Sepsis Overview and Pathophysiology

Definition and Overview

• Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection.
• It's characterized by systemic inflammatory response syndrome (SIRS) and the presence of a confirmed or suspected infection.
• The initial response is often triggered by bacteria, viruses, fungi, or parasites.
• The body's immune system initially attempts to fight the infection, triggering inflammation throughout the body.
• However, in sepsis, this inflammatory response becomes excessive and harmful, damaging tissues and organs.

Pathophysiology

• The dysregulated immune response involves a complex interplay of inflammatory mediators and mediators of coagulation and the complement system.
• Sepsis progression involves a cascade of events, such as the release of cytokines.
• These excessive inflammatory mediators cause widespread vasodilation, leading to reduced blood pressure and tissue hypoperfusion.
• Microvascular thrombosis contributes to organ dysfunction as blood flow to organs diminishes.
• Metabolic abnormalities and alterations in cellular function are observed in sepsis.

Risk Factors

• Underlying conditions like diabetes, chronic kidney disease, and cancer make individuals susceptible to sepsis.
• Compromised immune systems, such as those receiving immunosuppressive therapy, increase the risk.
• Elderly individuals and neonates are also at higher risk due to their anatomical and physiological vulnerabilities.
• Certain medical procedures, notably invasive ones, raise the risk, as these create pathways for microbial invasion.
• Patients with severe infections, including pneumonia, urinary tract infections, and bloodstream infections, are at a heightened risk of developing sepsis.

Clinical Presentation

• Early signs of sepsis may be nonspecific, including fever, chills, rapid heart rate, rapid breathing, and altered mental status.
• Patients may exhibit signs of decreased blood pressure or low blood volume, suggesting hypoperfusion.
• Severe sepsis and septic shock are characterized by more profound organ dysfunction, including low blood pressure that doesn't respond to fluid resuscitation.
• Septic shock is a severe form of sepsis marked by decreased blood pressure despite adequate fluid resuscitation.
• There may be neurological, mental, or cardiovascular impairments.
• Organ dysfunction, such as kidney failure, respiratory distress syndrome, and liver failure, can occur.

Diagnosis

• Diagnosis relies on evaluating clinical signs, laboratory findings, and suspected infection source.
• A combination of clinical judgment, including vital signs and physical examination, alongside laboratory tests (including blood cultures, complete blood count, and inflammatory markers like C-reactive protein and procalcitonin), is necessary.
• Cultures to identify the causative organism are critical for appropriate treatment.

Treatment

• Early, aggressive treatment of the infection via antibiotics is crucial.
• Fluid resuscitation is often needed to restore and maintain blood pressure.
• Vasopressors may be necessary to maintain blood pressure in patients with septic shock.
• Supportive care, including respiratory support and oxygen therapy, is generally required.
• Other critical care interventions may be necessary to manage specific complications.

Complications

• Septic shock and multi-organ dysfunction syndrome (MODS) are severe consequences.
• Long-term complications can include chronic organ damage and disability.
• Increased risk of death is associated with sepsis and septic shock. Mortality rates vary by age group, stage, and comorbidities.
• Sepsis-related post-intensive care syndrome (PICS) can affect survivors, leading to neurological, cognitive, and physical impairments.

Prevention

• Prevention strategies are often focused on infection control.
• Vaccinations to reduce the risk of acquiring infections can be valuable.
• Prompt diagnosis and treatment of infections are essential to prevent progression to sepsis.
• Maintaining good hygiene practices can contribute to risk mitigation.