Bleeding Disorder: Causes and Characteristics

Bleeding Diathesis

• Caused by inherited or acquired defects of vessel wall, platelets number and/or function, and coagulation system
• Characterized by spontaneous bleeding and extensive bleeding after minimal trauma

Vascular Disorders

• Congenital:
  • Ehlers-Danlos syndrome (increased skin elasticity, capillary fragility, and hypermobility of joints)
  • Hereditary hemorrhagic telangiectasia (thin and dilated capillary walls, autosomal dominant, presents in adults)
  • Giant hemangioma (angiomatous malformation)
• Acquired:
  • Scurvy (vitamin C deficiency)
  • Senile, sepsis (meningococcal), steroid use
  • Malignancy
  • Immune (vasculitis)
  • Idiopathic (purpura simplex, more common in females)

Clinical Picture

• Purpura, raised and ecchymosis
• Mucosal bleeding
• Internal bleeding
• Rare muscle bleeding
• No hemarthrosis
• Investigation: positive Hess test, prolonged bleeding time, normal CBC, PT, APTT, and clotting time

Henoch-Schonlein Purpura

• Usually seen in children, often following an acute upper respiratory tract infection
• Immunoglobulin A (IgA) mediated vasculitis
• Characterized by purpuric rash, localized edema, and itching on the buttocks and extensor surfaces of the lower legs and elbows
• Can also cause painful joint swelling, hematuria, and abdominal pain
• Self-limiting condition, but can occasionally lead to renal failure
• Systemic affection may require steroid therapy
• Investigation: positive Hess test, normal platelets, PT, and APTT, elevated IgA, and skin biopsy showing IgA deposits

Platelet Disorders

• Disorders of platelet number:
  • Thrombocytopenia
  • Thrombocytosis
• Disorders of platelet function

Classification of Platelet Disorders

• Quantitative disorders
  • Abnormal distribution
  • Dilution effect
  • Decreased production
  • Increased destruction
• Qualitative disorders
  • Inherited disorders (rare)
  • Acquired disorders
  • Medications
  • Chronic renal failure
  • Cardiopulmonary bypass

Decreased Marrow Production of Megakaryocytes

• Congenital disorders:
  • Thrombocytopenia with absent radii (TAR)
  • Fanconi's anemia (pancytopenia)
• Acquired disorders:
  • Marrow infiltration with malignant cells
  • Marrow fibrosis
  • Aplastic and hypoplastic anemias (idiopathic, drugs, toxins)
  • Deficiency states (vitamin B12, folate)
  • Paroxysmal nocturnal hemoglobinuria

Splenic Sequestration of Circulating Platelets

• Splenic enlargement due to tumor infiltration
• Splenic enlargement due to portal hypertension

Increased Consumption

• Disseminated intravascular coagulation (DIC)
• Hemolytic-uremic syndrome
• Thrombotic thrombocytopenic purpura

Increased Destruction of Circulating Platelets

• Primary:
  • Idiopathic thrombocytopenic purpura (ITP), acute and chronic
• Secondary:
  • Drug-induced thrombocytopenia
  • Chronic autoimmune disorders, SLE
  • Infection (HIV), EBV
  • Malignancies, lymphoma

Idiopathic Thrombocytopenic Purpura (ITP)

• Most common cause of isolated thrombocytopenia
• Autoimmune disease with antiplatelet antibodies and shortened platelet life span
• Forms of ITP:
  • Acute ITP:
    • Children (90% of pediatric cases of immune thrombocytopenia)
    • Preceded by viral infection
    • Sex equal
    • Spontaneous recovery within 4-6 weeks in 90% of patients
  • Chronic ITP:
    • 20-40 years
    • Women predominance (F:M=3:1)
    • Chronic course
    • Secondary to other autoimmune diseases

Clinical Features of ITP

• Petechiae
• Ecchymoses
• Mucosal membrane bleeding
• Menorrhagia
• Rare internal, intracranial bleeding
• No organomegaly

Diagnosis of ITP

• Platelet count