Blood Flashcards
hemoglobin
the iron containing pigment of the RBC. fxn is to carry oxygen to tissues. conjugated protein= iron containing pigment called heme & a simple protein/globin. combines readily w/ o2 in lungs & liberates that o2 to tissues in exchange for co2.
normocytic/normochromic
blood loss, bone marrow infiltrate
microcytic/hypochromic
iron deficiency, lead poisoning, thalassemia
macrocytic/normochromic
vit b12 def or folate def (megaloblastic anemia), drug rxn.
G6PD
red cell enzyme defect. a drug induced hemolytic anemia d/t def of __ enzyme in rbc. genetic transmission as x-linked recessive trait. usually present w/ hx of recent infection requiring pharm tx or other drug ingestion. most common offending drugs: asa, fava beans, sulfa drugs, & antimalarials. tx is supportive w/ transfusions sometimes necessary. the ___enzyme normally protects the rbc from oxidative damage by maintaining intracellular levels of the reducing agent NADPH. sx’s: back pain, fatigue, dark red urine, low grade fever, jaundice, pallor, tachy.
elev’d reticulocyte
fxning bone marrow
depressed reticulocyte
marrow failure (aplastic anemia)
serum haptoglobin
low levels suggest hemolysis
serum ferritin
usually low in iron def anemia. measures the level of iron stores in the liver, spleen, & bone marrow.
pernicious anemia
progressive megaloblastic macrocytic anemia resulting from lack of intrinsic factor essential for absorption of cyanocobalamin (vit b12). intrinsic factor secretion fails b/c of gastric acid mucosal atrophy. often post op w/ sm bowel or gastric surgery. onset gradual. prolong period of def before pt is sx. Sx: mucosal pallor, GI ℅ anorexia & diarrhea, glossitis (beefy red, smooth, sore tongue), peripheral neuropathies). dx critical or may result in irreversible neuro deficits. megaloblastic/macro anemia, dec’d hgb, & rbc’s, leukopenia w/ hyper segmented neutrophils, thrombocytopenia, & elev’d MCV, dec’d MCHC), retic low/nl, cobalamin level dec’d.
tx: cobalamine 1000 mcg/wk IM x4-6wk f/u 1000 mcg/month IM for life. refer: GI for endoscopy upon dx & q 5 yrs to r/o malignancy.
Thalassemia
hypochromic/microcytic anemia. heterogeneous group of d/o’s of hgb synthesis that have in common a def synthesis of 1+ polypeptide chains of the nl human hgb resulting in quantitative abnormality of hgb thus produced. most common genetic d/o worldwide. genes must be inherited from both parents to acquire dz. if 1 gene inherited- considered carrier only. Dx: cbc w/ diff (inc’d wbc & plt, dec’d MCV, MCHC, RDW), peripheral smear, hgb electrophoresis, retic inc’d, ferritin nl/inc’d, iron nl/inc’d, TIBC nl/dec’d, RDW nl/inc’d, LFT’s.
genetic counseling, prenatal screen, no tx for thal min. refer to hematology for thal maj. goal: maintain hgb >10 thru exchange transfusions q 3-5wks w/ iron chelation tx. splenectomy & bone marrow transplant may be indicated.
heterozygous state
thalassemia minor & minima (silent carrier)
homozygous state
thalassemia intermedia & major (cooley anemia)
alpha thalassemia
caused by mutation of genes from globin chain. most prevalent in SE asia & african west coast. silent carrier- no sx’s. see mild anemia & minimal red cell changes. loss of all 4 __ globin chains results in stillbirth of hydrophic fetus. microcytosis in absence of IDA, mild anemia, hgb electrophoresis nl
beta thalassemia
most prevalent in ppl in areas of italy & greece. mutation in globin chain. infant sx in 1st yr of life. will see pallor, failure to thrive, hepatosplenomegaly, & severe anemia. left untx’d frontal bossing & maxillary overgrowth will develop as result of bone marrow expansion. microcytosis (mcv 55-80), nl RDW, smear: nucleated rbc’s, aniscocytosis, poikilocytes, polychromatophilia, howell-jolly bodies), hgb electrophoresis absent or dec’d hgb A, inc’d fetal hgb.
heterozygous beta thalassemia (thal min)
mainly asymp may have mild pallor & splenomegaly. typically detected in asymp pt’s undergoing eval for a microcytic/hypochromic anemia that doesn’t respond to iron.
homozygous beta thalassemia (thal maj)
see bone deformities of skull & long bone, hepatosplenomegaly, iron overload leading to cardiomyopathy, DM, hypogonadism, growth retardation, & susceptibility to infection.
sickle cell anemia
rbc d/o. nl hgb A replaced by hgb S (HB S). substitution of Valine for glutei acid- occurs at 6th position of beta chain- less soluble than nl hgb A- assume ___ shape when deoxygenated. blood viscosity inc’d- clumped cells- obstructs microcirculation leading to tissue ischemia. anemia results d/t removed of ___ rbc’s by phagocytic cells of spleen, further exacerbates tissue hypoxia. remission/exacerbation (crisis). 6mos Hb S predominant, usually precipitated by resp/GI infection- anemia, weakness, fatigue, & growth impairment.
tx: prophylactic abx= PCN V 150 mg bid up to age 6. std immunizations, pneumococcal vaccine- age 2. folate acid 1mg/d help make new rbc. avoid temp extremes. rx supportive w/ analgesics for pain, fluids to dec blood viscosity, & o2 tx. blood transfusion when hgb drops more than 2g of nl.
Hemophilia A
hereditary bleeding d/o caused by low Factor VIII coagulant. affects males. females are carriers. inherited sex-linked recessive trait- defective gene located on chromosome. 50% of male offspring (female carriers) have dz, & 50% of their female offspring are carriers. all female kids of a male w/ __ are carriers of trait. CP: bleeding often seen in joints- hot, swollen, painful joints & subsequent crippling joint deformity, bleeding into muscles & GI tract, compartment syndrome from lg hematomas, hematuria, excessive bleeding (cuts, tooth extractions), spontaneous bleed. admin factor VIII during acute bleeding and before surgery and dental work. DDAVP. aminocaproic acid when unresponsive to factor 8 and desmopressin.
Hemophilia B (Christmas Dz)
low levels of Factor IX coagulant activity. inherited sex linked trait. clinically indistinguishable from ___. Corrects w/ Fac IX supplementation. Fac IX concentrates contain other proteins that inc risk of thrombosis w/ recurrent use- use only when clearly indicated.
Intrinsic to cell
G6PD syndrome, sickle cell dz (hemoglobinopathy), thalassemia.
Extrinsic to cell
autoimmune hemolytic anemia, antibody mediated anemia (fetal/maternal)
bleeding- normocytic/normochromic
may be acute or chronic.
