111 - Disorders of Platelet & Vessel Wall Flashcards
Platelets are activated by attaching to __ and __ found in the sub-__ which has been exposed due to injury or shear force. The activated platelets activate the production of __
vWV
collagen
epithelium
fibrin
Platelets are released from __ in response to stimulation by __ which is produced in the __
megakaryocytes
TPO
liver
What are the main reasons or thrombocytopenia?
decreased production (do BM biopsy) splenic aggregation increase in destruction (HUS/vasculitis/TTP/DIC/ITP) pseudothrombocytopenia
Why and how should we approach to a 60 years old patient with thrombocytopenia?
Looking for MDS, performing BM biopsy
What is the most common non-iatrogenic factor leading to thrombocytopenia?
infection:
DIC in G(-) systemic infection
ITP in viral infection and HIV
HIT= __
heparin induced thrombocytopenia
HIT does not increase the risk for __ as much as it does for __
bleeding
thrombosis
HIT is caused as antibodies against the __/__ complex are produced. It can also happen due to treatment with __, but is much more common when treating with __.
PF4/heparin
LMWH
UFH
What are the 5T for HIT?
thrombocytopenia Timing Thrombosis oTher Type of heparin
How do you treat HIT?
early diagnosing
stop heparin->switch to different anti coagulant (e.g. coumadin)
perform imaging to rule out thrombosis (lower limbs doppler)
Why coumadin should be administrated to patients with HIT only after platelets are back to normal level?
It decrease the level of protein C&S which may lead to skin necrosis
ITP= ___. It is an __ disorder, leading to immune mediated destruction of platelets.
Immune Thrombocytopenic Purpura
acquired
ITP tends to be __ in children, and secondary after: 4
acute SLE HIV HCV HP
When considering ITP, what may suggest a life threatening bleeding?
Wet purpura and retinal bleeding, together with low platelets and otherwise normal CBC
What is the typical clinical presentation of ITP? 3
cutaneous bleeding (ecchymoses / petechia)
membranous bleeding- wet purpura
other (retinal, GI, menorrhagia, CNS)
What are the 4 tools in diagnosing ITP?
- serology for HIV/HCV/SLE
- serum protein electrophoresis + immunoglobulin levels (hypogammaglobulinemia + IgA deficiency )
- coombs (looking for hemolysis- EVANS syndrome)
- BM examination
What is Evans syndrome?
autoimmune hemolysis + ITP
What is the goal of treating ITP?
reduce platelets destruction and reduce antibodies production
What is the indication to start treatment ITP?
when platelets < 30K
What are the 3 lines of treating ITP?
prednisone
anti RhD
IVIg
Only ITP patients with __ can be treated with anti RhD
positive
Rh +
__ is more efficient than other lines for treating ITP
IVIg
Name two S/E for IVIg when treating ITP (remember those are rare S/E)
RF
aseptic meningitis
If the patient with ITP is experiencing severe __, extreme thrombocytopenia ( __ is required
bleeding
5K
illness
hospitalization
Hospitalized ITP patients should be treated with: __+__ /__. Sometimes other__ drugs are used. If refractory- add __. If glucocorticoids do not help- perform
steroids + IVIg/ anti RhD
rituximab (anti CD20)
splenectomy
TTP= __
thrombotic thrombocytopenic purpura
What is the TTP pentad?
thrombocytopenia microangiopathic hemolytic anemia RF neurological signs fever
TTP can be __ or __
idiopathic
inherited
Idiopathic TTP is when antibodies for __ are produced. They slice __ after it is secreted which leads to the platelets attaching to the __ wall. More common in 3
ADAMTS13
vWF
blood vessels
women/HIV/pregnancy
Give 2 drugs which can cause TTP
cyclosporine
ticlopidine
What lab results will suggest TTP?
elevated LDH elevated unconjugated bilirubin elevated reticulocytes decreased haptoglobin In peripheral blood look for schistocytes and polychromasia
How should you treat TTP?
plasma exchange for 2 days, possibly with steroids. If refractory- rituximab/cyclophosphamide/splenectomy
HUS= __
hemolytic uremic syndrome
What is the HUS triad?
ARF
microangiopathic hemolytic anemia
thrombocytopenia
HUS is more common in __, usually after __ due to __ infection
children
hemorrhagic diarrhea
E. Coli O157P:H7
Atypical HUS appears without __. Treatment is with-
diarrhea
eculizumab
Unlike TTS, in HUS __ levels are normal
ADAMTS13
Treating HUS is usually __, but __ can also be required
supportive
dialysis
What is the most common bleeding disease?
Von Willebrand disease
How many Von Willebrand disease types are there?
Type I
Type II
Type III
Type I VWD is the most common type (_%). The factor level’s are __ together with factor __. Bleedings will appear in late __. __ blood types are less affected.
80 decreased VIII childhood O
Type II VWD is more __ than quantitative. There are 4 subtypes:
2A- over sensitivity to __ by __
2B- mutation leading to increased __ attachment to platelets
2M- faulty __
2N- faulty binding to factor __
qualitative cleavage ADAMTS13 vWF function VII
Type III VWD is considered __. Patients will experience multiple __, low levels of factor __ and low __. Higher chances to developed infused vWF
severe
bleeding
VIII
vWF
How will you treat type I vWD? what are the S/E?
nasal/IV DDAVP
hyponatremia- add water for 24 hours
How will you treat vWD II-III?
vWF replacement + antifibrinolytic treatment (epsilon aminocaproic acid) before dental procedures and mucosal bleeding.
When epsilon aminocaproic acid is C/I?
patients with upper UT bleeding- risk for ureter blockage
