BLEEDING DISORDERS
Bleeding disorders are
the conditions characterized by prolonged bleeding time or clotting time.
Bleeding disorders are
of three types:
1. Hemophilia.
2. Purpura.
3. von Willebrand
disease.
1. Hemophilia
Hemophilia is a group of sex-linked inherited blood disorders, characterized by prolonged clotting time. However, the bleeding time is normal. Usually, it affects the males, with the females being the carriers.Because of prolonged clotting time, even a mild trauma causes excess bleeding which can lead to death. Damage of skin while falling or extraction of a tooth may cause excess bleeding for few weeks. Easy bruising and hemorrhage in muscles and joints are also common in this disease.
Causes of hemophilia
Hemophilia occurs due
to lack of formation of prothrombin activator. That is why the coagulation time
is prolonged. The formation of prothrombin activator is affected due to the
deficiency of factor VIII, IX or XI.
Types of hemophilia
Depending upon the
deficiency of the factor involved, hemophilia is classified into three types:
i. Hemophilia A or classic hemophilia: Due
to the deficiency of factor VIII. 85% of people with
hemophilia are
affected by hemophilia A.
ii. Hemophilia B or Christmas disease: Due
to the deficiency of factor IX. 15% of people with
hemophilia are
affected by hemophilia B.
iii. Hemophilia C or factor
XI deficiency: Due to the deficiency of factor XI. It is a very rare bleeding
disorder.
Symptoms of
hemophilia
i. Spontaneous
bleeding.
ii. Prolonged bleeding
due to cuts, tooth extraction and surgery.
iii. Hemorrhage in
gastrointestinal and urinary tracts.
iv. Bleeding in joints
followed by swelling and pain
v. Appearance of blood
in urine.
Treatment for
hemophilia
Effective therapy for
classical hemophilia involves
replacement of missing
clotting factor.
2. Purpura
Purpura is a disorder
characterized by prolonged bleeding time. However, the clotting time is normal.
Characteristic
feature of this disease
is spontaneous bleeding under the skin from ruptured capillaries. It causes
small tiny hemorrhagic
spots in many areas of the body. The hemorrhagic spots under the skin are
called purpuric spots (purple
colored patch like appearance). That is why this disease is called purpura.
Blood also sometimes collects in large areas beneath the skin which are called ecchymoses.
necrosis.
4. Necrosis and
infarction
Necrosis is a general
term that refers to tissue death caused by loss of blood supply, injury,
infection,
inflammation, physical
agents or chemical substances. Infarction means the tissue death due to loss of
blood supply. Loss of
blood supply is usually caused by occlusion of an artery by thrombus or embolus
and sometimes by atherosclerosis. Area of tissue that undergoes infarction is
called infarct. Infarction commonly occurs in heart, brain, lungs, kidneys and
spleen.
3. von Willebrand
Disease
von Willebrand disease
is a bleeding disorder, characterized by excess bleeding even with a mild
injury.
It is due to
deficiency of von Willebrand factor, which is a protein secreted by endothelium
of damaged blood vessels and platelets. This protein is responsible for adherence
of platelets to endothelium of blood vessels during hemostasis after an injury.
It is also responsible for the survival and maintenance of factor VIII in plasma.
Deficiency of von Willebrand factor suppresses platelet adhesion. It also
causes deficiency of factor VIII. This results in excess bleeding, which
resembles the bleeding that occurs during platelet dysfunction or hemophilia.
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