Bleeding Disorders Flashcards
Hemophilias
hemophilia A - factor 8 (VIII) deficiency
-MC*
hemophilia B - factor 9 (IX) deficiency
-Christmas disease
congenital clotting disorders
- X-linked recessive (so–>affects males)
- Severe pain in weight-bearing joint (hemophilic arthropathy)*
Labs: Instrinsic pathway affected so aPTT is long. Bleeding time is normal in hemophilia
Platelet disorders
- Dysfunction (acquired or congenital)
- Splenic spequestration
- Increased destruction
- Impaired production
Signs of bleeding
Petechiae (<2mm)
Purpura (2-10mm)
Ecchymosis (>1cm)
What are the 4 components of a basic screen for a patient you suspect has a bleeding disorder?
- CBC
- Peripheral smear
- PT/INR, aPTT
- Bleeding time
Platelet counts
Normal:
150,000 -450,000/mm3
Thrombocytopenia:
<100,000/mm3
When does spontaneous bleeding occur?
<20,000/mm3 platelets
Bleeding time
the measure of time from bleeding to hemostasis (coagulation)
Prolonged bleeding time:
- Platelet disorder (ex. von Willebrand’s Disease)
- Severe thrombocytopenia
What are the 3 stages of hemostasis
Just after vessel injury…
- Vasoconstriction
“vascular spasm”
-more effective in small vessels - PRIMARY Hemostasis/Platelet plug formation:
- activated by von Willebrand factor
- platelets adhere to exposed collagen, release ADP and thrombaxane A2 - SECONDARY Hemostasis/Coagulation cascade:
- formation of fibrin from fibrinogen
- Extrinsic, Instrinsic, and Common pathways
What do Protein C, S, and ATIII do?
regulate clot formation.
If you don’t have these, you clot TOO MUCH!
Prothrombin Time (PT)
- Extrinsic pathway (or common)
- For monitoring Warfarin
PTT or aPTT (Activated partial thromboplastin Time)
- Intrinsic pathway (or common)
- For monitoring heparin therapy (not LMWH)
-Significant for Hemophilia, vW disease, Vitamin K deficiency
INR (International Normalized Ratio)
-more accurate, standardized way of looking at PT (extrinsic pathway)
MC sites of bleeding for hemophilias A & B
- Joints (spontaneous hemarthrosis, is sign of severe disease)
- Muscles
- Skin
- GI
- GU
Hemophilia A: Labs
- Platelets and PT are normal
- aPTT will be prolonged**
Hemophilia A: treatment
- Factor VIII infusions
- Desmopressin
- AVOID aspirin
Dysfunctional platelets
Acquired versus congential
- Acquired (MC)**
ex. Drugs, uremia, alcoholism, myeloproliferative disease
LABS: prolonged bleeding time (otherwise normal)
TX:
- stop offending drug
- hemodialysis in uremic pt
- platelet transfusion if serious bleeding
Platelets and the spleen
Splenomegaly/hypersplenism = thrombocytopenia
Post-splenectomy = (reactive) thrombocytosis
Platelet disorders: Increased destruction
ITP (idiopathic thrombocytopenic purpura)
-autoimmune destruction
Platelet disorders: Platelet consumption
- TTP (thrombotic thrombocytopenic purpura)
- HUS (hemolytic-uremic syndrome)
- DIC (disseminated intravascular coagulation)
ITP (idiopathic thrombocytopenic purpura)
-antibody mediated destruction of platelets
Primary ITP: not related to another condition
Secondary ITP: related to another condition (ex. CLL, SLE, HIV)
Acute ITP
- kids 2-4
- IgG associated
- preceeded by viral URI
- Self-limited
Chronic ITP
Females> males
20-50 yrs
-insidious onset
-usually secondary ITP, associated with another condition
ITP:signs
- petechiae, purpura
- epistaxis, oral bleeding
- NO splenogmegaly
ITP: labs
Platelets often below 20,000
Coagulation studies normal
BM–> increased megakaryocytes
ITP: treatment
Acute: usually children don’t need treatment
Chronic ITP: HIGH dose dexamethasone or prednisone***
HIT (heparin-induced throbocytopenia)
- IgG autoantibody against complexes of heparin and platelet factor 4
- Associated with arterial and venous thrombosis**
Tx: stop heparin
TTP (thrombotic thrombocytopenic purpura)
Microangiopathic hemolytic anemia with thrombocytopenia***
-RBCs are getting sliced on the fibrin and platelets in vessels
Symptoms:
- abdominal pain (pancreatitis is common)
- Jaundice
- fever, fatigue, toxic-appearing
- Neuro findings
IF a child presents with what looks like TTP folllowing E. coli infection what could it be?
HUS (hemolytic uremic syndrome)
Sx: bloody diarrhea before onset
-microangiopathic hemolytic anemia + thrombocytopenia**
- NO neuro findings
- Renal failure predominates**
TTP and HUS: Labs
- Microangiopathic hemolytic anemia
1. Increased retics
2. Increased LDH
3. Increased indirect bilirubin
4. Negative Coombs test
Schistocytes (helmet cells) on peripheral smear
-Normal coagulation tests
TTP-HUS: treatment
Corticosteroids***
- plasmapheresis
- Rituximab if refractory
DIC (Disseminated Intravascular Coagulation)
First, extensive thrombosis
Second, bleeding/hemorrhage once all the platelets are used up
DIC: labs
Decreased platelets
Decreased fibrinogen
Increased PT and PTT
Increased D-Dimer
-Schistocytes on peripheral smear
DIC: treatment
Transfusion support**
- Cryoprecipitate
- FFP
- Platelet transfusion
- RBC transfusion
Von Willebrand’s Disease
- Autosomal dominant
- MC coagulopathy
- Reduced levels of factor VIII antigen or ristocetin cofactor
Type 1 is most common (decreased vWF)
Acquired vW disease –> bone marrow malignancy MC*
What does Von Willebrand Factor do?
- makes platelets adherent to subendothelium
2. Plasma carrier of factor VIII
Von Willebrand disease: Labs
Prolonged bleeding time
(hemophilia has normal bleeding time)
- Low vWF
- INR normal
Von Willebrand disease: treatment
- Desomopressin for type
- releases stored vWF from endothelial cells
