13. bleeding disorders Flashcards
Haemostasis
Mechanism which maintains the integrity of the circulatory system after vascular damage
haemostasis achieved by
vessel constriction platelet plug (primary haemostasis) activation of the coagulation cascade and fibrin deposition (secondary haemostasis)
Lab for primary hemostasis
Platelets count
Bleeding time
Platelets function assay
Platelets agrigometry
PM and BM study
normal PTT and PT time
PTT 25-37
PT 10-13
If ptt increased and pt normal problem in
intrinsic
if ptt and pt increase
common pathway
if ptt normal and pt increase
extrinsic pathway problem
which factor has longest and shortest half life
longets factor 2
shortest factor 7
The clinical significance of hemorrhage depends on
Volume of the bleed – rapid loss > 20% of the blood volume can cause hemorrhagic (hypovolemic) shock,
Rate of bleeding – chronic or recurrent external blood loss results iron deficiency anemia
Location – trivial in subcutaneous tissues vs deadly in the brain
Defects in blood vessel
Vasculitis
Scurvy
Amyloidosis
Malignant HTN
Uterine atony
henoch scholein purpura clinical manifestation
palpable purpura
joint pain
blood in urine
pain in abdomen
primary heamostasis defect because of
defect in platlet either qualitatively or quantitavily
von willebrand diesease both
qualitative defect in platelet divided into 2
genetic and acquired
genetic qualitative defect in platelet
Bernard-Soulier syndrome
Glanzmann thrombasthenia
Bernard-Soulier syndrome
defect in glucoprotein Ib-IX-V
enlarged platlets
Glanzmann thrombasthenia
defect in glycoprotein IIb-IIIa
acquired qualitative defect in platelet
uremia
drugs - asprin
quantitative defects include
thrombocytopenia
idiopathic thrombocytopenic purpura
thrombotic microangiopathy - ttp - hus - dic
waterhouse fridrichsen syndrome
trousseaus syndrome
Thrombocytopenia
(< 150,000 platelets/μL)
causes of thrombocytopenia
decreased production
ineffective production
increased destruction
increased sequestration
dilution
idiopathic thrombocytopenic purpura
primary immune thrombocytopenia
pathogenesis antibody against platlet antigen
thrombotic microangiopathy divided into
ttp
hus
dic
thrombotic thrombocytopinic purpura ttp
low ADAM13 (cleaves von wille)
platelet aggregation
lysis
5 characteristics of ttp
fever
thrombocytopenia
microangiopathic hemolytic anemia
neurologic
renal failure
Hemolytic uremic syndrome hus
cause pathogenesis clinical manifestation
shiga toxin
endothelial damage
thrombocytopenia
clinical
renal failure
hemorragic diarrhea
Disseminated intravascular coagulation
dic
cause
tf release
obg comlication
trauma
gm -ve endotoxins
cancer
DIC lab findings
↓platelet count,
prolonged PT/PTT,
decreased fibrinogen, and
↑ fibrin split products (D dimers).
waterhouse fridrichsen syndrome
adrenal gland failure
cause bacterial infection
trousseus syndrome
recurrent venous thrombi formation due to procooagulant factors formed by cancer cells
pancreatic cancer
von willebrand diesease
plus lab finding
autosomal dominant
normal platlet count
normal pt
increased ptt
increased bleeding time
Defects of secondary hemostasis are in
coagulation factors
2 types of secondary heamostasis defect
hereditary and acquired
hereditary include
hemophilia a b and c
hemophilia a
and lab
x linked recessive
defect in factor 8
ptt prolonged
normal everything
hemophilia b
x linked recessive
defect in factor 9 (christmas factor)
hemophilia c
defect in factor 11
autosomal recessive
acquired secondary heamostasis defects
vit k deficiency
warfarin
liver failure
deficient transfer of factors in transfusion
coagulation factor inhibitors
mixed study
The patient’s plasma is collected and mixed in equal parts with normal pooled plasma that contains all clotting factors.The mixture is then subjected to a series of clotting tests, such as the activated partial thromboplastin time (aPTT) or prothrombin time (PT), depending on the suspected coagulation pathway involved.The clotting times of the patient’s mixture are compared to the clotting times of a control sample (normal plasma mixed with normal pooled plasma).
Corrected or normalized clotting times: If the abnormal clotting times of the patient’s mixture correct or normalize after mixing with normal plasma, it suggests a factor deficiency as the cause of the coagulopathy. The presence of adequate clotting factors in the normal plasma compensates for the deficiency observed in the patient’s plasma.Persistent abnormal clotting times: If the clotting times of the patient’s mixture remain prolonged or abnormal after mixing with normal plasma, it suggests the presence of an inhibitor. An inhibitor can neutralize or interfere with the activity of clotting factors, leading to impaired blood clotting.
