Which of the following is an example of primary MODS?

• A. Pulmonary contusion from steering wheel collision
• B. Renal failure following trauma
• C. Sepsis-induced MODS
• D. An isolated liver injury with no systemic response

Answer: (A)

Primary MODS occurs when organ dysfunction starts directly from the initial injury to a specific organ, before a broader systemic inflammatory response has developed. Pulmonary contusion from blunt chest trauma directly injures the lungs, disrupts gas exchange, and can trigger inflammation that contributes to dysfunction—this is an example of a problem that begins with the local injury, fitting the idea of primary MODS. In contrast, renal failure after trauma usually results from systemic factors like shock, hypoperfusion, or infection that arise after the initial injury, which characterizes secondary MODS. Sepsis-induced MODS is driven by infection and the ensuing systemic inflammatory response, also a secondary process. An isolated liver injury with no systemic response would not constitute MODS, since MODS implies dysfunction involving multiple systems or a systemic cascade. Therefore, the pulmonary contusion best represents primary MODS.