Coagulation Disorders and Treatment

The clotting factor cascade

Diseases of Hemostatsis

 Thromboembolic disorders

  • occur when undesirable clots are formed
  • Thrombus = stationary clot
  • Embolus = a travelling clot
  • Deep vein thrombosis = thrombi in veins, usually form in leg veins

  • thrombi can form in the atria during atrial fibrillation
  • R atrium thrombi can dislodge and travel to lungs = pulmonary embolism
  • L atrial thrombus can dislodge can cause CVA or arterial infarct elsewhere in the body

  • arterial thrombi and emboli can result from procedures involving arterial punctures such as angiography

 Thrombocytopenia

  • abnormal clot formation
  • deficiency of platelets
  • a result of bone marrow function is suppression
  • Etiology: chemotherapeutic agents and immunosuppressant

 Hemophilias

  • genetic clotting factor deficiency
  • classified by prolonged coagulation times that result in persistent bleeding that can be acute
  1. Hemophilia A
  • lack of clotting factor VIII
  • 80% of all cases

 2. Hemophilia B (Christmas Disease)

  • deficiency of factor IX
  • 20% of cases

Tx:

  • administration of the absent clotting factor

 3. von Willebrand’s disease (vWD)

  • decrease in the quantity or quality of von Willebrand factor, role in platelet aggregation
  • Tx: factor VIII concentrate
  • desmopressin, which promotes release of stored vWF
  • infusion of plasma products containing vWF

Four Mechanisms of hemostasis modification

Drug Classification Mechanism Type of Modification
Anticoagulants Inhibition of specific cloting factors Clot formation prevention
Anticoagulant/antiplatelets Inhibition of platelet actions Clot formation prevention
Thrombolytic Dissolution of clot thrombolytics
Antifibrinolytic Inhibition of the destruction of fibrin Antifibrinolytics – Promotion of thrombosis by inhibiting the normal removal of fibrin, keeping the clot in place for a longer period of time

Anticoagulants

  • prolong bleeding time in order to prevent clot formation
  • Tx of thromboembolic disease
  • Heparin
  • Warfarin

Mechanism of action:

  • exert a negative charge on the surface of the platelets
  • cell aggregation is inhibited

Heparin:

  • acts by enhancing the inhibitory actions of antithrombin III

Warfarin:

  • acts by inhibiting the hepatic synthesis of coagulation factors II, VII, IX and X

Low Molecular weight heparins (LMWHs)

  • inhibit active X factor
  • possess same anticoagulant activity as heparin
  • yet are less likely to thrombocytopenia
  • last 2-4 times longer than heparin

Thrombin Inhibitors

  • bind both clot-bound and circulating thrombin preventing the formation of fibrin clots

 Adams, Micheal, Patrick, Bostwick, Paula, Manuel, Holland, Leland, Norman jr, and King, Shirley, Linda. 2009. Pharmacology for Nurses: A pathological approach. Pearson Canada, Toronto.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: