Hemodialysis is a life-sustaining treatment for individuals with severe kidney failure, mechanically filtering waste products and excess fluid from the blood. The procedure involves circulating a patient’s blood outside the body through a dialyzer before returning the cleansed blood. While generally safe, this purification process leads to rapid shifts in the body’s internal chemistry. Seizures are a known, though uncommon, neurological complication that can arise during or shortly after a session.
The Confirmed Connection
Yes, hemodialysis can provoke a seizure. These events are classified as acute symptomatic seizures, meaning they are triggered by a temporary, identifiable medical condition rather than a permanent brain disorder. Although the overall risk is low, the incidence of seizures is higher in patients with chronic kidney disease compared to the general population. These events typically manifest during the treatment or within the immediate hours following its completion.
The rapid removal of toxins and fluid alters the internal environment, temporarily destabilizing brain activity. Seizures occurring in this context are related to the mechanical and biochemical action of the hemodialysis machine. This distinguishes them from seizures caused by underlying kidney failure, such as uremic encephalopathy, which occurs before dialysis begins.
How Dialysis Triggers Seizures
The primary cause of a dialysis-associated seizure is Dialysis Disequilibrium Syndrome (DDS), which results from an osmotic imbalance between the blood and the brain. Hemodialysis efficiently removes solutes, particularly urea, from the bloodstream faster than they are cleared from brain tissue. This concentration difference creates a temporary osmotic gradient, causing water to shift into the brain cells. The resulting cerebral edema, or brain swelling, increases intracranial pressure and can lead to neuronal instability and seizures.
The dynamic nature of hemodialysis can also cause rapid shifts in electrolyte concentration, which is necessary for stable neuronal signaling. Rapid drops or spikes in sodium levels (hyponatremia or hypernatremia) can directly affect the brain’s electrical stability. Similarly, sharp decreases in calcium or magnesium levels during treatment can destabilize neuron membranes, leading to excitability and seizure activity. These metabolic disturbances disrupt normal brain function.
Intradialytic hemodynamic instability, particularly a sudden drop in blood pressure, is another factor. Hemodialysis often involves removing excess fluid, which can lead to hypotension. A severe drop in blood pressure temporarily reduces blood flow to the brain, a condition called cerebral hypoperfusion. This oxygen and nutrient deprivation can impair brain function and induce a seizure, especially in patients with pre-existing vascular issues.
Reducing Risk and Immediate Treatment
Strategies to mitigate seizure risk focus primarily on controlling the rate of chemical and fluid changes. For new patients or those with very high toxin levels, dialysis treatment may be prescribed for shorter durations with slower blood flow rates. This gentler approach helps prevent the rapid solute removal that causes Dialysis Disequilibrium Syndrome. Adjusting the dialysate composition, such as increasing the sodium concentration, is another method used to lessen electrolyte shifts.
Individuals with a higher susceptibility require extra precautions during treatment. High-risk patients include those starting their first hemodialysis session, those with very high Blood Urea Nitrogen (BUN) levels, and individuals with a pre-existing neurological disorder. Older patients and children are also more vulnerable to the rapid changes induced by the procedure. For those with a history of seizures, a low dose of prophylactic anti-epileptic medication may be given before the session.
If a seizure occurs during treatment, the medical team follows a protocol to ensure patient safety and quickly stabilize the situation. The first step involves stopping or significantly slowing down the dialysis session to halt further adverse shifts in fluid or solute balance. The patient is protected from injury, and emergency medications are administered intravenously to stop the seizure activity. The immediate response centers on reversing the physiological trigger while providing supportive care, such as supplemental oxygen, until the seizure resolves.