Anemia Flashcards
Microcytic Anemia
Iron Deficiency
Increased requirements (pregnancy)
Poor intake
decreased absorption
chronic blood loss
anemia of chronic disease (late)
normoctic early, microcytic later
thalassemia
sideroblastic anemia
other hemoglobinopathies (sickle cell)Iron deficiency
blood loss
major cause of iron deficiency
occult bleeding more difficult to track down and
usually result of gi blood loss examples:
upper-pepic ulcer, esophageal varices, gastritis
lower-hemorrhoids, diverticula, colorectal caner, ibd (crohns and ulcerative colitis)
Iron deficiency iron stores
normal iron content 3-4 grams
hemoglobin-2 grams
iron containing proteins (myoglobin,..) 400 mg
Iron bound to transferrin- 3-7 mg
remainder is in ferritin or hemosiderin
most iron is in hemoglobin
most ferritin is stored in liver
iron deficiency clinical manifestations
usually presenting sxs in adults are primarily due to anemia include weakness, HA, irritability, and varying degrees of fatigue and exercise intolerance
however many pts are asymptomatic and present only w/ anemia
Pica- cravings for non food stuff
pagophagia-pica for ice (very specific for iron)
sxs are highly dependent on rate of blood loss..the more acute, the more sxs appear. w/ chronic loss, usually takes substantial loss before pt becomes symptomatic
iron deficiency labs
serum ferritin-excellent indicator of iron stores (gold standard test) normal-15-200 ng/ml serum iron (reduce) Total iron binding capacity (increased) transferrin saturation (low)
fe deficiency happens in stages 1. serum ferritin decreases 2. serum iron decreases. 3. TIBC increases
RDW and iron deficiency
RDW measures anisocytosis so looks at variation in size of rbc
Microcytic anemia w/ a low or normal RDW= anemia of chronic disease or thalassemia
microcytic anemia w/ high RDW=iron deficiency
tx of iron deficiency anemia
correct underlying cause
iron supplementation
Anemia of Chronic disease (late)
KEY IS THAT ACD FERRITIN IS HIGH AND IDA FERRITIN IS LOW
SERUM IRON LOW IN BOTH ANEMIA OF CHRONIC DISEASE AND IRON DEFICIENCY ANEMIA, AND TOTAL IRON BINDING CAPACITY IS HIGH IN IDRON DEFICIENCY ANEMIA AND LOW IN ANEMIA OF CHRONIC DISEASE
EPO is low in almost all cases
anemia usually moderate Hb around 7-11
tx of anemia of chronic disease
correction of underlying disorder if possible
pts w/ low epo levels can be given EPO
common diseases associated w/ anemia of chronic disease
RA lupus hiv tb carcinomas lymphomas leukemias
megaloblastic vs nonmegaloblastic
megaloblastic-presence of oval macrocytes and hypersegmented neutrophils
nonmegaloblastic-absence of neutrophil hypersegmentation along w/ the presence of round macrocytes
macrocytic megaloblastic anemias
Abnormalities of dna metabolism
b12 deficiency (cobalamin)
folate deficiency
drug side effects
what separates Folate from B12 deficiency
neurological sxs occur only w/ b12(cobalamin) indicating that additional mechanisms are involved in the central nervous system
what does absorption of b12 depend on 5 factors
adequate dietary intake acid pepsin in the stomach pancreatic proteases gastric secretion of functional IF ileum w/ functioning cobalamin-intrinsic factor receptors
anything that interferes w/ any of these steps can lead to a deficiency in b12 w/ a subsequent anemia and potential neurological sxs
B12 adequate dietary intake
meat and dairy provide b12
total body stores of cobalamin is 2-5 mg, one half which is in the liver, so it takes years to develop vitamin b12 deficiency after absorption of dietary b12 ceases
what can interfere w/ the dietary intake of b12
vegan diet
what interferes w/ acid pepsin in stomach
gastrectomy/bariatric surgery, gastritis
what interferes pancreatic enzymes
pancreatic insufficiency
what interferes w/ IF secretion
pernicious anemia
what interferes w/ absorption in ilium
absorption interference: crohns or ileal resection
pernicious anemia
autoimmune
parietal cells in stomach fail to secrete enough IF to ensure intestinal absorption of b12
sx- weakness, glossitis (enlarged, smooth tongue), paresthesias, gi sxs-diarrhea, N/v, and pain, severe anemia can reveal signs of cardiac failure
eval of pernicious anemia
review pts drug list
measure of serum b12 and folate
smear to look for megaloblasts (macroovalocytes) and hypersegmented neutorphils
how to tell from labs folate vs b12
specific metabolites (methylmalonae and homocysteine) serum conc of homocysteine as well as serum and urinary conc of methylmalonic acid are elevated in b12 deficiency due to a decreased rate of metabolism
only Homocysteine is elevated in folate deficiency since folate does not participate in methylmalonic acid metabolism
antibodies to IF
Tx of B12 deficiency
parenteral or sublingual b12
vegans can take oral therapy cause they don’t have absorption problem 25-100 micrograms
IMPORTANT- a person treated w/ folate who has a b12 deficiency may have their sxs masked…which is bad news cause neurological damage form b12 deficiency can be irreversible so have to make sure you find the underlying problem
folate deficiency
comes form animal products and leafy vegetables
folate stores are low can develop megablastosis within 4-5 months
MOST COMMON CAUSE OF of folate deficiency is nutritional due to poor diet and/or alcoholism
other causes include increased requirements in pregnancy and w/ pts w/ hemolytic anemia
drugs also interfere w/ folate metabolism (trimethoprim, methotrexate, phenytoin)
nonmegaloblastic macrocytic anemias
alcoholism liver disease aplastic anemia drug induced myelodysplastic syndrome pregnancy myeloma hypothyroidism
cells characteristic of liver disease
target cells-area of central density surrounded by a halo of pallor.
Diff Diagnosis for normocytic anemia
N=normal preg o=over hydration r-renal disease (lack of epo) m=marrow problems, mixed anemia a=acute blood loss l=liver disease (can be macrocytic) si=systemic inflammation (anemia of chronic disease (early) z=zero prod (aplastic anemia (can be macrocytic)) e=endocrine disorder hemolytic anemias
anemia of chronic renal failure
don’t confuse w/ anemia of chronic disease
tx- Human recombinant EPO (procrit)
Mixed Anemia
very important to order a smear cause MCV will be normal
if have microcytic cells from iron deficiency and macrocytic cells from a b12 deficiency the MCV may be normal
RDW would be increased
Reticulocytes
young immature RBC that contain residual RNA, which explains their tendency to stain w/ certain dyes
make up 1% of rbc
circulate 1 day before maturing to rbc
what does reticulocyte count represent
ability of bone marrow to produce mature rbc
normal 1-2%
In an anemic pt an increase in the reticulocyte count provides evidence that the bone marrow is adequately responding to the anemia (in an effort to maintain the hemoglobin level)
have blue stains on smear
Reticulocyte count
very useful in context of a normocytic anemia
3 situations
acute blood loss
hemolytic anemia
response to iron, folate, or b12 replacement
Anemia of acute blood loss
initially hemoglobin is normal but after time hemoglobin will fall
Retic count will be normal for the first few days but will increase shortly after
Hemolytic anemias
RBC destruction marrow prod can't compensate for rbc destruction extravascular (spleen, liver, marrow) intravascular (rare) intrinsic abnormalities of rbc contents (Hb, enzymes) membranes extrinsic to rbc serum antibodies traumas in the circulation infectious agents
Extravascular destruction of rbc- Intrinsic defects
Enzyme deficiencies (G6PD or pyruvate kinase)
Hemoglobinopathies (sickle cell, thalassemia,
unstable hemoglobin
Membrane defects (hereditary spherocytosis,
elliptocytosis)
extravascular destruction of rbc-extrinsic defects
Liver disease hypersplenism infections oxidant agents other agents (snake bites, lead, etc) microangiopathic (DIC, TTP) Autoimmune hemolytic anemia intravenous immune globulin infusion large granular lymphocyte leukemia
what is main sx of hemolytic anemia
jaundice
tests for hereditary spherocytosis
Reticulocyte count elevated MCHC (mean corpuscular HgB conc)-most helpful osmotic fragility testing ektacytometery acidified glycerol lysis test cryohemolysis test eosin 5 maleimide binding test
