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9 possible symptoms except pulmonary embolism if D-dime elevated
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9 possible symptoms except pulmonary embolism if D-dime elevated . 9-point interpretation of elevated D-dimer, don’t just think of pulmonary embolism!
D-dimer is the most important laboratory indicator reflecting thrombosis and thrombolytic activity (the normal range of different reagents is different, usually <0.5 mg/L). So, what are the reasons for the increase in D-dimer?
One. Venous Thromboembolism
Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE).
Treatment and Prevention of Pulmonary Thromboembolism recommends:
- Patients with low clinical evaluation, such as negative D-dimer test, can basically rule out acute PE;
- For suspected PE patients with unstable hemodynamics, D-dimer is of little significance, and CT pulmonary angiography (CTPA) or echocardiography can be performed directly.
However, radioactivity limitations often make doctors worry about choosing. In 2019, researchers from McMaster University created a new method that greatly improved the diagnostic specificity of D-dimer.
This method uses C-PTP to assign different scores to symptoms, heart rate, immobility, medical history, malignant tumor status, etc., and cumulatively judge the PE risk.
Different from the previous exclusion criteria (low-risk and D-dimer <0.5 mg/L), the study concluded that low-risk patients with D-dimer <1 mg/L and intermediate-risk patients with D-dimer <0.5 mg /L can be used as a criterion to exclude PE.
In addition, for suspected PE patients> 50 years old, it is recommended to increase the diagnostic threshold of D-dimer (age * 0.01 mg/L) to improve the effectiveness of disease identification.
Two. Aortic dissection
The 2017 “Chinese Expert Consensus on the Diagnosis and Treatment of Aortic Dissection” pointed out that the rapid rise of D-dimer is more likely to be diagnosed as aortic dissection (AD).
Within 24 hours of onset, when D-dimer reaches 0.5 mg/L, the sensitivity for diagnosing acute aortic dissection (AAD) is 100%, and the specificity is 67%, so it can be used as an exclusion index for the diagnosis of AAD.
Three, myocardial infarction
In patients with acute myocardial infarction (AMI), an increase in D-dimer can be observed, and the concentration of D-dimer after thrombolysis with urokinase is lower than before. Therefore, patients with coronary heart disease are accompanied by increased D-dimer. -Dimers may indicate a higher risk of AMI.
However, it is not an independent predictor. The sensitivity and specificity in the diagnosis of AMI are not yet satisfactory, and there is also a contradiction with the prognosis of AMI, and it cannot be used to guide treatment for the time being.
Fourth, thrombolytic therapy
- After thrombolytic therapy, D-dimer increased significantly in a short period of time, and then gradually decreased, indicating that the treatment is effective;
- D-dimer continues to rise or falls slowly, indicating the presence of new thrombosis and insufficient dosage of thrombolytic drugs;
- If the D-dimer does not change much, it may be an old organic thrombus.
After thrombolysis of acute myocardial infarction and cerebral infarction, the peak value of D-dimer often appears within 1 to 6 hours and drops to the level before thrombolysis within 24 hours; in DVT thrombolysis treatment, the peak value of D-dimer often appears within 24 hours Or later.
Five, diffuse intravascular coagulation
Diffuse intravascular coagulation (DIC) is characterized by extensive fibrin deposition and platelet aggregation in the microcirculation, leading to diffuse microthrombosis and a secondary fibrinolytic state.
In the early stage of DIC, D-dimer is increased, and it can continue to increase by 10 times or even more than 100 times with the development of the disease. Therefore, D-dimer can be used as the main indicator for early diagnosis of DIC and monitoring of disease course, except for normal DIC.
In addition, the sensitivity, specificity and diagnostic efficiency of fibrinolysis marker fibrin degradation products (FDP) combined with D-dimer can reach 91%, 94% and 95%, respectively. Therefore, the two are listed in the International Thrombosis and Hemostasis Association. As a high-value indicator in the DIC diagnostic criteria.
Six, malignant tumors
Tumors can cause an increase in the concentration of D-dimer, and can be used as criteria for staging and prognosis.
Jiang Xuanxing and others conducted D-dimer testing on 150 patients with advanced colorectal cancer and 150 healthy subjects. The comparison found that the level of D-dimer in patients before chemotherapy was significantly higher than that in healthy subjects, and those who were effective in chemotherapy had D-dimer levels after chemotherapy. The dimer was significantly lower than before chemotherapy, and the D-dimer was significantly higher after chemotherapy than before chemotherapy for those who were ineffective in chemotherapy.
The results of the study were published in the Chinese Journal of Anorectal Diseases in 2019, showing that the changes in D-dimer levels before and after chemotherapy can be used as a preliminary predictor of the prognosis of patients with advanced colorectal cancer.
It is speculated that the hypercoagulable state in tumor patients is related to tissue factor-dependent exogenous pathways and non-tissue factor-related tumor coagulation effects.
For example, in acute promyelocytic leukemia, a large number of azurophilic granules are released after the destruction of tumor cells, which consumes coagulation factors and promotes fibrinolysis, leading to diffuse intravascular coagulation, abnormally elevated D-dimer, and clinical manifestations that are large and difficult to correct Of bleeding, and the mortality rate is very high.
Seven, renal insufficiency
Patients with abnormal renal function are usually accompanied by an increase in the level of D-dimer, and with the decrease of eGFR, the increase is obvious:
- Estimate the glomerular filtration rate (eGFR) of 30 to 60 mL/min, and there is a high proportion of them with elevated D-dimer;
- eGFR 15～30 mL/min, there are almost all D-dimer abnormalities;
- eGFR <15 mL/min, fibrin degradation is reduced, D-dimer metabolic half-life is prolonged, and the level rises significantly.
Eight, liver disease
The concentration of D-dimer can be used as a marker to judge the degree of liver damage:
In the case of liver dysfunction, due to insufficient synthesis of coagulation factors, it causes bleeding and initiates the positive feedback process of coagulation-fibrinolysis, and D-dimer is secondary to increase;
In liver failure, the detoxification effect decreases. Inflammatory factors and pathogens can damage the vascular endothelium to activate coagulation. At the same time, the ability of plasminogen activator decreases, which also causes hyperfibrinolysis and D-dimer to increase significantly;
In liver cancer, the secretion of procoagulant factors leads to hyperfibrinolysis and increased D-dimer.
In all stages of pregnancy, there may be pathological factors related to thrombosis such as venous blood stasis, hypercoagulable state, and vascular wall damage; physiological changes can lead to increased intravenous blood volume and venous vasodilation. At 3 months of pregnancy It is more obvious afterwards.
At this time, it is difficult to use D-dimer to judge thrombosis, and more emphasis is on imaging examinations such as ultrasound.
In addition, certain diseases can also cause an increase in D-dimer.
Compared with normal pregnant women, D-dimer is more obvious in patients with pregnancy-induced hypertension, which may be caused by changes in vascular endothelial cell damage and placental ischemia in pregnancy-induced hypertension, which activate secondary fibrinolysis System.
D-dimer in patients with pre-eclampsia can reach 4 times that of normal pregnant women, especially in the third stage of pregnancy. The D-dimer does not decrease but rises after delivery, and it returns to normal after 4-6 weeks. . The main pathological changes are coagulation activation and fibrinolysis enhancement, leading to microvascular thrombosis and increased D-dimer.
Questions:After grasping the significance of the increase in D-dimer, how should we analyze the increase in D-dimer in clinical practice?
At present, clinical D-dimer detection is often used in the diagnosis and treatment of acute venous thromboembolism, aortic dissection, and DIC.
1. Exclude the diagnosis
According to the above, if D-dimer is negative, diseases such as acute pulmonary embolism, aortic dissection, and DIC can be basically ruled out.
2. Combine clinical and other test results
If D-dimer is positive, it needs to be combined with clinical symptoms and other auxiliary examinations for comprehensive analysis.
1) Venous thromboembolism
The D-dimer test is only suitable for patients with acute VTE. The symptoms of D-dimer can gradually decrease after more than 10 days.
For patients with long thrombosis, intermuscular venous thrombosis of the lower extremities, and distal PE, D-dimer may not increase. The evaluation must incorporate the risk factors for thrombosis, the duration of onset, clinical symptoms and other auxiliary examinations.
2) Aortic dissection
For patients with high possibility of clinical evaluation of AD, D-dimer sensitivity decreases instead. Therefore, imaging examinations are essential for patients with suspected AD.
Also according to the 2017 consensus, full aortic CTA is recommended as the first choice for diagnosis. When full aortic CTA cannot be performed due to iodine allergy, severe renal damage, pregnancy, and hyperthyroidism, MRI can be used to confirm the diagnosis.
According to the 2017 China Expert Consensus on the Diagnosis of DIC, elevated D-dimer cannot be directly diagnosed as DIC, and a scoring system (CDSS) is needed to perform primary disease, clinical manifestations, and laboratory indicators (platelet count, prothrombin, and prothrombin). Partially activated thromboplastin time, fibrinogen) dynamic score.
Usually D-dimer within 5 mg/L in the third trimester of pregnancy can be regarded as no obvious abnormality, and it is enough to do a good coagulation monitoring;
If the D-dimer is greater than 5 mg/L and it is determined that there is no risk of bleeding, low molecular weight heparin sodium or calcium can be given to prevent deep vein thrombosis.
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3. Unexplained increase in D-dimer
For unexplained D-dimer levels that are significantly increased, even if there is no clinical manifestation, the possibility of VTE should be considered; after thrombotic diseases and liver and kidney diseases are excluded, the possibility of malignant tumors should be highly suspected.
(source:internet, reference only)