Clin Med - Clinical Approach to Bleeding Patient Flashcards
What constitutes a referral to hematologist?
In a generally healthy patient:
- unusual, spontaneous ,prolonged or delayed bleeding
- abnormal coag test results obtained as part of preop eval
Ill patient w/ underlying medical issue
What is the significance of the age of onset in bleeding disorders?
- early age onset correlates w/ severity and indicates it’s congenital
- bleeding later in life may indicate an aquired problem or suggestive of milder congenital disease
Normal bruising in kids
- bruising over forehead, knees and shins appears when children begin to crawl
- small bruises over bony prominences common in preschool/school aged children
Abnormal bruising in kids
- in non-mobile (<9 mo) infant, significant bruising is unusual
- abnormal sites for bruising: back, buttocks, arms and shoulder
Good predictors of bleeding disorders
- family members diagnosed
- profuse bleeding w/ small wounds
- profuse surgical related bleeding
- muscle/joint- related bleeding
Fair predictors of bleeding disorder
- bruising
- epistaxis
- menorrhagia
- post-partum hemorrhage
Poor predictors of bleeding disorder
- family member that bruises easily
- gum bleeds
- hematuria
- BRBPR
What are important things to find out in a PMH about bleeding disorders?
- response to trauma (surgery, injury, dental procedures)
- rule out renal disease, malabsorption, Ehlers-Danlos
Why are women w/ bleeding disorders more likely to be diagnosed?
menstruation, therefore women w/ bleeding disorders are also more likely to be symptomatic
Most gynecological conditions present with what?
- bleeding, such as fibroids and polyps
- symptoms secondary to bleeding, such as endometriosis or ovarian cysts
menorrhagia
heavy menstrual bleeding that lasts for more than 7 days or results in the loss of more than 80mL of blood per menstrual cycle
How do you determine what constitutes blood loss more than 80mL in menstruation?
- clots greater than 1 inch in size
- low ferritin (Fe deficiency)
- changing a pad/tampon more than hourly (flooding)
Prevalence of bleeding disorders in women w/ menorrhagia across all age groups
~ 20%
How is the prevalence of bleeding disorders in women w/ menorrhagia effected in other populations?
- in adolescent pts w/ heavy periods since menarche: increases to 40%
- in women w/ idiopathic menorrhagia: increases to 50%
hemostasis
responsible for maintaining fluidity of blood in the vessels and thrombus formation upon loss of vascular integrity
What 2 things are required for normal hemostasis?
- normal number and function of platelets
- normal levels of clotting factors
If there are abnormalities in the hemostatic system what can be the result?
excessive bleeding or thrombosis
primary hemostasis
- formation of primar platelet plug
- involves platelets, blood vessel wall and vWF
Mucous membrane bleeding (epistaxis, menorrhagia, gums) points to a problem w/ what?
-primary hemostasis (platelet disorder or VWD)
What is the most common inherited bleeding disorder?
Von Willebrand Disease
-deficiency or dysfunction of VWF
Functions of vWF
- initiates platelet adhesion and mediates platelet aggregation
- transports and stabilizes factor 8
secondary hemostasis
-formation of fibrin through the coagulation cascade
What is the central event in blood coagulation?
generation of the enzyme thrombin from its precursor prothrombin
What is suggestive of problems in secondary hemostasis?
bleeding into soft tissues or joints
-e.g: deficiency of a coag factor
coagulation cascade
review flow chart
What does PT measure?
factor 7
What does aPTT measure?
- factor 8
- factor 9
- factor 11
- factor 12, HMWK, prekallikrein
if there is an increase in PT but PTT is normal what is the likely cause?
-factor 7 is the only thing that could be going wrong
What factors are associated with both PT and aPTT?
-fibrinogen
-prothrombin
-factors 5 and 10
(common pathway)
What are the 2 options for causes of prolonged PT and PTT?
-a protein/factor is missing
OR
-there is interference/inhibitor in the sample
mixing study
distinguishes between factor deficiency and factor inhibitors
examples of factor inhibitors that could cause elevated PT/PTT
- lupus anticoagulant
- specific factor inhibitor
If a mixing study corrects a prolonged PT/PTT, what was the causative source?
factory deficiency
If a mixing study does not correct a prolonged PT/aPTT, what was the causative source?
presence of inhibitor or lupus anticoagulant
Case:
elevated PT
normal platlets and aPTT
what is going on?
- factor 7 deficiency
possibilities: - Warfarin (milk vit.K deficiency)
- mild liver disease (Factor 7 is rate limiting)
What are the vit. K dependent factors?
- 2
- 7
- 9
- 10
Effect of warfarin on labs
- it is an anticoagulant
- works by interfering w/ vit. K so all vit. K dependent factors are effected
Case:
- elevated aPTT
- normal platelets and PT
- pt is bleeding
what is going on?
- factor 8, 9, 11 deficiency – hemophilia, VWD
- acquired inhibitor to above factors