Disseminated Intravascular Coagulation (DIC)


πŸ” Definition:

DIC is a systemic process resulting in widespread activation of coagulation pathways, leading to:

  • Formation of microvascular thrombi
  • Consumption of clotting factors and platelets
  • Secondary activation of fibrinolysis

➀ Result: Simultaneous thrombosis and bleeding


πŸ”¬ Pathophysiology:

πŸ”Ή Trigger β†’ Endothelial injury or inflammatory cytokines (e.g., IL-6, TNF-Ξ±) activate:

  • Tissue factor (TF) expression
  • Extrinsic coagulation cascade
  • Platelet aggregation + fibrin deposition in microcirculation

πŸ”Ή Consequences:

Pathway Activated

Consequence

Coagulation cascade

Fibrin clots β†’ Microvascular thrombosis

Fibrinolysis

↑ D-dimers from fibrin degradation

Platelet consumption

Thrombocytopenia

Clotting factor use

Coagulopathy β†’ bleeding



⚠️ Causes of DIC (Mnemonic: STOP Making New Thrombi)

Category

Examples

S: Sepsis

Gram-negative (LPS), Gram-positive, fungal

T: Trauma

Especially head trauma, crush injury

O: Obstetric

Abruption, amniotic fluid embolism, IUFD

P: Pancreatitis

Acute pancreatitis, esp. necrotizing

M: Malignancy

AML (esp. M3), adenocarcinoma

N: Nephrotic syndrome

Rare, usually in combination

T: Transfusion

Hemolytic transfusion reactions



🧬 Types of DIC

Type

Features

Acute DIC

Sudden, severe β†’ bleeding & thrombosis (e.g., in sepsis, trauma)

Chronic (compensated)

Gradual, low-grade activation (e.g., malignancy, retained fetus)



πŸ§ͺ Clinical Features

πŸ”Ή Thrombotic:

  • Digital ischemia
  • Renal failure
  • Pulmonary embolism
  • Stroke-like symptoms

πŸ”Ή Hemorrhagic:

  • Petechiae, ecchymosis
  • Bleeding from IV sites, mucosa, surgical drains
  • Hematuria, GI bleed


πŸ” Laboratory Findings in DIC

Parameter

Typical Findings

Platelet count

↓ (thrombocytopenia)

PT, aPTT, INR

↑ (prolonged)

Fibrinogen

↓ (used up in clots)

D-dimer / FDP

↑↑ (marker of fibrinolysis)

Peripheral smear

Schistocytes (MAHA)

Antithrombin III

↓



πŸ“Š ISTH Scoring System for Overt DIC (International Society of Thrombosis and Hemostasis)

Parameter

Score

Platelet count

<50 Γ—10⁹/L = 2; 50–100 = 1

Elevated D-dimer

Strongly ↑ = 3; moderate ↑ = 2

PT prolongation

>6 sec = 2; 3–6 sec = 1

Fibrinogen

<1 g/L = 1


Total score β‰₯ 5 = overt DIC


πŸ’Š Management of DIC

Cornerstone: Treat the Underlying Cause

  • Antibiotics for sepsis
  • Deliver fetus in obstetric DIC
  • Chemotherapy for leukemia
  • Surgical source control


πŸ§ͺ Supportive Therapy

Situation

Management

Active bleeding + low fibrinogen

Cryoprecipitate (fibrinogen <100 mg/dL)

Platelets <50,000 + bleeding

Platelet transfusion

PT/INR ↑ + bleeding

FFP (Fresh Frozen Plasma)

No bleeding but thrombosis

Consider low-dose heparin (controversial)



🚨 Avoid:

  • Empirical anticoagulation unless thrombotic complications dominate
  • Platelet transfusion in non-bleeding patients with mild thrombocytopenia (unless surgery planned)


🧠 Key ICU Points

  • Monitor platelets, PT/INR, fibrinogen, D-dimer daily in septic patients
  • DIC may precede overt clinical bleedingβ€”early lab clues are critical
  • Do not delay treatment of infection/sepsis for coagulopathy correction
  • Citrate anticoagulation in CRRT can worsen DIC-related hypocalcemia


🧩 DIC vs TTP vs HELLP

Feature

DIC

TTP

HELLP

PT/aPTT

↑

Normal

Usually normal

Fibrinogen

↓

Normal

Normal or ↓

D-dimer

↑↑

Mild ↑

Mild ↑

Schistocytes

+

+++

+

Platelets

↓

↓↓

↓↓