Seizures following anesthesia and surgery are a complex phenomenon with multiple potential etiologies, ranging from pre-existing neurological conditions to metabolic disorders and anesthetic effects. These seizures can manifest postoperatively immediately or after a delay, often complicating the recovery process and requiring urgent medical attention. Understanding the underlying mechanisms can help reduce risk and optimize perioperative management strategies.

One of the major causes of seizures after anesthesia and surgery is anesthetic-induced neurotoxicity. The commonly used inhalational anesthetics isoflurane and sevoflurane, for example, have been reported to have proconvulsant properties in susceptible individuals (1). In addition, ketamine, an NMDA antagonist, has been associated with epileptiform discharges, although its overall effect on seizure activity remains controversial. Furthermore, patients with a history of epilepsy or latent seizure disorders may experience anesthetic-induced breakthrough seizures despite preoperative seizure control.

Another contributing factor is metabolic imbalance, which frequently occurs in the perioperative setting. Both hypoglycemia and hyperglycemia can precipitate seizures due to their effects on neuronal excitability. Inadequate glucose regulation, particularly in diabetic patients undergoing surgery, has been associated with an increased risk of seizures (2). In addition, electrolyte disturbances, including hyponatremia, hypocalcemia, and hypomagnesemia, are known triggers of seizures after anesthesia and surgery. Hyponatremia, in particular, can result from excessive intravenous fluid administration, syndrome of inappropriate antidiuretic hormone secretion (SIADH), or stress reactions to surgery.

Hypoxia and ischemia are additional concerns in the postoperative period, as cerebral hypoxia is a well-documented precipitant of seizures. Postoperative complications such as respiratory depression, airway obstruction, and thromboembolic events can lead to transient or prolonged cerebral ischemia, which may result in cortical irritation and seizure activity. Patients with underlying cerebrovascular disease, including previous stroke or transient ischemic attack, are at increased risk (3).

In some cases, posterior reversible encephalopathy syndrome (PRES) has been identified as a cause of seizures after anesthesia and surgery. PRES is characterized by reversible vasogenic edema, often precipitated by hypertensive crises, renal dysfunction, or fluctuations in blood pressure during surgery. Patients with PRES may present postoperatively with seizures, altered mental status, and visual disturbances (3). This condition highlights the importance of perioperative blood pressure management in preventing neurologic complications.

In addition, the use of certain medications in the perioperative period may contribute to the development of seizures. Drugs such as meperidine, tramadol, and fluoroquinolone antibiotics have been associated with seizure activity due to their effects on neuronal excitability. Withdrawal from chronic benzodiazepine or alcohol use may also precipitate seizures in susceptible individuals, particularly if abrupt cessation occurs before or after surgery (1). This requires careful preoperative evaluation and perioperative management to reduce withdrawal-related complications.

Finally, structural brain abnormalities, whether preexisting or induced by surgery, may serve as foci for seizure activity. Neurosurgical procedures, particularly those involving cortical manipulation or resection, carry an inherent risk of postoperative seizures. Traumatic brain injury, even mild, can predispose individuals to post-traumatic epilepsy, a condition characterized by seizures occurring days to years after an initial insult (1). The interplay between surgical trauma, inflammatory responses, and neuronal hyperexcitability contributes to this risk.

References

1. Eger EI 2nd. Characteristics of anesthetic agents used for induction and maintenance of general anesthesia. Am J Health Syst Pharm. 2004;61 Suppl 4:S3-S10. doi:10.1093/ajhp/61.suppl_4.S3
2. Yeoh C, Teng H, Jackson J, et al. Metabolic Disorders and Anesthesia. Curr Anesthesiol Rep. 2019;9(3):340-359. doi:10.1007/s40140-019-00345-w
3. Ferraz I, Carvalho S, Schuler V, Antunes P. Delayed Emergence From Anesthesia Due to Posterior Reversible Encephalopathy Syndrome (PRES): A Case Report. Cureus. 2024;16(10):e71986. Published 2024 Oct 21. doi:10.7759/cureus.71986