Usera: RBC 2 Flashcards
What is the range of MCV for normocytic anemias?
80-100
List five causes of normocytic anemias
acute blood loss early iron deficiency and anemia of chronic disease aplastic anemia chronic renal failure malignancy
Normocytic anemia can be caused by intrinsic or extrinsic defects. List 3 intrinsic defects and 2 extrinsic defects.
Intrinsic: membrane defect, abnormal Hb, enzyme deficiency
Extrinsic: truama, immune destruction
Normocytic anemia can be caused by (blank) hemolysis when splenic and hepatic macrophages phagocytose (blank). The (blank) become bound by IgG with or without the deposition of C3b. The red cells can then take on an abnormal shape such as (blank) or (blank)
extravascular; RBCs; RBCs; spherocytosis; sickling
Two laboratory findings in extravascular hemolysis?
increased unconjugated bilirubin (too much RBC destruction)
increased serum LDH
Normocytic anemia can be caused by (blank) hemolysis, which occurs when RBC phagocytosis by splenic/hepatic macrophages occurs within (blank).
intravascular; blood vessels
3 reasons why RBC hemolysis would occur within blood vessels?
enzyme deficiency (G6PD) mechanical trauma complement/immune destruction
4 lab findings in intravascular hemolysis?
increased unconjugated bilirubin
increased serum LDH
decreased serum haptoglobin
hemosiderinuria (brown urine)
This is an acute phase reactant that complexes with hemoglobin… the complex then binds to macrophages and is phagocytosed.
haptoglobin
Why is serum haptoglobin DECREASED in normocytic anemias?
Hb is released from RBCs in excess and complexes w haptoglobin, causing the free haptoglobin levels to decrease
Hereditary spherocytosis is most commonly due to a mutation in (blank), which causes the RBCs to become (blank) instead of biconcave. It can also be due to mutations in the following…
ankyrin; spherical;
band 3, spectrins, protein 4.2
Hereditary spherocytosis is autosomal (blank) and prevents with what 4 symptoms?
dominant; jaundice (chronic hemolysis), gallstones, splenomegaly, aplastic crisis in children
What makes up the gallstones in hereditary spherocytosis?
calcium bilirubinate
What happens to the following in hereditary spherocytosis?
MCHC?
Osmotic fragility?
LDH and bilirubin?
Increased MCHC (>conc of Hb)
Increased osmotic fragility (hyper-permeability to sodium) can lead to rupture in a hypotonic solution
increased LDH and bilirubin
Are all spherocytes due to genetic disease?
no, anything that affects the surface area of the red cell membrane can cause spherocytes
Hereditary elliptocytosis is an autosomal (blank) disease due to a defect in (blank).
dominant; spectrin tetramers or 4.1
Two clinical findings in hereditary elliptocytosis?
mild anemia
splenomegaly
What causes sickle cell anemia on a genetic level?
recessive missense mutation; Valine instead of Glutamic acid in beta-globin chain
If you are heterozygous for sickle cell trait, do you have anemia? What is this called?
no anemia; HBAS
**occurs in 10% of blacks
If you are homozygous for sickle cell trait, what type of hemoglobin do you make? What percentage of this type is the threshold for disease?
HBSS; 60% HBS is threshold for disease
In people heterozygous for HgbS (carriers of sickling hemoglobin), the polymerisation problems are (blank), because the normal allele is able to produce over 50% of the haemoglobin. In people homozygous for HgbS, the presence of long-chain polymers of HbS distort the (blank) of the red blood cell from a smooth doughnut-like shape to ragged, making it fragile and susceptible to breaking within capillaries.
minor; shape
What type of hemolysis occurs in sickle cell anemia?
predominantly extravascular hemolysis
What are three triggers for HBS molecules to polymerize?
low pH (acidosis) low O2 (hypoxia) volume depletion (dehydration)
Why are newborns with sickle cell anemia protected from sickling for 5-6 months?
they have HBF (two alpha, two gamma chains)
**treatment w hydroxyurea can increase levels of HbF
List as many clinical findings in sickle cell anemia that you can…
What is the most common cause of death in sickle cell patients?
dactylitis (pain in hands and fingers) acute chest syndrome**most common cause of death stoke gallstones (calcium bilirubinate) priapism aspetic necrosis of femoral head aplastic crisi autosplenectomy
Sickle cell anemia causes susceptibility to infections by (blank), due to a dysfunctional (blank). It can also cause osteomyelitis by (blank)
encapsulated organsims, like strep. pneumoniae and H. influenzae; spleen; Salmonella paratyphi
What does sickle cell anemia do to the kidneys?
can occur in peritubular capillaries and cause microhematuria (collection of RBCs in the tubules) and renal papillary necrosis
How can you treat sickle cell anemia? When should you give a transfusion?
infectious prophylaxis or pain management; only give transfusion if acute chest syndrome or aplastic crisis
G6PD deficiency is a recessive (blank) disease; it affects 22% of (blank); (blank) are asymptomatic; (blank) RBCs are usually affected while (blank) RBCs have are normal or near-normal
X-linked; blacks; females; old; young
What is the problem pathophysiologically with having G6PD deficiency?
you aren’t converting NADP+ to NADPH, which is required for glutathione to be reduced - reduced glutathione protects RBCs from oxidative damage and hemolysis
3 inciting causes of G6PD deficiency?
infection
drugs: primaquine, sulfas
fava beans
This is a more severe variant of G6PD deficiency; decreased enzyme activity throughout life span of RBCs
Mediterranean G6PD