Which agent class is associated with rapid onset of dizziness, weakness, and seizures due to impairment of cellular oxygen use?

• A. Vesicants
• B. Blood agents
• C. Pulmonary agents
• D. Biological agents

Answer: (B)

Blood agents disrupt the body's ability to use oxygen at the cellular level. They block a key enzyme in the mitochondrial electron transport chain, most notably cytochrome oxidase, so oxygen cannot be translated into energy. As a result, cells experience hypoxia even though the lungs are delivering oxygen, leading to rapid neurologic symptoms like dizziness, weakness, and seizures as the brain and muscles are starved for energy. Metabolic changes, such as lactic acidosis from a shift to anaerobic metabolism, contribute to the fast decline. The quick onset reflects the systemic and immediate impact on cellular respiration.

Other agent classes cause different effects — vesicants damage skin and mucous membranes; pulmonary agents irritate the airways and lungs; biological agents involve infection with variable and often delayed symptoms. The rapid, systemic neurologic signs point to a blood agent that blocks cellular oxygen use.