Hematology Flashcards
roles of blood
transport of oxygen, carbon dioxide, other waste products transport of hormones acid base balance key role in body defence body temperature regulation
how do kidneys aid in blood production?
sensitivity to oxygen levels
low oxygen levels stimulate the release of kidney hormone ethytropoeitin which stimulates red blood cell production in bone marrow
composition of plasma
90% water
contains electrolytes, nutrients, wastes, gases, hormones, plasma proteins (large molecules, albumin which helps maintain oncotic pressure, globulins immunology, fibrinogen involved in coagulation cascade)
purpose: medium for transport
composition of leukcytes
white blood cells
large cells involved in immune system
life span variable
life span of erthythrocytes
120 days
platelets
smallest elements of blood (megacaryocytes break up into 1000 platelets)
initiate coagulation at the site of damaged blood vessel walls
lifespan about 10 days
because they’re the lightest component, they float near the edges of the vessel
reservoir in the spleen
What are the four phases of hemostasis?
primary
seconday
finbrinolysis
restoration of normal blood flow
primary hemostasis
constricts to slow bloodflow
platelets contact collagen layer and release adhesive proteins, coagulation and growth factors
platelets change shape and becomes sticky, adhering to one another
platelet plug is formed
secondary hemostasis
intrinsic and extrinsic coagulation cascades are activated
formation of fibrin clot to stabilize the platelet plug
compare intrinsic and extrinsic clotting pathways
intrinsic - slow, takes 2-6 minutes to begin, inside the vessel, damaged endothelium, contact with plaque
extrinsic - rapid, begins in 15 seconds, outside vessel, tissue damage
which electrolytes are required and where are they stored?
calcium and vitamin k
fibrinogen, prothrombin, factor 4,5,6,7 found in the liver
describe the clotting cascade
factor ten, common pathway, prothrombin, thrombin, fibrinogen, fibrin, clot formation
what happens at the activation of factor ten?
platelets continue to aggregate
thrombin and fibrin are created
fibrin stabilizing factor is activated
clot is stabilized
fibrinolysis process
the process in dissolving the clot
to restore blood flow through the healed vessel, the fibrin clot must be lysed
endothelial cells secrete tissue plasminogen activators
leukocytes begin to clean up debris
hematocrit
measurement of volume of RBCs in 100ml of blood - comparing percentage of rbcs to plasma
looks at hydration status - elevated level indicative of decreased fluid volume
normal 0.36-0.46
prothrombin time
evaluates the extrinsic pathway and common clotting pathway
normal 8-13 seconds
if clotting factors are deficient, PT will be prolonged
used to evaluate therapeutic range for warfarin
INR
international normalized ratio
ptt
partial thromboplastin time
evaluates intrinsic system and common pathway
if clotting factors deficient it will be elevated
normal <40 seconds
used to evaluate heparin anticoagulation therapy
fibrinogen
an essential plasma protein synthesized by liver
ordered to further investigate abnormal bleeding
decreased level - liver disease, disseminated intravascular coagulation, leukemia, anemia,
increased level - acute infections, collagen diseases, inflammatory disorders
d-dimer
a protein fragment produced and usually only detectable during clot degredation
used to diagnose conditions related to thrombosis such as pulmonary embolism, DIC, DVT
reticulocyte count
yields information on bone marrow function
reticulocytes are immature cells released by bone marrow that become rbcs
useful in determining cause of anemia
esr
erythrocyte sedimentary rate
can be elevated in inflammatory states
c reactive protein
levels increase more rapidly than esr during acute inflammation
peripheral smear
most informative of all blood tests
time consuming
a person takes the time to look and count and differentiate
what are some causes of anemia in the adult icu patient?
decreased rate of erythropoeisis acute kidney injury chronic renal failure heorrhage hemolysis inflammation liver disease excessive phlebotomy
anemia treatment
medications (b12, erythropoeitin, folate, iron) crrt blood transfusion blood conversion nutritional consult
diagnosis and treatment of dvt
venous ultrasound
blood work
prevention
if on bedrest, elevate injured leg
analgesic
anticoagualtion
what are some risk factors for development of dvt?
immobility surgery invasive procedues spinal cordi njury obesity age sepsis trauma
pulmonary embolus patho and management
a clot that travels through right side of the heart and gets lodged in pulmonary vasculature
dvt common cause
can be blood, fat, tumor tissue
treatment anticoagulation therapy, inferior venacava filter, surgical removal
chest pain, rapid onset sob, increased oxygen demands, radiating pain to neck, jaw, worsens with inspiration
what are some examples of coagulation disorders
thrombotic thrombocytopenic purpura
hellp
hit - heparin induced thrombocytopenia
dic
ttp patho, presentation
thrombotic thrombocytopenia purpura
usually caused by under regulation coagulation component von Willebrand factor, red blood cell damage
spontaneous platelet aggregation
presents with fever, renal injury, micro hemolytic anemia, neurologic abnormalities
hellp
hemolytic elevated liver enzyme low platelet count
happens with pre-eclampsia
can lead to stroke
hit
sudden onset with drop in platelets when patient on heparin
50% drop in platelet count
usually occurs about 4 days of receiving heparin, has occurred up to 3 weeks after heparin discontinued
type 1 - benign, moderate but transient decrease in the platelet count
type 2 - severe, immune mediated formation of heparin-antibody complexes, greater risk for thrombosis than bleeding, thrombin released and platelet clumps are formed, complexes adhere to platelets and endothelium
what are some triggers of DIC?
sepsis
severe trauma
obstetrical events such as placental abruption
severe inflammation
Describe the hemorrhagic signs for various systems
integ- oozing, bleeding from access sites, surgical sites and mucous membranes, purpura, ecchymosis, cyanosis neuro- altered loc pulm- hemoptysis gi- gi bleed, abdominal distension renal- hematuria
Describe the micro-emboli signs for various systems
integ- patchy cyanosis neuro- altered loc, cva pulm- pe, ards gi - bowel infarct renal- hematuria, oliguria, renal failure
how does lab work change in dic
ptt elevated pt/inr elevated d-dimer elevated platelets low fibrinogen low
what is treatment of hemorrhage aimed to prevent
decreased oxygen carrying capacity
decreased waste removal
tissue and organ ischemia
circulatory collapse
what are some of the risk associated with blood and blood product transfusion?
acute transfusion reaction
allergic reaction (anaphylaxis)
TRALI not related to volume overload (transfusion related acute lung injury)
hypothermia (blood products stored in fridge)
metabolic alkalosis (sodium citrate in blood products to prevent clotting, which breaks down into water and bicarb)
volume overload
ffp
each unit has 650mg of fibrinogen
indicated to reverse bleeding, reverse coagulopathy prior to surgery,
cryopreciptate
the precipitate of ffp
ffp without the extra fluid
contains fibrinogen, factors 8 and 13 and von willebrand factor
indicated in hemophilia, bleeding from excessive anticoagulation, hemorrhage, dic
important thing to remember about platelet infusions
never via pressure bag or with warming
prothrobin complex concentrates
derived from pooled plasma contains multiple clotting factors protein stored at room temp vitamin k administered with initial dose indicated in reversal of warfarin, vitamin k deficiency with life threatening emergency
transexamic acid
synthetic
inhibits fibrinolysis
indicated in polytrauma, hemorrhage, risk of bleeding
organs of immunology
lymphatics- bacteria, virus, and debris are removed by wbcs
mucous membranes and skin - immuno globulin a
gastric fluid
thymus - t lymphocyte maturation
tonsils and adenoids - exchange lymphocytes with lymph, produce antibodies and sensitized t cells, remove microbes
spleen - exchanges lymphocytes with blood, produced antibodies an d sensitized t cells, removes microbes, stores rbcs
bone marrow- origin of all blood cells, b lymphocyte maturation
appendix - rich in lymphoid cells, manufactures hormones in fetal development
goals of the immune system
defence against invading organisms
removal of worn out cells and tissue debris
homeostasis
surveillance with recognition and removal of mutant/abnormal foreign cells
what are the components of the general immune response?
inflammatory
humoral (antibody) slower to response, b cells
cellular immune response t cells
inflammatory response
release of phagocytes, wbcs
secretion of inflammatory mediators
immediate and nonspecific
inflammatory mediators
molecules released by immune cells against invaders
initiate, augment, and terminate aspects of the inflammatory response
MAST CELLS is one of the key activators in the inflammatory response
hitamine, bradykinin, prostaglandins
what are some local and systemic symptoms of inflammatory response?
inflamatory mediators being released from cells
local vasodilation and increased capillary permeability
increased blood delivery to tissue and local accumulation of fluid
redness, heat, swelling and pain
innate immunity
skin, chemicals in blood, phagocytes,
first line of defence
adaptive immunity
recognition and processing of specific antigen
creation of special antibodies to attack a specific antigen
slower response to invader
adaptive immunity
recognition and processing of specific antigen
vaccines
exposure related immunity
creation of special cells and antibodies to attack a specific antigen
slower response to invader
slower to invader
b cell lymphocytes
mature in bone marrow storedi n lymph nodes some circulatei n blood responsable for production of antibodies or immunoglobulins inactive circulating antigens
what are the five classes of immunoglobulins?
IgG- responsible for the majority of antibody basedi mmunity, only antibody crosses placenta to fetus
IgM- first on the scene, largest, starts working to eliminate pathogens before there is enough IgG
IgA prevents colonization of pathogens, found on the skin
IgD- activates basophils and mast cells
IgE involved in allergic response and against parasites
how does the complement system amplify the immune response?
help phagocytes engulf the pathogen attract more phagocytes to site (chemotaxis) create pores in bacterial membranes increase vascular permeability neutralize some viruses
t cell lymphoctyes
mature in thymus
function in the peripheral tissues
acquire the ability to distinguish self and non self
60-70% lymphocytes
provides protection against viruses, intracellular bacteria and cancer cells
three types: cytotoxic ( killer, release lymphotoxins causing cell lysis)’ helper (immune managers, secrete lymphokines that stimulate ta nd b cells, attract neutrophils and enhance macrophages ability)’ suppressor (inhibit t cell production when no longer needed)
natural killer cells
less than 2% of circulating volume
from innate immunity system
seek and destroy
neutorphils
most abundant first responder to inflammation very involved in bacterial infection segmented mature banded immature increased bands indicates an accelerated production or release of neutrophils
basophils
less than 1% of wbc
secrete inflammatory mediators that attract leukocytes to injury site
eospinophils
less than 6% of wbcs
levels may increase with parasitic infection and allergic response
gram positive
staphylococcus
streptococcus
c-diff
gram negative
e coli salmonella pseudomonas enterobacter legionella klebsiella
bone marrow aspirate
reveals number, size, shape of cells throughout all stages of development
diagnosis and staging of hematologic disease, or to confirm a diagnosis
define infection
the invasion and multiplication of microorganisms in body tissue, making you unwell
may be clinically unapparent
may result in localized cellular injury
may extend to a systemic infection
define colonization
microorganisms live on or in a host but do not invade or cause cellular damage
once colonization invades or begins to cause localized cell injury, it becomes an infection
hypersensitivity
allergic reaction
anaphylaxis
four varieties based on mediators
autoimmune disease
inappropriate immune response of the body against substances and tissue normally present in the body
may be systemic or against a specific organ
the immune system mistakes some part of the body as a pathogen and attacks its own cells
