Surgical Significance and Immune Response Quiz

Study Notes

Systemic response is essential for recovery in surgery, akin to managing a car's speed.
Inflammatory response plays a critical role in addressing infections, trauma, and burns during surgery.
Sepsis can be diagnosed even without positive cultures if signs and symptoms are present.

Damage-Associated Molecular Patterns (DAMPs) are released after tissue injury, initiating a sterile inflammatory response.
Types of DAMPs include:
- High Mobility Group Protein B1 (HMGB1): released within 30 minutes of trauma, best characterized DAMP.
- Mitochondrial DNA (mtDNA): triggers inflammatory responses associated with necrosis.
- C-reactive Protein (CRP): a marker of pro-inflammatory response, synthesized in response to IL-6.
- F-actin: indicates cell damage recognized by the immune system.

PAMPs, alongside DAMPs, interact with cell receptors to activate the immune system.
Examples include:
- Endotoxin: released by bacteria upon cell destruction.
- Flagellin: activates a broad range of immune cells.
- dsRNA: derived from viral infections.

Initial immune response stimuli can arise from both PAMPs in infections and DAMPs in trauma.
The immune response can lead to several outcomes:
- Immunoparesis, which paralysis the immune system during sepsis.
- Endothelial and organ damage due to trauma can result in coagulation and further tissue damage, which release more DAMPs.

SIRS is characterized by fulfilling at least two of the following criteria:
- Elevated or decreased body temperature.
- Increased heart rate (≥ 90 bpm).
- Increased respiratory rate (≥ 20 breaths/min).
- Decreased arterial carbon dioxide (PaCO2 ≤ 32 mmHg).
- Abnormal white blood cell count.
Sepsis is diagnosed when SIRS is present alongside an identifiable source of infection.
Severe sepsis involves sepsis with associated organ dysfunction, indicating a critical condition.