Which of the following is the most characteristic finding in the lungs of a victim who died from freshwater drowning?

Explanation

## Pathophysiology of Freshwater Drowning **Key Point:** Freshwater drowning results in characteristic pulmonary edema with frothy, foam-like fluid in the airways and lungs. ### Mechanism Freshwater is hypotonic relative to blood. When aspirated: 1. Water crosses the alveolar-capillary membrane into the bloodstream 2. This causes pulmonary edema and foam formation in the airways 3. The foam is often blood-stained, giving a characteristic "pink frothy fluid" appearance 4. Surfactant is disrupted, leading to alveolar collapse ### Distinguishing Features: Freshwater vs. Saltwater Drowning | Feature | Freshwater | Saltwater | |---------|-----------|----------| | Fluid type | Hypotonic | Hypertonic | | Lung finding | Pulmonary edema, frothy fluid | Pulmonary edema, less foam | | Blood effect | Hemodilution, hemolysis | Hemoconcentration | | Mechanism | Water enters bloodstream | Water leaves bloodstream | | Cardiac arrhythmia | Ventricular fibrillation (VF) | Asystole | **High-Yield:** The **pink frothy fluid** (pulmonary edema with foam) is the hallmark autopsy finding in freshwater drowning and is highly specific for this cause of death. **Clinical Pearl:** This frothy fluid may overflow from the mouth and nostrils, creating a characteristic appearance at the scene that aids in preliminary diagnosis.