3.13 - Sepsis and Septic Shock

Sepsis is not simply infection, but rather the body's dysregulated response to infection that causes life-threatening organ dysfunction.

sepsis vs septic shock

• sepsis — life-threatening organ dysfunction caused by dysregulated host response to infection

• septic shock — sepsis needing vasopressors to keep mean arterial pressure at 65 mmHg or more, with lactate above 2 mmol/L despite fluids

  • hypotension and metabolic dysfunction persist

• qSOFA is a bedside screen, where a score of 2 or more is a warning

  1. respiratory rate ≥ 22/min

  2. altered mental state

  3. systolic BP ≤ 100 mmHg

how infection causes septic shock

septic shock results in low pressure + leaky vessels + blocked microcirculation all at once, which contributes to organ failure

1. microbial products trigger innate immunity

   • PAMPs activate pattern-recognition receptors (TLRs)

   • inflammatory mediators released

     • TNF, IL-1, complement, prostaglandins flood circulation

2. endothelial activation

   • vasodilation → decreased systemic vascular resistance leads to hypotension

   • increased permeability → fluid leaks from vessels to cause edema and decreased effective circulating volume

   • prothrombic shift → endothelium becomes procoagulant

     • microthrombi cause impaired microvascular perfusion and potentially DIC

3. cardiac depression

   • inflammatory cytokines reduce myocardial contractility

metabolic and immune changes in sepsis

sepsis results in hyperinflammation + subsequent immune suppression

• metabolic changes → insulin resistance and high glucose

  • high glucose impairs neutrophils and worsens infection control

  • early cortisol surge, with possible later adrenal insufficiency

  • Waterhouse-Friderichsen syndrome — meningococcal infection + DIC

    • causes adrenal hemorrhage

• immune suppression → anti-inflammatory counter-response overshoots

  • lymphocytes die in spleen and lymph nodes

  • surviving lymphocytes vulnerable to secondary infection

• organ dysfunction follows acute respiratory distress syndrome, acute kidney injury, liver dysfunction, and confusion

treatment principles in sepsis

every hour of delay in antibiotics for septic shock raises mortality

1. obtain blood cultures and prescribe antibiotics as early as possible, with attempt to remove the source

   • drain abscess, extract tooth

2. IV fluids with vasopressors (NE) if BP stays low

3. support failing organs, providing corticosteroids for refractory shock

odontogenic sepsis

dental infection can progress into systemic disease

• examples — spreading cellulitis, Ludwig’s angina

• watch for red flags → same-day hospital referral or EMS, prioritizing airway first

  • fever with fast pulse and fast breathing, confusion, low BP

  • trismus, difficulty swallowing or breathing, floor-of-mouth swelling

  • immunosuppressed, diabetic, or elderly patients may not mount a fever

    • absence of fever does not rule out serious infection or sepsis