Coagulopathies, Oncologic Emergencies and Autoimmune Crises

Complex Coagulopathies: DIC, HIT, and Immune Thrombocytopenia

Disseminated intravascular coagulation (DIC) represents a severe disruption of hemostasis where systemic microvascular thrombosis consumes platelets and coagulation factors. DIC can cause both microvascular thrombosis and bleeding from platelet and coagulation-factor consumption; fibrinolysis varies and may be suppressed, particularly in sepsis-associated DIC. Think of DIC like a massive plumbing disaster where all the sealant in a city is used up to plug thousands of microscopic pipe fissures simultaneously, leaving none available when an open main line begins to bleed. In DIC, critical care nurses must promptly recognize and report suspected underlying triggers, such as sepsis or trauma, while providing supportive care and implementing prescribed treatments.

Early DIC may have no obvious bleeding; nurses should assess for petechiae, purpura, or oozing while also tracking platelet trends and signs of thrombotic organ dysfunction. Concurrently, microvascular thrombi cause ischemic organ injury that manifests as oliguria, altered mental status, acrocyanosis, and gangrene of the digits. Acute DIC commonly produces a falling platelet count and elevated D-dimer, with PT and aPTT often prolonged; fibrinogen may fall but can initially be normal or elevated, especially during inflammation, so serial trends matter. Bedside administration of blood components must follow institutional thresholds: cryoprecipitate is administered specifically to replace depleted fibrinogen; fresh frozen plasma (FFP) is indicated in actively bleeding patients to replace consumed clotting factors and correct prolonged coagulation times; and platelet transfusions may be ordered for active bleeding, invasive procedures in patients with low counts, or profound thrombocytopenia with high bleeding risk.

Heparin-induced thrombocytopenia (HIT) is an immune-mediated disorder caused by IgG antibodies binding to heparin-platelet factor 4 complexes, which triggers widespread platelet activation. Unlike common drug-induced hypoplasias, HIT is predominantly a prothrombotic condition carrying high risks of deep vein thrombosis, pulmonary embolism, arterial occlusion, and skin necrosis rather than bleeding. The condition typically manifests 5 to 10 days after heparin initiation, but rapid onset can occur within 24 hours upon reexposure, especially if heparin was received within the preceding 30 days. The clinical hallmark of HIT is an unexplained decline in platelet count of 50 percent or greater from baseline, even if the absolute platelet count remains above 100,000/mcL.

When HIT is suspected, the nurse must immediately hold heparin infusions and flushes per protocol, notify the provider, and verify that all heparin sources, including line locks and heparin-coated devices, are reviewed for discontinuation or replacement as ordered. Routine platelet transfusions must be avoided due to thrombotic risks, though they may be ordered for major bleeding or an urgent invasive procedure. Prescribed non-heparin anticoagulation often involves an IV direct thrombin inhibitor such as argatroban or bivalirudin. Argatroban clearance is predominantly hepatic, necessitating dosage reductions and vigilant monitoring via aPTT in liver dysfunction. Bivalirudin is cleared primarily by proteolysis with a renal component, making it an option when hepatic dysfunction limits argatroban, though renal impairment requires dose adjustments and monitoring. Warfarin is strictly contraindicated during the acute phase of HIT because it depletes protein C, which can precipitate venous limb gangrene and skin necrosis. In contrast, immune thrombocytopenia (ITP) features autoimmune destruction of circulating platelets and impaired platelet production, presenting as isolated thrombocytopenia with normal PT/INR and aPTT. First-line provider-directed therapies for severe or symptomatic ITP commonly include corticosteroids and intravenous immunoglobulin (IVIG) when a rapid rise is needed, with anti-D immunoglobulin as an option for select eligible patients. For any severe thrombocytopenia, nurses must avoid intramuscular injections and rectal instrumentation, minimize unnecessary noninvasive blood pressure cuff cycling, and maintain indicated hemodynamic monitoring.