptoms, which can sometimes be subtle or non-convulsive, is a primary step. To confirm and characterize seizure activity, especially non-convulsive seizures, continuous electroencephalogram (EEG) monitoring is often employed. EEG measures the brain’s electrical activity and can detect abnormal patterns indicative of seizures that might not be outwardly visible. Imaging tests like CT or MRI scans are also used to assess the bleed’s location and size, and to rule out other causes of neurological changes.
Medical management of seizures after a brain bleed typically involves the use of anti-seizure medications, also known as anticonvulsants. Common medications include levetiracetam and phenytoin, though the use of specific drugs can vary and has evolved over time based on new data and side effect profiles. While phenytoin was historically common, its use has declined, with levetiracetam becoming a more frequently prescribed alternative due to its ease of use and lower side effect profile.
Treatment is highly individualized, considering the patient’s specific circumstances, the type and location of the bleed, and their overall health. The goal of medication is to control existing seizures and prevent their recurrence, as seizures can potentially worsen the brain injury by increasing intracranial pressure and metabolic demand.
While some studies suggest that acute symptomatic seizures are associated with worse outcomes, the routine prophylactic use of anti-seizure medication to prevent a first seizure is generally not recommended unless specific risk factors are present.