What is the appropriate diagnosis for a patient with a urinary tract infection, fever, dysuria, flank pain, positive urine culture and organ dysfunction meeting a Sequential Organ Failure Assessment (SOFA) increase ≥2 (or quick Sequential Organ Failure Assessment (qSOFA) ≥2)?

Urosepsis

In a patient with urinary tract infection, fever, dysuria, flank pain, positive urine culture, and organ dysfunction meeting SOFA increase ≥2 (or qSOFA ≥2), the appropriate diagnosis is urosepsis—defined as life-threatening organ dysfunction caused by a dysregulated host response to urinary tract infection.

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Diagnostic Framework

Core Definition of Sepsis (Sepsis-3 Criteria)

• Sepsis is defined as life-threatening organ dysfunction resulting from a dysregulated host response to infection, operationalized by an acute increase in the Sequential Organ Failure Assessment (SOFA) score of ≥2 points, which correlates with in-hospital mortality >10%. 1, 2, 3

• The term "severe sepsis" is now obsolete and should not be used; all sepsis by definition represents organ dysfunction. 2

• When the infection source is the urinary tract (confirmed by positive urine culture, pyuria, and urinary symptoms such as dysuria, fever, or flank pain), the diagnosis is urosepsis. 1, 4

SOFA Score Components (0–4 points per organ system)

• Respiratory: PaO₂/FiO₂ <400 = 1 point; <300 = 2 points; <200 with mechanical ventilation = 3 points; <100 with mechanical ventilation = 4 points. 2

• Cardiovascular: MAP <70 mmHg = 1 point; dopamine ≤5 or any dobutamine = 2 points; dopamine >5 OR epinephrine/norepinephrine ≤0.1 µg/kg/min = 3 points; dopamine >15 OR epinephrine/norepinephrine >0.1 µg/kg/min = 4 points. 2

• Hepatic: Bilirubin 1.2–1.9 mg/dL = 1 point; 2.0–5.9 = 2 points; 6.0–11.9 = 3 points; ≥12.0 = 4 points. 2

• Coagulation: Platelets <150,000/µL = 1 point; <100,000 = 2 points; <50,000 = 3 points; <20,000 = 4 points. 2

• Renal: Creatinine 1.2–1.9 mg/dL = 1 point; 2.0–3.4 = 2 points; 3.5–4.9 or urine output <500 mL/day = 3 points; ≥5.0 or urine output <200 mL/day = 4 points. 2

• Neurological: Glasgow Coma Scale 13–14 = 1 point; 10–12 = 2 points; 6–9 = 3 points; <6 = 4 points. 2

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Quick SOFA (qSOFA) for Rapid Bedside Screening

qSOFA Criteria (1 point each; ≥2 = high risk)

• Respiratory rate ≥22 breaths/min 2, 5, 3

• Altered mental status (Glasgow Coma Scale <15) 2, 3

• Systolic blood pressure ≤100 mmHg 2, 5, 3

Clinical Utility and Limitations

• qSOFA ≥2 identifies patients with suspected infection who have >10% in-hospital mortality risk and require immediate full SOFA assessment, ICU-level monitoring, and urgent source control. 2, 3

• qSOFA has higher sensitivity for early identification of at-risk patients compared to the traditional hypotension threshold of SBP <90 mmHg, allowing earlier intervention. 5

• However, qSOFA has lower sensitivity than NEWS2 for initial screening; the 2024 NICE guideline recommends NEWS2 over qSOFA for bedside risk stratification in emergency and acute-care settings. 2

• A significant proportion (57%) of patients meeting older septic shock criteria (SBP <90 mmHg after fluids + SIRS) do not meet Sepsis-3 criteria, yet still demonstrate 14% mortality and significant organ failure, underscoring that qSOFA should not be the sole screening tool. 6

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Septic Shock Criteria (Subset of Sepsis)

• Septic shock is defined as sepsis with persistent hypotension requiring vasopressors to maintain MAP ≥65 mmHg AND serum lactate >2 mmol/L despite adequate volume resuscitation; this combination is associated with >40% hospital mortality. 1, 2, 3

• Lactate must be measured after initial fluid resuscitation (not before) to accurately identify septic shock; patients whose lactate normalizes after fluids (<2 mmol/L) have significantly lower mortality (8.2% vs 25.5%) and should not be classified as septic shock. 7

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Diagnostic Algorithm for Urosepsis

Step 1: Confirm Urinary Tract Infection

• Both pyuria (≥10 WBC/HPF or positive leukocyte esterase) AND acute urinary symptoms (dysuria, frequency, urgency, fever >38.3°C, flank pain, or gross hematuria) must be present. 1, 4

• Obtain urine culture with susceptibility testing before antibiotics; a single predominant uropathogen at ≥10⁵ CFU/mL (or ≥10⁴ CFU/mL in catheterized specimens) confirms infection. 1, 4

• Flank pain or costovertebral angle tenderness indicates upper-tract involvement (pyelonephritis), which increases sepsis risk. 1, 4

Step 2: Calculate qSOFA at Bedside

• If qSOFA ≥2, immediately proceed to full SOFA assessment and initiate sepsis management protocols. 2, 3

• If qSOFA <2 but clinical suspicion remains high (e.g., immunocompromised, elderly, diabetic), calculate full SOFA score anyway. 2

Step 3: Calculate Full SOFA Score

• Baseline SOFA is assumed to be zero unless chronic organ dysfunction is documented; an acute increase of ≥2 points confirms sepsis. 2, 3

• Serial SOFA scores every 48–72 hours track trajectory; worsening scores indicate poor prognosis and need for escalation. 2

Step 4: Assess for Septic Shock

• Check if vasopressors are required to maintain MAP ≥65 mmHg despite adequate fluid resuscitation (typically 30 mL/kg crystalloid). 2, 3

• Measure serum lactate after fluids; if >2 mmol/L while on vasopressors, diagnose septic shock. 2, 7, 3

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Special Considerations

Sepsis-Induced Coagulopathy (SIC)

• Calculate SIC score (platelet count + PT ratio + SOFA score) in patients with thrombocytopenia; SIC score ≥4 identifies coagulopathy requiring specific interventions and predicts 32.5–37.2% mortality. 2

• SIC has 95.7% negative predictive value for overt disseminated intravascular coagulation (DIC) and allows earlier detection than traditional DIC criteria. 2

Catheter-Associated UTI (CA-UTI)

• CA-UTI is the leading cause of secondary healthcare-associated bacteremia, with approximately 20% of hospital-acquired bacteremias arising from the urinary tract and 10% mortality. 1

• In catheterized patients, asymptomatic bacteriuria and pyuria are nearly universal; testing and treatment are warranted only when systemic signs (fever, hypotension, rigors, suspected urosepsis) are present. 1, 4

• Replace the indwelling catheter before obtaining a urine specimen if urosepsis is suspected or if the catheter has been in place >2 weeks. 4

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Common Pitfalls to Avoid

• Do not delay sepsis recognition by waiting for full SOFA calculation; qSOFA ≥2 should trigger immediate action. 2, 3

• Do not diagnose septic shock based on hypotension alone; lactate >2 mmol/L after fluids is required. 7, 3

• Do not treat asymptomatic bacteriuria (bacteria + pyuria without symptoms) even in the presence of organ dysfunction from another cause; this does not represent urosepsis. 1, 4

• Do not assume all patients with old septic shock criteria (SBP <90 mmHg + SIRS) meet Sepsis-3 definitions; 57% do not, yet still have 14% mortality and require aggressive management. 6

• Do not use qSOFA as the sole screening tool in emergency departments; NEWS2 has superior sensitivity for initial risk stratification. 2