///2015 Abstract Details
2015 Abstract Details2019-08-02T16:54:43-06:00

Seizure versus Subdural Catheter: Every Dose is a Test Dose

Abstract Number: F-47
Abstract Type: Case Report/Case Series

Lauren D Rosenberg MD1 ; Marie-Louise Meng MD2; Stephanie Goodman MD3

Introduction: Subdural block is a rare complication of epidural anesthesia(1,2). Signs and symptoms can include relative hemodynamic stability, slow onset, high or patchy sensory block, variable motor block, and recovery within hours(1,2). Presentation is highly variable depending on spread of local anesthetic, often leading to a delayed or missed diagnosis.

Case: A 25 year-old term G1P0 woman received combined spinal epidural labor analgesia uneventfully at L3-L4 (spinal: bupivacaine 2.5mg, fentanyl 10mcg). Catheter aspiration was negative and an epidural infusion of bupivacaine 0.0625% and fentanyl 2mcg/cc at 12cc/hr was started.

Two hours later, pain returned. Aspiration of the catheter was again negative and 10cc of bupivacaine 0.125% was administered. Within minutes, the patient complained of lightheadedness and became unresponsive with intermittent slow jerking movements in all extremities. Blood pressure increased to 192/128, heart rate to 100, and oxygen saturation decreased to 87%. Bag-mask ventilation was initiated. Midazolam, ativan and keppra were administered for possible seizure. Twitches of the upper extremities and facial muscles persisted (BP 128/50, HR 120s-140). Despite a category 1 tracing, Cesarean delivery was decided and general anesthesia was induced. Epinephrine 15mcg was administered through the catheter with no change in HR.

After extubation, there were no neurological deficits and head CT was normal. Postoperatively, the patient could accurately recall all events that occurred prior to induction of GA. She described after the catheter bolus feeling onset of ascending weakness and numbness to the neck and that she could not breathe. She reported that during the event she was trying to move to signal that she was awake.

Discussion: The majority of radiographically-proven subdural catheters do not aspirate CSF(2). Cases of subdural catheters presenting as uneventful initiation of anesthesia with later deterioration following bolus dosing have been reported(2). Iatrogenic dissection of the subdural space causes fissures with considerable variability in form that may explain the cervical block and relative sparing of ventrally-located sympathetic nerves and patchy sensory and motor block.

Initially, the myoclonic movements in this patient were attributed to a seizure, which was unlikely with no signs of preeclampsia and the small dose of local anesthetic given. Sudden apnea initially suggested an intrathecal catheter. In hindsight, hypertension, tachycardia, and the observed movements likely represented awareness, with attempts at voluntary muscle movement in a profoundly weak patient. While no imaging of the spine was done prior to catheter removal and therefore the cause of this patient’s condition cannot truly be known, the combination of signs and symptoms makes a subdural injection of local anesthetic the most likely explanation.


1. Anesth Analg 67(2): 175-179.

2. Reg Anesth Pain Med 34(1): 12-16.

SOAP 2015