Parturients Vulnerability to Hyperbaric Bupivacaine-Induced Neurotoxicity After Intrathecal Administration: A Series of Four Cases

Spinal anaesthesia using intrathecal hyperbaric bupivacaine is widely employed in caesarean sections due to its rapid onset, effective analgesia, and minimal foetal transfer. While generally safe, neurotoxicity following intrathecal bupivacaine is rare. This case series highlights an unusual cluster of neurotoxic events observed exclusively in pregnant patients. Four parturients undergoing lower segment caesarean section (LSCS) under spinal anaesthesia with 10 mg (2 ml) of 0.5% hyperbaric bupivacaine developed neurological complications. Neurological symptoms ranging from headache, nausea, vomiting, altered sensorium to generalized tonic-clonic seizures within two to three hours postoperatively. Two of the parturients required mechanical ventilation due to recurrent seizures and cerebral edema evident on MRI. Supportive management with airway protection, benzodiazepines, anti-edema therapy, and antiepileptics led to full recovery without long-term sequelae. Importantly, no neurotoxicity was reported in non-pregnant patients who were exposed to the same drug batch. The findings suggest a pregnancy-specific vulnerability to intrathecal bupivacaine neurotoxicity. Physiological changes in pregnancy-such as reduced cerebrospinal fluid volume, venous engorgement, hormonal modulation of neuronal excitability, and altered blood-neural barrier permeability-may predispose parturients to enhanced CNS exposure and toxicity, even at standard doses. The clustering of cases linked to a single suspected faulty batch further underscores the need for stringent pharmacovigilance and drug quality assurance. Early recognition, airway management, and supportive therapy are crucial for desired outcomes. Enhanced vigilance, dose optimization, and robust quality control of anaesthetic agents are essential to improve obstetric anaesthesia safety.