Treatment. The treatment of von Willebrand disease depends on the severity of bleeding. Desmopressin is the treatment of choice for most bleeding episodes in patients with type 1 disease and some patients with type 2 disease. When high levels of vWF are needed but cannot be achieved satisfactorily with desmopressin, treatment with a virally attenuated, vWF-containing concentrate (Humate P) may be appropriate. The dosage can be calculated as for factor 8 in hemophilia. Cryoprecipitate should not be used because it is not virally attenuated. Hepatitis B vaccine should be given before the patient is exposed to plasma-derived products. As in all bleeding disorders, aspirin should be avoided.
For discussion of vitamin K deficiency, see Chapters 27 and 31.
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Etiology. Disseminated intravascular coagulation (DIC) is a disorder in which widespread activation of the coagulation mechanism is usually associated with shock. Normal hemostasis is a balance between hemorrhage and thrombosis. In DIC,
Meningococcemia (purpura fulminans) Other gram-negative bacteria (Haemophilus, Salmonella, Escherichia coli)
Rickettsiae (Rocky Mountain spotted fever) Virus (cytomegalovirus, herpes, hemorrhagic fevers) Malaria Fungus
Central nervous system trauma (massive head injury) Multiple fractures with fat emboli Crush injury Profound shock or asphyxia Hypothermia or hyperthermia Massive burns
Maternal toxemia Group B streptococcal infections Abruptio placentae Severe respiratory distress syndrome Necrotizing enterocolitis Congenital viral disease (e.g., cytomegalovirus infection or herpes) Erythroblastosis fetalis
Severe acute graft rejection Acute hemolytic transfusion reaction Severe collagen vascular disease Kawasaki disease Heparin-induced thrombosis Infusion of “activated” prothrombin complex concentrates Hyperpyrexia/encephalopathy, hemorrhagic shock syndrome
From Scott JP: Bleeding and thrombosis. In Kliegman RM, editor: Practical Strategies in Pediatric Diagnosis and Therapy, Philadelphia, 1996, WB Saunders.
this balance is altered by the severe illness, so the patient has activation of coagulation (thrombosis) mediated by thrombin and fibrinolysis mediated by plasmin (bleeding). Coagulation factors—especially platelets, fibrinogen, and factors 2, 5, and 8—are consumed, as are the anticoagulant proteins, especially antithrombin, protein C, and plasminogen. Endothelial injury, tissue release of thromboplastic procoagulant factors, or, rarely, exogenous factors (snake venoms) directly activate the coagulation mechanism (Table 151-4).
Differential Diagnosis of Coagulopathies That Can Be Confused with Disseminated Intravascular Coagulation
Vitamin K deficiency ↑↑ Normal Normal Normal Malabsorption, liver disease
From Scott JP: Bleeding and thrombosis. In Kliegman RM, editor: Practical Strategies in Pediatric Diagnosis and Therapy, Philadelphia, 1996, WB Saunders. DIC, Disseminated intravascular coagulation.
Clinical Manifestations. The diagnosis of DIC usually is suspected clinically and is confirmed by laboratory findings of Thrombomodulin a decline in platelets and fibrinogen associated with elevated Thrombin prothrombin time, partial thromboplastin time, and elevated levels of D-dimer, formed when fibrinogen is clotted and then Protein Ca degraded by plasmin (Table 151-5). In some patients, DIC may evolve more slowly and there may be a degree of compensation. S