Transient neurologic syndrome (TNS) is most commonly seen after the spinal anesthetic injection of which local anesthetic?

Transient neurologic syndrome (TNS) is most commonly seen after the spinal anesthetic injection of which local anesthetic?

• A. Lidocaine
• B. Bupivacaine
• C. Prilocaine
• D. Tetracaine

Answer: (A)

Transient neurologic syndrome after spinal anesthesia arises from transient irritation or mild toxicity to the nerve roots or cauda equina from the intrathecal local anesthetic. The drug most commonly linked to this phenomenon is lidocaine. Its intrathecal use is associated with a higher risk of this reversible neuropathic pain and dysesthesia than other spinal anesthetics, which is why lidocaine stands out as the best answer. Other agents—such as bupivacaine, tetracaine, and prilocaine—can cause neurologic symptoms, but they are far less likely to produce TNS, so they’re not the typical culprits. The symptoms usually begin within 6 to 48 hours after the block and resolve spontaneously over days to weeks, without lasting deficits.

Transient neurologic syndrome after spinal anesthesia arises from transient irritation or mild toxicity to the nerve roots or cauda equina from the intrathecal local anesthetic. The drug most commonly linked to this phenomenon is lidocaine. Its intrathecal use is associated with a higher risk of this reversible neuropathic pain and dysesthesia than other spinal anesthetics, which is why lidocaine stands out as the best answer.

Other agents—such as bupivacaine, tetracaine, and prilocaine—can cause neurologic symptoms, but they are far less likely to produce TNS, so they’re not the typical culprits. The symptoms usually begin within 6 to 48 hours after the block and resolve spontaneously over days to weeks, without lasting deficits.