In addition to blurred vision, which of the following may be an early sign of local anesthetic toxicity?

• A. Headache
• B. Tinnitus
• C. Fatigue
• D. Nausea

Answer: (B)

Blurred vision is indeed a recognized early sign of local anesthetic toxicity, and tinnitus is also associated with this condition. Tinnitus, or ringing in the ears, can occur as a result of the central nervous system being affected by the elevated levels of local anesthetics in the bloodstream. When local anesthetics are absorbed into the systemic circulation, they can interfere with normal neurological functioning, potentially causing sensory disturbances such as tinnitus.

Other options, while they may present with various health conditions, are less specific to the early signs of local anesthetic toxicity. Headaches can arise from numerous causes, including tension or dehydration, and don't have a direct correlation with local anesthetic toxicity. Fatigue may be attributed to a wide variety of factors, none particularly indicative of an adverse effect from local anesthetics, and nausea, while occasionally noted in toxic reactions, is not as directly connected to the initial neurological effects seen with local anesthetic toxicity as is tinnitus.

Understanding the symptoms is critical for timely recognition and intervention in cases of toxicity. Thus, identifying tinnitus as an early sign alongside blurred vision aligns well with clinical observations related to local anesthetic complications.