What is urosepsis, particularly in older adults or individuals with underlying medical conditions or compromised immune systems?

What is Urosepsis

Urosepsis is sepsis caused by an infection originating from the urogenital tract, characterized by life-threatening organ dysfunction resulting from a dysregulated host response to urinary tract infection. 1

Core Clinical Definition

Urosepsis follows the Sepsis-3 consensus criteria, which defines it as life-threatening organ dysfunction caused by a dysregulated host response to infection originating from the urinary tract. 1 The condition accounts for approximately 25% of all sepsis cases and represents the infection source in 10-30% of severe sepsis or septic shock cases. 2, 3

Organ dysfunction is clinically indicated by an increase in Sequential Organ Failure Assessment (SOFA) score of 2 points or more. 1

Pathophysiology and Origin

The underlying urinary tract infection in urosepsis is almost exclusively a complicated UTI with involvement of parenchymatous urogenital organs, particularly:

• Kidneys (pyelonephritis) 2, 4
• Prostate (prostatitis) 2, 4

Urosepsis is mainly a result of obstructed uropathy of the upper urinary tract, with ureterolithiasis being the most common cause. 3 The severity of sepsis depends mostly upon the host response rather than the pathogen itself. 2, 4

Clinical Recognition Criteria

Quick SOFA (qSOFA) Score

The qSOFA score has replaced SIRS criteria for rapid identification and includes three parameters: 1

• Respiratory rate ≥22 breaths/min
• Altered mental status
• Systolic blood pressure ≤100 mmHg

The presence of two or more qSOFA criteria should trigger immediate concern for sepsis. 1

Clinical Presentation in Older Adults

In long-term care facility residents and older adults, urosepsis presents with specific features: 5

• High fever
• Shaking chills
• Hypotension
• Delirium or altered mental status
• Recent catheter obstruction or change (in catheterized patients)

Symptomatic UTI may also present as fever with clinical pyelonephritis or irritative symptoms including dysuria, increased confusion, incontinence, anorexia, or functional decline. 5

Septic Shock Definition

Septic shock is defined as a subset of sepsis requiring persistent hypotension (SBP <90 mmHg or MAP <65 mmHg) despite adequate fluid resuscitation, or lactate >4 mmol/L after fluid resuscitation. 1 This represents profound circulatory and cellular/metabolic abnormalities that substantially increase mortality. 1

Mortality and Prognosis

The mortality rate remains approximately 10% even with optimal treatment, making early recognition critical. 1 Severe sepsis and septic shock carry a mortality rate ranging from 30% to 40%. 3 In community-onset urosepsis, the 30-day all-cause mortality is approximately 14%. 6

Key Risk Factors for Mortality

The two predominant risk factors for mortality are: 6

• Radiologically detected urinary tract disorder, particularly hydronephrosis from obstructive stones (OR = 4.63)
• Microbiologically inappropriate empirical antibiotic therapy (OR = 4.19)

Time to radiological diagnosis and decompression of obstruction for source control are critical prognostic factors for survival. 6

Diagnostic Evaluation in Suspected Urosepsis

Laboratory Testing

If urosepsis is suspected, urine and paired blood specimens should be obtained for culture and antimicrobial susceptibility testing, and a Gram stain of uncentrifuged urine should be requested. 5

Special Considerations for Catheterized Patients

Residents with long-term indwelling urethral catheters and suspected urosepsis should have catheters changed prior to specimen collection and institution of antibiotic therapy. 5 Evaluation is indicated if there is suspected urosepsis, especially in the context of recent catheter obstruction or change. 5

Important Diagnostic Pitfall

The Sepsis-3 guidelines discontinued the use of SIRS (Systemic Inflammatory Response Syndrome) criteria for sepsis classification, though SIRS remains useful as a screening tool. 1 Do not rely solely on SIRS criteria for diagnosis.

High-Risk Populations

Urosepsis particularly affects: 7

• Older adults in long-term care facilities
• Individuals with indwelling urinary catheters
• Patients with diabetes (increased risk for catheter-associated UTI)
• Those with underlying urological abnormalities or obstruction
• Immunocompromised individuals

Prolonged catheterization, female sex, and diabetes are key risk factors for catheter-associated UTI that can progress to urosepsis. 7