Transcript Hemorrhagic diseases

Hemorrhagic diseases
Pathophysiology




Lesions of the blood vessels
Abnormal platelets
Abnormalities in the coagulation cascade
Combinations of abnormalities
Lesions of the blood vessels
 Senile purpura
 is a common, benign
condition characterised
by recurrent formation
of purple ecchymoses
(bruises) on the
extensor surfaces of
forearms following
minor trauma.
 It is also known as
Bateman purpura,
after British
dermatology
pioneer Thomas
Bateman, who first
described it in 1818.
Who is at risk of senile
purpura?
Senile purpura affects over 10% of those aged over 50 years old. It is equally common
in males and females.
Other risk factors include chronic sunlight exposure, and the use of corticosteroids and
anti-coagulants (blood thinners).
What causes senile purpura?
With age and photodamage, the dermal tissues
become thin and increase the fragility of blood vessels.
As a result, superficial vessels tear and rupture even
with negligible trauma. The subsequent extravasation of
blood into the surrounding dermis results in the
development of dark purple ecchymoses.
Persistent brown pigmentation following the resolution
of the bruises results from the deposition of
haemosiderin, a component of red blood cells.
SCURVY
 Vitamin C deficiency
gingival bleeding( ANY mucous membrane)
bleeding into muscles
bleeding into subcutaneous tissues
bleeding around hair follicles; corkscrew-like
hair
 Normal collagen synthesis depends upon the
hydroxylation of proline and lysine
 enzymes that catalyze the hydroxylation require
ascorbic acid
Hemorrhage in the hair follicles;
corkscrew hair in scurvy
Henoch-Schonlein Purpura
Hypersensitivity vasculitis in young children
Allergic purpura
Antibodies damage vascular endothelium
Fever, arthralgia, hemorrhagic urticoria, GiT
& renal disease
Osler-Weber-Rendu Syndrome
Hereditary hemorrhagic telangiectasia
Autosomal dominant inheritance
Localized malformations of capillaries and
venules of skin and mucous membranes
Recurrent epistaxis
Ataxia telangiectasia
Thrombocytopenia (low platelets
count)





Petechiae in the skin
Oozing from mucosal membranes
Bleeding within the brain
Low platelet count
Prolonged bleeding time
Causes of thrombocytopenia




Drugs, chemicals
Irradiation
Leukemia
Myelophthisis (tumor cells replace normal
bone marrow cells)
 Splenic sequestration
 Multiple blood transfusions
 DIC
Idiopathic thrombocytopenic purpura
 ITP
 Antibodies against platelets
 Damaged platelets are removes by
macrophages in the spleen
 Low platelets
 Normal/increased megakaryocytes
Thrombotic thrombocytopenic
purpura




TTP
Hyaline aggregates in small blood vessels
Low platelets
Anemia (abnormal blood vessels trap the
RBC)
 Renal, CNS abnormalities, fever
 Cause: von Willebrand disease, enzyme
deficiency
 Von WIllebrand disease: abnormal platelet
adhesion
 Aspirin intake: low TxA2; abnormal platelet
aggregation
Abnormalities in the Coagulation
cascade
 Bleeding from larger vessels
hemarthroses (joints)
large hematomas/ ecchymoses
extensive bleeding with trauma




Normal bleeding time; 2-7 min
Normal clotting time
Prothrombin time; 10- 12 sec
Partial thromboplastin time: 30- 45 seconds
 Prothrobin time: is a blood test measuresthe
time it takes for the liquid portion( plasma) of
ur blood to clot.
Abnormalities in the Coagulation
cascade
 Classic hemophilia
 Christmas disease
 Vitamin K deficiency
Classic hemophilia





Hemophilia A
Factor VIII deficiency
X-linked
Occurs worldwide
Bleeding into the :
muscles
Subcutaneous tissues
Joints
 “royal disease”
Christmas disease
 Factor IX deficiency
 Less common than Hemophilia A
 Same presentation
Vitamin K deficiency
 Vit –K is known as the clotting
vitamin.Adults: fat malabsorption in diseases
of the pancreas or small intestines
 Infants: Hemorrhagic disease of the
newborn
- intestines have small amounts of bacteria
-decrease factors II, VII, IX, X
Combination of abnormalities
 Von Willebrand disease
 DIC
 Coagulopathy of liver disease
Von Willebrand disease
 MOST COMMON HEREDITARY
BLEEDING DISORDER
 Autosomal dominant
 Decreased in vWF: Decrease platelet
adhesion to the injured blood vessel
(prolonged bleeding time)
DIC
 Consumption of platelets and coagulation
factors II, V, VIII
 Low fibrinogen
 Hemorrhage and thrombosis
 Anemia
 Cause: release of thromboplastin, triggers
the extrinsic pathway of coagulation;
increased fibrinolysis
DIC
 Obstetric complications
Toxemia
Amniotic fluid embolism
retained dead fetus
placental accidents
 Cancer – lung, pancreas, prostate, stomach
 Infection – bacteria
 Trauma
 Immune diseases
Coagulopathy of liver disease
 Liver plays a central role in hemostasis, as it
is the site of synthesis of clotting factors,
cogulation inhibitors, and fibrinolytic
proteins.
 Cause; thrombocytopenia, impaired clotting
factors.