Bleeding Disorders Flashcards
What are the 2 clotting D/O we need to know?
Hemophilia A (Factor 8 Def)
Hemophilian B (Factor 9 Def)
Hemophilia A is what factor deficiency?
8
Hemophilia B is what deficiency?
Factor B
What are the 4 types of platelet disorders?
- dysfunction (acquired or congenital)
- splenic sequestration
- increased destruction
- impaired production
What are the 3 signs of bleeding disorders on physical exam?
- Petechiae <2mm
- Purpura 2-10 mm
- Ecchymosis >1cm
What is petechiae?
focal areas of subcutaneous bleeding
DO NOT BLANCHE with pressure
may occur in periorbital areas after vomiting/coughing
What is purpura?
palpable or nonpalpable
What 5 lab studies should you order for a pt with suspected bleeding disorder?
CBC (platelet count)
Peripheral smear
PT/INR, aPTT
bleeding time
fibrinogen
What does the platelet count look at?
# of platelets (thrombocytes) per cubic ml of blood
looks at quantity, not quality.
What is the normal platelet count?
150,000-400,000
What lab value is considered thrombocytopenia?
<100,000
What can happen if the platelet count is <40,000?
prolonged bleeding from vascular injury can occur
What can happen if platelet count is <20,000?
spontaneous bleeding
What does bleeding time measure?
measures time for hemostasis (stopping of blood flow)
screens for microvasculature and platelet function
Prolonged bleeding time occurs in what 2 disorders?
platelet disorders (von wildebrand’s disease)
severe thrombocytopenia
What is the 1st hemostatis response when vessel injury occurs?
spastic contraction of the damaged microvessels (vasoconstriction)
What is the 2nd hemostatic response when vessel injury occurs?
platelets adhere to the affected area (platelet plug formation)
What is the 3rd hemostatic response when vessel injury occurs?
initiation of coagulation cascade
Vasoconstriction is also known as what
vascular spasm
Vasoconstriction
happens immediately
smooth muscle on damaged vessels will constrict which reduced blood flow to the area (limits blood loss)
Collagen is exposed which promotes platelets to adhere to the injury site.
Primary hemostasis in platelet plug formation
platelets clump together through platelet adhesion: adhere to damaged endothelium, form platelet plug & degranulate (thromboregulation)
what is platelet plug formation activated by?
glycoprotein: vWF
What do platelets release once they adhere to exposed collagen?
ADP & TAz (thromboxane) to activate more platelets and increase the effect of vasoconstrictionq
Seconday Hemostasis
once platelet plug has been formed, clotting factors are activated = “coagulation cascade”
Leads to formation of fibrin (from inative fibrinogen) = fibrin mesh produced all around platelet plug to hold it in place.
Secondary Hemostasis is comprised of what 3 pathways?
intrinsic pathway
extrinsic pathway
common pathway
PT (prothrombin time) is prolonged with abnormalities in which pathway?
prolonged with abnormalities in extrinsic pathway (or common)
PT is used to monitor what?
warfarin (coumadin) therapy
What does PT assess?
liver function/damage
PTT or aPTT is prolonged in what abnormality?
intrinsic pathway abnormalities
PTT is used to monitor what?
unfractionated hepatin therapy
What conditions will you see an abnormal PTT with?
hemophilia
vW disease
liver damage
Vit K deficiency
T/F: INR is a more accurate reflection of PT
True
What is INR?
standardized ratio of prothrombin time compared to a control
results are independent of reagents or methods used
What is the Goal INR level dependent on?
underlying need for anticoagulation
What is INR used to monitor?
warfarin anticoag therapy
Characteristics of clotting disorders?
associated with excessive or repetitive bleeding at unusual sites (joints, muscles, GI, GU tract) with normal activity.
clotting disorders are classified as either ________ or _________.
clotting disorders are classified as either congenital or acquired.
What are the 2 congenital clotting disorders?
Hemophllia A & B
What is christmas disease?
Hemophilia B (Factor 9)
Which hemophilia is most common?
Hemophilia A (Factor 8 deficiency)
Both are X-linked recessive
predominately affects males
can affect females born to affected father and carrier mother
What dz?
Hemophilia A & B
Dz severity correlates with factor levels
Which dz?
Hemophilias
Clinical Px of Hemophilia A & B
most = asx for first few months of life
1st episode of sx bleeding: occurs after newborn period but within 1st 2 years of life (spontaneous or with minimal injury)
severe pain in weight-bearing joints (hemophilic arthropathy)
Repeated episodes of bleeding
MC sites of bleeding in Hemophilia
Joints
muscles
skin
GI, GU
spontaneous hemarthrosis = sign of severe dz
Lab studies for Hem A
platelet count: nml
PT: nml
aPTT: prolonged (can be normal in prolonged disease)
Factor 8 assay
Hem A mgmt
Factor 8 concentrate administration/infusions
Desmopressin (DDAVP)
Pt education for Hem A
avoid trauma, high risk activity
avoid certain meds (ASA)
genetic counseling
Potential causes of low platelets
recent infection
platelet consumption syndrome
immune d/o
chronic liver dz
bleeding
potential causes of high platelets
cause of significant inflammation
significant infection
abnormal peripheral smear
essential thrombocytosis sx
iron deficiency anemia
inappropriate clotting or bleeding
metastatic malignancy
is acquired or congenital a more common cause of platelet dysfunction?
acquired: drugs, uremia, alcoholism, myeloproliferative disease
What will lab studies show for dysfunctional platelets?
normal count and morphology
prolonged bleeding time
mgmt for dysfunctional platelet disorders
discontinue offending agent
hemodialysis in uremic cases
platelet TF if serious bleeding
What causes sequestering platelet disorders?
splenomegaly/hypersplenism = thrombocytopenia
post-splenectomy = ractive (thrombocytosis)
Increased platelet destruction disorder (autoimmune)
ITP (idiopathic thrombocytopenic purpura)
increased platelet consumption disorders
TTP (thrombotic thrombocytopenic purpura)
HUS (hemolytic-uremic syndrome)
DIC (disseminated intravascular coagulation)
Pathophys of ITP
reduced platelet llifespan due to antibody mediated destruction of platelets
What are the 2 types of ITP?
Primary: due to autoimmune mechanisms leading to platelet destruction and platelet underproduction that is not triggered by an associated condition.
Secondary: associated with another condition: HIV, Hep C, SLE, CLL
What type of ITP?
self limited
common in children (2-4 yrs old)
IgG associated
prior viral URI
Acute ITP
What type of ITP?
females > males
peak incidence 20-50 y/old
insidious onset
associated with other autoimmune dz, HIV
Chronic ITP
CPx of ITP
can be asx
peteichiae
pupura
hemorragic bullae on skin & mucus membranes
SAH, ICH
splenomegaly should NOT be present
Lab studies for ITP
thombocytopenia: Plt <20
Coag studies = nml
BM: increased megakaryocytes
Dx of exclusion
ITP Mgmt
avoid platelet antagonists (NSAIDs, ASA)
Acute ITP: resolves spontaneously, may require steroids/splenectomy
Chronic ITP: high-dose prednisone or dexamethasone, IVIG, If refractory: splenectomy, danazol
Emergency ITP tx
stop bleeding
platelet TF
Life-threatening complication of exposure to heparin
results from an autoantibody directed against endogenous platelet factor 4 (PF4) in complex with heparin.
What dz?
Heparin-induced thrombocytopenia (HIT)
Removal of IgG-coated platelets by macrophages of the reticuloendothelial system (eg, spleen, liver, bone marrow)
What dz?
HIT
what is HIT associated with?
arterial and venous thrombosis (hypercoagulable)
tx for HIT
STOP HEPARIN
etiology of TTP
Idiopathic
Infection/autoimmune/malignancy: Includes HIV
Drugs
Pregnancy/post-partum
Stem-cell transplant
Shigatoxin producing E. Coli – follows bloody diarrhea prodrome
TTP CPx
abrupt onset: can be acute, chronic, relapsing
fever, toxic-appearing
fatigue
abdominal patin (pancreatitis common)
HA, AMS, focal neuro deficits (waxes and wanes)
Skin pallor, petechiae, purpura, jaundice
20-50 year olds
Endothelial layer of small vessels is damaged and results in fibrin deposition and platelet aggregation (platelet consumption)
As RBCs travel through damaged vessels, they are fragmented which results in intravascular hemolysis.
Pathophys of what dz?
Microangiopathic hemolytic anemia + thrombocytopenia
Children with atecedent E Coli infection
MHA(microangiopathic hemolytic anemia + thrombocytopenia)
Mainly seen in infants and chlidren (MC follows E coli infection)
W/o neurologic findings
Which dz?
HUS (Hemolytic Uremic syndrome)
Cpx of HUS
Abdominal pain & bloody diarrhea 5-10 days prior to onset
Like TTP (anemia, thrombocytopenia, fatigue), but CNS involvement is less common
If neuro symptoms predominate: TTP
If renal failure predominates : HUS
How do you differentiate between TTP and HUS?
TTP: neuro sx predominate
HUS: renal failure predominates
Most commonly adults
Microangiopathic hemolytic anemia
Thrombocytopenia
Renal dysfunction
Severe CNS symptoms
Fever
TTP or HUS?
TTP
Mostly children
Microangiopathic hemolytic anemia
Thrombocytopenia
Acute renal failure
No CNS symptoms
TTP or HUS?
HUS
Lab studies for TTP-HUS
Microangiopathic hemolytic anemia:
Reticulocytosis
Increased LDH, indirect bilirubin
Negative coombs test
Thrombocytopenia
Schistocytes (helmet cells) on peripheral smear
Normal coagulation tests (separates TTP from DIC)
renal insufficiency
TTP-HUS Management (adults)
Corticosteroids
Plasmapheresis
Rituximab for refractory cases
High-risk mortality
TTP-HUS mgmt in children
IVF, electrolyte repletion
Potentially life threatening condition in which proteins which control blood clotting become overactive.
Pathophys of what dz?
DIC
First, you get extensive thrombosis.
Then as clotting factors and platelets are used up, bleeding/hemorrhage may occur.
Widespread platelet consumption.
Patho of which dz?
DIC
What dz is typically associated with severe underlying systemic illness?
DIC
Widespread activation of the coagulation cascade–>increased fibrin clots which entrap platelets–>microthrombi cause RBC destruction and small vessel occlusion –> massive consumption of platelets, fibrin, and coagulation factors –> results in uncontrolled bleeding.
Mechanism of what dz?
DIC
Clinical conditions associated with which dz?
•Sepsis
- Trauma
- Cancer (myeloproliferative disorders, solid tumors)
- Obstetrical complications (amniotic fluid embolus, abruption)
- Vascular disorders (giant hemangioma, aortic aneurysm)
- Reactions to toxins (snake venom, drugs, amphetamines)
- Immunologic disorders
- Severe allergic reactions
- Hemolytic transfusion reactions
- Transplant rejection
DIC
DIC Clinical Px
- Variable, onset may be acute or gradual
- Patients VERY sick with bleeding/clotting: Bleeding>clotting
- Multiple organ systems affected
- Hemorrhage and/or thrombosis
What is the origin of hemorrhage in DIC?
microvasculature:
- petechiae
- bleeding from venipuncture sites or surgical wounds
- GI, lung, obstetrical bleeding
DIC lab studies
•Decreased platelets
•Increased PT & PTT
•Decreased fibrinogen
•Increased fibrinolysis –> results in increased fibrin degradation products
•Increased D-dimer (very sensitive): Fibrin degradation product, Assesses fibrinolysis
•Microangiopathic hemolytic anemia present in 25% of cases
•Peripheral smear: schistocytes
DIC Mgmt
quick recognition and aggressive tx of underlying cause
TF support:
- Cryoprecipitate (fibrinogen replacement)
- FFP (coagulation factors)
•Platelet transfusion
•RBC transfusion
•Autosomal dominant (affects males & females)
•Most common congenital coagulopathy (1/100)
Reduced levels of factor VIII antigen or risocetin cofactor
What dz?
Von Willebrand’s Dz
Causes of acquired vW dz
MC: bone marrow malignancies
valproic acid, SLE
Von Willebrand factor serves what two main functions?
Facilitates platelet adhesion by linking platelet membrane to vascular subendothelium
Serves as a plasma carrier for Factor VIII
what is the result of low level of vWF or defect?
bleeding
Cpx of vW Dz
- Bleeding (nasal, sinus, vaginal, GI)
- Spontaneous hemarthrosis and soft-tissue bleed less common than in hemophilia A
- Bleeding worse with ASA, decreases with estrogen/pregnancy
vW Dz Labs
•Prolonged bleeding time: Helps differentiate vW disease from hemophilia: Bleeding time is normal in hemophilia
•Low vWF (fancy confirmatory test): must test at different times
•INR normal
vW Dz mgmt
•Desmopressin acetate (DDAVP) for Type 1: Releases stored vWF from endothelial cells
•Factor VIII infusion
•Humate-P: Derived from human plasma & Contains both factor VIII and vWF