What is the next best step in managing a patient with fever, fatigue, and low back pain after recent sepsis due to complicated urinary tract infection (UTI)?

Management of Fever, Fatigue, and Low Back Pain After Recent UTI-Related Sepsis

Performing an urgent transthoracic echocardiograph is the most appropriate next step for this patient with persistent fever, fatigue, and low back pain after recent sepsis due to complicated UTI.

Clinical Assessment

This 67-year-old man presents with several concerning features:

• Recent hospitalization for sepsis due to complicated UTI (2 weeks ago)
• Current fever (101.3°F)
• Tachycardia (pulse 115)
• Persistent fatigue and low back pain
• Blood cultures positive for MSSA (methicillin-sensitive Staphylococcus aureus)
• Elevated inflammatory markers (WBC 12,500)
• Type 2 diabetes (risk factor for complications)

Diagnostic Reasoning

The patient's presentation strongly suggests infective endocarditis (IE) as a complication of his recent sepsis, warranting urgent echocardiography:

1. Positive blood cultures with MSSA: The presence of S. aureus bacteremia is highly concerning for endocarditis and requires thorough evaluation 1.

2. Persistent fever and systemic symptoms: The patient's ongoing fever despite initial treatment suggests either inadequate source control or development of a metastatic infection 1.

3. Low back pain: This could represent septic emboli or metastatic infection to the vertebrae, a known complication of endocarditis 1.

Management Algorithm

Step 1: Urgent Diagnostic Evaluation

• Perform urgent transthoracic echocardiography (TTE) to evaluate for vegetations on heart valves
• If TTE is negative but clinical suspicion remains high, proceed to transesophageal echocardiography (TEE)

Step 2: Source Control Assessment

• Evaluate for persistent or recurrent UTI (already addressed with blood cultures and initial treatment)
• Consider additional imaging based on echocardiography findings

Step 3: Antimicrobial Management

• Continue vancomycin pending complete susceptibility results
• Adjust antibiotics based on culture results and identified source
• For S. aureus bacteremia, plan for extended antibiotic course (minimum 2 weeks if uncomplicated, 4-6 weeks if endocarditis) 1

Rationale for Choosing Echocardiography Over Other Options

1. Orthopedic consultation: While low back pain could suggest vertebral osteomyelitis, the first step should be to rule out endocarditis, which is more immediately life-threatening and could be the source of any vertebral infection.

2. Bladder ultrasound: Less urgent as the patient already has positive blood cultures, suggesting the infection has spread beyond the urinary tract.

3. MRI spine: While this might eventually be needed, echocardiography should be performed first to establish or exclude endocarditis, which would guide the overall management plan.

Key Considerations

• S. aureus bacteremia is never benign: Any S. aureus in blood cultures requires thorough evaluation for endocarditis, especially with persistent fever 1.

• Timing is critical: The Surviving Sepsis Campaign guidelines emphasize prompt diagnosis and source control within 12 hours when possible 1.

• Diabetes increases risk: Patients with diabetes have higher risk of complications from bacteremia, including endocarditis 1.

Common Pitfalls to Avoid

• Focusing only on the urinary tract: While the initial infection was a UTI, the positive blood cultures with S. aureus and persistent symptoms suggest a more complex picture.

• Delaying echocardiography: Early detection of endocarditis significantly improves outcomes by allowing appropriate antibiotic duration and consideration of surgical intervention if needed.

• Inadequate antibiotic duration: S. aureus bacteremia requires longer treatment courses (2-6 weeks depending on complications) compared to uncomplicated UTIs 1.