Disseminated intravascular coagulation (DIC).
Identification of DIC and distinguish DIC from other bleeding disorders, laboratory analysis, and blood product support.
Disseminated intravascular coagulation is an acquired bleeding diathesis. It is observed as a secondary event due to an underlying severe primary disease such as neonatal sepsis, trauma, asphyxia, blood product transfusion reactions, and respiratory distress. The ill neonate appears to be at particularly high risk of coagulopathy, due to quantitatively low plasma levels of procoagulant and anticoagulant factors at birth. Infection, asphyxia, or trauma can result in rapid depletion of these plasma factors, particularly in the ill preterm infant.
Although neonatal hemostasis is finely balanced in the healthy newborn, due to physiologically low neonatal procoagulant, anticoagulant, and fibrinolytic levels, exogenous events such as infection can readily disrupt this finely balanced system with a resultant hemorrhagic or thrombotic state in the ill neonate. In the healthy newborn, most of the procoagulant factors (vitamin K factors, contact factors) reach adult levels by 6 months of age. Similar findings are noted for several anticoagulants (antithrombin III, heparin cofactor II, and protein C and protein S).
DIC is characterized by coagulation activation, fibrin deposition, and microangiopathic thrombi, resulting in secondary fibrinolysis. Due to the varied clinical spectrums observed in neonatal DIC, the differential diagnosis of a bleeding neonate may be difficult to establish, and additional laboratory studies characterizing the activation of coagulation and fibrinolysis may or may not aid in the diagnosis. Newborn laboratory analysis must be based on neonatal age−corrected ranges. Laboratory analysis in neonatal DIC includes a decreased platelet count, prolonged PT/INR, aPTT, and decreased fibrinogen (Table 35.1). Fibrinogen depletion is associated with increased bleeding. Peripheral blood smear findings are often notable for schistocytes, due to the underlying microangiopathic changes. Typical confirmatory laboratory tests for DIC (i.e., D-dimer) in the newborn are generally unreliable due to a lack of specificity from altered plasma clearance.
TABLE 35.1.Neonatal Laboratory Changes Associated with Bleeding Disorders ||Download (.pdf) TABLE 35.1. Neonatal Laboratory Changes Associated with Bleeding Disorders
|Disorder ||Platelet Count ||PT/INR ||aPTT ||Fibrinogen |
|DIC ||Decreased ||Increased ||Increased ||Decreased |
|HDN ||Normal ||Increased ||Normal ||Normal |
|Liver coagulopathy ||Normal/Decreased ||Increased ||Increased ||Normal/Decreased |
|Hemophilia A or B ||Normal ||Normal ||Increased ||Normal |
|NAIT ||Decreased ||Normal ||Normal ||Normal |
Abnormal bleeding, thrombotic complications, or hemorrhage can be observed in the ill neonate with DIC. In contrast, abnormal bleeding in an otherwise healthy infant is more concerning for a congenital hemorrhagic disorder. The clinical spectrum of DIC may vary from mild clinical symptoms and coagulopathy to a fulminant thrombohemorrhagic state. Abnormal bleeding from central and peripheral line sites, catheterized sites, skin, and/or mucosal ...