Bleeding Disorders
A bleeding disorder is an acquired or inherited tendency to bleed excessively. Normally, blood remains in the circulatory system inside the blood vessels. However, if veins or arteries are injured, they will begin to leak blood, either externally or into body tissues. The body stops the blood loss through a complex clotting process called hemostasis. During hemostasis, the injured blood vessel constricts to reduce blood flow, platelets adhere to the injury site and clump together to form a loose platelet plug, and a process of clot formation called the coagulation cascade is initiated.
Bleeding disorder occur when something goes wrong with the clotting process. If a component is missing, deficient, or dysfunctional, excessive bleeding may occur. Such bleeding may be severe, with bleeding episodes beginning in early childhood, or mild – involving bleeding for an extended period of time following a surgery, dental procedure, or trauma. Bleeding disorder may cause symptoms that range from nosebleeds, bleeding gums, bruising, heavy menstrual periods, and blood in the stool and urine to arthritis type symptoms (damage from bleeding into joints), loss of vision, and chronic anemia.
Structural problems with blood vessels:
Inherited
Hemorrhagic Telangiectasia - blood vessels are more fragile than usual leading to recurrent bleeding episodes
Ehlers-Danlos syndrome - collagen that supports blood vessels is unusually weak and elastic, making blood vessels less protected and more prone to injury
Acquired
Allergic purpura - small blood vessels are inflamed and prone to leakage, a condition thought to be an autoimmune response and that may be acute or chronic
Platelet deficiency (thrombocytopenia) or dysfunction
- Bone marrow not making enough (bone marrow disorder)
- Idiopathic thrombocytopenic purpura (ITP), decreased platelets, cause unknown, thought to have autoimmune component. May go away on its own.
- Drugs such as heparin, quinine, sulfa antibiotics, and gold salts may decrease number of platelets
- Drugs such as aspirin and nonsteroidal anti-inflammatory drugs may cause dysfunctional platelets
- Disease related: HIV, liver disease, kidney failure, leukemia, multiple myeloma, cirrhosis of the liver, and systemic lupus erythematosus may all cause decreased platelet counts
- Massive blood replacement (platelets don’t last in stored blood)
- Cardiopulmonary bypass surgery (platelets are activated and become deficient and dysfunctional)
Coagulation Factor deficiency or dysfunction
Hemophilia A (Factor VIII deficiency) - X-chromosome linked bleeding disorder that occurs primarily in males. The first bleeding episode may be with circumcision or other procedure as an infant. The severity of the bleeding caused by a factor VIII deficiency depends on its activity level (how well it is functioning). If it is very low it may cause severe life threatening bleeding, if it is moderate it may only cause mild to moderate bleeding – becoming an issue primarily when having surgery or dental procedures.
von Willebrand’s disease - relatively common, resulting from defective or missing von Willebrand factor. Von Willebrand factor is a protein that adheres platelets to the site of a blood vessel injury. It is associated with factor VIII: if VIII is deficient then vWF may be affected.
Other factor deficiencies - II, V, VII, IX, X, (Hemophilia B, also called Christmas disease)
Acquired:
- Liver dysfunction or disease
- Vitamin K deficiency
- Fat malabsorption
- Snake venom
- Therapy for bone marrow and myeloproliferative disorders
- Factor inhibitors (antibodies that target a specific clotting factor, such as factor VIII, decreasing its level and making factor replacement more of a challenge).
- Anticoagulant drugs: such as coumadin (warfarin) or heparin, these drugs are used to treat clotting disorders but in excessive amounts may cause bleeding
- Some bacterial infections
- DIC (disseminated intravascular coagulation), may cause both bleeding and clotting. It is usually an acute condition, may be from a complicated childbirth – as a result of uterine tissue contacting the blood stream, from an endotoxin produced during a severe infection, or due to certain cancers such as leukemia. DIC causes tiny clot formation throughout the body, using up clotting factors at an accelerated rate – leading to excessive bleeding.
There is no cure for most bleeding disorder. Typically, they are identified, monitored, and controlled both to prevent excessive blood loss and to prevent complications that may arise. Bleeding disorder treatment is centered around avoidance, replacement, and prevention. The degree and frequency of treatment needed will depend on the severity of the deficiency or condition, whether or not there is a stimulus for bleeding – such as surgery or trauma, and whether or not the condition progresses or worsens over time.
Simply avoiding injury, limiting physical contact sports for instance, and setting up the daily environment to avoid cuts, bruises, and trauma may be enough to minimize bleeding episodes in those with mild conditions, and under most circumstances, in those with moderate bleeding tendencies. Someone with severe deficiencies, such as Hemophilia A (factor VIII), and/or someone who is having an acute bleeding episode will need to have one or more of their coagulation factors replaced. Factor VIII and a few other individual factors are available in a concentrated form that is expensive but effective. Single and multiple factor deficiencies can also be treated with transfusions of fresh frozen plasma or plasma concentrates that contain all of the coagulation factors. These concentrates and replacements can be given during a bleeding episode and as a preventative measure before necessary surgeries and dental procedures to control excessive bleeding.
If the bleeding disorder is due to dysfunctional or deficient platelets, they may also be transfused. If the disorder is due to von Willebrand’s disease or a mild form of Hemophilia A, a drug called desmopressin (DDAVP) may be given to improve clotting temporarily. It causes the release of stored factor VIII and vWF, and may temporarily raise levels high enough and long enough to allow procedures to be performed without transfusions.
Informations obtained from National Institute of Health.