What are the symptoms of local anesthetic systemic toxicity?

Local anesthetic systemic toxicity (LAST) occurs when local anesthetics enter the systemic circulation, leading to potentially serious effects on the central nervous system (CNS) and cardiovascular system. The symptoms associated with this condition are characteristic and often progress in stages.

One of the early signs of local anesthetic systemic toxicity includes CNS disturbances, which can manifest as symptoms like tinnitus (ringing in the ears) and a metallic taste in the mouth, indicating neurological involvement. As toxicity progresses, seizures may occur due to excessive excitation of neuronal activity. If severe toxicity continues, it may lead to cardiovascular collapse, which is a critical state characterized by profound cardiovascular dysfunction that can result in shock or arrest.

Understanding these symptoms is crucial for quick identification and intervention in cases of LAST, as the management may involve administering lipid emulsion therapy to reverse the toxicity. This choice provides a clear representation of the expected symptoms of LAST and aligns with the pathophysiological mechanisms involved in this condition.