Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pathoma > CH4 - Hemostasis and Related Disorders > Flashcards

CH4 - Hemostasis and Related Disorders Flashcards

1
Q

What is hemostatsis?

A

Damage to the wall is repaired by hemostasis,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Hemostasis involves the formation of?

A

a thrombus (clot) at the site of vessel injury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Hemostasis stages?

A

primary and secondary.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Primary hemostasis?

A

forms a weak platelet plug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Primary hemostasis is mediated by?

A

interaction between platelets and the vessel wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Secondary hemostasis?

A

stabilizes the platelet plug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Secondary hemostasis is mediated by?

A

the coagulation cascade.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is Step 1 in secondary hemostasis?

A

Transient vasoconstriction of damaged vessel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is Step 1 in secondary hemostasis mediated?

A

by reflex neural stimulation and endothelin release from endothelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is Step 2 in secondary hemostasis?

A

Platelet adhesion to the surface of disrupted vessel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

In step 2 of secondary hemostasis, how does platelet adhesion occur?

A

Von Willebrand factor (vWF) binds exposed subendothelial collagen,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do platelets bind to vWF?

A

via the GPIb receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

vWF is derived from?

A

the Weibel-Palade bodies of endothelial cells and a-granules of platelets.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is Step 3 in secondary hemostasis?

A

Platelet degranulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

In step 3 of secondary hemostasis what does Adhesion induce?

A

shape change in platelets and degranulation with release of multiple mediators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the mediators released in step 3 of secondary hemostasis?

A

ADP and TXA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the role of ADP in step 3 of secondary hemostasis?

A

it is released from platelet dense granules; promotes exposure of GPIIb/IIIa receptor on platelets.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the role of TXA in step 3 of secondary hemostasis?

A

it is synthesized by platelet cyclooxygenase (COX) and released; promotes platelet aggregation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is step 4 in secondary hemostasis?

A

Step 4?Platelet aggregation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where and how do Platelets aggregate in step 4 of secondary hemostasis?

A

at the site of injury via GPIIb/IIIa using fibrinogen (from plasma) as a linking molecule;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does platelet aggregation result in?

A

formation of platelet plug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Platelet plug?

A

It is weak; coagulation cascade (secondary hemostasis) stabilizes it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are disorders of primary hemostasis usually due to?

A

Usually due to abnormalities in platelets;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Disorders of primary hemostasis are divided into?

A

quantitative or qualitative disorders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are some Clinical features for disorders of primary hemostasis?

A

mucosal and skin bleeding.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the most common overall symptom in mucosal bleeding?

A

epistaxis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are symptoms of mucosal bleeding?

A

epistaxis, hemoptysis, GI bleeding, hematuria, and menorrhagia. Intracranial bleeding occurs with severe thrombocytopenia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the symptoms of skin bleeding?

A

include petechiae (1-2 mm), ecchymoses (> 3 mm), purpura (> 1 cm), and easy bruising;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Petechiae are a sign of what?

A

thrombocytopenia and are not usually seen with qualitative disorders.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are some useful laboratory studies for disorders of primary hemostasis?

A

platelet count, bleeding time, blood smear, bone marrow biopsy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Platelet count

A

normal 150-400 K/pL; < 50 K/pL leads to symptoms,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Bleeding time

A

normal 2-7 minutes; prolonged with quantitative and qualitative platelet disorders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Blood smear

A

used to assess number and size of platelets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Bone marrow biopsy

A

used to assess megakaryocytes, which produce platelets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is immune thrombocytopenic purpura?

A

(ITP) is an autoimmune production of IgG against platelet antigens (GPIIb/IIIa)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the most common cause of thrombocytopenia in children and adults?

A

immune thrombocytopenic purpura

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

In ITP what results in thrombocytopenia?

A

Antibody-bound platelets are consumed by splenic macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

ITP is divided into?

A

acute and chronic forms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Acute form of ITP?

A

arises in children weeks after a viral infection or immunization;selflimited, usually resolving within weeks of presentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Chronic form of ITP?

A

arises in adults, usually women of chilbearing age. May be primary or secondary (e.g SLE).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is the risk involved in chronic ITP?

A

May cause short-lived thrombocytopenia in offspring since antiplatelet IgG can cross the placenta.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

laboratory findings for ITP include

A

decreased platelet count, often < 50 K/pL, Normal PT/FTT, Coagulation factors are not affected. increased megakaryocytes on bone marrow biopsy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is the Initial treatment for ITP?

A

corticosteroids.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

How will children and adults respond to the initial treatment for ITP?

A

Children respond well; adults may show early response, but often relapse.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

In addition to corticosteroids what else is used in the treatment of ITP?

A

IVIG is used to raise the platelet count in symptomatic bleeding, but its effect is short-lived,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is a permenant solution for patients with ITP?

A

Splenectomy eliminates the primary source of antibody and the site of platelet destruction (performed in refractory cases).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is microangiopathic hemolytic anemia?

A

Pathologic formation of plateletmicrothrombin small vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

How are plateletmicrothrombin formed and what is the result?

A

Platelets are consumed in the formation of microthrombi sheering the RBCs as they cross microthrombi, resulting in hemolytic anemiawith schistocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What is microangiopathic hemolytic anemia seen in?

A

thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What is TTP due to?

A

decreased ADAMTS13 which is an enzyme that normally cleaves vWF multimers into smaller monomers for eventual degradation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

How does TTP lead to microangiopathic hemolytic anemia?

A
  1. Large, uncleaved multimers lead to abnormal platelet adhesion, resulting in microthrombi.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Decreased ADAMTS13 is usually due what?

A

an acquired autoantibody;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

TTP is most commonly seen in?

A

adult females

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

HUS is due to?

A

Hemolytic uremic syndrome is due to endothelial damage by drugs or infection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

HUS is classically seen in?

A

children with E coli G157;H7 dysentery, which results from exposure to undercooked beef

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

How is E Coli related to microangiopathic hemolytic anemia?

A

E coli verotoxin damages endothelial cells resulting in platelet microthrombi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

The clinical findings for HUS and TTP include

A

Skin and mucosal bleeding, Microangiopathic hemolytic anemia, Fever, Renal insufficiency, CNS abnormalities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Renal insufficiency is more common in HUS or TTP?

A

HUS ? thrombi involve vessels of the kidney

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

CNS abnormalities are more common in HUS or TTP?

A

TTP ? Thrombi involve vessels of the CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Laboratory findings for microangiopathic hemolytic anemia include?

A

Thrombocytopenia with increased bleeding time Normal PT/PTT (coagulation cascade is not activated), anemia with schistocytes, increased megakaryocytes on bone marrow biopsy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Treatment for microangiopathic hemolytic anemia?

A

involves plasmapheresis and corticosteroids, particularly in TTP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What are the qualitative platelet disorders?

A

bernard-soulier, Glanzmann thrombasthenia, asprin, uremia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Bernard-Soulier syndrome

A

is due to a genetic GPIb deficiency; platelet adhesion is impaired.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

In Bernard-Soulier what lab test are you interested in?

A

Blood smear which shows mild thrombocytopenia with enlarged platelets.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Glanzmann thrombasthenia is due to?

A

a genetic GPIIb/IIIa deficiency; platelet aggregation is impaired.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Aspirin and microangiopathic hemolytic anemia?

A

it irreversibly inactivates cyclooxygenase; lack of TXA, impairs aggregation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Uremia and microangiopathic hemolytic anemia

A

disrupts platelet function; both adhesion and aggregation are impaired.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

What does secondary hemostasis do?

A

Stabilizes the weak platelet plug via the coagulation cascade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

In secondary hemostasis the coagulation cascade generates?

A

thrombin, which converts fibrinogen in the platelet plug to fibrin.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

In secondary hemostasis what happens to fibrin?

A

It is cross-linked, yielding a stable platelet-fibrin thrombus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Where are the factors of the coagulation cascade produced?

A

In the liver in an inactive state.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What does activation of the factors of the coagulation cascade require?

A

exposure to an activating substance, Phospholipid surface of platelets, calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What are the activating substances involved in the activation of the factors of the coagulation cascade?

A

Tissue thromboplastin activates factor VII (extrinsic pathway). Subendothelial collagen activates factor XII (intrinsic pathway).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

Where does the Calcium involved in the activation of the factors of the coagulation cascade come from?

A

derived from platelet dense granules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

Disorders of secondary hemostasis are usually due to?

A

factor abnormalities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

What are the clinical features of disorders of secondary hemostasis?

A

they include deep tissue bleeding into muscles and joints (hemarthrosis) and rebleeding after surgical procedures (e.g circumcision and wisdom tooth extraction).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

Laboratory studies for Disorders of secondary hemostasis include?

A

PT (prothrombin time) and PTT (partial thromboplastin time)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

Prothrombin time (PT)

A

measures extrinsic (factor VII) and common (factors II, V, X, and fibrinogen) pathways of the coagulation cascade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

Extrinsic pathway of the coagulation cascade

A

factor VII

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

Common pathway of the coagulation cascade

A

factors II, V, X, and fibrinogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

Partial thromboplastin time (PTT) measures

A

intrinsic (factors XII, XI, IX, VIII) and common (factors II, V, X, and fibrinogen) pathways of the coagulation cascade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

What is involved in Hemophilia A?

A

Genetic factor VIII (FVIII) deficiency, X-linked recessive (predominantly affects males)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

Does Hemophilia A require a family history of it?

A

Can arise from a new mutation (de novo) without any family history

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

Hemphilia A presents with?

A

deep tissue, joint, and postsurgical bleeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

Clinical severity of hemophilia A depends on?

A

the degree of deficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

Laboratory findings of hemophilia A include

A
  1. increased PTT; normal PT 2. decreased FVIII 3. Normal platelet count and bleeding time
87
Q

What does treatment of hemophilia A involve?

A

recombinant FVIII.

88
Q

What is christmas disease?

A

Hemophilia B - Genetic factor IX deficiency, Resembles hemophilia A, except FIX levels are decreased instead of FVIII

89
Q

What is coagulation factor inhibitor?

A

Acquired antibody against a coagulation factor resulting in impaired factor function; anti-FVIII is most common,

90
Q

Clinical and lab findings for hemophilia B?

A

its similar to hemophilia A, PTT does not correct upon mixing normal plasma with patient’s plasma (mixing study) due to inhibitor; PTT does correct in hemophilia A.

91
Q

How can you tell the difference between hemophilia A and B?

A

mixing study

92
Q

von Willebrand Disease

A

Genetic vWF deficiency

93
Q

What is the most common inherited coagulation disorder?

A

von Willebrand disease

94
Q

Does von Willebrand Disease result in qualitative or quantitative disorders?

A

Multiple subtypes exist, causing quantitative and qualitative defects;

95
Q

What is the most common type of von Willebrand Disease?

A

is autosomal dominant with decreased vWF levels

96
Q

von Willebrand Disease presents with?

A

mild mucosal and skin bleeding; low vWF impairs platelet adhesion.

97
Q

Laboratory findings for von Willebrand Disease include

A
  1. increased bleeding time 2. increased PTT: normal PT ? Decreased FVIII half-life (vWF normally stabilizes FVIII); 3. Abnormal ristocetin test
98
Q

What is usually not seen with von Willebrand Disease that is unusual

A

deep tissue, joint, and postsurgical bleeding are usually not seen.

99
Q

Why is there an Abnormal ristocetin test in von Willebrand disease

A

Ristocetin induces platelet aggregation by causing vWF to bind platelet GPIb; lack ofvWF ?> impaired aggregation ?> abnormal test.

100
Q

What is the treatment for von willebrand disease?

A

desmopressin (ADH analog), which increases vWF release from Weibel-Palade bodies of endothelial cells

101
Q

How does vitamin K deficiency relate to hemostasis?

A

Disrupts function of multiple coagulation factors

102
Q

What is involved in Vitamin K activation?

A

Vitamin K is activated by epoxide reductase in the liver

103
Q

What does Activated vitamin K do?

A

it gamma carboxvlates factors II, VII, IX, X, and proteins C and S; gamma carboxylation is necessary for factor function.

104
Q

Vitamin K deficiency occurs in?

A
  1. Newborns 2. Long-term antibiotic therapy 3. Malabsorption
105
Q

Why is there vitamin K deficiency in newborns?

A

its due to lack of GI colonization by bacteria that normally synthesize vitamin K; vitamin K injection is given prophylactic ally to all newborns at birth to prevent hemorrhagic disease of the newborn

106
Q

How does Long-term antibiotic therapy elad to Vitamin K deficiency?

A

disrupts vitamin K-producing bacteria in the GI tract

107
Q

How does Malabsorption lead to Vitamin K deficincy?

A

leads to deficiency of fat-soluble vitamins, including vitamin K

108
Q

What are some other causes of secondary hemostasis?

A

liver failure, large volume transfusion,

109
Q

How does liver failure lead to secondary hemostasis?

A

decreased production of coagulation factors and decreased activation of vitamin K by epoxide reductase;

110
Q

How is the effect of liver failure on coagulation followed?

A

followed using PT.

111
Q

How does Large-volume transfusion lead to secondary hemostasis?

A

it dilutes coagulation factors, resulting in a relative deficiency

112
Q

What is Heparin induced thrombocytopenia?

A

Platelet destruction that arises secondary to heparin therapy

113
Q

How does Heparin induced thrombocytopenia lead to thrombosis?

A

Fragments of destroyed platelets may activate remaining platelets, leading to thrombosis

114
Q

What is disseminated intravascular coagulation?

A

Pathologic activation of the coagulation cascade

115
Q

What does disseminated intravascular coagulation result in?

A
  1. Widespread microthrombi result in ischemia and infarction, 2. Consumption of platelets and factors results in bleeding, especially from IV sites and mucosal surfaces (bleeding from body orifices).
116
Q

Is disseminated intravascular coagulation usually primary or secondary?

A

Almost always secondary to another disease process

117
Q

What are some situations that may result in disseminated intravascular coagulation?

A

Obstetric complications, sepsis, adenocarcinoma, Acute promyelocytic leukemia, Rattlesnake bite

118
Q

Obstetric complications and disseminated intravascular coagulation

A

Tissue thromboplastin in the amniotic fluid activates coagulation

119
Q

Sepsis and disseminated intravascular coagulation

A

(especially with E. coli or Neisseria meningitidis) ? Endotoxins from the bacterial wall and cytokines (e.g TNF and IL-1) induce endothelial cells to make tissue factor.

120
Q

Adenocarcinoma and disseminated intravascular coagulation

A

Mucin activates coagulation.

121
Q

Acute promyelocytic leukemia and disseminated intravascular coagulation

A

Primary granules activate coagulation.

122
Q

Rattlesnake bite and and disseminated intravascular coagulation

A

Venom activates coagulation

123
Q

Laboratory findings for disseminated intravascular coagulation include?

A

decreased platelet count, increased PT/PTT, decreased fibrinogen, Microangiopathic hemolytic anemia, Elevated fibrin split products, particularly D-dimer

124
Q

What is the best screening test for DIC?

A

Elevated D-dimer

125
Q

D dimer is derived from?

A

splitting of cross-linked fibrin; D-dimer is not produced from splitting of fibrinogen.

126
Q

Treatment of DIC involves?

A

addressing the underlying cause and transfusing blood products and cryoprecipitate (comains coagulation factors), as necessary.

127
Q

What does normal fibrinolysis do?

A

Normal fibrinolysis removes thrombus after damaged vessel heals

128
Q

Tissue plasminogen activator (tPA)

A

converts plasminogen to plasmin

129
Q

Plasmin

A

cleaves fibrin and serum fibrinogen, destroys coagulation factors, and blocks platelet aggregation.

130
Q

a2-antiplasmin

A

inactivates plasmin.

131
Q

What are the disorders of fibrinolysis due to? What does this result in?

A

plasmin overactivity resulting in excessive cleavage of serum fibrinogen.

132
Q

What are some examples of disorders of fibrinolysis?

A

radical prostatectomy, cirrohsis of the liver

133
Q

How does radical prostatectomy lead to a disorder of fibrinolysis?

A

Release of urokinase activates plasmin

134
Q

How does cirrhosis of the liver lead to a disorder of fibrinolysis?

A

reduced production of a2-antiplasmin

135
Q

How does disorders of fibrinolysis present?

A

with increased bleeding (resembles DIC)

136
Q

Laboratory findings for disorders of fibrinolysis include

A

Increased PT/PTT, increased bleeding time with normal platelet count, Increased fibrinogen split products without D-dimers

137
Q

Why is there increased fibrinogen split products without D-dimers in disorders of fibrinolysis?

A

Serum fibrinogen is lysed; however, D-dimers are not formed because fibrin thrombi are absent

138
Q

Why is there increased bleeding time with disorders of fibrinolysis?

A

Plasmin blocks platelet aggregation

139
Q

Why is there increased PT/PTT with disorders of fibrinolysis?

A

Plasmin destroys coagulation factors.

140
Q

What is the treatment for disorders of fibrinolysis?

A

it is aminocaproic acid, which blocks activation of plasminogen.

141
Q

What is thrombosis?

A

Pathologic formation of an intravascular blood clot (thrombus), Can occur in an artery or vein,

142
Q

What is the most common location for thrombosis?

A

it is the deep veins (DVT) of the leg below the knee

143
Q

What is thrombosis characterized by?

A

lines of Zahn and attachment to vessel wall

144
Q

What are the lines of Zahn?

A

alternating layers of platelets/fibrin and RBCs

145
Q

What distinguishes thrombus from a postmortem clot?

A

lines of Zahn and attachment to vessel wall

146
Q

What are three major risk factors for thrombosis?

A

disruption in blood flow, endothelial cell damage, and hypercoagulable state (Virchow triad)

147
Q

What is normal blood flow?

A

blood flow is normally continuous and laminar; keeps platelets and factors dispersed and inactivated

148
Q

What happens to blood flow that causes an increase in the risk for thrombosis?

A

Stasis and turbulence of blood flow increases risk for thrombosis

149
Q

What are some examples of disruption of normal blood flow?

A

Immobilization?increased risk for deep venous thrombosis 2. Cardiac wall dysfunction (e.g arrhythmia or myocardial infarction) 3. Aneurysm

150
Q

How does endothelial cell damage increase the risk for thrombosis?

A

Endothelial damage disrupts the protective function of endothelial cells, increasing the risk for thrombosis

151
Q

How do endothelial cells prevent thrombosis?

A
  1. Block exposure to subendothelial collagen and underlying tissue factor 2. Produce prostacyclin (PGI2) and NO, 3. Secrete heparin-like molecules, 4. Secrete tissue plasminogen activator (tPA) 5. Secrete thrombomodulin
152
Q

How does endothelial cells use the secretion of tPA to prevent thrombosis?

A

converts plasminogen to plasmin, which (1) cleaves fibrin and serum fibrinogen, (2) destroys coagulation factors, and (3) blocks platelet aggregation

153
Q

How does the secretion of thrombomodulin from endothelial cells prevent thrombosis?

A

redirects thrombin to activate protein C, which inactivates factors V and VIII

154
Q

How do endothelial cells use the secretion of heparin-like molecules to prevent thrombosis?

A

augment antithrombin III (ATIII) which inactivates thrombin and coagulation factors

155
Q

How does endothelial cells use the production of prostacyclin (PGI2) and NO to prevent thrombosis?

A

vasodilation and inhibition of platelet aggregation

156
Q

What are the causes of endothelial cell damage?

A

atherosclerosis, vasculitis, and high levels of homocysteine

157
Q

Vitamin B12 and folate deficiency result in?

A

mildly elevated homocysteine levels, increasing the risk for thrombosis.

158
Q

What does folic acid circulate as?

A

methyl-THF (tetrahydrofolate, THF) in the serum,

159
Q

How does THF participate in the synthesis of DNA precursors?

A

Methyl is transferred to cobalamin (vitamin B12) which transfers methyl to homocysteine resulting in methionine

160
Q

What does a lack of vitamin B12 or folate lead to?

A

decreased conversion of homocysteine to methionine resulting in buildup of homocysteine

161
Q

Cystathionine beta synthase (CBS) deficiency results in what?

A

high homocysteine levels with homocystinuria,

162
Q

What does CBS do?

A

CBS converts homocysteine to cystathionine

163
Q

CBS deficiency leads to?

A

homocysteine buildup

164
Q

CBS deficiency is characterized by?

A

vessel thrombosis, mental retardation, lens dislocation, and long slender fingers

165
Q

what is a hypercoagulabe state due to?

A

excessive procoagulant proteins or defective anticoagulant proteins; may be inherited or acquired

166
Q

What is the classic presentation for a hypercoagulable state?

A

recurrent DVTs or DVT at a young age, usually occurs in the deep veins of the leg; other sites include hepatic and cerebral veins

167
Q

What are some causes of a hypercoagulable state?

A

protein C and S deficiency, factor V Liden deficiency, prothrombin 20210A, ATIII deficiency, oral contraceptives

168
Q

protein C or S deficiency

A

(autosomal dominant) decreases negative feedback on the coagulation cascade (hypercoagulable state)

169
Q

Proteins C and S normally do what?

A

inactivate factors V and VIII

170
Q

Protein C and S deficiency increases the risk for what?

A

warfarin skin necrosis

171
Q

What does the initial stage of warfarin therapy result in?

A

a temporary deficiency of proteins C and S (due to shorter half-life) relative to factors II, VII, IX, and X

172
Q

In preexisting C or S deficiency, what danger does the initial stage of warfarin therapy present?

A

a severe deficiency is seen at the onset of warfarin therapy increasing the risk for thrombosis, especially in the skin

173
Q

What is Factor V Leiden?

A

a mutated form of factor V that lacks the cleavage site for deactivation by proteins C and S

174
Q

What is the most common inherited cause of hypercoagulable state?

A

Factor V Leiden

175
Q

What is Prothrombin 20210A?

A

it is an inherited point mutation in prothrombin that results in increased gene expression,

176
Q

Increased prothrombin (prothrombin 20210A) results in what?

A

increased thrombin, promoting thrombus formation.

177
Q

What does ATIII deficiency result in?

A

decreases the protective effect of heparin-like molecules produced by the endothelium, increasing the risk for thrombus

178
Q

What do heparin-like molecules normally do?

A

activate ATIII, which inactivates thrombin and coagulation factors

179
Q

What happens in ATIII deficiency?

A

PTT does not rise with standard heparin dosing.

180
Q

Pharmacologic heparin works by doing what?

A

binding and activating ATIII

181
Q

High doses of heparin in someone with ATIII deficiency results in what?

A

activate limited ATIII; Coumadin is then given to maintain an anticoagulated state.

182
Q

How are oral contraceptives associated with a hypercoagulable state?

A

Estrogen induces increased production of coagulation factors, thereby increasing the risk for thrombosis

183
Q

What is an embolism?

A

Intravascular mass that travels and occludes downstream vessels; symptoms depend on the vessel involved

184
Q

What is a thromboembolus due to?

A

a thrombus that dislodges;

185
Q

What is the most common type of embolus?

A

thromboembolus (>95%)

186
Q

Atherosclerotic embolus is due what?

A

to an atherosclerotic plaque that dislodges.

187
Q

Atherosclerotic embolus is characterized by what?

A

the presence of cholesterol clefts in the embolus

188
Q

Fat embolus is associated with what?

A

bone fractures, particularly long bones, and soft tissue trauma

189
Q

When does a fat embolus develop?

A

while fracture is still present or shortly after repair

190
Q

What is fat embolus characterized by?

A

dyspnea (fat, often with bone marrow elements, is seen in pulmonary vessels and petechiae on the skin overlying the chest

191
Q

Gas embolus is classically seen in what?

A

decompression sickness.

192
Q

Decompression sickness

A

Nitrogen gas precipitates out of blood due to rapid ascent by a diver (gas embolus)

193
Q

What does gas embolus presents with?

A

joint and muscle pain (bends) and respiratory symptoms (chokes)

194
Q

Caisson disease

A

Chronic form of gas embolus that is characterized by multifocal ischemic necrosis of bone

195
Q

Gas embolus and laproscopic surgery?

A

may also occur during laparoscopic surgery (air is pumped into the abdomen)

196
Q

Amniotic fluid embolus

A

enters maternal circulation during labor or delivery

197
Q

How does amniotic fluid embolus present?

A

with shortness of breath, neurologic symptoms, and DIC (due to the thrombogenic nature of amniotic fluid)

198
Q

How is amniotic fluid embolus characterized?

A

by squamous cells and keratin debris, from fetal skin, in the embolus

199
Q

pulmonary embolism is usually due to?

A

thromboembolus;

200
Q

What is the most common source of thromboembolus?

A

deep venous thrombus (DVT) of the lower extremity usually involving the femoral, iliac, or popliteal veins

201
Q

Pulmonary embolism is most often clinically silent because?

A

the lung has a dual blood supply via pulmonary and bronchial arteries and the embolus is usually small (self-resolves)

202
Q

When does pulmonary infarction occur?

A

if a large- or medium-sized artery is obstructed in patients with pre-existing cardiopulmonary compromise; only 10% of PEs cause infarction

203
Q

How does pulmonary infarction present?

A

with shortness of breath, hemoptysis, pleuritic chest pain, and pleural effusion

204
Q

In pulmonary infarction what does the V/Q lung scan show?

A

a mismatch; perfusion is abnormal.

205
Q

In pulmonary infarction what does the spiral CT show?

A

a vascular filling defect in the lung

206
Q

What is useful in determining DVT?

A

lower extremity Doppler ultrasound is useful to detect DVT

207
Q

In pulmonary infarction what happens the the D-dimer

A

it is elevated

208
Q

In pulmonary infarction what does gross examination reveal?

A

a hemorrhagic, wedge-shaped infarct

209
Q

In pulmonary infarction sudden death occurs with?

A

a large saddle embolus that blocks both left and right pulmonary arteries or with significant occlusion of a large pulmonary artery

210
Q

In pulmonary infarction sudden death with a large saddle embolus, death is due to?

A

electromechanical dissociation

211
Q

Pulmonary hypertension may arise with what?

A

chronic emboli that are reorganized over time.

212
Q

Systemic embolism is usually due to?

A

thromboembolus

213
Q

Where does systemic embolism most commonly arise?

A

in the left heart and travels down systemic circulation to occlude flow to organs, most commonly lower extremities

Pathoma (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions