Bleeding Disorders

Intro to Bleeding - First Clues

• Bleeding Patterns:
  • Mucocutaneous (petechiae, purpura, epistaxis, gingival): Suggests platelet defect or von Willebrand Disease (vWD).
  • Deep tissue/Joint (hemarthrosis, hematoma): Suggests coagulation factor deficiency.
• Initial Lab Screen:
  • Platelet Count (PC)
  • Prothrombin Time (PT): Extrinsic & common pathways (Factors VII, X, V, II, Fibrinogen).
  • Activated Partial Thromboplastin Time (aPTT): Intrinsic & common pathways (Factors XII, XI, IX, VIII, X, V, II, Fibrinogen).

⭐ Isolated prolonged aPTT with bleeding often points to Hemophilia A (Factor VIII) or B (Factor IX).

Platelet Disorders - Sticky Situations

• Immune Thrombocytopenic Purpura (ITP)
  • Anti-GpIIb/IIIa IgG. Acute (kids, post-viral) / Chronic.
  • Sx: Petechiae, purpura. Dx: Isolated Plt < 100k/μL. Normal PT/APTT.
  • Rx (Kids): Observe/Steroids (Plt < 20-30k/bleed)/IVIG.
  • Rx (Adults): Steroids, IVIG, Anti-D, TPO-RAs, Splenectomy.
• Qualitative Disorders (↑BT)
  • Bernard-Soulier Syndrome (AR): ↓GpIb. Giant platelets, mild thrombocytopenia. Ristocetin: ↓agg (no normal plasma fix). 📌 BS = Big Suckers.

    ⭐ Giant platelets on peripheral smear are a hallmark of Bernard-Soulier Syndrome.

  • Glanzmann Thrombasthenia (AR): ↓GpIIb/IIIa. Agg: ↓(ADP, collagen), normal (ristocetin).
  • Storage Pool Disease: Granule defect. Impaired 2° aggregation.
• Wiskott-Aldrich Syndrome (XLR)
  • Triad: Thrombocytopenia (small platelets), Eczema, Recurrent infections. 📌 WATER. ↓IgM. oka

Coagulation Defects - Cascade Crumble

• Hallmarks: Deep tissue bleeding (e.g., hemarthrosis, intramuscular hematomas), delayed bleeding after trauma or surgery. Normal platelet count & Bleeding Time (BT).
• Lab Indicators: Prolonged Activated Partial Thromboplastin Time (APTT) for intrinsic/common pathway defects. Prolonged Prothrombin Time (PT) for extrinsic/common pathway defects.
• Hemophilia A:
  • Factor VIII deficiency; X-linked recessive inheritance.
  • ↑ APTT, normal PT.
  • Severity based on FVIII activity: Mild (>5%), Moderate (1-5%), Severe (<1%).
• Hemophilia B (Christmas Disease):
  • Factor IX deficiency; X-linked recessive inheritance.
  • ↑ APTT, normal PT. Clinically indistinguishable from Hemophilia A.
• Vitamin K Deficiency:
  • Impaired synthesis of Factors II, VII, IX, X, Protein C & S.
  • ↑ PT (Factor VII has shortest half-life: $4-6$ hours, affected first), then ↑ APTT.
  • Causes: Neonates (Hemorrhagic Disease of Newborn - HDN), malabsorption, prolonged antibiotics.
  • 📌 Mnemonic: Factors "1972" (X, IX, VII, II) + Protein C & S.

⭐ Mixing studies using normal plasma help differentiate: correction of PT/APTT indicates factor deficiency, while no correction suggests a factor inhibitor (e.g., antibody).

Acquired & Vascular - Unexpected Leaks

• Vitamin K Deficiency Bleeding (VKDB):
  • ↑PT, ↑aPTT (Factors II, VII, IX, X ↓).
  • Causes: Poor intake, malabsorption, maternal drugs.
  • Rx: Vitamin K.
• Liver Disease:
  • ↓Factor synthesis.
  • Labs: ↑PT, ↑aPTT, ↓platelets.
• Disseminated Intravascular Coagulation (DIC):
  • Triggers: Sepsis, trauma.
  • Labs: ↑PT, ↑aPTT, ↓platelets, ↓fibrinogen, ↑D-dimer; schistocytes.
• Henoch-Schönlein Purpura (HSP) / IgA Vasculitis:
  • Palpable purpura (buttocks, legs), arthritis, abdominal pain, renal.
  • Normal platelets & coags.

  ⭐ HSP: Most common childhood vasculitis; often follows URI.

• Scurvy (Vit C def): Perifollicular hemorrhage, gum bleeding.

High‑Yield Points - ⚡ Biggest Takeaways

• Hemophilia A & B: X-linked recessive; hemarthrosis, ↑aPTT, normal PT/BT.
• Von Willebrand Disease (vWD): Most common inherited; mucocutaneous bleeding, ↑BT, often ↑aPTT.
• Immune Thrombocytopenic Purpura (ITP): Autoimmune isolated thrombocytopenia; post-viral, petechiae.
• DIC: Systemic coagulation activation; consumes platelets/factors; ↑PT/aPTT/BT, ↓platelets, ↑D-dimer.
• Vitamin K Deficiency: ↓Factors II, VII, IX, X, C, S; ↑PT/aPTT.
• Platelet Defects: Bernard-Soulier (GpIb, giant platelets); Glanzmann (GpIIb/IIIa). Both ↑BT.