Bleeding disorder


 Excessive bleeding can result from deficiency of any one
of the many blood-clotting factors.
 Three particular types of bleeding tendencies that have
been studied to the greatest extent are discussed here:
bleeding caused by
 (1) Vitamin K deficiency,
 (2) Hemophilia, and
 (3) Thrombocytopenia (platelet deficiency).
Conditions which causes Excessive
bleeding in Humans

 Decreased Prothrombin, Factor VII, Factor IX, and
Factor X Caused by Vitamin K Deficiency.
 With few exceptions, almost all the blood-clotting
factors are formed by the liver.
 Therefore, diseases of the liver such as
 Hepatitis,
 Cirrhosis, and
 Acute yellow atrophy
 Depress the clotting system so greatly that the
patient develops a severe tendency to bleed.
Vitamin K Deficiency


 Another cause of depressed formation of clotting
factors by the liver is vitamin K deficiency.
 Vitamin K is an essential factor to a liver carboxylase
that adds a carboxyl group to glutamic acid residues
on five of the important clotting factors:
 Prothrombin,
 Factor VII,
 Factor IX,
 Factor X, and
 Protein C.

 In adding the carboxyl group to glutamic acid
residues on the immature clotting factors, vitamin K
is oxidized and becomes inactive.
 Another enzyme, vitamin K epoxide reductase
complex 1 (VKOR c1), reduces vitamin K back to its
active form.
 In the absence of active vitamin K, subsequent insuf-
ficiency of these coagulation factors in the blood can
lead to serious bleeding tendencies.

 Hemophilia is a bleeding disease that occurs almost
exclusively in males.
 In 85% of cases, it is caused by an abnormality or
deficiency of Factor VIII; this type of hemophilia is
called hemophilia A or classic hemophilia.
 In the other 15% of hemophilia patients, the
bleeding tendency is caused by deficiency of Factor
IX.
 Both of these factors are transmitted genetically by
way of the female chromosome.
HEMOPHILIA

 Females will be a hemophilia carrier, transmitting
the disease to half of her male offspring and
transmitting the carrier state to half of her female
offspring.
HEMOPHILIA


HEMOPHILIA
 The bleeding trait in hemophilia can have various degrees
of severity, depending on the character of the genetic
deficiency.
 Bleeding usually does not occur except after trauma, but in
some patients, the degree of trauma required to cause
severe and prolonged bleeding may be so mild that it is
hardly noticeable.
 For instance, bleeding can often last for days after
extraction of a tooth.

 Factor VIII has 2 active components -
 A large component with a molecular weight in the
millions and
 A smaller component with a molecular weight of
about 230,000.
 The smaller component is most important in the
intrinsic pathway for clotting, and it is deficiency of
this part of Factor VIII that causes classic hemophilia.
 Another bleeding disease with somewhat different
characteristics, called von Willebrand’s disease,
results from loss of the large component.
HEMOPHILIA

 Classic hemophilia experiences severe prolonged
bleeding, almost the only therapy that is truly
effective is injection of purified Factor VIII.
 The cost of Factor VIII is high, because it is gathered
from human blood and only in extremely small
quantities.
 Use of Recombinant Factor VIII will make this
treatment available to more patients with classic
hemophilia.
TREATMENT

 Thrombocytopenia means the presence of very low
no. of platelets in the circulating blood.
 People with thrombocytopenia have a tendency to
bleed, except that the bleeding is usually from many
small venules or capillaries.
 As a result, small punctate hemorrhages occur
throughout the body tissues.
 The skin of such a person displays many small,
purplish blotches, giving the disease the name
thrombocytopenic purpura.
THROMBOCYTOPENIA


 Bleeding will not occur until the number of platelets in
the blood falls below 50,000/μl, rather than the normal
150,000 to 300,000.
 Levels as low as 10,000/μl are frequently lethal.
 Idiopathic thrombocytopenia, which means
thrombocytopenia of unknown cause.
 Specific antibodies have formed and react against the
platelets themselves to destroy them.
 TREATMENT-By giving fresh whole blood
transfusions that contain large numbers of platelets.
 Splenectomy is often helpful, almost complete cure.
THROMBOCYTOPENIA


 An abnormal clot that develops in a blood vessel is
called a thrombus.
 Once a clot has developed, continued flow of blood
past the clot is likely to break it away from its
attachment and cause the clot to flow with the blood;
such freely flowing clots are known as emboli.
 emboli that originate in large arteries or in the left
side of the heart can flow peripherally and plug
arteries or arterioles in the brain, kidneys, or
elsewhere.
 Emboli that originate in the venous system or in the
right side of the heart generally flow into the lungs
to cause pulmonary arterial embolism.
Thromboembolic conditions


 The causes of thromboembolic conditions in the
human being are usually two:
 (1) Any roughened endothelial surface of a vessel—
as may be caused by arteriosclerosis, infection, or
trauma.
 (2) Blood often clots when it flows very slowly
through blood vessels, where small quantities of
thrombin and other procoagulants are always being
formed.
Causes


 Use of t-PA in Treating Intravascular Clots.
 Genetically engineered t-PA (tissue plasminogen
activator) is available.
 It is effective in activating plasminogen to plasmin,
which in turn can dissolve some intravascular clots.
TREATMENT

 Occasionally the clotting mechanism becomes activated in
widespread areas of the circulation, giving rise to the
condition called disseminated intravascular coagulation.
 This often results from the presence of large amounts of
traumatized or dying tissue in the body that releases great
quantities of tissue factor into the blood.
 Frequently, the clots are small but numerous, and they
plug a large share of the small peripheral blood vessels.
 This occurs especially in patients with widespread
septicemia, in which either circulating bacteria or
bacterial toxins—especially endotoxins—activate the
clotting mechanisms.
Disseminated Intravascular Coagulation


 Plugging of small peripheral vessels greatly diminishes
delivery of oxygen and other nutrients to the tissues—a
situation that leads to or exacerbates circulatory shock.
 It is partly for this reason that septicemic shock is lethal in
85 percent or more of patients.
 A peculiar effect of DIC is that the patient on occasion
begins to bleed.
 The reason for this is that so many of the clotting factors
are removed by the widespread clotting that too few
procoagulants remain to allow normal hemostasis of the
remaining blood.
Disseminated Intravascular Coagulation

Bleeding disorder

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