Nonbacterial thrombotic endocarditis

Nonbacterial thrombotic endocarditis (NBTE), also known as marantic endocarditis, is a rare form of endocarditis that is not caused by an infection. It is characterized by the formation of sterile thrombi on the heart valves, which can lead to serious complications such as stroke and systemic embolism.

Etiology

NBTE is most commonly associated with malignancy, particularly adenocarcinoma and lung cancer. It can also occur in patients with autoimmune diseases such as systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS). Other conditions that can lead to NBTE include sepsis, burns, and trauma.

Pathophysiology

In NBTE, the endothelium of the heart valves becomes damaged, leading to the formation of non-infectious thrombi. These thrombi can break off and travel through the bloodstream, causing systemic embolism. The exact mechanism of endothelial damage in NBTE is not fully understood, but it is thought to involve an inflammatory response triggered by malignancy or other underlying conditions.

Clinical Presentation

Patients with NBTE often present with symptoms of systemic embolism, such as stroke or myocardial infarction. Other symptoms can include fever, weight loss, and malaise. In many cases, the diagnosis of NBTE is made post-mortem, as the condition can be difficult to detect clinically.

Diagnosis

The diagnosis of NBTE is typically made based on the presence of sterile vegetations on echocardiography, in conjunction with clinical symptoms and the absence of a bacterial infection. Other diagnostic tests can include blood cultures and serologic tests for autoimmune diseases.

Treatment

The treatment of NBTE primarily involves addressing the underlying condition. This can include chemotherapy for malignancy, or immunosuppressive therapy for autoimmune diseases. Anticoagulation with heparin or warfarin is also typically used to prevent further thrombus formation.

Prognosis

The prognosis of NBTE is generally poor, due to the high risk of systemic embolism and the often advanced stage of the underlying condition. However, early detection and treatment can improve outcomes.