Coagulation Part 2: Disorders of Coagulation Flashcards
describe abnormal morphology of platelets
- giant platelets or shift platelets
-larger than RBCs
-will function normally
-suggests accelerated thrombopoiesis (platelet regeneration)
-MPV generally increased
describe thrombocytopenia
4 causes: SPUD
Sequestration: trapping of platelets within the spleen, usually causes a mild, transient decrease in platelet counts; due to splenomegaly, splenic congestion, splenic neoplasia
Production;
-decreased production:
–bone marrow diseases; will see other cytopenias; due to aplastic anemia, toxins, and other causes
–infectious diseases: ehrlichia and other rickettsial organisms; viral organisms (FeLV/FIV, parvovirus)
–macrothrombocytopenia (CKCS): nonpathogenesis: idiopathic condition in Cavalier King Charles Spaniels due to both abnormal platelet morphology and decreased platelet production; will have fewer, larger platelets; decreased platelet count with increased MPV, normal plateletcrit; platelets normal in function
Utilization: increased
-indicates increased platelet consumption due to DIC, vasculitis, endocarditis, SEVERE acute blood loss from hemorrhage
Destruction:
-Immune-mediated thrombocytopenia: can be primary or secondary; will see marked thrombocytopenia with normal coagulation testing
-primary: autoantibodies targeting platelets and megakaryocites; breed predispositions
secondary: antibody production triggered by an inciting cause; neoplasia, infectious disease, drugs, vaccines; RULE out all secondary causes before diagnose primary
describe thrombocytosis
- commonly seen but not often clinically significant but can predispose to thrombosis
- divided int primary and secondary (reactive)
describe primary thrombocytosis
- very rare; associated with a persistent, extreme thrombocytosis
- due to a neoplastic cause: essential thrombocytopenia, acute megakaryoblastic leukemia, chronic myoproliferative diseases
- patients may have an increased risk of thrombosis or hemorrhage, depending on platelet function
describe reactive (secondary) thrombocytosis
several causes:
1. increased procudtion: due to inflammation, recovery from recent thrombocytopenia, chemotherapeutic drugs, iron deficiency
2. redistributive or physiologic: epinephrine mediated or exercise = splenic contraction and transient thrombocytosis
3. decreased removal: recent splenectomy, seen post-op
4. excess cortisol: endogenous (Cuhsings) or exogenous (glucocorticoud admin)
describe abnormal platelet function
thrombopathy or thrombocytopathy;
can be inherited or acquired; associated with
1. adherence or aggregation
2. surface membrane receptors
3. abilit to synthesice and release products
platelet count normally WRI or increased!
what are causes of congenital platelet dysfunction?
- vin willebrand disease: most common hemostatic disorder in dogs (esp dobermans, scotties, shelties, rare in others)
-a deficinecy or abnormality of vWF due to either
–quantitative or qualitative defect
–acquired vWD is uncommon in vet med - clinical signs of vWD:
common: prolonged bleeding from wounds and mucosal hemorrhage - diagnosis of vWD:
-definitive requires assessment of vWF concentration and/or function
-use vWF antigen concentration; ELIA method, eletrophoresis, functional assays, genetic assays
what is a cause of acquired platelet dysfunction?
hyporesponsive platelets
due to:
1. drugs: NSAIDs (cox inhibitors), calcium channel blockers
2. liver or renal failure
3. marked elevation in globulins
4 infectious diseases
5. DIC
what are the 2 disorders of the extrinsic pathway?
- inherited factor 7 deficinecy or inhibiton: seen in beagles, mild idsease associated with bruising
- acquired factor 7 deficiency or inhibition: associated with early vitamin K deficiency or inhibition, since factor 7 has the shortest half life it will be the first to go; only PT will be prolonged
give disorders of the intrinsice pathwya1
- hereditary factor 12 deficiency/Hageman’s disease: prolonged ACT or PTT with no clinical bleeding; more common in cats
- hereditary factor 11 deficiency/Hemophilia C: mildly prrlonged bleeding seen after surgery; seen in dogs and holstein cattle
- hereditary factor 9 deficiency/Hemophilia B: X chromosome linked = more common in males; affected males have variable clinical signs and spontaneous internal hemorrhage can occur; affected females are usually carriers; seen in dogs and cats
- hereditary factor 8 deficiency/hemophilia A: most common inherited coagulation factor disorder!; X chromosome linked = more common in males; affected males and females like hemophilia B, but seen in dogs, cats, SHEEP, CATTLE, HORSES
- vitamin K antagonism or deficiency: factors 2. 7, 9, 10:
-often affects multiple pathways: both PT and PTT prolonged, but will see PT prolonged first bc factor 7 has the shortest half life
-antagonism due to rodenticides, moldy sweet clover
-deficiency due to liver or GI disease
describe common pathway disorders
- cause prolonged PT and PTT
- hereditary is rare but can see
-factor 10 deficiency in dogs and cats or
-fibrinogen deficiency in goats and dogs - acquried is usually associated with multi-pathway disorders
describe multple pathway disorders
1, vitamin K antagonism or deficiency (2, 7, 9, 10)
2. liver failureL decreased production of coag factors
3. DIC consumes factors
4. multiple factor defieicnecy is very rare; usually congenital disease only affect one factor
describe disseminated intravascular coagulation
- syndrome in which disseminated, consumptive doagulation and fibrinolysis occurs
- initially starts as a hypercoagulable state with widepsread, excessive activation of hemostasis that generates excess thrombin and microvascular thrombi
- gradual consumption of clotting factors exceeds the rate of syntehsis and leads to hypercoagulable state and increased risk of hemorrhage
- always secondary to another condition that causes excessive consumption: neoplasia, heatstroke, IMHA, envenomation, sepsis, heartworm disease
- triggered by excessive tissue factor release from:
-damaged endothelial cells
-neoplastic cells
-endotoxin stimulated cells
list consequences of DIC
describe diagnosis of DIC
