Sepsis and septic shock

Pathophysiology & Definitions - The Body's Overreaction

• Sepsis: Life-threatening organ dysfunction due to a dysregulated host response to infection. Essentially, the body's response to an infection damages its own tissues.
• Septic Shock: A subset of sepsis with profound circulatory, cellular, and metabolic abnormalities, associated with a greater risk of mortality.
  • Criteria: Persistent hypotension requiring vasopressors to maintain MAP ≥65 mmHg AND serum lactate >2 mmol/L despite adequate fluid resuscitation.

⭐ Even in patients who are not hypotensive, a serum lactate level >2 mmol/L suggests occult hypoperfusion (cryptic shock) and is a key diagnostic and prognostic marker.

Diagnosis & Workup - Spotting the Signs

• Initial Assessment: Secure Airway, Breathing, Circulation (ABCs).
• Bedside Screening (qSOFA): For non-ICU patients with suspected infection. Score ≥ 2 suggests organ dysfunction.
  • Respiratory Rate ≥ 22/min
  • Altered Mental Status (GCS < 15)
  • Systolic BP ≤ 100 mmHg
• Sepsis Diagnosis: Confirmed by suspected infection + an acute SOFA score increase of ≥ 2 points.
• Septic Shock: Sepsis with persistent hypotension requiring vasopressors to maintain MAP ≥ 65 mmHg AND serum lactate > 2 mmol/L despite adequate fluid resuscitation.
• Core Workup:
  • Labs: Lactate, CBC, CMP, coags, CRP, procalcitonin.
  • Cultures: Two sets (aerobic/anaerobic) from separate sites before antibiotics.

⭐ Obtain blood cultures before starting antibiotics, but never delay antimicrobial therapy if sample collection is prolonged.

Management - Hour-1 Protocol

• "Surviving Sepsis Campaign: Hour-1 Bundle" - immediate, life-saving interventions.
• Measure lactate level: Remeasure if initial lactate is > 2 mmol/L.
• Obtain blood cultures: Crucial before administering antibiotics.
• Administer broad-spectrum antibiotics: Within the first hour of recognition.
• Rapid fluid resuscitation: Administer 30 mL/kg IV crystalloid for hypotension or lactate ≥ 4 mmol/L.
• Apply vasopressors: If hypotension persists during or after fluids, to maintain Mean Arterial Pressure (MAP) ≥ 65 mmHg.
  • Target MAP: $MAP \approx (2 \times DBP + SBP) / 3$

⭐ Exam Favorite: For every hour delay in administering antibiotics in septic shock, mortality increases by approximately 7.6%. Early source control and antibiotics are paramount.

High‑Yield Points - ⚡ Biggest Takeaways

• Sepsis is life-threatening organ dysfunction (↑ SOFA ≥2) from a dysregulated host response to infection. Use qSOFA (AMS, RR ≥22, SBP ≤100) for rapid screening.
• Septic shock is sepsis with persistent hypotension requiring vasopressors to maintain MAP ≥65 mmHg and a serum lactate >2 mmol/L despite adequate fluid resuscitation.
• Key interventions include broad-spectrum antibiotics within 1 hour and 30 mL/kg IV crystalloid for hypotension.
• Norepinephrine is the first-line vasopressor.
• Obtain blood cultures before antibiotics and aggressively pursue source control.