Can a mural thrombus cause fever?

Can Mural Thrombus Cause Fever?

Yes, mural thrombus can cause fever, particularly when associated with inflammatory processes or when it develops rapidly after endovascular procedures. This relationship is most clearly documented in post-implantation syndrome following thoracic endovascular aortic repair (TEVAR) 1.

Pathophysiological Mechanisms

Mural thrombus can trigger fever through several mechanisms:

1. Post-implantation syndrome (PIS):

   • Characterized by noninfectious continuous fever and elevated inflammatory markers
   • Associated with new-onset mural thrombus formation after endovascular procedures
   • Studies show significantly higher volumes of new-onset thrombus in patients who develop fever (61 cm³ vs. 12 cm³) 1

2. Inflammatory response:

   • Thrombus formation activates inflammatory cascades
   • Releases cytokines and inflammatory mediators
   • Can trigger a systemic inflammatory response

3. Arterial wall inflammation:

   • Subacute/chronic arteritis associated with mural thrombus
   • Luminal myofibroblastic proliferation (LMP) involves inflammatory cells 2
   • Persistent inflammatory processes can continue for months to years

Clinical Presentations

The association between mural thrombus and fever appears in several clinical contexts:

1. Mycotic Aneurysms and Infected Thrombi

• Fever is present in ≥70% of patients with infected aortic mural thrombi 2
• Back pain is present in 65-90% of cases
• Blood cultures are positive in 50-90% of cases with infected mural thrombi 2

2. Post-Endovascular Procedures

• Younger patients more frequently develop post-implantation syndrome with fever after TEVAR (52.2 ± 11.6 vs. 61.5 ± 13.6 years) 1
• Fever typically develops within 24 hours of the procedure
• Associated with elevated white blood cell count (>12,000/μL)

3. Hypercoagulable States

• COVID-19 patients with aortic thrombi may present with fever 3
• Other hypercoagulable disorders can predispose to both thrombus formation and inflammatory responses 4

Differential Diagnosis

When evaluating fever in a patient with mural thrombus, consider:

1. Infectious causes:

   • Infected thrombus/mycotic aneurysm
   • Endocarditis (present in 2.2-7.1% of cases with catheter-related thrombi) 2
   • Other sources of infection (pneumonia, UTI, etc.)

2. Non-infectious causes:

   • Post-implantation syndrome
   • Pulmonary infarction (occurs in 0.1-5.6% of cases with catheter-related thrombi) 2
   • Venous thromboembolism (can cause fever independently) 2

Diagnostic Approach

For patients with fever and suspected mural thrombus:

• Blood cultures: Essential to rule out infected thrombus
• Imaging: CTA is the initial imaging procedure of choice 2
• Laboratory tests: Check inflammatory markers (WBC, CRP, ESR)
• Exclude other causes: Evaluate for other sources of fever listed in guidelines 2

Management Implications

The presence of fever in a patient with mural thrombus should prompt:

1. Evaluation for infection: Blood cultures and appropriate imaging
2. Anticoagulation consideration:
   • For non-infected thrombi, anticoagulation is first-line therapy 5
   • Surgical intervention may be needed for mobile thrombi or recurrent embolism 4
3. Close monitoring: For complications such as embolization or rupture

Key Points to Remember

• Fever is more common with infected mural thrombi but can occur with sterile thrombi
• New-onset mural thrombus formation is strongly associated with post-implantation fever syndrome
• The combination of fever and mural thrombus should always prompt evaluation for infection
• Hypercoagulable states (including COVID-19) can predispose to both thrombus formation and inflammatory responses
• Management depends on whether the thrombus is infected or sterile, its location, and associated complications

When evaluating a patient with fever and mural thrombus, a systematic approach to determine the relationship between the two findings is essential for appropriate management.