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Pathoma KAM > 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,

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2
Q

Hemostasis involves the formation of?

A

a thrombus (clot) at the site of vessel injury

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3
Q

Hemostasis stages?

A

primary and secondary.

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4
Q

Primary hemostasis?

A

forms a weak platelet plug

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5
Q

Primary hemostasis is mediated by?

A

interaction between platelets and the vessel wall

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6
Q

Secondary hemostasis?

A

stabilizes the platelet plug

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7
Q

Secondary hemostasis is mediated by?

A

the coagulation cascade.

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8
Q

What is Step 1 in secondary hemostasis?

A

Transient vasoconstriction of damaged vessel

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9
Q

How is Step 1 in secondary hemostasis mediated?

A

by reflex neural stimulation and endothelin release from endothelial cells

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10
Q

What is Step 2 in secondary hemostasis?

A

Platelet adhesion to the surface of disrupted vessel

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11
Q

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

A

Von Willebrand factor (vWF) binds exposed subendothelial collagen,

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12
Q

How do platelets bind to vWF?

A

via the GPIb receptor

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13
Q

vWF is derived from?

A

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

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14
Q

What is Step 3 in secondary hemostasis?

A

Platelet degranulation

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15
Q

In step 3 of secondary hemostasis what does Adhesion induce?

A

shape change in platelets and degranulation with release of multiple mediators

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16
Q

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

A

ADP and TXA

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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.

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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

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19
Q

What is step 4 in secondary hemostasis?

A

Step 4?Platelet aggregation

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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;

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21
Q

What does platelet aggregation result in?

A

formation of platelet plug

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22
Q

Platelet plug?

A

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

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23
Q

What are disorders of primary hemostasis usually due to?

A

Usually due to abnormalities in platelets;

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24
Q

Disorders of primary hemostasis are divided into?

A

quantitative or qualitative disorders

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25
Q

What are some Clinical features for disorders of primary hemostasis?

A

mucosal and skin bleeding.

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26
Q

What is the most common overall symptom in mucosal bleeding?

A

epistaxis

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27
Q

What are symptoms of mucosal bleeding?

A

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

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28
Q

What are the symptoms of skin bleeding?

A

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

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29
Q

Petechiae are a sign of what?

A

thrombocytopenia and are not usually seen with qualitative disorders.

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30
Q

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

A

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

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31
Q

Platelet count

A

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

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32
Q

Bleeding time

A

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

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33
Q

Blood smear

A

used to assess number and size of platelets

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34
Q

Bone marrow biopsy

A

used to assess megakaryocytes, which produce platelets

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35
Q

What is immune thrombocytopenic purpura?

A

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

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36
Q

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

A

immune thrombocytopenic purpura

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37
Q

In ITP what results in thrombocytopenia?

A

Antibody-bound platelets are consumed by splenic macrophages

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38
Q

ITP is divided into?

A

acute and chronic forms

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39
Q

Acute form of ITP?

A

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

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40
Q

Chronic form of ITP?

A

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

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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.

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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

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43
Q

What is the Initial treatment for ITP?

A

corticosteroids.

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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.

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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,

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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).

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47
Q

What is microangiopathic hemolytic anemia?

A

Pathologic formation of plateletmicrothrombin small vessels

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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

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49
Q

What is microangiopathic hemolytic anemia seen in?

A

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

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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.

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51
Q

How does TTP lead to microangiopathic hemolytic anemia?

A
  1. Large, uncleaved multimers lead to abnormal platelet adhesion, resulting in microthrombi.
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52
Q

Decreased ADAMTS13 is usually due what?

A

an acquired autoantibody;

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53
Q

TTP is most commonly seen in?

A

adult females

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54
Q

HUS is due to?

A

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

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55
Q

HUS is classically seen in?

A

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

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56
Q

How is E Coli related to microangiopathic hemolytic anemia?

A

E coli verotoxin damages endothelial cells resulting in platelet microthrombi

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57
Q

The clinical findings for HUS and TTP include

A

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

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58
Q

Renal insufficiency is more common in HUS or TTP?

A

HUS ? thrombi involve vessels of the kidney

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59
Q

CNS abnormalities are more common in HUS or TTP?

A

TTP ? Thrombi involve vessels of the CNS

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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

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61
Q

Treatment for microangiopathic hemolytic anemia?

A

involves plasmapheresis and corticosteroids, particularly in TTP.

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62
Q

What are the qualitative platelet disorders?

A

bernard-soulier, Glanzmann thrombasthenia, asprin, uremia

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63
Q

Bernard-Soulier syndrome

A

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

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64
Q

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

A

Blood smear which shows mild thrombocytopenia with enlarged platelets.

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65
Q

Glanzmann thrombasthenia is due to?

A

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

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66
Q

Aspirin and microangiopathic hemolytic anemia?

A

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

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67
Q

Uremia and microangiopathic hemolytic anemia

A

disrupts platelet function; both adhesion and aggregation are impaired.

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68
Q

What does secondary hemostasis do?

A

Stabilizes the weak platelet plug via the coagulation cascade

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69
Q

In secondary hemostasis the coagulation cascade generates?

A

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

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70
Q

In secondary hemostasis what happens to fibrin?

A

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

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71
Q

Where are the factors of the coagulation cascade produced?

A

In the liver in an inactive state.

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72
Q

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

A

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

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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).

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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

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75
Q

Disorders of secondary hemostasis are usually due to?

A

factor abnormalities

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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).

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77
Q

Laboratory studies for Disorders of secondary hemostasis include?

A

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

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78
Q

Prothrombin time (PT)

A

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

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79
Q

Extrinsic pathway of the coagulation cascade

A

factor VII

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80
Q

Common pathway of the coagulation cascade

A

factors II, V, X, and fibrinogen

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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

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82
Q

What is involved in Hemophilia A?

A

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

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83
Q

Does Hemophilia A require a family history of it?

A

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

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84
Q

Hemphilia A presents with?

A

deep tissue, joint, and postsurgical bleeding

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85
Q

Clinical severity of hemophilia A depends on?

A

the degree of deficiency

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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 KAM (19 decks)

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