Which of the following are causes of chronic disseminated intravascular coagulation (DIC): viral infections, vascular aneurysms, graft rejection, neoplasms, or placental abruption?

Causes of Chronic Disseminated Intravascular Coagulation (DIC)

Neoplasms (d) and vascular aneurysms (b) are the primary causes of chronic DIC from the options listed, while placental abruption (e) causes acute DIC, and viral infections (a) and graft rejection (c) are not established triggers of chronic DIC. 1, 2, 3

Understanding Chronic vs. Acute DIC

DIC is fundamentally an acquired syndrome characterized by intravascular activation of coagulation arising from different underlying causes, and a mandatory condition for diagnosis is the presence of an underlying disorder known to be associated with DIC. 1 The distinction between chronic and acute forms is critical:

• Acute DIC develops over hours to days with rapid changes in laboratory parameters and is typically associated with severe infections/sepsis, trauma, obstetric complications, and acute liver failure. 1, 3
• Chronic DIC develops more insidiously over weeks to months with compensated laboratory abnormalities and is characteristically associated with malignancies and certain vascular disorders. 4, 5

Analysis of Each Option

d. Neoplasms (CORRECT for Chronic DIC)

Malignancies are well-established causes of chronic DIC, particularly solid tumors and hematologic malignancies. 6, 4, 5

• Cancer-associated DIC can present as a chronic, compensated process where the body maintains a precarious hemostatic balance despite ongoing low-grade coagulation activation. 6, 4
• Solid adenocarcinomas (especially pancreatic, prostate, and lung cancers) frequently cause chronic DIC through continuous release of tissue factor and other procoagulant substances. 6, 5
• Hematologic malignancies can trigger DIC through various mechanisms including direct activation of coagulation pathways. 1, 4
• The thrombotic phenotype is more common in cancer-associated chronic DIC, presenting with arterial ischemia, digital ischemia, and venous thromboembolism rather than bleeding. 7

b. Vascular Aneurysms (CORRECT for Chronic DIC)

Large vascular aneurysms can cause chronic DIC through continuous low-grade activation of coagulation within the abnormal vascular structure. 4

• The dilated vascular space with turbulent blood flow and activated endothelial surfaces facilitates ongoing platelet and coagulation activation. 1
• This represents a localized but persistent trigger for systemic coagulation activation that can evolve into chronic consumptive coagulopathy. 4

e. Placental Abruption (INCORRECT - Causes ACUTE DIC)

Placental abruption is a classic cause of acute, not chronic, DIC in obstetric settings. 8, 9

• Abruptio placentae triggers massive, sudden release of tissue factor and thromboplastin into maternal circulation, causing fulminant DIC within hours. 8, 9
• This obstetric complication is associated with high mortality and morbidity rates due to the acute nature of coagulation activation. 8, 9
• Other acute obstetric DIC triggers include amniotic fluid embolism, acute peripartum hemorrhage, and septic abortion—all characterized by rapid onset. 8, 9

a. Viral Infections (INCORRECT - Not Established DIC Trigger)

Viral infections are not recognized as primary triggers of DIC according to current guidelines. 1

• The ISTH definition requires a mandatory underlying disorder known to be associated with DIC for diagnosis. 1
• Severe bacterial infections and sepsis are well-established DIC triggers, but viral infections are not specifically mentioned in major guidelines as DIC-causing conditions. 1, 3, 4
• When infections cause DIC, it is typically through bacterial endotoxin-mediated mechanisms leading to acute rather than chronic DIC. 1, 3

c. Graft Rejection (INCORRECT - Not Established DIC Trigger)

Graft rejection is not listed among the recognized underlying disorders associated with DIC in current guidelines. 1, 4

• The established categories of DIC triggers include infections, malignancies, trauma, obstetric complications, and severe liver disease—but not transplant rejection. 1, 3, 4
• While the inflammatory cascade in rejection could theoretically activate coagulation, this is not documented as a clinically significant cause of DIC in the literature. 1, 4

Clinical Implications

When evaluating for chronic DIC, always search for underlying malignancy or vascular abnormalities as the primary triggers. 2, 4

• Laboratory findings in chronic DIC may show only modest abnormalities with compensated thrombocytopenia, mildly prolonged PT/PTT, and elevated D-dimer. 7, 4
• The key diagnostic feature distinguishing chronic from acute DIC is the time course—chronic DIC shows stable or slowly progressive laboratory changes over weeks to months rather than rapid deterioration over hours to days. 1, 7
• Treatment of chronic DIC focuses primarily on addressing the underlying malignancy or vascular disorder, as supportive measures alone are insufficient. 2, 4, 5

Common Pitfalls

• Do not confuse acute obstetric DIC triggers (like placental abruption) with chronic DIC causes—the pathophysiology and time course are fundamentally different. 8, 9, 4
• Do not assume all infections cause DIC—only severe bacterial infections/sepsis are established triggers, and these cause acute rather than chronic DIC. 1, 3, 4
• Always identify the underlying trigger before diagnosing DIC—laboratory abnormalities alone without a recognized underlying condition do not constitute DIC. 1