Sepsis & Septic Shock - Symptoms, Pathophysiology, Diagnosis, Treatment
Sepsis is a medical emergency and a major global health concern. It is the body’s life-threatening response to infection that can lead to tissue damage, organ failure, and death if not recognized and treated promptly.
- Clinical Scenario Example
A dysregulated host response to infection that leads to life-threatening organ dysfunction.
- According to the Sepsis-3 Consensus (2016):
- Sepsis = infection + acute increase in SOFA score ≥ 2.
- Septic shock is a subset of sepsis with circulatory, cellular, and metabolic abnormalities associated with a higher risk of mortality (persistent hypotension requiring vasopressors despite fluids + elevated lactate >2 mmol/L).
Sepsis develops from a cascade of immune and inflammatory responses:
- Infection triggers the immune system (bacteria, virus, fungi, parasites).
- Cytokine storm: pro-inflammatory mediators (TNF-α, IL-1, IL-6) are released excessively.
- Endothelial dysfunction: capillary leakage, vasodilation, microvascular thrombosis.
- Imbalance: pro-inflammatory vs anti-inflammatory mechanisms → immune dysregulation.
- Organ dysfunction: reduced tissue perfusion, mitochondrial dysfunction → multi-organ failure.
Sepsis can be caused by a wide range of infections. Common sources:
- Respiratory tract – pneumonia (most common cause)
- Urinary tract – urosepsis, pyelonephritis
- Abdominal – peritonitis, intra-abdominal abscess
- Skin/soft tissue – cellulitis, necrotizing fasciitis
- Bloodstream – catheter-related infections, endocarditis
- Post-surgical/wound infections
Risk factors: elderly, neonates, immunocompromised, diabetics, cancer patients, ICU patients.
Signs and symptoms vary but often include:
- General: fever, chills, rigors, sweating
- Circulatory: tachycardia, hypotension, cold extremities
- Respiratory: tachypnea, hypoxia
- Neurological: confusion, delirium, reduced consciousness
- Renal: decreased urine output
- Metabolic: high lactate, metabolic acidosis
Two main scoring systems are widely used:
- qSOFA (Quick SOFA) – bedside tool (≥ 2 suggests poor outcome):
- Respiratory rate ≥ 22/min
- SOFA (Sequential Organ Failure Assessment) – detailed ICU score including:
- PaO₂/FiO₂ ratio (respiratory function)
- Platelet count (coagulation)
- Bilirubin (liver function)
- Mean arterial pressure/vasopressors (circulation)
- Creatinine/urine output (renal)
Management of sepsis follows the “Sepsis Bundle” approach (within 1–6 hours):
- Early recognition – high index of suspicion in any suspected infection + organ dysfunction.
- Blood cultures before antibiotics
- CBC, renal, liver function, coagulation profile
- Imaging for infection source
- IV fluids (30 ml/kg crystalloid within 3 hrs if hypotension or lactate ≥ 4)
- Broad-spectrum IV antibiotics within 1 hour of recognition
- Drain abscess, remove infected catheter, surgery if required
- Vasopressors (norepinephrine is first choice) if hypotension persists after fluids
- Monitoring & supportive care
- Organ support (dialysis, ventilator if needed)
Clinical Scenario Example
A 68-year-old diabetic woman presents with fever, confusion, and shortness of breath.
- Vitals: BP 85/55 mmHg, HR 120/min, RR 28/min, Temp 39.5°C.
- Labs: WBC 18,000, lactate 4.5 mmol/L, creatinine 2.0 mg/dL.
- Chest X-ray: right lower lobe pneumonia.
- Organ dysfunction: confusion, renal impairment, high lactate
- Meets sepsis criteria (SOFA ≥ 2).
- Persistent hypotension + lactate > 2 despite fluids = septic shock.
- Broad-spectrum IV antibiotics within 1 hour
- Blood cultures before antibiotics
- Admission to ICU + vasopressors started
Outcome depends on early recognition and aggressive treatment.
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