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==== Pathophysiology of Bleeding/Hemorrhagic Disorders in modern medicine ====

==== Pathophysiology of Bleeding/Hemorrhagic Disorders in modern medicine ====

Per biomedicine, bleeding disorders are a group of heterogenous conditions that occur when the blood cannot clot properly. In normal clotting, platelets stick together when prompted by a stimulus that invokes the clotting pathway to ultimately form a plug at the site of an injured blood vessel. Proteins in the blood (clotting factors) are activated when either a pathogen or an exposed cell wall signal rupture of the blood vessel. An interactive cascade then leads to the formation of a fibrin clot, which holds the platelets in place and allows repair to occur at the site of the injury while preventing blood from escaping the blood vessel. While too much clotting can create either a thrombus or embolus that may lead to a heart attack and stroke, the inability to form clots can be very dangerous as well, as excess bleeding will also interrupt the integrity of the vascular system.   

Per biomedicine, bleeding disorders are a group of heterogenous conditions that occur when the blood cannot clot properly. In normal clotting, platelets stick together when prompted by a stimulus that invokes the clotting pathway to ultimately form a plug at the site of an injured blood vessel. Proteins in the blood (clotting factors) are activated when either a pathogen or an exposed cell wall signal rupture of the blood vessel. An interactive cascade then leads to the formation of a fibrin clot, which holds the platelets in place and allows repair to occur at the site of the injury while preventing blood from escaping the blood vessel. While too much clotting can create either a thrombus or embolus that may lead to a heart attack and stroke, the inability to form clots can be very dangerous as well, as excess bleeding will also interrupt the integrity of the vascular system.   

Many bleeding disorders are considered to be hereditary. Hemophilia, affecting mostly males, is perhaps the most well-known bleeding disorder, although it is relatively rare (affecting about 1 in 5,000 people worldwide.  Many more people are affected by von Willebrand disease (VWD), the most common bleeding disorder in the USA. von Willebrand disease can affect both males and females.

Many bleeding disorders are considered to be hereditary. Hemophilia, affecting mostly males, is perhaps the most well-known bleeding disorder, although it is relatively rare (affecting about 1 in 5,000 people worldwide).  Many more people are affected by von Willebrand disease (VWD), the most common bleeding disorder in the USA. von Willebrand disease can affect both males and females.

Normal coagulation pathophysiology is described according to its major components:

Normal coagulation pathophysiology is described according to its major components:

I. Hemorrhagic disorders can also occur from functional abnormalities of the vascular wall and are classified as:  

a. Hereditary: hereditary hemorrhagic telangiectasia, hereditary disorders of connective tissue such as Ehlers-Danlos syndrome

b.  Secondary: infections, chemical factors or drugs, disorders of metabolism (Vitamin C or K deficiency), pathological changes of vascular wall (atherosclerosis), connective tissue diseases

c. Allergy: allergic purpura

d. Other purpuras: purpura simplex, senile purpura, mechanic purpura, paraproteinemia

 

===== I. Hemorrhagic Disorder Classifications =====

 

Hemorrhagic disorders can also occur from functional abnormalities of the vascular wall and are classified as:

 

#'''''Hereditary''''': hereditary hemorrhagic telangiectasia, hereditary disorders of connective tissue such as Ehlers-Danlos syndrome

#'''''Secondary''''': infections, chemical factors or drugs, disorders of metabolism (Vitamin C or K deficiency), pathological changes of vascular wall (atherosclerosis), connective tissue diseases

#'''''Allergy''''': allergic purpura

#'''Other purpuras''': purpura simplex, senile purpura, mechanic purpura, paraproteinemia

 

a. Thrombocytopenia: ① Diminished or defective platelet production: aplastic anemia, marrow infiltration (carcinoma, leukemia, myelofibrosis, tuberculosis, etc), infections, drugs that act on platelet production (alcohol, thiazide diuretics).② Enhanced platelet destruction: idiopathic thrombocytopenic purpura, drug-induced, thrombotic thrombocytopenic purpura. ③Sequestration of platelets: hypersplenism

a. Thrombocytopenia: ① Diminished or defective platelet production: aplastic anemia, marrow infiltration (carcinoma, leukemia, myelofibrosis, tuberculosis, etc), infections, drugs that act on platelet production (alcohol, thiazide diuretics).② Enhanced platelet destruction: idiopathic thrombocytopenic purpura, drug-induced, thrombotic thrombocytopenic purpura. ③Sequestration of platelets: hypersplenism

b. Thrombocytosis: ① Primary: essential thrombocythemia.② Secondary: infections, injury, post-splenectomy chronic myelocytic leukemia, other myeloproliferative disorders (such as polycythemia vera)

b. Thrombocytosis: ① Primary: essential thrombocythemia.② Secondary: infections, injury, post-splenectomy chronic myelocytic leukemia, other myeloproliferative disorders (such as polycythemia vera)