Pathoma: Primary Hemostasis and Related Bleeding Disorders

Question 1

The platelet plug is relatively _______.

Answer 1

weak

Question 2

The very first step of primary hemostasis is _________.

Answer 2

vasoconstriction

Question 3

What is vasoconstriction mediated by?

Answer 3

It is (1) a neural reflex and (2) a result of released endothelin

Question 4

After vasoconstriction, the next step is __________.

Answer 4

von Willebrand factor to bind to collagen

Question 5

Platelets bind von Willebrand through _________.

Answer 5

GPIb

Question 6

von Willebrand factor is held within _________.

Answer 6

Weibel-Palade bodies

Question 7

What is the first step that activates platelets?

Answer 7

Binding to vWF

Question 8

Activated platelets release _________, which activate __________.

Answer 8

thromboxane A2 and ADP; other platelets, causing them to express GPIIb/IIIa

Question 9

There are _________ and __________ platelet disorders.

Answer 9

qualitative; quantitative

Question 10

Clinically, patients with disorders of primary hemostasis present with _________.

Answer 10

easy bruising, mucosal bleeding, and skin bleeding

Question 11

The feared complication of thrombocytopenia is ___________.

Answer 11

intracranial bleeding

Question 12

Explain the cellular biology of immunogenic thrombocytopenia.

Answer 12

Patients develop IgG against GPIIb/IIIa and the splenic macrophages destroy the platelets

Question 13

IgG can actually cross the ____________.

Answer 13

placenta, so women with chronic ITP can have thrombocytopenic infants

Question 14

Other than eliminating the troublesome macrophages, what does splenectomy accomplish?

Answer 14

It also removes some of the plasma cells that are producing anti-platelet antibody.

Question 15

In addition to producing schistocytes, microangiopathic hemolytic anemia also leads to ____________.

Answer 15

thrombocytopenia due to platelet consumption

Question 16

The two kinds of microangiopathic hemolytic anemia are ___________.

Answer 16

thrombotic thrombocytopenic purpura and hemolytic uremic syndrome

Question 17

What enzyme is deficient in TTP (thrombotic thrombocytopenic purpura)?

Answer 17

ADAMSTS13; this enzyme breaks down vWF multimers; without it, vWF remains active, platelets adhere, and lots of little thrombi form.

Question 18

What bacteria causes HUS?

Answer 18

Eschericia coli 0157:H7; it produces verotoxin that damages the endothelial cells, leading to similar symptoms of TTP

Question 19

Where does E. coli 0157:H7 come from?

Answer 19

Undercooked beef

Question 20

Other than thrombocytopenia, what are symptoms of microangiopathic hemolytic anemia?

Answer 20

Fever, renal insufficiency, and CNS abnormalities

Question 21

In those with microangiopathic hemolytic anemia, what PTT/PT pattern will you see?

Answer 21

Normal!

Question 22

Bernard-Soulier results from __________.

Answer 22

genetic defects in GP1b

Question 23

Genetic defect of GPIIb/IIIa is called _________.

Answer 23

Glanzmann thrombasthenia