Certified Neuroscience Registered Nurse (CNRN) Practice Exam

What are the signs and symptoms of Local Anesthetic Systemic Toxicity (LAST)?

1. Headache, fever, and rash

2. Metallic taste, ringing in ears, and vision changes

3. Nausea, vomiting, and diarrhea

4. Hypertension, tachypnea, and confusion

The correct answer is: Metallic taste, ringing in ears, and vision changes

Local Anesthetic Systemic Toxicity (LAST) is a serious condition that can occur when local anesthetics enter the systemic circulation, leading to potential neurological and cardiovascular complications. The hallmark signs and symptoms of LAST primarily affect the central nervous system and can include neurological manifestations such as a metallic taste, tinnitus (ringing in the ears), and changes in vision, among others. The presence of a metallic taste indicates alterations in sensory perception, which can occur as the toxicity affects neurotransmitter functions and nerve signal transmission. Tinnitus is another classic symptom linked to CNS involvement, suggesting that the inner ear or auditory pathways are being impacted by the toxic effects of the anesthetics. Vision changes could include blurred vision or even visual disturbances like diplopia, which further highlight the neuromuscular interference caused by elevated levels of local anesthetics in the blood. Understanding these symptoms is critical for prompt recognition of LAST, enabling timely intervention to prevent more severe complications such as seizures or cardiovascular collapse. The other symptoms listed in the different options may stem from various conditions or complications, but they are not specifically indicative of LAST in the same direct manner as the symptoms highlighted in the correct choice.