Platelets Too Few and Too Many Flashcards
1
Q
thrombocytopenia
A
- too few platelets
2
Q
thrombocytosis other name
A
- thrombocythemia
3
Q
thrombocytosis
A
- too many platelets
4
Q
when evaluating a patient with thrombocytopenia, first make sure the patient doesn’t have
A
- pseudothrombocytopenia
5
Q
another name for pseudothrombocytopenia
A
- platelet clumping
6
Q
platelet count in tubes in pseudothrombocytopenia
A
- falsely low
- make a substance that causes platelets to clump when blood added to EDTA tubes
7
Q
platelet count in vivo in pseudothrombocytopenia
A
- higher
8
Q
bleeding consequences in pseudothrombocytopenia
A
- no bleeding consequences
9
Q
treatment in pseudothrombocytopenia
A
- no treatment needed
10
Q
first symptoms appear at a platelet count of
A
50-20
11
Q
usually need to treat at a platelet count of
A
20-10
12
Q
risk of spontaneous intracranial hemorrhage at a platelet count of
A
< 10
13
Q
three categories of thrombocytopenia
A
- underproduction
- peripheral destruction
- splenic sequestration
14
Q
underproduction due to
A
- marrow failure
- marrow infiltration
- marrow toxins
15
Q
marrow failure conditions
A
- myelodysplasia
- asplastic anemia
- vitamin deficiencies
16
Q
marrow infiltration conditions
A
- tumor
- granulomatous diseases
- fibrosis
- leukemias
- lymphomas
17
Q
marrow toxins
A
- drugs (chemo)
- radiation
- infections
- alcohol
18
Q
non-immune mechanisms of peripheral destruction
A
- DIC
- TTP
19
Q
immune mechanism of peripheral destruction
A
- antibody mediated platelet destruction
20
Q
antibody mediated platelet destruction
A
- provoked by drugs
- associated with HIV
- associated with other autoimmune disease
- can be idiopathic
21
Q
DIC characterized by
A
- abnormal activation of coagulation
- generation of thrombin
- consumption of clotting factors
- destruction of platelets
- activation of fibrinolysis
22
Q
DIC diagnosis
- PT
- platelets
- fibrinogen
- D dimers
- peripheral smear
A
- elevated PT
- low platelets
- low fibrinogen
- elevated D dimers
- schistocytes on peripheral smear
23
Q
elevated PT in DIC due to
A
- consumption of factor VII
24
Q
treatment of DIC
A
- treat underlying cause
25
DIC etiologies
- gram negative sepsis
- severe burns
- obstetrical disasters
- leukemias
- shock
- insect or snake venoms
26
supportive measures of DIC
- transfusion of platelets
- clotting factors (FFP)
- fibrinogen (cryoprecipitate)
27
TTP characterized by
- abnormal activation of platelets and endothelial cells with vWF and fibrin deposition in microvasculature
- peripheral destruction of platelets and red cells
28
TTP diagnostic features
- MAHA
- low platelets
- fever
- neurologic manifestations
- renal manifestations
29
MAHA features in TTP
- elevated LDH
- elevated bilirubin
- schistocytes
30
renal manifestations in TTP
- hematuria
- proteinuria
- elevated BUN/creatinine
31
TTP etiology
- due to antibody against ADAMTS-13 protease
32
role of ADAMTS-13 protease
- cleaves large molecular weight vWF
33
result of antibody blocking function of ADAMTS-13 protease
- accumulation of large molecular weight vWF multimers
34
result of large vWF multimers
- abnormal platelet activation
35
TTP can be induced by
- drugs
- pregnancy
- HIV/AIDS
36
drugs that can induce TTP
- quinine
- cyclosporine
- tracrolimus
37
% fatality of TTP without therapy
> 90%
38
% who survive TTP with therapy
80-90%
39
TTP treatment relies on
- plasma exchange (PLEX)
| - corticosteroids
40
secondary measures of TTP treatment
- spenectomy
| - rituximab
41
TTP and platelet transfusions
- avoid platelet transfusions
42
HUS preciptated by
- diarrheal illness
| - shiga toxin E. coli
43
atypical HUS
- HUS without diarrhea
44
atypical HUS cause
- inherited disorder of complement regulation
45
trigger of atypical HUS
- infection
| - pregnancy
46
clinical features of Atypical HUS
- MAHA
- thrombocytopenia
- renal failure
- evidence of complement activation
47
treatment of atypical HUS
- plasma exchange
| - eculizumab
48
drugs that can cause thrombocytopenia
- beta lactams
- trimoprim-sulfamethoxozole
- sulfa drugs
- quinine
- heparin
49
heparin induced cytopenia caused by
- antibodies against heparin/PF4
50
if platelets fall while patient is on heparin
- stop heparin immediately
51
heparin induced thrombocytopenia can also lead to
- thrombosis
52
diagnostic test for ITP-
- no diagnostic test
53
suspect ITP in patients with
- isolated thrombocytopenia
54
In adults specific therapy required for ITP if patient's platelet count is
- < 20-30
55
initial therapy of ITP relies on
- corticosteroids
56
if platelet count is <10 or patient is bleeding In ITP, what do you use to treat
- IVIg
57
second line treatment of ITP
- rituximab
| - splenectomy
58
blood bank platelet count
- will have a platelet count above which they will not release platelets
- not a magic number that should serve as a trigger to transfuse platelets
59
platelet transfusions in ITP
- only if severe bleeding
60
platelet transfusion in TTP
- contraindicated
61
platelet transfusion in DIC
- give to treat bleeding
62
platelets transfusions for splenic sequestration
- only for severe bleeding
63
hypo production platelet number to transfuse
- 10K
