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S2 E081 Coagulation Disorders

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Coagulation Factor Disorders

von Willebrand Disease

  • A spectrum of low production to production of poorly functioning von Willebrand’s Factor.
  • von Willebrand’s factor (vWF) has two major functions.
    • vWF helps platelets to stick together in the subendothelial collagen
    • vWF binds to and maintains Factor VIII in circulation. Factor VIII breaks down very quickly in the bloodstream if not bound to vWF.
  • von Willebrand was a pediatrician who first described the disease in 1926
  • von Willebrand is the most common inherited clotting disorder

Clinical Presentation

  • Easy bruising
  • Frequent bloody noses
  • Bleeding from gums
  • Heavy menstrual periods

Labs and Studies

  • Platelets are normal
  • PT/INR is normal
  • PTT is usually prolonged
  • Total plasma von Willebrand factor (VWF) antigen
  • VWF function testing
  • Plasma factor VIII level

Treatment

  • Desmopressin
    • Synthetic antidiuretic hormone (vasopressin)
    • Stimulates release of vWF
  • Factor VIII concentrate
  • Platelet concentrates may be given in severe cases

Hemophilia A & B

  • Hemophilia A is a deficiency in factor VIII
  • Hemophilia B is a deficiency in factor IX
  • Hemophilia B is also known as Christmas disease. Stephen Christmas was the first patient diagnosed with the disease in 1953.
  • Both are X linked recessive therefore males only need inherit one mutant gene whereas females need to inherit one from each parent
  • About 30% of patients have no family history of hemophilia
  • Many different mutations cause hemophilia so there is a wide range of severity

Clinical Presentation

  • Bleeding
  • Prolonged bleeding times from minor injuries
  • Muscle and joint pain secondary to hemorrhage

Labs and Studies

  • PT/INR are normal
  • Platelets are normal
  • Bleeding time is normal
  • PTT is prolonged
  • Low factor VIII
  • Low factor IX

Treatment

  • In severe cases patients may need factor concentrate. This may be necessary two or three times a week
  • Patients may develop an antibody to factor VIII and IX secondary to treatment
  • Mild cases may be managed with Desmopressin which will elevate circulating factor VIII

Hemophilia C

  • Primarily occurs in Ashkenazi Jews
  • There is a deficiency in the coagulation factor XI
  • These patients do not have bleeding into the joints

Clinical Presentation

  • Symptoms are more mild than other hemophilias and typically do not require treatment
  • Prolonged bleeding times
  • Frequent nose bleeds
  • Heavy menstrual bleeding

Labs, Studies and Physical Exam Findings

  • No blood bleeding test will isolate a factor XI deficiency

Treatment

  • Treatment is usually unnecessary unless there is severe trauma or surgery
  • Fresh frozen plasma
  • Platelets
  • Desmopressin

Platelet dysfunction

  • Normal platelet count is between 150,000 and 450,000
  • Thrombocytopenia is defined as a platelet count below 50,000
  • Petechiae
    • Red or purple discoloration of the skin that do not blanch
    • They are 1-3mm in size
  • Purpura
    • Red or purple discoloration on the skin that do not blanch.
    • These are 3mm – 10mm in size
  • This can be poor production, increased destruction or use of platelets, splenic sequestration or dilution.
  • Megathrombocytes
    • Immature platelets recently released from the bone marrow.

Idiopathic Thrombocytopenic Purpura (ITP)

  • Autoimmune disease with anti-platelet antibodies
  • The acute form of this disease happens in children typically following an upper respiratory infection
  • The chronic form of this disease occurs in adults
  • A majority of patients have platelet antibodies

Clinical Presentation

  • Sudden onset of petechiae and purpura found on mucous membranes and on the skin
  • Severe nosebleed
  • Excessive menstrual bleeding
  • Noticeably long bleeding times

Labs, Studies and Physical Exam Findings

  • Petechiae and purpura are found on the skin and mucous membranes
  • Low platelet with no apparent reason
  • Peripheral blood smear may show megathrombocytes
  • This is a diagnosis of exclusion so a complete hematologic workup may be necessary
  • Peripheral blood smear may show megalothrombosites
  • Anti- platelet antibodies may be detectable

Treatment

  • Avoid aspirin and NSAIDS
  • Typically no treatment is necessary for either acute or chronic disease
  • Steroids
  • Splenectomy – reduces platelet destruction but the surgery has obvious risk
  • Platelet transfusion in cases of severe trauma