What are the characteristic findings on cut section of lungs in drowning?

Characteristic Findings on Cut Section of Lungs in Drowning

The lungs in drowning victims typically appear voluminous, heavy, edematous, and congested on cut section, with frothy fluid exuding from the airways and parenchyma.

Pathophysiological Changes in Drowning

Drowning is defined as "a process resulting in primary respiratory impairment from submersion/immersion in a liquid medium" 1. This process involves a sequence of physiological changes that directly affect lung tissue and can be observed on cut section:

Primary Pathological Features

1. Pulmonary Edema

   • Heavy, waterlogged appearance of lung tissue
   • Frothy, sometimes blood-tinged fluid exuding from cut surfaces
   • Result of increased capillary-alveolar permeability and surfactant washout 2

2. Emphysematous Changes

   • Overinflated appearance in some areas
   • Alternating with areas of atelectasis (collapsed alveoli)
   • Creates a characteristic mottled appearance

3. Congestion

   • Prominent vascular engorgement
   • Dark red to purple discoloration of lung parenchyma
   • Reflects the hypoxic damage to pulmonary vasculature

4. Alveolar Damage

   • Disruption of alveolar architecture
   • Presence of inflammatory cells
   • Evidence of surfactant destruction 3

Differences Based on Drowning Medium

While the 2003 Utstein guidelines note that both salt and fresh water drowning cause similar pathology 1, some subtle differences may be observed:

Fresh Water Drowning

• More pronounced alveolar distension
• Greater destruction of surfactant
• Potentially more severe pulmonary edema
• Possible hemolysis in alveolar capillaries 4

Salt Water Drowning

• More prominent inflammatory exudate
• Potentially more protein-rich edema fluid
• Greater tendency toward atelectasis
• More pronounced interstitial edema 4

Microscopic Findings

While not directly visible on gross cut section, these microscopic changes contribute to the macroscopic appearance:

• Destruction of alveolar epithelium
• Loss of surfactant-producing cells
• Inflammatory cell infiltration
• Hyaline membrane formation in prolonged cases
• Atelectasis alternating with hyperinflation 2, 3

Time-Dependent Changes

The appearance of lungs on cut section may vary depending on:

1. Duration of submersion

   • Longer submersion typically results in more severe changes
   • The Utstein guidelines note that submersion duration is the most important predictor of outcome 1

2. Survival time after rescue

   • "Secondary drowning" can develop hours after the initial event
   • Progressive worsening of pulmonary edema may occur 5

3. Resuscitation efforts

   • Mechanical ventilation can alter the appearance
   • Barotrauma from resuscitation may cause additional changes

Clinical Correlations

These pathological findings correlate with clinical manifestations:

• Decreased lung compliance
• Increased right-to-left shunting
• Ventilation-perfusion mismatch
• Noncardiogenic pulmonary edema 2

Common Pitfalls in Interpretation

• Confusing drowning-related changes with those of decomposition in postmortem examinations
• Failing to distinguish between drowning-related edema and cardiogenic pulmonary edema
• Not accounting for the effects of resuscitation efforts on lung appearance
• Overlooking the possibility of pre-existing lung disease

The characteristic findings on cut section of lungs in drowning reflect the pathophysiological sequence of submersion, aspiration, surfactant destruction, and inflammatory response, creating a distinctive pattern that aids in forensic and clinical diagnosis.