Which of the following is considered an extra pulmonary cause of ARDS?

Acute Respiratory Distress Syndrome (ARDS) can arise from a variety of causes, which are typically categorized into pulmonary and extra pulmonary causes. An extra pulmonary cause refers to conditions that lead to ARDS without involving direct damage to the lung parenchyma.

Drug overdose is classified as an extra pulmonary cause of ARDS because it typically leads to respiratory distress due to systemic factors such as sedation, respiratory muscle depression, or metabolic disturbances rather than direct lung injury. Substances like opioids or barbiturates can severely impair the central nervous system's ability to regulate breathing, which in turn affects gas exchange and contributes to the development of ARDS.

In contrast, pneumonia, aspiration, and pulmonary contusion are examples of pulmonary causes of ARDS. These conditions directly affect lung tissue, causing inflammation and fluid accumulation in the alveoli, which fundamentally disrupts normal gas exchange and leads to the clinical picture associated with ARDS. By understanding these distinctions, it's clear how different underlying mechanisms contribute to the pathophysiology of ARDS.