BIIC Pathology Lecture 4_Bleeding Disorders Flashcards
What do the Prothrombin Time (PT) and the Partial Thromboplastin Time (PTT) tests test for?
PT tests for the coagulation factors of the extrinsic and common pathways. The PTT tests for the coagulation factors of the intrinsic and common pathway.
NOTE: the coagulation factors of all three types of hemophilia (VIII, IX, XI) are tested for by the PTT
How do survey and Ehlers-Danlos Syndrome cause microvascular bleeding?
They both compromise collagen which weakens the vasculature.
What are the symptoms of Henoch-Schonlein Purpura?
IT is a systemic immune disotder of unknown cause. It causes a purpuric rash, colicky abdominal pain, polyarthlagias, and accute glomerulonephritis
What is Hereditary Hemorrhagic Telangiectasia?
It is an autosomal dominant disorder that disrupts the signaling of TGF-beta. It presents with dilated torturos blood vessels with thin walls that bleed easily. This is most common through the nose, tongue, mouth, eyes and through the GI tract
What are the two main mechanisiums of Thrombocytopenia? How can they be distinguished?
Increased Platelet destruction or reduced production. When the mechanisium is increased destruction, Bone marrow shows an increase in the number of magakaryocytes
What causes chronic ITP
It is caused by antibody mediated destruction of platlets that occures mostly in the spleen.
What can ITP be secondary to? How is a diagnosis of primart ITP made?
It can be secondary to other conditions including lupus, HIV, and B cell neoplasms. A primary diagnosis is made only after ruling out the other conditions
What are two major clinical features of chronic ITP?
The spleen shows enlargment of splenic Follicles with prominent germinal centers. Bone marrow shows an increased number of magakaryocytes. Also, you get the weird big platlets and PT and PTT are normal
What is Thrombotic thrombocytopenic Purpura (TTP)? What are the 5 clinical symptoms
It is a condition that results from inappropriate thrombocytes developing throughout the vasculature. This depleates the platelets (because they are used up in the development of thrombocytes). It presents clinically with a pentad of symptoms
1) Fever
2) Thrombocytopenia
3) microangiopathic hemolytic anemia
4) Transient Neurologic defects
5) renal failure
How does Hemolytic Uremic Syndrome (HUS) differ from TTP?
There is no nurologic envolvment, it has acute renal failure, and is frequent in children
What enzyme deficiency is associated with TTP? What does this enzyme do?
deficiency in enzyme ADAMTS13. ADAMTS13 multimers of Von Willebrand factor. In the absance of ADAMTS13 the vWF multimers promote platelet activation
What causes HUS?
HUS is typically associated with E. coli strain O157:H7 which secrets shiga-like toxin. Shiga-like toxin alters endothelial function and causes platelets to activate and aggregate
What is Bernard-Soulier syndrome?
It is an autosomal recessive disorder characterized by deficiency in platelet membrane complex Gp1b. Gp1b is what adhers to vWF. This prevents platlets from adhering and patients have sever bleeding tendencies
What is Glanzmann thrombasthenia?
It is an autosomal recesive disorder charicterized by deficiency in GpIlb-Illa. This prevents platlets from aggregating.
How do NSAIDs effect platelet function?
They inhibit it. This is because they inhibit cyclooxegenase. COX typically produces thromboxane A2 and prostaglandins, both of which play a role in causesing platelets to aggrigate
