Transient Neurologic Symptoms
Temporary sensory disturbances, typically burning pain or dysesthesias in the buttocks and thighs, occurring after spinal anesthesia. More common with lidocaine and in lithotomy position.
Full Definition
Transient neurologic symptoms (TNS) are temporary sensory disturbances that can occur within 24 hours after spinal anesthesia, characterized by burning pain, aching, or dysesthesias typically distributed in the buttocks, posterior thighs, and calves. The symptoms usually resolve within 72 hours without permanent sequelae. TNS has a strong association with lidocaine use for spinal anesthesia, with reported incidences ranging from 4-37% compared to less than 1% with bupivacaine. Risk factors include the lithotomy position, outpatient procedures, and potentially the concentration of local anesthetic used. The exact etiology remains unclear but may involve direct neurotoxicity or neural ischemia. In obstetric anesthesia, TNS is relatively uncommon due to the predominant use of bupivacaine, but awareness is important when lidocaine-based solutions are used for short procedures.
Usage
Usage note: Abbreviate as TNS after first use. Distinguish from more serious permanent neurologic complications.
In Context
- "The patient developed transient neurologic symptoms 18 hours after spinal anesthesia with 5% lidocaine." — Complication report
- "To minimize the risk of TNS, the department switched from lidocaine to bupivacaine for spinal blocks." — Quality improvement initiative