Disorders characterized by increased vascular fragility

on 9.2.09 with 0 comments

  • These diseases are also called nonthrombocytopenic purpuras because they aren’t associated with platelet abnormalities; they make petechial and purpuric hemorrhages on the skin and mucus membranes without a lot of bleeding

  • Platelet count, bleeding time, and other coagulation tests are usually normal unless DIC complicates the issue

  • Microbiological damage to the vessels (vasculitis)

    • From bacteria: menigococcemia, sepsis from other bacteria, typhoid F, scarlet F, leptospirosis, diphtheria, TB

    • Viruses like measles and small pox

    • Rickettsial diseases like RMSF and typhus

    • Protozoal diseases like malaria and toxoplasmosis

  • Drug reactions

    • Often from Abs made to drugs and vascular deposition of immune complexes with production of hypersensitivity (leukocytoclastic = necrotic neutrophils around the blood vessels) vasculitis

    • Examples

      • Atropine

      • Quinine

      • Phenacetin

      • Aspirin

      • Coumarin

  • D/o of collagen production lead to decreased vessel support

    • Inherited

      • Ehlers-Danlos syndrome

      • Osteogenesis imperfecta

      • Pseudoxanthoma elasticum

    • Acquired

      • Scurvy

      • Corticosteroid purpura (protein wasting)

      • Cushing’s syndrome (protein wasting)

      • Senile purpura (atrophy of collagen)

  • Henoch-Schonlein purpura

    • Systemic hypersensitivity reaction of unknown cause with vascular deposition of immune complexes

    • The purpuric rash is seen with colicky pain, polyarthralgia, and acute GN

    • A barium enema will show a “thumbprint” sign from filling defects of the colon due to bleeding into and edema of the bowel (impinges on lumen)

  • Hereditary hemorrhagic telangiectasis

    • AD d/o

    • Associated with dilated, tortuous, thin walled blood vessels

  • Amyloidosis

    • Primary or secondary lymphoproliferative syndrome

    • Amyloid infiltration of blood vessel walls weaken them and cause mucocutaneous petechiae

Category: Medical Subject Notes , Pathology Notes



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