What are the requirements for an individual, particularly the elderly, infants, or those with compromised immune systems due to chronic conditions (e.g. diabetes, cancer, HIV/AIDS) or immunosuppressive therapy, to be at risk of developing sepsis?

Diagnostic Criteria for Sepsis

Sepsis is diagnosed when a patient has a proven or highly suspected infection PLUS evidence of life-threatening organ dysfunction, defined as an acute increase in Sequential Organ Failure Assessment (SOFA) score of 2 points or more. 1

Core Diagnostic Requirements

Infection Component

• Proven or highly suspected infection from any source (bacterial, viral, or fungal) 1
• Most common sites include: lungs (pneumonia), abdomen, bloodstream (catheter-associated), and urinary tract 2

Organ Dysfunction Component (≥2 SOFA points)

The patient must demonstrate at least 2 points increase in SOFA score, which can manifest through any of the following organ systems 1:

Cardiovascular Dysfunction

• Systolic blood pressure ≤90 mmHg, mean arterial pressure ≤70 mmHg, or systolic blood pressure decrease ≥40 mmHg from baseline 1
• Need for vasopressors to maintain mean arterial pressure ≥65 mmHg 1, 3

Respiratory Dysfunction

• PaO₂/FiO₂ ratio ≤300 1
• SpO₂ ≤90% with or without supplemental oxygen 1
• Respiratory rate ≥22 breaths/minute 1

Renal Dysfunction

• Acute oliguria (urine output ≤0.5 mL/kg/h for at least 2 hours despite adequate fluid resuscitation) 1
• Creatinine increase ≥0.5 mg/dL or ≥44.2 µmol/L 1

Hepatic Dysfunction

• Hyperbilirubinemia (total bilirubin ≥4 mg/dL or ≥70 µmol/L) 1
• Clinical jaundice 1

Coagulation Dysfunction

• Thrombocytopenia (platelet count ≤100,000/µL) 1
• INR ≥1.5 or PTT ≥60 seconds 1
• Petechiae, ecchymoses, or bleeding from puncture sites 1

Neurological Dysfunction

• Glasgow Coma Scale score ≤13 1
• Altered mental status, confusion, or disorientation 1

Gastrointestinal Dysfunction

• Ileus (absent bowel sounds) 1

Simplified Bedside Screening (qSOFA)

For rapid identification outside intensive care settings, patients with suspected infection who have ≥2 of the following qSOFA criteria should be evaluated for sepsis 1:

• Respiratory rate ≥22/minute 1
• Altered mentation (Glasgow Coma Scale ≤13) 1
• Systolic blood pressure ≤100 mmHg 1

Septic Shock Definition

Septic shock is identified when a patient with sepsis requires vasopressors to maintain mean arterial pressure ≥65 mmHg AND has serum lactate >2 mmol/L (>18 mg/dL) despite adequate fluid resuscitation. 1 This subset carries significantly higher mortality risk 1.

Resource-Limited Settings Criteria

When laboratory testing is unavailable, sepsis can be diagnosed with proven/suspected infection plus ≥2 of the following 1:

• Heart rate ≥90 bpm 1
• Respiratory rate ≥20 bpm 1
• Temperature ≤36°C or ≥38°C 1
• Malaise and/or apathy 1

High-Risk Populations Requiring Lower Threshold for Diagnosis

Certain patient groups warrant heightened suspicion and earlier intervention 1, 4, 5:

• Immunocompromised patients: those with hematologic malignancies, prior chemotherapy, HIV/AIDS, or on corticosteroids/immunosuppressive therapy 1, 4, 5
• Elderly patients (>70 years) 1
• Infants and neonates 6
• Patients with chronic conditions: diabetes, cancer, chronic organ dysfunction (liver/renal failure) 1
• Patients with invasive devices: central venous catheters, urinary catheters 1, 5
• Neutropenic patients 1

Critical Pitfalls to Avoid

• Do not wait for positive blood cultures to diagnose sepsis—up to 42% of sepsis cases are culture-negative 6
• Do not require all SIRS criteria (fever, tachycardia, tachypnea, leukocytosis)—the Sepsis-3 definition eliminated SIRS as a requirement 1, 7
• Do not dismiss sepsis in patients with attenuated responses—elderly patients and those on immunosuppressive therapy may present with fewer classic signs 1
• Recognize that "severe sepsis" is no longer a valid term—the current framework uses only "sepsis" and "septic shock" 1, 7