Can mural thrombi cause fever?

Mural Thrombi and Fever

Mural thrombi typically do not cause fever unless they become infected or are associated with underlying inflammatory conditions. While mural thrombi themselves are generally non-pyrogenic, they can be associated with fever in specific clinical scenarios 1.

Pathophysiological Mechanisms of Fever in Mural Thrombi

Fever may occur in association with mural thrombi through several mechanisms:

1. Infected mural thrombi:

   • Fever is present in ≥70% of patients with infected aortic mural thrombi 1
   • Often accompanied by back pain and positive blood cultures
   • Represents a serious complication requiring prompt intervention

2. Inflammatory response:

   • Thrombus formation can trigger an inflammatory cascade
   • Release of cytokines and inflammatory mediators may induce fever
   • This is more common in large or rapidly developing thrombi

3. Post-implantation syndrome:

   • Can occur after endovascular procedures
   • Characterized by fever, leukocytosis, and elevated inflammatory markers

Clinical Contexts Where Mural Thrombi May Be Associated with Fever

1. Mycotic Aneurysms with Mural Thrombi

• Mycotic (infected) aneurysms frequently present with fever (65-85% of cases) and leukocytosis 2
• While mural thrombosis is less common in mycotic aneurysms than in atherosclerotic aneurysms, when present, it can be associated with fever 2
• Table 5 from the AHA guidelines indicates that mural thrombosis is "uncommon" in mycotic aneurysms compared to being "common" in atherosclerotic aneurysms 2

2. Inflammatory Bowel Disease with Aortic Mural Thrombi

• Patients with inflammatory bowel disease may develop aortic mural thrombi that can be associated with systemic inflammation and fever 3
• The underlying inflammatory condition likely contributes to both thrombus formation and fever

3. Left Ventricular Mural Thrombi

• While LV mural thrombi themselves typically don't cause fever, they may be associated with underlying conditions that do cause fever
• Occurs in approximately 10% of patients with LV thrombus following MI 2
• Anticoagulation is recommended for patients with LV mural thrombus to prevent embolization 2

Diagnostic Approach to Fever in a Patient with Mural Thrombus

When a patient with known mural thrombus presents with fever:

1. Blood cultures are essential to rule out infection of the thrombus 1
2. Inflammatory markers (CRP, ESR, leukocyte count) should be measured 1
3. Imaging (CTA or MRI) to assess thrombus characteristics and look for signs of infection 2, 1
4. Evaluation for other sources of fever is critical as the thrombus itself may not be the cause 1

Management Considerations

Management depends on whether the thrombus is infected or sterile:

1. For infected mural thrombi:

   • Appropriate antibiotic therapy based on culture results
   • Surgical intervention may be necessary for infected aortic thrombi
   • Close monitoring for embolic complications

2. For non-infected mural thrombi:

   • Anticoagulation is the mainstay of treatment 4
   • Complete resolution of aortic mural thrombi with anticoagulation has been documented at a median of 60 days 4
   • For LV mural thrombi, oral anticoagulation with a target INR of 2.0-3.0 for at least 3 months is recommended 2

Important Caveats

1. Don't assume the thrombus is causing fever:

   • Always investigate for other sources of infection
   • Consider that the underlying condition causing the thrombus may be responsible for the fever

2. Watch for embolic complications:

   • Mural thrombi can embolize to various organs, potentially causing ischemia and infarction
   • Embolic events may themselves cause fever through tissue necrosis

3. Consider hypercoagulable states:

   • Patients with unexplained mural thrombi should be evaluated for hypercoagulable conditions 4
   • These underlying conditions may contribute to both thrombus formation and systemic symptoms

In summary, while mural thrombi themselves are not typically pyrogenic, fever in a patient with mural thrombus should prompt evaluation for infection of the thrombus, embolic complications, or underlying inflammatory conditions that may be responsible for both the thrombus and the fever.