Hemostasis 1 Flashcards
primary vs secondary hemostasis
primary: vessel wall and platelet
secondary: plasma proteins
___ is a more stable clot than thrombin
fibrin
these will activate thrombin (extrinsic pathway)
factor x with factor v –> prothrombin –> thrombin
these will activate thrombin (intrinsic pathway)
factor 11 -> factor 9 +8 -> factor 10 + factor 5 -> prothrombin -> thrombin
three major events in secondary hemostasis
initiation
amplification
propagation
normal platelet count
150,000/uL to 450,00/uL
indications for abnormal or high wbc
infection, examine bone marrow for leukemia
low plt, hb and wbc is normal
peripheral smear must be done to see if plt are clumped (falsely low plt)
fragmented rbcs in smear
microangiopathic hemolytic anemias
normal rbc moprhology in smear
drug induced thrombocytopenia
infection induced thrombocytopenia
idiopathic immune thrombocytopenia
congenital thrombocytopenia
causes for thrombocytopenia
decreased production (aplastic anemia, bone marrow infiltration) increased destruction (immune mediated) increased sequestration (hypersplenism) infections drugs
memorable drugs that can cause thrombocytopenia
acetaminophen amlodipine ampicillin ceftriaxone cotrimoxazole heparin
pathophysio of hepatin induced thrombocytopenia
antibodies to pf-4 is recognized with heparin -> ig recognize and mark the hep-pf-4 complex -> macrophages in the spleen recognize complexes - platelet removal by splenic macro -> thrombocytopenia + thrombosis
LOW PLATELET + THROMBOSIS
4t score
thrombocytopenia
timing of platelet count fall
thrombosis or other sequelae
other causes for thrombocytopenia
4t score interpretation
predicts if patient might have heparin-induced thrombocytopenia
<4 = 0.8% risk 4-5 = 11% risk >5 = 34% risk
management of heparin induced thrombocytopenia
discontinue heparin alternative anticoagulants (lepirudin, argatroban, fondparinux) do not give low molecular weight heparins
patho in immune thrombocytopenia
macrophages destroy antibody coated platelets resulting to thrombocytopenia
clinical characteristics of ITP
children: acute, remits in 6 mos
adults: chronic and more persistent
- rule out other disorders
- mucocutaneous bleeding (gums, nose, petechiae)
indications for treatment of ITP
indication: plt <30,000 + bleeding = transfution
first line treatment for itp
ivig
steroids
anti-rh
second line treatment for itp
rituximab (anti-cd20 antibody)
tpo receptor agonists (eltrombopag, romiplostim)
splenectomy (last resort)
patho in thrombotic thrombocytopenic purpura
deficiency of mmp adamts13 or antibodies for adamts13
adamts13 = cleaves vwf to make is usable
non cleaved vwf -> large numbers of platelets attached to vwf –> one big clot -> thrombocytopenia
pentad of ttp
hemolytic anemia thrombocytopenia renal failure (clots in gloms) neurologic findings fever
conditions that push a patient to develop ttp
hiv, pregnancy, medications, malignancy
prognosis of ttp
poor if not treated early, 95% mortality
treatment for ttp
plasmapheresis with plasma exchange
steroids to temporize ttp
most common inherited bleeding disorder
von willebrand disease
patho in von willebrand disease
insufficient or dysfunctional vwf
presentation of vwf disease
mucocutaneous bleeding
post-op bleeding
menorrhagia
childhood: excessive bruising, epistaxis
types of vwf disease
type 1 (quantitative): vwf production is low, most common type 2 (qualitative): vwf is sufficient but abnormal type 3 (combination): most severe, like hemophilia
treatment for vwd
desmopressin: release the vwf stored in endothelium
- prone to tachyphylaxis
- hyponatermia
vwf concentrates
imtermediate purity factor 8
anti-fibrinolytic agents (txa)
