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

This quiz covers the causes and characteristics of bleeding disorders, including inherited and acquired defects of vessel walls, platelets, and coagulation systems. It also touches on congenital vascular disorders such as Ehlers-Danlos syndrome.