AAAAA
Forum Fanatic
Topics: 156
Posts: 1,991
|
suzy wrote:
Anyone know why PT is normal in Idiopathic thrombocytopenia purpura and PTT is prolonged?
Without even opening the textbook, you should know the pathways affecting PT & PTT are different.
So I will also review with you !
Check the coagulation cascade and understand which factor affects PT, and which pathway affect PTT !
___________________
seeking study partner in USMLE, Canadian MCC OSCE examination
|
| AAAAA
Forum Fanatic
Topics: 156
Posts: 1,991
|
A low platelet count with an otherwise normal CBC, normal PT/PTT and large platelets on the peripheral smear points to idiopathic thrombocytopenic purpura (ITP).
___________________
seeking study partner in USMLE, Canadian MCC OSCE examination
|
| AAAAA
Forum Fanatic
Topics: 156
Posts: 1,991
|
suzy wrote:
Anyone know why PT is normal in Idiopathic thrombocytopenia purpura and PTT is prolonged?
Isolated thrombocytopenia is the key finding regarding laboratory evaluation.
Truly giant platelets on peripheral smear suggest congenital thrombocytopenia.
The WBC count and hemoglobin typically are normal, unless severe hemorrhage has occurred.
Coagulation studies are normal, and a bleeding time is not useful
PT & PTT are normal !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
The disease ITP is due to antibodies IgG which has nothing to do with the coagulation cascade !
___________________
seeking study partner in USMLE, Canadian MCC OSCE examination
|
| MAZI
Forum Elite
Topics: 8
Posts: 245
|
i agree with AAAAA
in TTP and ITP , PT and PTT is normal
|
| aml
Forum Senior
Topics: 5
Posts: 132
|
PT & APTT are normal
|
| achilles
Forum Guru
Topics: 90
Posts: 1,228
|
yup PT and APTT are normal in ITP. there is isolated thrombocytopenia and megakaryocytes.
___________________
" it's not whether you get knocked down, it's whether you get up"
" i have miles to go before i sleep "
|
| suzy
Forum Junior
Topics: 13
Posts: 40
|
That is what i thought...however came across this question in one of the question books...
A 22 year od women comes to the emergency department with epistaxis and heavy periods. She has a PT of 11 seconds, a PTT of 40, and 217,000 platelets?
the answer was given as ITP...?
|
| AAAAA
Forum Fanatic
Topics: 156
Posts: 1,991
|
Still, It is very important to know about PT is affected by the extrinsic pathway. factor VII
The prothrombin time is the time it takes plasma to clot after addition of tissue factor (obtained from animals). This measures the quality of the extrinsic pathway (as well as the common pathway) of coagulation.
The speed of the extrinsic pathway is greatly affected by levels of factor VII in the body. Factor VII has a short half-life and its synthesis requires vitamin K. The prothrombin time can be prolonged as a result of deficiencies in vitamin K, which can be caused by warfarin, malabsorption or lack of intestinal colonization by bacteria (such as in newborns). In addition, poor factor VII synthesis (due to liver disease) or increased consumption (in disseminated intravascular coagulation) may prolong the PT.
___________________
seeking study partner in USMLE, Canadian MCC OSCE examination
|
| AAAAA
Forum Fanatic
Topics: 156
Posts: 1,991
|
The PT is sensitive to deficiency of extrinsic pathway factors X, VII, V, II, and fibrinogen.6,7,8 Congenital deficiencies of these factors are relatively ...
It was in the examination. PT is affected by the coagulation factors X, VII, V, II
( Factors 2,5,7,10 !!!)
___________________
seeking study partner in USMLE, Canadian MCC OSCE examination
|
| suzy
Forum Junior
Topics: 13
Posts: 40
|
thank you AAAAA, appreciate the help! 
|
| drhyd
Forum Senior
Topics: 7
Posts: 82
|
PTT here is high normal..according to usmle cd ptt is around 20 to 40... corect me if iam wrong. MY exam is on 31st july. anyone taking on that day or near to that.
ok bye
|
|
| |
| | | | | | | | | | | |
Similar forum topics