1. Disseminated Intravascular Coagulation (DIC)

Quick Recap

Hematology System, Protocol 1/8.

1. Definition & Epidemiology

DIC = a consumptive coagulopathy reflecting an underlying systemic disease that drives simultaneous, dysregulated procoagulant and fibrinolytic activation — rapid, excessive fibrin clot formation in small/mid-size vessels causes thrombotic occlusion and end-organ damage, while the coagulation factors consumed in this process are exhausted faster than they can be replenished, producing a superimposed bleeding tendency. Bleeding manifestation from DIC occurs in ~1% of hospital admissions. DIC is ALWAYS a symptom of an underlying condition, never a primary diagnosis — the central management principle is finding and treating that underlying driver, not just correcting the lab abnormalities.

2. Underlying Causes

3. Immediate Stabilization (ABCDE)

Circulation — initial resuscitation and access considerations:

• Stabilize hemodynamics; start blood/blood product transfusion as needed per Section 6
• Venous access in an actively bleeding, coagulopathic patient requires special care: peripheral access is preferable to central; use ultrasound guidance where possible; preferentially choose COMPRESSIBLE sites (internal jugular or femoral vein) over subclavian if central access is unavoidable, given the inability to apply direct compression to a subclavian bleed; avoid arterial punctures given bleeding risk in this population
• Acidosis exacerbates coagulopathy — correcting perfusion/acid-base status is itself a coagulopathy-directed intervention, not merely supportive

Checklist:

4. Diagnosis — ISTH Scoring System

Characteristic lab pattern: prolonged PT/aPTT/TT, thrombocytopenia (typically <100,000/mcL), microangiopathic hemolytic anemia (schistocytes on smear). Fibrinogen may be NORMAL early in the disease from pathologic compensation — significant hypofibrinogenemia is a feature of SEVERE, not early, DIC; do not exclude the diagnosis based on a normal fibrinogen alone. D-dimer is markedly elevated and is the key test distinguishing DIC from other thrombocytopenic coagulopathies.

ISTH Overt DIC Score (points, prerequisite: a known DIC-associated underlying condition present):

Score >=5 is consistent with overt DIC. (Other validated scoring systems exist — JMWH requires >=7 points, JAAM requires >=4 points using a somewhat different variable set including SIRS score — the ISTH system is the most internationally standardized and referenced here as primary.)

Antithrombin levels, where available, provide an additional severity/prognostic indicator beyond the core diagnostic score.

5. Differential Diagnosis — Distinguishing DIC from Mimics

TTP (thrombotic thrombocytopenic purpura) is the major differential given shared thrombocytopenia, microangiopathic hemolytic anemia, and schistocytes — the key discriminator: DIC has an associated COAGULOPATHY (prolonged PT/aPTT/TT, low fibrinogen, elevated FDP), all of which should be NORMAL in TTP. Platelet count is typically MORE severely depressed and LDH more profoundly elevated in TTP compared to DIC. See the dedicated TTP protocol for full detail on this distinction and TTP-specific management, since the therapies diverge significantly (plasma exchange for TTP vs treating the underlying cause + selective blood product support for DIC).

Heparin-induced thrombocytopenia (HIT) is a separate consideration if the patient is on heparin — isolated thrombocytopenia without the DIC coagulation-panel abnormalities, requiring immediate cessation of all heparin products and transition to a non-heparin anticoagulant (argatroban, bivalirudin) if HIT is confirmed/strongly suspected.

6. Evidence-Based Management

Primary goal: treat the underlying disease driving DIC — this is often not rapidly achievable, so concurrent supportive hemostatic management is usually required.

Fluid resuscitation: crystalloids preferred; AVOID colloids, which interfere with clotting. If colloids must be used, gelatin or tetrastarch carry less coagulation-profile impact than other starches — do not exceed 50 mL/kg/day if starches are used.

Blood product management (guided by BLEEDING status, not lab values alone in the absence of bleeding):

• FFP: consider for PT >1.5x upper normal limit in a BLEEDING patient; initial dose 10-15 mL/kg (~4-6 units); goal is generally PT <2x normal control
• Platelets: transfuse in a bleeding patient to maintain count >50,000/mcL; 1 unit single-donor platelets (or 4-6 random platelet concentrates), with post-transfusion count guiding further dosing
• Cryoprecipitate: given in pools of ~10 units (providing ~1,500-2,000mg fibrinogen in 150mL) to keep fibrinogen >60-100 mg/dL (some guidance favors the higher target) in a bleeding patient with hypofibrinogenemia
• PCC (prothrombin complex concentrate): an alternative to FFP if FFP is unavailable or volume cannot be tolerated, but many experts recommend AVOIDING PCC in DIC specifically given absent supporting data and theoretical potential to worsen the thrombotic component of the disease (PCC lacks the balancing anticoagulant proteins C/S present in FFP in the same ratio) — use with caution, not as a routine FFP substitute in this specific condition
• CRITICAL PRINCIPLE: in the ABSENCE of active bleeding, prophylactic FFP, cryoprecipitate, or platelet transfusion has NOT been shown to reduce bleeding risk or improve outcomes and should be AVOIDED — do not correct DIC lab abnormalities reflexively in a non-bleeding patient; this mirrors the general critical care principle against transfusing to a number rather than to a clinical indication, seen throughout this protocol library
• ROTEM/TEG (viscoelastic testing) can guide more precise, goal-directed blood product administration where available, rather than relying on standard coagulation panels alone

Antifibrinolytics: generally AVOID — tranexamic acid and similar agents may AGGRAVATE thrombosis in the typical consumptive-coagulopathy DIC picture. EXCEPTION: DIC with a primary HYPERFIBRINOLYTIC state and severe bleeding (a distinct pathophysiologic subtype, more fibrinolysis-dominant than the typical thrombosis-dominant picture) can be treated with tranexamic acid (e.g., 1g every 8h) — this requires recognizing which DIC phenotype is present rather than applying a blanket antifibrinolytic avoidance rule.

Heparin/anticoagulation: NO role in actively bleeding DIC patients. Consider ONLY where THROMBOSIS predominates — arterial or venous thromboembolism, or severe purpura fulminans with vascular skin infarction. Heparin has shown particular utility in SUBACUTE DIC associated with acute promyelocytic leukemia, abdominal aortic aneurysm, and purpura fulminans — specific, narrower indications rather than routine DIC management. Antithrombin III concentrate role remains controversial in most DIC scenarios.

Recombinant factor VIIa: reserved for RARE cases where bleeding is not controlled despite adequate blood product resuscitation — associated with clinically significant thrombosis risk and should be used with caution; no well-defined dosing study exists for this off-label use, though 20-90 mcg/kg is generally cited as providing adequate hemostatic control when used.

7. Organ Support

Blood product support per bleeding-driven indications above (not prophylactic); standard ICU supportive care for the underlying condition driving DIC (septic shock management, obstetric emergency management, etc. per their respective dedicated protocols); correction of acidosis to support coagulation function.

8. Consultation Matrix

9. Monitoring Framework

Serial coagulation profile and CBC/platelet count (frequent, given the rapidly evolving consumptive process), fibrinogen trend, D-dimer trend, ROTEM/TEG if available to guide ongoing product administration, bleeding site surveillance (line sites, mucosal, GI), thrombotic complication surveillance (DVT, arterial thrombosis, purpura fulminans skin changes).

10. Complications

Severe hemorrhage, end-organ damage from microvascular thrombosis (renal, hepatic, pulmonary, CNS), purpura fulminans, transfusion-related complications from blood product support, thrombotic complications if heparin/PCC used inappropriately. Prevention: aggressive treatment of the underlying cause, bleeding-driven (not prophylactic) blood product use, correct phenotype recognition (thrombotic vs hyperfibrinolytic) before choosing antifibrinolytic/heparin therapy. Rescue: escalating blood product support per bleeding severity, rFVIIa as a last resort for refractory bleeding, heparin for confirmed thrombosis-predominant presentations.

11. Escalation & De-escalation

Escalate: worsening bleeding despite standard blood product support -> consider rFVIIa (with thrombosis-risk caution); thrombosis-predominant presentation -> consider heparin per the narrow indications in Section 6.

De-escalate: underlying cause controlled, coagulation panel normalizing, no active bleeding -> discontinue blood product support (do not continue prophylactically), transition to standard monitoring.

12. ICU Discharge Criteria

Underlying cause identified and being treated/controlled, coagulation panel stable or normalizing, no active bleeding or thrombotic complications, blood product requirements resolved.

13. Documentation & Medicolegal Checklist

14. Key Guidelines

Levi M, Toh CH, Thachil J, Watson HG. Guidelines for the diagnosis and management of disseminated intravascular coagulation. Br J Haematol. 2009;145:24-33. Squizzato A, et al. Supportive management strategies for disseminated intravascular coagulation: an international consensus. Thromb Haemost. 2016;115(5):896-904.

15. Controversies

The role of FFP/cryoprecipitate/platelet transfusion in DIC remains explicitly described as "controversial" even in primary references, given the tension between correcting a genuine consumptive coagulopathy and avoiding unnecessary prophylactic transfusion. PCC use in DIC is generally avoided by expert consensus despite being a theoretically reasonable FFP alternative, reflecting genuine uncertainty rather than settled evidence given the absence of dedicated trial data in this population. Antithrombin III concentrate and heparin roles remain controversial outside the narrow subacute/APL/purpura fulminans indications noted above.

16. References

1. Coagulation Disorders in Critical Illness (DIC section). Washington Manual of Critical Care, 4th ed, 2025 (Ch. 66).
2. Patil V, Amin N, Ambulkar R, Kulkarni A. Disseminated Intravascular Coagulation and Thrombocytopenia. ICU Protocols: A Step-wise Approach, 2nd ed. Springer; 2020 (Ch. 8).
3. Levi M, Toh CH, Thachil J, Watson HG. Guidelines for the diagnosis and management of disseminated intravascular coagulation. Br J Haematol. 2009;145:24-33.
4. Squizzato A, et al. Supportive management strategies for disseminated intravascular coagulation: an international consensus. Thromb Haemost. 2016;115(5):896-904.
5. Levi M. Current understanding of disseminated intravascular coagulation. Br J Haematol. 2008;124:567-576.

See also: TTP, HUS (Hematology System) for the critical differential diagnosis; Tumor Lysis Syndrome (Renal System) and Sepsis/Septic Shock (Infectious Diseases System) for common underlying DIC triggers.