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What factor is deficient in Hemophila A?
Factor VIII deficiency
Which is more common, Hemophilia A or B?
What factor is deficient in Hemophelia B?
Factor IX deficiency
Can you clinically distinguish Hemophilia A from B?
How are both Hemophilias inherited?
Both A and B are sex linked recessive so will occur most often in males.
Again Hemophilia A (factor 8 has two parts, coagulant factor 8 and vWF) so typically Hemophilia A have normal amount of ___ but decreased or defective ____.
normal amount of vWF but decreased or defective 8c.
What is the incidence of Hemophilia A?
Incidence is 1/10,000males
What are the % of Hemopilia disorder for A, B, & C?
What are the different levels of bleeding severity in Hemophilia A?
- Mild: factor level of 5-30% usually only have problem w/bleeding after major trauma
- Moderate: factor level of 1-5% of normal and they may occasionally bleed spontaneously.
- Severe: most patient have the severe form, less than 1% of normal levels of the factor and they will frequently have spontaneous bleeding.
How would you diagnose Hemophilia A?
- Based on history of bleeding
- Prolonged aPTT
- Factor assays showing deficient factor 8c normal levels of vWF and normal levels of factor 9 and 11.
- Typically the PT & bleeding time will be normal
What is the treatment for Hemophilia A? What is the target if the patient is bleeding and what is the target for elective surgery?
- Factor 8.
- Common target would be factor level of 25% if patient is bleeding, replace until level of 25%.
- For elective surgery the level is elevated to 50-100% of normal.
What do hemophiliacs who have gotten recombinant factor 8 develop? Why is this important to know?
- Develop inhibitors to the factor.
- Repeated increased amount of concentration are necessary to get the amount you want because they are inhibiting or destroying some of what you’re giving.
Besides Factor 8, what else can we give to someone w/Hemophilia A?
- DDAVP will also increase plasma factor 8c and vWF and may be helpful and mild Hemophilia A.
- How responsive the patient is will be variable .
- Giving IV dose is 0.3mcg/kg in 50ml of NS over 15-30min.
- Unfortunately tachyphylaxis develops but dose help. Limited usefulness long term.
What is the incidence of Hemophilia B?
Incidence of 1/25,000
How do we treat Hemophilia B??
If patient has minor bleeding, managed by increasing factor level from 20-30% of normal but again pre-op of 50-100% are desired. Factor 9 recombinant concentrate is what’s used.
How is Hemophilia C inherited?
What else is Hemophilia C called?
What factor is deficient in Hemophilia C?
Hemophilia C is found in ~__% of individual of Ashkenazi Jewish decent of eastern Europe.
Does Hemophilia C have the same bleeding tendencies as the other Hemophilias?
No, it has a mild bleeding tendency
What is the bleeding tendency in Hemophilia B?
What are the anesthesia implications for Hemophilia A?
Factor VIII:C levels near normal
- Initial infusion: 50-60 U/kg (3500-4000 U for 70 kg)
- 25 – 30 U/kg q 8 – 12 hours (factor VIII ½ life = 12 hours)
What should we avoid during anesthesia for Hemophiliacs?
- Nasal intubation
- IM injections
- Regional anesthesia
For each unit/kg given the plasma factor 8 level will increase about __%
What is different about the pediatric hemophiliac patient?
Pedi: ½ life of factor 8 may be short at 6hrs, more frequent dosing w/lab assays would be needed to monitor.
How long would we continue therapy for hemophiliacs during the post-op period?
- Therapy continued up to 2 weeks post-op to avoid any bleeding that would interfere w/wound healing.
- Bone or joint continue up to 4- 6weeks post-op.
In hemophiliac treatment, those antibodies or inhibitors of concentrate may develop and can appear as soon as __-___ days after receiving the therapy.
What is the most common congenital bleeding disorder?
- von Willebrand's disease
- Prevalence ranges form 1:100 – 3:100,000 (~1%)
Is von Willebrand's disease autosomal dominant or recessive?
Is it platelet quantity or quality that's effected in von Willebrand's disease?
- Quality!--the function is affected
- Platelet adhesion is the problem. vWF is essential for platelet plug formation because it mediates the adhesion of the platelets to the subendothelial surface of the vessel.
There are three types of von Willebrand's disease, which is most common?
Type 1 (80% of cases)
How is type 1 von Willebrand's inherited?
autosomal dominant (and a mild disease)
What is type 1 von Willlebrand's disease?
decreased amount of vWF
What is the treatment for von Willebrand's disease?
- DDAVP so patient will usually respond w/anywhere from 2-5fold increase in factor 8 (the von willebrand part of factor 8) within 30min of getting DDAVP.
- One dosing reference: 0.3mcg/kg in 50ml given over 30min IV. But also recommends checking w/hematologist.
What is type 2 von Willebrand's disease? What is the treatment
qualitative problem (Abnormal vWF)
There are actually several subtypes but won’t go into particulars but referred to as 2a, 2b, 2n.
And consequently DDAVP has a variable effect
How is vWF affected in type 3 von Willebrand's disease?
- Absence of the factor.
What is the treatment for type 3 von Willebrand's disease?
- Pt can have very little or no plasma or platelet vWF so they don’t respond to DDAVP.
- Could consider giving factor 8, vWF, concentrate 50Iu/day for major surgery and every other day for minor surgery. Again consultation w/ hematologist is recommended.
The anesthesia implications for von Willebrand's disease will depend on type, severity, & surgical procedure. however, DDAVP optimizes levels of vWF, how does it do this??
When giving IV it will stimulate release of vWF from endothelial cells to get an immediate increase in vWF and factor 8 activity. That will consequently will help to enhance platelet function and decrease bleeding time.
How long does DDAVP last?
- In general response to DDVAP lasts 12-24hrs at best and tachyphylaxis develops.
- Because of relatively short duration and tachyphylaxis, it’s really considered to be most useful for treatment severe bleeding and surgical prophylaxis
Besides DDAVP, what else can be given for von Willebrand's disease?
- Cryoprecipitate or purified concentrate containing vWF/Factor 8 complex can also be given.
- If there is severe type 1 or 3 then in general manage like Hemophilia A, increase factor 8 levels to 50%-70% for major surgery and 30-50% for minor surgery or less severe bleeding.
Recommended doses of both vWF and factor 8 for bleeding and surgical prophylaxis:
initial dose of 40-75IU/kg. followed by repeat doses of 40-60 at 8-12hr intervals. After bleeding is controlled a single daily dose is usually sufficient
What are the acquired coagulopathies
- immune-mediated factor defects
- Non immune-mediated factor defects
what are the non immune mediated factor defects of the acquired coagulopathies?
- ↓ synthesis (liver disease or in neonates)
- Abnormal production (coumadin therapy)* Most common cause
- Vitamin K deficiency
- Factor loss/sequestration (nephrotic syndrome)
- Factor destruction or consumption (DIC)
- Factor inactivation (thrombolytic therapy)
What are the immune mediated factor defects in the acquired coagulopathies?
- Acquired hemophilia A – most common
- Alloantibody factor inhibitors
Of the immune mediated factor defects in the acquired coagulopathies, which is most common?
Acquired Hemophilia A
What are the % for Alloantiboody factor inhibitors of Hemophilia A and B for the acquired coagulopathies?
- 4 – 30% of hemophilia A patients
- 5 % of hemophila B patients
What could cause the acquired platelet disorder thrombocytopenia d/t bone marrow suppression??
- Radiation & chemo Rx
- Chronic disease: hemolytic uremic syndrome
What types of drugs cause BM suppression?
- thiazide diuretics
What types of infections can cause bone marrow supression.
- Hep B, TB, and any situation of overwhelming sepsis regardless of the specific agent).
- Also associated w/chronic disease, uremia, liver disease
What types of things could cause an increase in non-immune mediated consumption of platelets causing acquired thrombocytopenia?
- Tissue trauma (burns or crush injuries)
- Vascular grafts
- Toxemia: HELLP syndrome
What types of things could cause an increase in immune mediated consumption of platelets causing acquired thrombocytopenia?
- Autoimmune disorders (TTP, ITP, & HIT)
What are the causes of acquired thrombocytopenia?
- Decreased bone marrow production
- Increased non-immune mediated consumption
- Immune-mediated consumption
What types of drugs can cause immune mediated consumption of platelets?
- Patient here often present w/platelet count less than 20,000. The drugs essentially trigger antibody formation to the platelets.
What are the autoimmune types of disorders causing immune mediated consumption of platelets?
- SLE, RA, Also thromboticytopenic purpura.
- TTP, ITP and HIT
How can we diagnose ITP?
ITP dx can only be made after excluding all other causes of immune and non immune platelet destruction. Have to exclude all other causes.
What is type 1 HIT?
- Non immune.
- Seen in majority of patient within 1st day of full dose unfractionated heparin therapy and will cause a modest decrease in the platelet count.
- The heparin will bind to the platelet and shorten the life span of the platelets.
- That particular form is transient and usually clinically insignificant.
What is type 2 HIT?
- Immune mediated and occurs in patient getting heparin for more than 5 days.
- Antibodies will induce platelet activation and aggregation and micro particles form in circulation and so decrease in platelet count and thrombus formation.
- Platelet used to form all these micothrombi
Because of the risk of Type 2 HIT, how often should we monitor platelets in the patient on heparin???
- Patient on heparin form ore than 5 days and have previously receive heparin should have closely monitored plt count every other day.
- If in monitoring platelet count, if it drops by 50% even if value is still in normal range, heparin should be d/c immediately and replaced w/thrombin inhibitor.
- Really a significant risk of a thromboembolic event, if any LMWH or heparin flushes eliminate them.
About ____ of all platelets are sequestered in spleen, if spleen enlarges an increase # of platelet are sequestered in the spleen.
What is DIC?
- Fibrin deposited throughout vascular tree
- Simultaneous depression of normal inhibitory mechanisms to prevent coagulation
- Impaired fibrin degradation
- Triggered by procoagulant material including TF
In DIC, of course by decreasing circulation, we deprive tissues of Oxygen and nutrients which will exacerbate circulatory shock so consequently septicemic shock is lethal in __% or more of patients.
What causes the bleeding seen in DIC?
while the body is forming all these little clots, its also using up all the coagulation factors so bleeding will occur. Combo of bleeding and clotting in the patient.
There’s no absolute set of lab findings consistent w/DIC. What would we usually see?
- Usually increase PT and PTT
- Decreased platelets
- Decreased fibrinogen
- Presence of fibrin degradation products and D dimer
Which organs will sustain the greatest damage?
- Organs most dependent on blood flow.
- Kidney and brain are the ones that will sustain the greatest damage.