Neurotrophic or Neurotoxic Disease

Central nervous system toxicity from local anesthetics is a biphasic process characterized initially by excitatory effects, including perioral numbness, visual disturbances, and lowered seizure threshold, progressing to depression with drowsiness, unconsciousness, and potentially coma or cardiac arrest. This toxicity is influenced by the drug's lipid solubility and protein-binding capacity, with symptoms arising from disruption of inhibitory neuronal activity. Early signs such as paresthesia and visual changes warrant immediate cessation of the procedure and preparation for potential seizures, managed with 100% oxygen, benzodiazepines, and airway support. Cardiac toxicity typically occurs at higher systemic concentrations and is particularly concerning with bupivacaine due to its high affinity for Purkinje fibers, leading to refractory arrhythmias like ventricular fibrillation, necessitating strict avoidance of intravascular injection. Neurotrophic factors are essential for neuronal growth, survival, and differentiation, supporting neural network formation and embryonic development, though they are not directly related to anesthetic toxicity.