Anemia Flashcards
(22 cards)
1
Q
hemoglobin formation
A
- Pyrroles from succinyl coA and glycine
- 4 pyrroles form protoporphyrin IX (Addition of iron forms Heme, Addition of globin polypeptide completes a subunit)
- 4 subunits (usually 2 alpha, 2 beta) combine to form hemoglobin (This gives you hemoglobin A)
2
Q
definition of anemia
A
- sign, not disease. May be indicator of serious disease.
- Porth: “Abnormally low number of circulating red blood cells or level of hemoglobin, or both, resulting in diminished oxygen-carrying capacity.”
- If you diagnose someone with anemia, you still need to figure out whats going on or classify it into one of multiple forms
- Anemia is a reduction in the O2 carrying capacity in the blood!!
- If you cannot carry enough O2 to meet your metabolic demands, you are anemic by definition
3
Q
Reduced O2 carrying capacity
A
- Impaired oxygen transport
- Reduced red cell indices/Hgb (When you order a CBC, you typically have the option to order a Hgb and HCT, CBC with or without red cell indices, CBC with or without differential, differential gives all the subtypes of WBC, red cell indices gives you details about the O2 carrying capacity of the blood and the erythrocytes, THE RED CELL INDCES IS THE MOST IMPORTANT LAB YOU ORDER FOR ANEMIA)
- Signs and symptoms of disease causing anemia (Condition typically results from red cell loss (hemolysis/hemorrhage), deficient erythropoiesis, or deficient hemoglobin production, Kidneys make EPO -> CKD pts may have anemia secondary to kidney dysfunction)
4
Q
effects of hypoxia
A
- if you’re hypoxic systemically, you feel this as fatigue, weakness, etc.
- Fatigue -> NOT the same as tired!! Fatigue is you are unable to carry out the functions of every day life (Tired you can overcome (get off the couch and do what you need to do))
- Weakness
- Dyspnea
- Angina
- HA, faintness, dim vision
- If you have low O2, you will be tachycardic because your body is cycling the blood faster
- Might also increase ventilation rate -> is this hyperventilating? NO BECAUSE ITS APPROPRIATE TO THE CIRCUMSTANCE
5
Q
blood redistribution
A
-Pallor of skin, mucus membranes, conjunctiva, nails
6
Q
types of anemia
A
- Blood loss
- Hemolytic
- Red Cell Production
7
Q
Blood loss anemia
A
- Acute or chronic (If youre losing blood at a very slow rate, you feel bad at much lower hemoglobin levels, If youre actively bleeding, you feel the symptoms of anemia at a much higher hemoglobin level)
- Acute – think hypovolemia/shock
- Fluid enter compartment, dilutes blood, Hgb/Hct fall with normal cell morphology
- Chronic loss leads to iron deficiency anemia over time, no volume depletion (microcytic anemia)
8
Q
hemolytic anemia
A
- Usually normocytic/normochromic (Microcytic = small cells, Macrocytic = large cells, Normochromic = normal hemoglobin level, Hypochromic = low hemoglobin)
- Increased reticulocyte count -> immature RBCs
- Possible jaundice - because of hemolysis - making hemosiderin faster than the liver can conjugate the bilirubin
9
Q
hereditary spherocytosis
A
- AD transmission
- Deficiency of red cell membrane proteins (spectrin, ankyrin)
- Red cell loses surface area throughout lifespan
- Characteristic shape lost, spheres remain
- Spherical shape leads to destruction
- Signs include jaundice, splenomegaly, bilirubin stones
- Aplastic crisis when red cell production disrupted as by virus
- Tx with splenectomy -> we take out the organ where most of this hemolysis is happening
10
Q
sickle cell anemia
A
- Point mutation in beta chain of hemoglobin, abnormal substitution
- Sickle Hgb transmitted by recessive pattern -> takes two recessive alleles to have the disease
- 40% sickling with heterozygotic trait
- 80-95% sickling in homozygote
- Low oxygen tension leads to sickling
- 2 results: chronic hemolytic anemia, blood vessel occlusion
11
Q
causes of sickling
A
o Cold o Stress o Exertion o Infection o Hypoxia o Dehydration o Acidosis
12
Q
thalassemias
A
- a: result of deletion of alpha subunit on Chromosome 16. In severe disease Hgb H formed.
- b: usually caused by point mutations in b subunit. Relative increases in Hgb A2 and F. Excess alpha chains unstable and precipitate causing cell damage.
- You order a hemoglobin electrophoresis
13
Q
disorders of red cell production
A
- Decreased bone marrow activity
- Metabolic deficiency
14
Q
IDA (iron deficiency anemia)
A
- MCC worldwide (dietary deficiency or bleeding)
- Deficiency of iron results in decreased heme production
- IDA results in small RBC with low hemoglobin content
- Also “poikilocytosis” and “anisocytosis”
- Membrane may become friable and predispose to hemolysis
- Microcytic, hypochromic anemia
15
Q
megaloblastic anemia
A
- Results from impaired nucleic acid synthesis -> the precursor cell has a nucleus and many of the steps in the lineage of erythroblast have nuclei -> its only toward the end that the cell loses its nucleus
- Enlarged RBC and deficient nuclear maturation
- MCC: B12 or folate deficiency – important cofactors for this synthesis
- Macrocytic anemia
16
Q
B12
A
- Bound to intrinsic factor in stomach
- Absorbed at terminal ileum
- Stored in liver (sufficient for 3 years without intake)
- Necessary cofactor for methionine and succinyl co-A production in 2 pathways
- Necessary for folate to work in DNA production
17
Q
folate
A
- Pteroylmonoglutamic acid (reduced to tetrahydrofolate)
- Also a cofactor in conversion of homocysteine to methionine and conversion of deoxyuridylate to thymidylate (DNA synthesis)
18
Q
B12/folate: parts of a balanced diet
A
- Deficiencies result in “macrocytic” anemia
- Remember: nuclear and cytoplasmic division are different processes
19
Q
Aplastic anemia
A
- AKA bone marrow depression
- Fatty replacement of bone marrow – loss of all 3 stem cell lines
- Remaining cells normal
- May occur at any age
- Petichiae and bruising from loss of platelets, and infections from WBC loss
- Often caused by exposures (radiation, chemicals, Felbamate & tegretol [AED])
- May require BMT
20
Q
ACD
A
- chronic disease
- Common result of chronic infections (eg AIDS, RA, SLE, Hodgkin’s)
- Theory focuses on macrophage and lymphocyte role in sequestering iron, destroying red cells, chemical suppression of EPO response, inhibited precursor cells, reduced Fe transport
- Similar to IDA (microcytic/hypochromic) – separate from CRF (normocytic/normochromic)
21
Q
red cell indices
A
- Included in CBC as means of evaluating erythrocyte health
- MCV (mean corpuscular volume) -> SIZE
- 80-100 = “normocytic”
- MCHC (mean corpuscular hgb content)
- 32-36% reference range (calculation [(hgbx100)/Hct] )Low = hypochromic, High = hyperchromic)
- RDW (Red cell distribution width) (Reference range = 11-14.5, High mean variability in size indicates production of new cells)
22
Q
evaluate anemia
A
- Hgb/Hct (look at this second) (14-18 men, 12-16 women)
- Check MCV and classify (look at this third)
- Check RBC count (look at this first)
- If the answer to any one of these are no, then the pt is anemic and you need to figure out why
- If all three are yes, then they are not anemic
