Sepsis, a severe, life-threatening condition where the body’s response to an infection damages its own tissues and organs, can cause seizures. A seizure is a sudden, uncontrolled burst of electrical activity in the brain that can lead to changes in behavior, movement, or consciousness. This article explains the mechanisms linking sepsis to seizures, how these seizures are identified, and their treatment and prognosis.
The Biological Connection Between Sepsis and Seizures
Sepsis can lead to brain dysfunction, known as Sepsis-Associated Encephalopathy (SAE), which can include seizures as a severe symptom. The widespread inflammation characteristic of sepsis plays a significant role in triggering these brain disturbances. Inflammatory substances, such as cytokines, are released throughout the body during sepsis. These inflammatory mediators can increase the permeability of the blood-brain barrier, a protective layer that normally restricts substances from entering the brain from the bloodstream.
When the blood-brain barrier becomes more permeable, these inflammatory substances can cross into the brain, causing irritation and hyperexcitability of neurons. This neuroinflammation can disrupt the normal balance between excitatory and inhibitory neurotransmission in the brain, favoring excessive electrical activity that triggers seizures. Sepsis also causes metabolic disturbances, such as low oxygen (hypoxia), low blood sugar (hypoglycemia), and imbalances in electrolytes. These changes can profoundly disrupt normal brain function and lower the seizure threshold.
Reduced blood flow to the brain is another mechanism contributing to sepsis-related seizures. Septic shock, a severe form of sepsis, often leads to low blood pressure, decreasing the supply of blood and oxygen to brain tissue. This diminished perfusion can result in brain injury, further impairing neuronal function and increasing seizure susceptibility. The combined effect of inflammation, metabolic imbalances, and reduced blood flow creates an environment in the brain that promotes abnormal electrical discharges, leading to seizures.
Types and Identification of Sepsis-Related Seizures
Sepsis-related seizures manifest in various ways, making identification challenging, particularly for non-convulsive types. Convulsive seizures are the most recognizable form, involving rhythmic body shaking, muscle stiffening, and temporary loss of consciousness. These can be generalized, affecting both sides of the body, or focal, originating in one brain area, causing localized shaking or movements.
Many sepsis-related seizures are nonconvulsive, meaning they lack overt physical convulsions and can be easily overlooked. These subtle seizures may present as staring spells, unresponsiveness, confusion, or repetitive movements like eye blinking or lip-smacking. Patients may appear more confused or lethargic, masking underlying seizure activity. Recognizing these subtle signs is important in critically ill patients, where altered mental status is common.
Diagnosis of seizures, particularly nonconvulsive types, primarily relies on an electroencephalogram (EEG). An EEG records the brain’s electrical activity through electrodes placed on the scalp. It can detect abnormal brain wave patterns characteristic of seizure activity, even without outward physical signs. Continuous EEG monitoring is often used in intensive care units when sepsis-related seizures are suspected, providing ongoing surveillance of brain activity and helping confirm the diagnosis.
Treatment and Patient Outlook
Treating seizures caused by sepsis primarily involves addressing the underlying infection and the body’s dysregulated response. This involves prompt administration of antibiotics, fluid resuscitation, and support for failing organs. Managing the systemic inflammatory response and correcting metabolic imbalances, such as blood sugar and electrolyte levels, also helps stabilize brain function and reduce seizure activity.
Anti-seizure medications (anticonvulsants) are used to stop active seizures and prevent recurrence. Benzodiazepines like midazolam or lorazepam are often first-line treatments for acute seizures due to their rapid action in calming brain activity. Other anticonvulsant drugs may be administered to maintain seizure control and reduce further episodes. The goal is to interrupt the pathological electrical circuits in the brain and prevent prolonged seizure activity.
The occurrence of seizures in sepsis can be a sign of more severe illness and is associated with a more serious patient outlook. Patients who experience seizures during sepsis may have a higher risk of long-term neurological issues compared to those without seizures. These potential long-term complications can include cognitive difficulties, such as problems with memory, attention, and verbal fluency, and a heightened risk of developing epilepsy. While not every patient will experience these lasting effects, careful monitoring and ongoing support after recovery from sepsis are important to address any emerging neurological challenges.