OVERVIEW
Nonbacterial thrombotic endocarditis (NBTE) has been referred to as “malignant endocarditis” or “consumptive endocarditis”. This is because it is often associated with a variety of diseases, including chronic wasting disease, malignancy, and disseminated intravascular coagulation (DIC). The disease is most common in the middle-aged and elderly, accounting for 79.2% of patients ≥50 years of age, but can occur in any age group.
Etiology
The etiology of the disease has not been elucidated.Gross et al. suggest that rheumatic valvulopathy is an important cause of nonbacterial thrombotic endocarditis.Allen and Sirota suggest that anaphylaxis and vitamin C deficiency are predisposing factors.Williams suggests that anaphylactic reactions and circulating immune complexes are the immunologic basis of valvular damage.
Symptoms.
The disease is most common in middle-aged and older adults, with 79.2% of those ≥50 years of age, but can be seen in any age group. The disease lacks specific signs and symptoms.
1. Heart murmur
Auscultation is not very helpful in the diagnosis of the disease, as heart murmurs are present in only 1/3 of the cases. The heart murmur is mostly located at the lower sternal border, occasionally traveling to the apex of the heart, and is soft in nature.
2. Embolism
Embolism can occur in half of the cases, such as cerebral embolism, hemiplegia, coronary embolism, myocardial ischemia or myocardial infarction, renal artery embolism, renal colic, and so on. However, due to the non-bacterial thrombotic endocarditis of the redundancy is small, and thus the embolus is tiny, so rarely caused by large and medium arterial embolism, mostly small arterial embolism, so most of the cases have embolism but no symptoms. Therefore, many cases are undiagnosed during life.
Examination
1. Laboratory examination
Positive laboratory test results for DIC and multiple negative blood cultures are helpful in the diagnosis of the disease.
2. Ancillary tests
Echocardiography may be helpful in the diagnosis as it may reveal a large redundant organism of NBTE, but in most cases the organism is too small to be detected. In addition, the diagnostic value of nuclide imaging such as 111 indium platelet labeling imaging, 99 technetium tin pyrophosphate, and 67 gallium citrate has been reported but has yet to be evaluated.The diagnostic value of CT and cardiac portal magnetic resonance imaging has yet to be studied.
Diagnosis
The diagnosis of nonbacterial thrombotic endocarditis may be considered in the following situations:
1. a condition known to be associated with nonbacterial thrombotic endocarditis.
2. the presence of a heart murmur or a new murmur or a change in a pre-existing murmur.
3. the presence of multiple emboli.
In addition, the laboratory diagnosis of venous thrombosis DIC as well as multiple negative blood cultures contribute to the diagnosis of nonbacterial thrombotic endocarditis. The diagnosis is further facilitated if the UCG reveals redundant organisms.
Differential diagnosis
This disease should be differentiated from acute infective endocarditis, subacute infective endocarditis, Loffer’s endocarditis, and Libman-Sacks endocarditis.
Complications
Embolism: Because the nonbacterial redundant organisms of nonbacterial thrombotic endocarditis are brittle and the lesions are superficial, dislodgement can produce arterial embolism. For example, cerebral embolism can appear hemiplegia; coronary artery embolism can cause myocardial ischemia or myocardial infarction; renal artery embolism can produce renal colic. However, due to the small non-bacterial organisms in this disease, the thrombus formed is also small, so that most cases have thrombus but no obvious clinical symptoms, resulting in missed diagnosis before birth.
Treatment
1. Treatment of primary disease
The occurrence of this disease is related to tumor and DIC, so the key lies in the treatment of primary disease.
2. Anticoagulation
Intravenous heparin is effective in preventing thrombosis by preventing fibrin and platelet deposition and aggregation on the valve. Warfarin is ineffective. The therapeutic value of antiplatelet drugs such as aspirin, dipyridamole (Pansentin), and sulfinpyrazone (benzosulfanilazone) needs to be further studied.
Prevention
Actively prevent and treat the primary disease. Patients who are old and frail, have chronic wasting disease, malignant tumors and other diseases should be carefully observed clinically for early detection and treatment.