Hematology Unit 1 BL class of 2019 Flashcards
hematology is concerned with what in relation to blood?
nature, function, diseases
what are the 3 major types of cells in blood?
erythrocytes (RBC), leukocytes (WBC), platelets
peripheral blood is what?
blood flowing through arteries and veins
what is hematopoiesis?
the making of blood in marrow from hematopoietic stem cells, differentiation of development, production of all types of blood cells
cellular component of blood makes up _______-______% of its volume.
40-45%
what is the rest of blood (the liquid stuff) called?
plasma
what do you need to do to blood when drawing for tests?
know if plasma or serum is needed and what anticoagulant you need
list the components of plasma, buffy, and RBC layers of blood samples.
Plasma is in the plasma, buffy is WBC and platelets, then RBC
erythrocytes
bulk of cellular blood. lack nucleus, lack mitochondria. contain mucho mucho hemoglobin. 120 day life span. 175 billion made per day.
hemoglobin
tetrameric protein, reason RBCs are red. most has 2 alpha globulin chains and 2 beta globulin chains—>Hemoglobin A. each of the tetramers are bound to a heme prosthetic group
mutations in hemoglobin can lead to:
molecules that bind O2 less well, unstable molecules (premature breakdown—hemolysis), polymerization into long chains/crystals, abnormally shaped/fragile cells
hemoglobin S
most common mutation in RBC, leads to sickle cell disease. glu—>val at 6th position in beta globin chain
imbalances in alpha or beta globin chains lead to ______.
thalassemias
what is porphyria?
mutations in enzymes involved in synthesis of heme prosthetic group
what type of metabolism do RBCs depend on?
anerobic
mutations in genes coding for enzymes needed for anaerobic metabolism cause _______.
hemolytic anemia. most common version is G6PD (x linked, 15% of african male population). G6PD is most common human enzyme defect.
why are RBC’s shaped like a biconcave disc?
provides 40% more surface area than sphere with same volume, allowing for more gas exchange. allows them also to squeeze into different shapes due to ratio. allows them to move through/be culled in endothelium of the spleen
what allows the RBC to be deformable and still maintain its structural integrity?
a 2D elastic network of cytoskeletal proteins tethered to cytoplasmic domains on the transmembrane proteins in the membrane.
what substrates does bone marrow need to make RBCs?
iron (can be decreased due to diet, blood loss, etc.), vit. B12 and folic acid, erythropoietin
what are the 5 WBCs:
lymphocytes, neutrophils (PMNs), monocytes, eosinophils, basophils
lymphocytes
key players in adaptive immune response (development of memory after exposure to an infectious agent)
innate immunity
protection against infection that relies on pre-existing mechanisms. capable of rapid response
neutrophils
WBC responsible for finding, ingesting (phagocytosis), digesting bacteria, cell debris, dead tissue. 7 hours half life in peripheral circulation. 70 billion made per day.
malignancies arise from cells of _______ origin.
hematopoietic. all are clonal, neoplastic (cells have undergone several mutations altering proliferative/differentiation capacity). some are classic mutations (translocations, etc.) others have no characteristic cytogenetic abnormalities
lukemia
malignant cells from bone marrow are in the bloodstream
lymphomas
extramedullary collections of malignant lymphoid cells (involving lymph nodes or organs)
what are the two classifications of lukemia?
acute or chronic. acute=cells are immature, progression is rapid. chronic=cells are more mature, more indolent course
hemostasis
arresting of bleeding, allows blood to clot in response to damaged vessels. due to platelets. results from complex interactions btw platelets, endothelial lining of bv, and coagulation factors in response to endothelial disruption
how many platelets can a megakaryocyte produce?
5000
complete blood count began as what?
a measurement of Hg and cellular components of peripheral blood.
hemoglobin is measured where?
in vitro-RBC is lysed and Hg is converted to a spectrometer friendly form. most techniques use cyanmethhemoglobin (absorbance=525/540nm). shows a linear relationship btw light absorption and concentration of a sample
hematocrit is a measure of what?
how much of a sample is occupied by RBCs. is a %. done with formula: %=RBCxMCV
physiologic variables affect one’s RBC’s include what 3 things?
age, sex, altitude
aperture impedance
Coulter principle. Counts RBC, WBC, platelets. an electrical current is run across an aperture of known size—>cell or particle passes through—>current flow changes—>voltage surges—>surge size tells you what size it is. number of pulses tells you how many cells/particles. measures size of nucleus and cytoplasmic granularity
what are the x and y axes of an aperture impedance histogram?
x=range of pulse magnitudes, y=number of events
what can cause inaccuracy in aperture impedence
multiple cells enter at once
light scattering techniques
collect forward, narrow/wide angle scattered light. estimates size of a cell based on the scatter (measures cross sectional diameter).
erythrocyte indices
calculations for size, content, Hgb concentration of red cells. can help characterize anemias. Healthy=little variation.
Mean Corpuscular Volume (MCV)
average volume of red cells. derived from height of voltage pulse, calculated with Hct=MCVx RBC (RBC and HCT are determined manually—> HCTx10/RBC)
mean corpuscular hemoglobin
MCH is weight of Hgb of average red cell. calculated from MCH=Hgb/RBC
mean corpuscular hemoglobin concentration (MCHC)
average concentration of Hgb in a volume of packed red cells. MCHC=(Hgb/Hct)x100
Red cell distribution width (RDW)
measure of variation in size of red cells and is proportional to the width of the measured histogram
reticulocytes
immature, anucleate RBC that still have RNA, ribosomes, organelles (enable continued Hg production). Bone marrow 3-4 days—>released to peripheral blood 1-2 days—> lose RNA and organelles—>mature RBC
what stains RNA, ribosomes, organelles in the reticulum?
Supravital staining (brillant cresyl blue, methylene blue)
nucleated RBCs
nucleated RBCs/100 WBCs
what is thrombocytopenia?
too few platelets
what is thrombocytosis?
too many platelets
what is thrombocythemia?
neoplastic expansion of platelets
optical platelet counting
high angle and low angle scatter signals are combined fore each cell. transformed into volume plotted on vertical axis/refractive index values on horizontal to give a platelet scattergram
combination of impedance and optical counting
impedance channels are used as defaults, but a fluorescent channel is backup when there is an abnormality.
platelet measurements are made how?
forward scatter for size, side scatter for internal structure, fluorescence for RNA/DNA stain
labeled-platelet counts
counted by measuring green fluorescence form FITC on monoclonal antibody in a reagent. Binds the CD61 antigen found on all normal platelets. useful when there’s lots of RBC/WBC fragments
when do white cell counts and differentials stop varying/changing?
after puberty
what is a sheath flow-based counting system?
enable passage of single cells through a sensing zone where multi-parameter analysis can happen when several sensors info is combined
flow cytometry and light scatter for WBC counts
determined with flow cytometry+semiconductor laser. cell info is obtained with forward light scatter for volume, lateral for internal structure, fluorescent light for RNA/DNA info. produces scattergram
cytochemistry and light scatter
peroxidase channel uses cytochemical rxn to produce black rxn. product. neutrophils, eosinophils, monocytes, lymphocytes fall into 4 clusters (separated by electronic thresholds)
what is a blood smear made from?
EDTA anti coagulated blood to prevent artifact. observe at low then high power.
what is red cell morphology on a smear?
little size/shape variation, well spread,
White cell morphology on a smear?
concentrated at the end of the film
neutrophils morphology
acidophilic with fine granules, clumped chromatin in nucleus divided into 5 lobes. too few lobes-neutropenia. too many lobes-neutrophilic.
lymphocyte morphology
scant cytoplasm, round nucleus, dense chromatin. most abundant WBC from age 2-8. too few=lymphopenia, too many=lymphocytosis
monocyte morphology
largest cells, irregular lobulated nucleus, ample grey-blue cytoplasm, azurophilic granules, outline of cytoplasm is irregular, vacuoles. too few=monocytopenia, too many=monocytosis
eosinophil morphology
larger than neutrophils, bi-lobed nucleus, larger spherical granules, count is constant in life. too many=eosinophelia
basophil morphology
similar in size to neutrophils, nucleus obscured by purple-black-coarse granules, least abundant. too many=basophilia
anemia
insufficient RBC mass to deliver oxygen to peripheral tissues. defined by measuring hemoglobin concentration (Hgb), hematocrit (Hct), RBC
_______ have lower Hgb and Hct values than men due in part to more tenuous iron stores.
menstruating women
what lab measurements are used to define anemia?
Hgb, Hct, RBC count, MCV, MCHC, rDW, WBC count, differentia of various types of WBC (%)
what stain is used to observe red cell morphology changes?
Wright’s stain
reticulocytes can be identified by presence of _______ in cell for 1st day in circulation.
mRNA. only peripheral cell where you can routinely evaluate production by quantitating # of young cells in circulation. counted as % of 1000 red cells counted.
what is the normal % of reticulocytes in the blood?
.4-1.7%. increased is when it’s 3.5-5 fold greater than this.
reticulocyte index is useful for correcting reticulocyte counts fro red cell concentration and _________.
stress reticulocytosis. normal RI should be between 1 and 2 for a healthy individual.
what are the stress factors for a reticulocyte count?
1.5 (mild anemia>9gm/dl); 2.0 (6.5-9); 2.5 (severe
what does and RI >2 with anemia indicate?
loss of RBC leading to increased compensatory production of reticulocytes to replace lost RBC.
in anemias that develop over weeks, ________ w/in cells increases to make oxygen dissociation more efficient to compensate for low oxygen carrying capacity.
2,3-DPG. however, if it develops acutely, there is not enough time to make this compensatory mechanism
what are some symptoms of anemia?
shortness of breath, fatigue, rapid heart rate, dizziness, claudication, pain with exercise, pallor
Know his freaking scheme for anemia
seriously, he’s only shown it to you a million times.
is anemia associated with other hematologic abnormalities? YES (means what?)
bone marrow examination to look for: leukemia, aplastic anemia, myelodysplasia, myelofibrosis, myelophthisis, megaloblasitc anemia
is anemia associated with other hematologic abnormalities? NO (means what?)
ask next, is there an appropriate reticulocyte response to anemia?
is there an appropriate reticulocyte response to anemia? YES (means what?)
is there evidence of hemolysis? (yes or no) increased bilirubin/lactic dehydrogenase, decreased haptoglobin, hemosiderin in urine
is there an appropriate reticulocyte response to anemia? NO (means what?)
ask: what are the RBC indices?
is there evidence of hemolysis? YES (means what?)
evaluate for cause of hemolysis
is there evidence of hemolysis? NO (means what?)
evaluate for hemorrhagic causes of anemia
MCV>100
evaluate for macrocytic anemia
MCV 80-100
evaluate for normocytic anemia
MCV <80
evaluate for microcytic anemia
basic concepts of biochemistry/distribution of iron that are important for iron deficiency anemia
- iron exists in 2 valence states, ferric and ferrous. activity depends on state.; 2. in aqueous solutions Fe forms insoluble hydroxides unless bound to a protein/compound; 3. Fe salts are more soluble than low pH; 4. Fe balance in body is controlled by absorption, there are no active mechanisms for excretion; 5. losses of Fe each day are small (skin/mucosal exfoliation, urine, menstruation)
where is the majority of iron contained?
hemoglobin (65%). 6% is in myogolobin, 25% is in ferritin and hemosiderin (storage forms of iron). v. small amount is bound to transferrin. remainder (
iron absorption
goes from stomach (pH and gastroferritin optimize solubility)—>duodenum—>brush border of mucosal cell is where dietary non-heme enters—>converted to ferrous iron by DCYTB—> enters cell through divalent transporter—>stored/transported across bask-lateral membrane
what increases intraluminal absorption of iron?
presence of protein, vitamin C (for valence state)
what decreases absorption of iron?
phytates, oxalates, other food constituents cause it to precipitate and be less biologically available
iron cycle
iron is bound to transferrin—>goes to marrow and maturing normoblasts—>transferrin receptors on cells are bound—>normoblast incorporates it into hemoglobin
transferrin
84kDa plasma protein made in liver. binds iron in ferric form
what happens to iron in dead RBCs?
macrophages turn cells over in spleen, and sequester iron in ferritin stores.
what is the ferritin molecule structure?
coat made of 24 alternating H and L chains. center has ferric salts and 4500 atoms of iron can be held in 1 ferritin
hepcidin
25 aa peptide mad in liver in response to high iron intake, inflammation, infection.
what happens when hepcidin is increased?
plasma flow from stores goes down, iron saturation and plasma iron decrease, erythropoiesis goes down
what happens when hepcidin is decreased?
binds to ferroportin, degrades it. iron export out of cell goes down, iron accumulates in ferritin
transferrin receptor provides ______ for the iron cycle
direction. transferrin enters cell through clathrin coated pit to make endosomes. become acidified, iron exits endosome through DMT1 to go to storage sites. Transferrin returns to surface
what are the general characteristics of iron deficiency?
decreased Hg, decreased cell proliferation, mild hemolytic component (cell rigidity), mildly defective muscle performance, neurophysiological disfunction, nail ridges, upper gastric involvement, immune dysfunction
how does iron deficiency develop?
excessive losses, failure to accumulate iron, on-going losses/inability to gain iron during growth
steps of iron depletion:
- iron ferritin levels diminish; 2. iron deficient erythropoiesis; 3. overt anemia
how do you diagnose anemia?
start with a history, and look a the various symptoms, look at lab tests
differential diagnosis of anemia
anemia of chronic inflammation/infection, anemia of chronic disease, thalassemia, sideroblastic anemias
how do you replace iron?
iron salts orally, intramuscular/iv route when absorption altered/compliance is an issue. slowly normalizes, serum iron responds quickly, normal RBCs in 3-5 days.
do you stop iron treatment once Hg has reached normal levels?
NO! you need to replenish ferritin stores, so continue for a while after (deficient cells survive 3 months, so need to support)
what is iron overload?
increase in body burden of iron beyond the norm. can be caused by increased intake in diet, mutation in HLApH gene, repeated transfusions for anemia.
what are the organs damaged by iron overload?
heart, liver, endocrine organs
how do you treat iron overload?
therapeutic phlebotomy, chelation (Desferal)
each red blood cell contains ______ molecules of Hg.
280 million
what is the predominant form of hemoglobin in adults?
A (alpha 2, beta 2)
absence of what chain is incompatible with life?
lack of alpha globin chains
describe the numbers of amino acids in alpha and beta chains.
141 aa for alpha, 146 aa in beta globin
where does heme link to a histadine?
on the 87 on alpha, and the 92 on gamma, beta, s chain
how is the delivery of oxygen to tissues accomplished by Hg?
through allosteric regulation. (configuration changes allow different binding affinities)
what is a way to quantify the difference in oxygen affinity?
by P50. partial pressure of oxygen where oxygen protein is 50% saturated. P50 for Hg is 27mmHg, myoglobin is 2.75 mmHg
basic shape of the O2 dissociation curve mnemonic (pp-%).
30-60, 60-90, 40-75
ph of Hg oxygen affinity
affinity increases over pH range of 6-8.5. O2 held more tightly in alkaline situation, easily released when there is a lower pH. Bohr effect
hemoglobins oxygen affinity varies ______ with temperature so that at higher temp, more O2 unloaded, less bound by Hg.
inversely
2.3-biphosphoglycerate (2,3-BPG)
biproduct of the aerobic glycolytic pathway. present in red cells at concentration of ~5mmol/L
chromosome 16 contains the ___ genes, with 2 copies of the _ globin gene itself.
alpha-like, alpha
beta like genes and beta globin chain and variants are on chromosome __.
11
what are the 3 hemoglobins that are present only btw. weeks 4-14 gestation?
Hemoglobin Gower 1 and 2 and Portland. All have higher affinity O2 than HgA
what predominates at 8 weeks gestation?
fetal hemoglobin. Bohr effect increased by 20% in fetal Hg.
tell me the ratios of HgF and HgA when a baby is born:
65-95% F, 20% A
hemolytic anemia is caused by variants altering _______ affinity.
Hg-O2. unstable molecules are also called Heinz body anemia
what are Heinz bodies?
precipitated, denatured Hg.
when is erythrocytosis is generally found when?
in people with high affinity hemoglobins b/c O2 delivery to tissues is reduced, causing increased erythropoeitin release from kidneys, stimulating RBC production.
Hemoglobin Zurich has a ________ point mutation that doesn’t affect oxygen binding, but does increase CO binding.
single.
what results if iron binds Hg when it is in ferric form?
methemoglobinemia. can occur because of too much methemoglbin production or b/c of reduced methemoglobin production
how is methemoglobin produced?
oxidation via free radicals, hydrogen peroxide, nitric oxide, OH-. can also occur with drug exposure (anesthetics, nitrates, etc.)
what is the most common cause of methemoglobinemia?
hereditary causes, most commonly the homozygous deficiency of cytochrome b5 reductase. also could be a mutation in Hg that causes you to make HgM. causes you to be cyanotic
what color is methemoglobinemia blood?
dark red/ chocolate/ blue-brown, doesn’t change with oxygen exposure
_______ can be given by IV to provide an artificial electron acceptor for reduction of methemoglobin via NADPH-dependent pathway, giving results in ~1 hour.
methylene blue.
when is cyanosis visually perceptible?
when reduced Hg exceeds 3 g/dL, O2 saturation below 85%.
how does a pulse oximeter work?
uses photo detectors with 2 light diodes that measure pulsatile flow
platelets
clotting factor of the blood. 7-10 days life span in peripheral circulation, 200 billion made per day
embryonal stage hematopoiesis
primitive blood cells are produced in yolk sac. finished by month 3
fetal stage hematopoiesis
months 2-7 liver and spleen are the sites of hematopoiesis. by birth its established in marrow
post natal hematopoiesis
marrow cavity is hematopoietically active. as age progresses, it becomes more localized in axial skeleton. by 18-20 years 90% of marrow is in vertebrae, pelvis, sternum, ribs, skull.
extramedullary hematopoeisis
hematopoiesis outside of marrow after birth. very weird and wrong.
myeloid
all non-erythroid, non lymphoid cells (eg: granulocytes, monocytes, megakaryocytes, platelets, etc)
lymphoid
T, B, NK cells and their precursors
self renewal in hematopoiesis
a dividing stem cell can differentiate in the process, so this process produces daughter cells that are unchanged from the original. It does not proliferate but can at a later time
mutipotential hematopoeitic stem cell (HSC)
mother of all blood cells, generates lymphoid and myeloid cells. can self renew or become a pluripotent stem cell
pluripotential stem cells/colony forming units (CFU)
CFU-GEMM is mother of all non-lymphoid blood cells. CFU-L is the mother of all lymphoid cells. can self renew or become progenitor cells
progenitor cells
self renewal is limited, and they commit to differentiating at various lineages.
Burst Forming Unit Erythroid (BFU-E)
progenitor cell that becomes CFU-E. comes from the exuberant colonies. can make precursor cells
precursor cells
recognizable, maturing cells in marrow specimens. can divide up to a point, but not self-renew. become mature, functional cells in peripheral blood, lymphoid organs, reticuloendothelial system
amplification
self renewal. few stem cells can become billions each day
bone marrow vasculature
arteries go through the marrow, branching in to capillary-venous sinuses. these are composed of endothelial/basement memb/adventitial layer. these flow into a central vein into systemic circulation. passage of cells into the sinuses is selective-only mature ones can move out.
stromal elements play a key role in _________.
hematopoiesis. include endothelial cells of C-V sinuses, reticular cells of the adventitia, fibroblasts, lymphocytes, macrophages, adipocytes, extracellular matrix
hematopoietic growth factors (HGF)
man different types exist, work on many target lineages, made by different cell types
erythropoietin (epo)
made by kidney cells during hypoxia. promotes erythropoiesis
thrombopoietin (tpo)
promotes megakaryopoiesis
granulocyte-monocyte colony stimulating factor
GM-CSF. promotes granulopoiesis and monopoiesis
granulocyte colony stimulating factor (G-CSF)
promotes granulopoiesis
monocyte colony stimulating factor (M-CSF)
promotes monopoiesis
interleukin-5 (IL-5)
promotes production of eosinophils
interleukin-3 (IL-3)
promotes production of basophils
describe steps of erythrocyte maturation
pronormoblast—>basophilic normoblast—>polychromatophilic normoblast—>orthochromatic normoblast—>reticulocyte—>erythrocyte
what characterizes erythrocyte maturation?
chromatin condenses and loses parachromatin, the nucleus degrades pyknotsicly, the pyknotic nucleus is extruded and an erythrocyte is formed, hemoglobin is accumulated and the organelles are lost. eventually it can no longer replicate
pronormoblast
first erythroid precursor. 18um wide. nucleus has fine, granular chromatin and 1-2 nucleoli. cytoplasm has lots of RNA so it’s very blue
basophilic normoblast
cytoplasm is basophilic-but a lighter perinuclear halo can be around. nuclear chromatin is coarser and condensed. smaller- 12-14 um.
polychromatophilic normoblast
10-12 um. starting to accumulate Hg. Hg+RNA makes it look purple-blue in cytoplasm. nucleus is smaller with chunky chromatin
orthochromatic normoblast
8-10 um. cytoplasm is red-orange from Hg. v. small and shrunken nucleus
reticulocyte
anucleate cell, with ribosomes and mitochondria. can be identified after supra vital staining-since it causes mitochondria and ribosomes to condense into strands
erythrocyte
reticulocyte ribosomes make Hg for 2-3 days and then they degrade, resulting in a a mature erythrocyte. 7-8um. biconcave disc.
list the steps of granulocyte maturation
myeloblast—>promyelocyte—>myelocyte—>metamyelocyte—>band—>segmented granulocyte (seg)
what features characterize granulopoeisis?
the nucleus matures with chromosome condensation, the nucleoli are lost, and the nucleus indents to eventually segment. primary and secondary cytoplasmic granules are acquired. eventually the ability to replicate is lost by the metamyelocyte stage
myeloblast
15um. 1st precursor. high nuclear:cytoplasmic ratio, fine chromatin, 1 or more nucleoli, blue cytoplasm w/ lots of RNA. no granules
promyelocyte
20um. chromatin are condensed/coarse. nucleoli are present. has a variable # of large purple granules. blue cytoplasm
myelocyte
15um. lavender secondary granules smaller than primary granules, large golgi, less granules than promyelocyte, condensed nucleus with coarse chromatin. last precursor that can divide
metamyelocyte
14-16um. lots of secondary granules that make it look pinkish purple, obscure primary granules (or they may be absent). nuclear chromatin is condensed and coarse and the nucleus has an indent (less than 1/2 the diameter of the nucleus)
band
13 um. horseshoe shaped nucleus. lots of secondary granules
segmented neutrophil
same size and cytoplasmic properties as band. nucleus is segmented into 2-5 lobes connected by strands
eosinophils
13um. cytoplasm is full of large orange-red granules. nucleus has heavily condensed chromatin, segmented into (2) round oval lobes.
basophils
10 um. lobular, non-segmented nucleus that is obscured by blue-purple granules.
list the steps of megakaryocytic maturation
megakaryoblast—>promegakaryocyte—>megakaryocyte—>platelet
what is megakaryocyte maturation characterized by?
dna undergoing repeated doublings (endoreduplication) to form a multilobulated nucleus wi/ around 32 sets of chromosomes. the cytoplasm is filled with granules and a network of membranes allows it to make platelets that it sheds into the vascular sinuses.
megakaryoblast
20-30um. large, round/indented nucleus with nucleoli and rim of basophilic cytoplasm. hard to differentiate from other blasts
promegakaryocyte
lobulated nucleus with condensed chromatin. granules are in the cytoplasm give an intense blue
megakaryocyte
lobulated, endoreduplicated nucleus with lots of cytoplasm that is granular and purpleish
platelet
megakaryocyte extends membrane into the lumen of the sinus. chunks break off and float away. 2-4 um, granular, purplish
list the steps of monocyte/macrophage development
monoblast—>promonocyte—>monocyte
what characterizes monocyte maturation?
nucleus goes from round and indented to variable and irregular. peroxidase-positive lysosomal granules and vacuoles appear in the cytoplasm, and monocytes travel to the connective tissue to become macrophages.
monoblast
16um. indented nucleus with fine chromatin and nuclei. blue cytoplasm with no granules.
promonocyte
16-18 um. indented nucleus with condensed chromatin and one or more nucleoli. red purple granules are in the cytoplasm
monocyte
15-18um, largest in peripheral blood. varied nuclei shape. no nucleoli, cytoplasm is bluish with “ground-glass” appearance. scattered red purple granules
cellularity of bone marrow means what?
portion that is hematopoietically active. the non-active part is occupied by stream elements (fat). Decreases with age. should be equal to 100-age
myeloid erythroid ratio (M:E ratio)
granulocytic:erythroid precursors, 3:1
maturation
precursors should mature, so it should look heterogeneous. lack of maturation is a homogenous apperance
marrow should be free of _________ findings.
abnormal. includes things like fibrosis, metazoic tumor, granulomas
pathophysiology of anemia of chronic disease
common mechanisms: malignancies/sepsis—TNF decreases Fe stores, decreases EPO, INF-beta inhibits erythropoeisis; chronic infection/inflammation—IL-1 diminishes Fe mobilization/EPO production, INF-gamma inhibits erythroid. Results are related to inability to use irons stores, less EPO, decreased erythropoiesis.
what do all anemias of chronic disease have?
reticulocytopenia. characteristically Fe is decreased, TIBC is normal to decreased and ferritin is normal to increased, EPO low
lead intoxication anemia
mild/moderate anemia, decreased reticulocyte count, microcytosis, basophilic stippling, increased Zn protoporphyrin. treat with chelation
renal insufficiency anemia
not seen until kidney function is
thyroid disorder anemia
normochromic, normocytic, microcytosis or macrocytosis. treat with hormone repalcement
adrenal insufficiency anemia
normochromic, normocytic
_______ and ______ are critical co-factors for normal hematopoiesis.
folic acid and vitamin B1 (cobalamin). the metabolite of folic acid donates a methyl group in the synthesis of methionine from homocysteine cogenerate tetrahydrofolate. this is important in the steps of DNA synthesis.
deficiencies in folic acid and vitamin b12 affect the _______ process of RBC precursors in marrow.
maturation. cells will increase in size and arrest in S phase then destroy themselves
do plants contribute B12 to the human diet?
NO!
where is vitamin B12 released upon ingestion?
in the acidic stomach. IF secreted by parietal cells binds it and then in the terminal ileum it is absorbed and released from IF, binding transcobalamin binding protein 2 (Tc2). It is then transported to the liver for storage or to the marrow for use
what is the most common cause of B12 deficiency?
pernicious anemia
pernicious anemia
caused by autoimmune destruction of IF producing gastric parietal cells. common in older population.
where is dietary folate absorbed?
in the jejunum. It is hydrolized, reduced, methylated before distribution to tissues or liver for storage.
what is the most common cause of folate deficiency?
inadequate dietary intake. other causes are malabsorption or increased demand, alcohol consumption.
how long does it take to develop folate and B12 deficiencies?
folate is weeks, B12 is months
what hematologic changes do you se with megaloblastic anemia?
M:E ratio is altered (more erythroid produced), marrow precursors have large/immature nuclei, anemia is variable in peripheral blood, macrocytosis, retic count is decreased (
________ involvement is classic in B12 deficiency
neurologic. sensory abnormalities, loss of proprioception, ataxia, spasticity, gait disturbances, positive babinski reflex may follow
if you treat an undiagnosed B12 deficiency with large doses of folic acid, what happens?
the neurologic damage can be exacerbated
what tests show B12 and folate deficiencies?
cobalmin (but must be aware won’t show deficiencies in tissues), serum folate, red folate, plasma homocysteine levels (more sensitive), methylmalonic acid levels
once B12 deficiency is diagnosed, it is important to know the ______.
cause.
shilling test
1ug of cobalamin given orally, IF combines with it and it eventuallyy enters bloodstream. Flushing dose give via IM at 2 hours to saturate trancobalamins. 5-35% of the absorbed Cbl is exceed in 24 hours due to being “wahshed out”
how do you treat B12 and folate deficiencies?
inject/oral B12. 1mg/day of oral Folate or parenterally.
thalassemia is a condition where there is ______ of a hemoglobin chain due to a variety of mutations that result in _____ or _____ function of the globin gene.
underproduction, poor or absent
alpha thalassemia
alpha chain is underproduced due to absence of 1 or more of 4 genes that control production. common Asian, African Mediterranean descent
beta thalassemia
beta globin chain is underproduced, due to point mutations resulting in dysfunctional genes. HbE is structurally abnormal hemoglobin due to point mutation (unstable), lower in RBC due to the instability causing changes. mediterranean, african, SE asian descent.
list the consequences of thalassemia defects:
low concentration of Hg in RBC, imbalance in chain production, increase in other hemoglobins
RBCs in thalassemia and HgE are ______, and have ______ MCHC with an excess of membrane, giving them a “target cell” shape.
smaller (low MCV), lower
underproduction of one globin chain results in ________ of the other globin chain.
unmatched excess. unused chains can precipitate, denature and oxidize, damage cell membranes and make RBCs more fragile.
diagnosis of Beta thalassemia is based on recognition of ___ and ____ relative to underproduced HbA1.
HbA2, HbF
if a person with Beta thalassemia becomes iron deficient, are you more or less likely to catch their thalassemia?
less. HbA2 values will appear normal instead of high due to the iron deficiency. you must be sure they aren’t iron deficient before starting Hg electrophoresis to evaluate for thalassemia
anemia with some increase in reticulocyte count in relation to chronic hemolytic anemia
degree will vary with thalassemia severity. Cooley’s anemia needs regular transfusions to sustain life. others may not need transfusions till later/or at all
chronic hemolytic anemia has:
anemia with increase in reticulocyte count, abnormal peripheral smear, splenomegaly, abnormal chemistry profile
how does bone marrow attempt to produce adequate RBC mass with thalassemia?
bone marrow expands to fill with RBC precursors even though they are ultimately fragile and destroyed.
people with severe forms of thalassemia ______ absorption of iron from the diet in response to anemia.
increase.
anemia, increased metabolism and ineffective erythropoiesis and encocrinopathies contribute to ______ growth and development.
delayed. can result in short stature and delayed puberty.
nearly 2/3 of patients with ________ anemia have abnormal endocrine function
Cooley’s. pituitary is affected, hypothyroidism/impaired glucose may occur (40-60% of patients)
persons with chronic hemolytic anemia (inc. thalassemia) are at risk for __________.
pulmonary hypertension. more common in splenectomy patients
how do you treat thalassemias?
transfusion support (combined often with chelation therapy and splenectomy), increasing fetal hemoglobin production, and bone marrow transplantation.
sickle cell is:
a. autosomal recessive
b. both B-globin genes are mutated
c. there is a single amino acid substitution
D. heterozygosity provides carrier advantage e. all of the above are true
All are true!
sickle cell disease occurs in people with 2 abnormal __________ genes where at least one of these has the sickle mutation.
beta globin. if the other gene also has the sickle cell mutation the disease is sickle cell anemia (HbSS)
sickle cell trait
occurs in person with 1 sickle cell gene and 1 normal gene. protects against disease devleopment
when deoxygenated, sickle hemoglobin polymerizes into _____strand helical fibers that ______ the shape of the RBC into a sickle form or other irregular shape
14; distort
when does a cell become irreversibly sickled
after several deoxygenation-reoxygenation cycles
the shape of the sickle RBC results in chronic hemolytic anemia-describe the characteristic changes in lab tests seen with this
anemia with compensatory increase in reticulocyte count, increased baseline WBC and platelet count, increased RDW, abnormal peripheral smears (sickle forms, schistocytes/broken cells, polychromasia/blue colored cells, anisocytosis/variation in size, poikilocytosis/variation in shape), abnormal chemistry profile
howell jolly bodies
small purple dots in RBCs. seen in patients w/o functioning spleen
target cells and hemoglobin C crystals
red “rods” in RBC, seen in HgSC
microcytosis
low MCV and target cells in SBthalassemia (+/- versions)
what shows up in an abnormal chemistry profile with SCD?
increased total/indirect bilirubin, lactate dehydrogenase (LDH) and aspartate aminotransferase as RBCs are lysed
what are the implications of chronic hemolytic anemia (SCD)?
aplastic crisis, growth retardation/delay, bilirubin gallstones
aplastic crisis
anything compromising bone marrow ability to produce RBCs can drop Hg quickly. Found via low reticulocyte count. can result from Parvos virus, infection, medication, vitamin deficiencies
RBCs in SCD are “_____” due to membrane injury and retention of adhesion molecules on surface.
Sticky!!! this results in adhesion of sickled RBCs in microvascular circulation. results in vaso-occlusion, vessel wall injury, endothelial remodeling, vessel narrowing, chronic organ damage
what organs are most affected by chronic RBC adhesion/vascular occlusion
spleen, CNS, lung, kidney, retina, femoral/humeral heads
spleen damage in Chronic RBC adhesion/vascular occlusion
large numbers of RBC trapped—>severe anemia and circulatory show occurs; splenic sequestration. results in autoinfarction/destruction of seen by 5 y/o.
CNS damage in Chronic RBC adhesion/vascular occlusion
up to 10% of children with HbSS have overt large vessel stroke due to chronic injury. learning disabilities and neurologic problems can occur. can be reduced w/blood transfusions.
lung damage in Chronic RBC adhesion/vascular occlusion
damage to microvessels makes it hard to let blood flow through, resulting in high pressure in pulmonary arteries—pulmonary arterial hypertension. puts strain on R side of the heart
kidney damage in Chronic RBC adhesion/vascular occlusion
tubules damaged via chronic vaso-occlusion. cannot concentrate urine to avoid dehydration. may have papillary necrosis (ischemia of collecting system) leading to blood in urine. renal insufficiency and permanent scarring/damage of glomerulus common
retina damage in Chronic RBC adhesion/vascular occlusion
vessels can form abnormally in retina and hemorrhage, leading to detached retina and blindness.
other issues and damage in Chronic RBC adhesion/vascular occlusion
femoral/humeral head avascular necrosis, joint deterioration, hip/shoulder replacement. skin ulcers, poor healing
sickle cell crisis
hypoxia, dehydration, inflammation, infection and stressors lead RBCs to sickle and leads to blood vessel damage and constriction—sudden vaso-occlusion. causes severe pain (commonly in arms, legs, chest abdomen).
what are other significant acute faso-occlusive complications?
hand-foot syndrome (swelling), acute chest syndrome (fluid leaks into lungs), acute multi-organ failure syndrome (renal and liver failure), priapism (ouchie), bone infaction (focal areas sustain ischemia, damaged, necrotic, painful)
list the 3 main treatments of SCD:
bone marrow transplantation, hydroxyurea therapy (chemo agent that induces fetal hemoglobin), transfusion therapy
how long do people with SCD live typically?
into their 50/60’s if cared for properly
hemolysis
decrease in RBC survival or increase in turnover beyond standard norms. determines whether anemia presents acutely or chronically.
what are the 2 mechanisms for red cell destruction to exist?
turnover w/in vascular space (intravascular) and ingestion/clearance by macrophages of the reticuloendothelial system (RE) (extravascular)
red cells undergoing intravascular hemolysis release Hg into __________.
circulation. tetramer form of Hg dissociates and binds haptoglobin, which is removed by the liver. Fe can also be oxidized to form methemeoglobin, dissociation of globulin means methane can bind albumin/hemopexin, both of which can be taken up by parenchymal cells and made into bilirubin.
in extravascular hemolysis, red cell is ____ by ____ of RE system.
ingested, macrophages. heme is separated from globin, iron is stored in ferretin, porphyrin ring is made into bilirubin. bilirubin is made water soluble by glucuronic acid via cytochrome P-450 enzyme in liver. It is then converted to urobilinogen which cycles in gut/liver or is excreted.
_______ is _______ if hemolysis is brisk enough o overcome bilirubin processing of liver, leading to increase in unconjugated fraction.
bilirubin, increased
what else suggests an increase of intravascular hemolysis?
decrease in serum haptoglobin levels, hemoglobin in urine or plasma, increase in methane or methealbumin
hereditary spherocytosis (HS)
familial disorder: anemia, intermittent jaundice, spenomegaly (responds to spelnectomy). loss of plasma membrane and formation of microspherocyte (suceptible to osmotic stress). Spectrin/ankyrin/band 3 weaken cytoskeleton to destabilize lipid layer. this leads to entrapment in spleen. Mostly auto dom, 25% is auto recessive. treat for chronic anemia, splenectomy. can result in aplastic crises and bilirubin stones.
glucose 6 phosphate dehydrogenase (G-6-PD) deficiency
sex linked recessive. may help with resistance to plasmodium vivid. G-6-PD provides protection against oxidant stress. loss of enzyme early on=denatured Hg attaches to membrane and damages spectrum. resulting deformability means splenic trapping and extravascular hemolysis.
Pyruvate Kinase (PK) deficiency
second most common enzyme deficiency, most common glycolytic defect. decreases conversion of phosphoenolpyruvate—>pyruvate, results in less ATP. Membrane plasticity down, destruction in spleen. support with folate, transfusion, supportive care
autoimmune hemolytic anemia
antibodies to universal red cell antigens can cause hemolysis bi intra/extra vascular destruction. Cold and hot.
cold antibodies
IgG/M bind red cell membrane in cooler areas of body, when they move back into the body they activate complement through C5-9 attack complex, makes holes in membrane. It dissociates at higher temperature and the cell destructs.
warm antibodies
IgG. bind cell with big affinity. have no/poor complement activating capacity, incites splenic macrophage to do antibody-mediated phagocytosis through Fc receptor. results in extravascular hemolysis
what tests are used for autoimmune hemolytic anemia?
antiglobulin or Coombs tests for IgG and or complement on cell surfaces. warm=positive DaT, max reaction at 37C, panagglutining w/o antigen specificity. cool=positive DAT, max react at 4C,antigen specifically for I or i
the most significant complication of splenectomy is ____ _____ _____, particularly associated with S. pneumonia. This risk is greatest in children
overwhelming bacterial sepsis
what temp is a trigger that you need to see your doctor if you have had a spenectomy?
>38.5C. see immediately for febrile illness
orthochromic normoblast
Pronormoblast
basophilic normoblast
polychromatophilic normoblast
reticulocyte
megakaryocyte
myeloblast
promyelocyte
myelocyte
metamyelocyte
band
segmented neutrophil
eosinophils
basophils
mast cells
monoblast
promonocyte
monocyte
lymphoblast
lymphocyte
the freaking chart we have to know
hemoglobin and myoglobin binding curves
heinz bodies
alpha thalassemia table
beta thalassemia table
CBC thalassemia lab results
sickle cell disease table
Development of Iron deficiency Table
Newborn Screening Tests table
