A 35-year-old man is admitted to the burns unit with thermal injuries sustained in a domestic accident. Which is the most common cause of death in acute thermal injuries within the first 48 hours?

Explanation

## Most Common Cause of Early Burn Death **Key Point:** Hypovolemic shock from massive fluid loss is the leading cause of death in the acute phase (first 48 hours) of severe thermal injury. ### Pathophysiology Severe burns cause: 1. Increased capillary permeability due to release of inflammatory mediators (histamine, bradykinin, leukotrienes) 2. Massive fluid shift from intravascular to interstitial space (third-spacing) 3. Protein loss and colloid osmotic pressure drop 4. Profound hypovolemia if fluid resuscitation is inadequate ### Timeline of Burn Mortality | Time Period | Primary Cause of Death | Mechanism | |---|---|---| | 0–48 hours (Acute phase) | **Hypovolemic shock** | Fluid loss, inadequate resuscitation | | 2–7 days | Inhalation injury, respiratory failure | Airway edema, carbon monoxide, cyanide | | >7 days | Sepsis, multi-organ failure | Infection, immunosuppression, ARDS | **High-Yield:** The Parkland formula (4 mL × body weight in kg × %TBSA burned over 24 hours) was developed specifically to prevent early hypovolemic shock in burns. **Clinical Pearl:** Fluid resuscitation must begin immediately in burns >15% TBSA in adults (>10% in children) to prevent irreversible shock and organ failure. ## Why Inhalation Injury Is Not the Most Common Early Cause While inhalation injury is a major contributor to mortality in burns, it typically becomes the dominant cause of death in the **2–7 day window** (when airway edema peaks and respiratory complications develop). In the **first 48 hours**, hypovolemic shock is more immediately lethal if resuscitation is inadequate. [cite:Parikh Textbook of Forensic Medicine Ch 19]