Exam 1 Part 2 Flashcards
Methemoglobin - how do you get it?
acquired or genetic
Acquired Methemoglobin
acquired from drugs, well water with nitrates, cyto B5 reductase
Acquired methemoglobin treatment
removal of inciting drug or chemical, treat with methylene blue to reduce cyanosis and tachypnea
Genetic methemoglobin
AR or AD; cytochrombe B5 reductase deficiency, mutation in alpha or beta globin.
Cyto B5 Reductase
keeps iron in ferrous form, reduced in genetic forms of methemoglobin
Newborns and Methemoglobin
more suseptible due to th HbF more readily oxidized to ferric state and lower Cyto B5 reductase activity
Carbon Monoxide binding afinity
240X higher than oxygen
Carboxyhemoglobin
formed when Hb binds to CO instead of O
Symptoms of CO poisoning
headache, malaise, nausea, dizzines, seizures, coma, MI, loss of cognition, movement disorders. Cherry Red.
Treatment and diagnosis of CO poisoning
100% oxygen or hyperbaric oxygen, diagnosis by CO-oximetry
How is pulse ox measured?
two light emitting diodes at 660 nm and 940 nm that measures the deoxyhemoglobin and oxyhemoglobin absorbption by pulsatile flow.
Flaws in pulse ox?
movement, nail polish, deeply pigmented skin, shock, anemia, does measure CO.
Anemia
insufficient Red cell mass to adequates deliver oxygen to peripheral tissue
how do we define the existence of anemia - lab?
Hb concentration, Htc, RBC count
Variation of Hb with age?
At birth Hb is 17% and drops to child level by 3months - 5 yars. Children have less Hb than adults 12%
Routine lab tests in the CBC for anemia?
Hb, Hct, RBC count, MCV, RDW, RBC morphology, Retic Count
how long are retics in marrow
3 days
how long are retics in blood
1 day
normal retic count
0.4-1.7%
Absolute Retic Count
% * RBC count
Retic Index use
corrects for altered red cell concentration and stress reticulocytes
RI calculation
Pt Hb/Normal Hb * (1/Stress retic factor)
symptoms of anemia
shortness of breath, tachypnea, Dyspnea (labored breathing), fatigue, Rapid HR (tachycardia), dizziness, claudication, angina, pallor,
Claudication
pain in extremeities while moving
Dyspnea
labored breathing
where is Fe more soluble?
low pH
How is Fe balanced?
controlled by absorbion and NOT through excretion
How is Fe lost?
exfolication of skin, mucosal surfaces GI, urine, mestruation
Iron is mostly stored where?
65% in Hb; 13% ferritin, 12% hemosiderin 6% myoglobin 0.1% trabsferrin
Iron Absorption on apical membrane
DCYTP converts from Ferric to Ferrous (2+) and transports through DMTI
DCYTP
Cytochrome B like protein - converst Ferric to ferrous on apical surface
DMT1
divalent metal ion transporter, transports Ferrous iron into epithelial cell
Iron Absorption on BL membrane
Ferroportin transporters Ferrous iron out and Hephasetin converst to Ferric
Ferroportin
on BL membrane and trasnporter Ferrous iron out of cell
Hephaestin
on BL membrane and converts Ferrous to Ferric
Hepcidin
produced by liver due to high iorn intake, inflammation and infection; concentration decreases with anemi and hypoxia
increasing hepcidin_.
decreases the amount of ferroportin and decrease iron transfer from epithelial cells
How do we increase Fe absorption?
Amino acids, vit C, high iron diet, increase erythropoesis, low pH, increase gastroferrin
how do we decrease Fe absorption?
phytates and oxalates
Hemochromatosis
deficiency in hepcidin
Iron Cycle
Fe from GI, liver, macrophages binds to Transferrin in Ferric form. Tansferrin interacts with receptors to bring iron intracellularly for Ferritin storage or use.
Ferritin vs Hemosiderin
both intracellular storage, but Ferritin binds reversibly to Ferric form
how do transferrin boudn iron get into cell?
binds to receptor on cell surface and forms clatharin coated vesicle
How does transferrin release iron onces encdocytosed?
opening of Proton pumps intracellularly.
How does iron get into cytoplasm from intracllular vesicle?
through DMT1 channel
Apo-Transferrin
Transferrin not boung to Fe
Intraluminal factors for Fe absorbtion
Gastric factors (low pH, gastroferrin), protein, AA, Vit C, phytates, oxalates, iron ingested
Extraluminal factors for Fe absorption
Erythropoietic activity
Transferrin
plasma mprotein that binds 2 molds of Ferric iron; high binding affinity
Ferritin vs Hemosiderin
Intracllular sotrage, mulimeric structure. Protein coat with center that contains feric.
How do splenic macrophages affect iron?
ingest RBCs and isoalte iron and bidn to Ferritin, where is it converted to ferrous and transproted by ferroprotin in plasma to bind with transferrin.
What converts Ferrous to Ferric on splenic macrophages
ceruloplasmin
what converst ferric to ferrous in splenic macrophages
xanthine oxidase
Hepcidin controls_
peptide produced by hepatocyte, negative regualtor for Fe absorption in GI, trasnprot by placent or release from macrophages.
Inflammation and infection with hepcidin
inhibition of ferroportin – iron retetion in macrophages and continued anemia
what lab tests are characteristic of iron depetion
low marrow Fe, slighly elevated transferrin IBC, low serum ferritin, increased iron absoprtion
what lab tests are characteristic of Iron deficient erythropoesis?
0 marrow Fe, elevanted transferrin and iron abosrption, low Serum ferritin AND, low Serum iron, low transferrin sat, lo
what lab tests are characteristic of iron deficient anemia
0 Marrow Fe, extremely elevanted Transferrin IBC, low serum ferritin, increased iron abs, low serum iron, low Trasnferrin saturation, microcytic cells
Characteristics of Iron Deficiency
decreased hb syntehesis and cell proliferation, multiple sympoms based
Iron deficient anema - nueromuscular defects
mild defects in performance, muerpsych dysfunction
Fe def anemia - epithelial cahnges
ridges and koilonychia on nails, papillary atrophy on tongue
Fe def anemia - GI
dysphagis, esophageal webs, gastritis, protein loosing enteropathy
Immune system and Fe Deficiency
innate and adaptive immune dysfunction
pica
eating things with iron to account for Fe deficiency
what population is Fe deficiency most common?
9% in infants/toddlers, 11% adolesecent females
what causes Fe deficiency?
decreased intake, increased loos, increased need (due to infancy, pregnancy, lactation)
Fe Def anemia diagnosis
decreased Hb and Hct, decreased Retic count, microcytsosis, hypochormia, increase RDW; dec serum Fe and ferritin, increase TIBC and FEP
Fe Deficient anemia treatment
oral iron 150-200 mg/day in 3 doses or 4-6 mg/kd/day in 3 doeses
Iron overload
due to increase in diet, increased abosprtion due to HFE gene, and repeat transfusions.
Iron overlad diagnosis
increased serum iron, infreased ferritin, invreased liver iron
symptoms of iron overlad
cardiac failure, liver dysfunction and failure, diabetes
treatment for hemochromatosis
therapeutic phlebotomy
Hemosiderosis
iron chelators
desferal
IV or SC infusion of iron chelator
Exjade
oral iron chelator
where does hematopoesis occur in embryonal state?
yolk sac
where does hematopoesis occur in fetal stage?
liver/spleen (switches from yolk sac at 4-5 months)
Post-natal hematopoiesis
at birth in marrow, including long bones. But as child ages switches to axial skeleton in vertebrae, pelivs, sternum, ribs,aand skull
Platelet life span
8.5 days; 200 billion per average man/day
how many RBC produced in average man
175 billion/day
Nuetrophils/granulocytes life span
7 hours; 70 billion per average man/day
myeloid
non-erythorid and non-lymphoid lineages - granulocytes, monocytes, megakaryoctes, platelets
Lymphoid
T, B and NK cells lineages
Self renew
production of daughter cell that are completely unchanged, capable of cell renewal or committed to differentiation.
hematopoietic Stem cells
mother of all blood cells and grive rise to lymphoid and myeloid elements
Pluripotent Stem cells
Colony Forming Units _ lymphoid or GEMM - granulocyte/erythroid,monocyte,megakaryocyte
Progenitor Cells
self renewal is liminted; irreverisbly commit to differenitation along myleoid progenitage or burst forming erythroid
Precursor Cells
maturing cells visible in the marrow; capable (somewhat of cell divison) but cannot self renew; give rise to mature functional cells in peripheral blood.
Cortical bone
bone in between trabeculae which holds marrow
Sinusoids:
leaky blood vessles to allow communication between marrow and periphery
Erythropoietin
EPO made by kidney in response to hypoxia, promote erythropoiesis
Thrombopoietin
TOP promotes megakaryopoiesis
Granulocyte-Monocyte colony stimulaiting factor
promotes granulopoiesis and monopoiesis
Granulocyte-colon stimulating factor
promotes grannulopoiesis
Interleukin 5
promotes eosinophil production
Interluekin 3
promotes basophil production
pattern of erythropoeisis
progenitor –> proerythroblast –> basophilic erythroblast –> reticulocyte –> erythrocyte
Function of EPO in erythropoiesis
differentiate and mature basophilic erythroblast and allows to leave marrow as reticulocyte
Hypoxia
biggest driving factor of RBC production; triggers EPO activation to increase mitosis and maturation and Hb levles
characteriscics of cell maturation
cells get slightly smaller with more condensed chromatin. Greyish cyto accumulates Hb.
Mekagaryopoiesis
Thrombopoesis. Megakaryblast matures to mekakarycoyte –> platelet.
treatment of G6PD deficiency
supportive care, avoid oxidant drugs/food, folate, transfusion if severe