MudPhud20XX

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Kaplan biochem says vit K def will prolong PT and it doesn't mention about PTT, but it should also prolong PTT right? Since factor 9 is missing as well as 7 right?
 

SBR249

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Apparently in early stages of VitK deficiency, PT will rise first because FVII has a shorter half life. So you have a transient period where PT is elevated but PTT is relatively normal or only slightly elevated.
 
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cruCiATE

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Sep 3, 2014
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My rule of Thumb for PT and PTT:

Disturbances in Factors I, II, V, VII, X & Fibrinogen will prolong PT (extrinsic)
Disturbances in ALL (ie. any factor) except VII, XIII will prolong PTT (intrinsic)

Got it from Pathoma and have not had any issues with Heme in uWORLD regarding PT or PTT prolongation
 
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Transposony

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Some Mnemonics:

- Extrinsic pathway (PT): "Lucky" pathway, because it is has the least amount of factors (TF and Factor VII :“Lucky number 7’)
- Common pathway (PT and PTT): “Small Dollar Bills" : Factors I, II,V, and X
- Order of common pathway: "Countdown From Ten" : Factors X--V--II--I
- Intrinsic pathway (PTT): Leftover factors not part of the extrinsic and common pathways : Factors XII, XI, IX, and VIII
 
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OP
MudPhud20XX

MudPhud20XX

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Nov 26, 2013
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Some Mnemonics:

- Extrinsic pathway (PT): "Lucky" pathway, because it is has the least amount of factors (TF and Factor VII :“Lucky number 7’)
- Common pathway (PT and PTT): “Small Dollar Bills" : Factors I, II,V, and X
- Order of common pathway: "Countdown From Ten" : Factors X--V--II--I
- Intrinsic pathway (PTT): Leftover factors not part of the extrinsic and common pathways : Factors XII, XI, IX, and VIII
Awesome! thanks!