Chapter 5 Flashcards
what are the lab findings for sideroblastic anemia
Laboratory findings include increased ferritin, decreased TIBC, increased serum iron, and increased %saturation
(iron-overloaded state)
hemoglobin barts
Four alpha genes deleted –> lethal in utero (hydrops fetalis); gamma chains form tetramers (Hb Barts) that damage RBCs; Hb Barts is seen on electrophoresis.
beta tetramers
Three alpha chains genes deleted –> severe anemia; chains form tetramers (HbH) that damage RBCs; HbH is seen on electrophoresis.
splenomegaly plus iron deficiency anemia…
really got to think thalassemias
hallmark of beta thal. minor…
increase in hemoglobin A2 (2 alpha, 2 delta)
as well as increased in fetal Hb (2 alpha, 2 gamma)
What is seen on the slide of beta thal MAJOR….
lots of varying RBCs all over the slide
- especially target cells
- increase in surface area to vol ratio
-in minor, versus iron deficiency anemia, won’t be a lot of variability…
why is there erythroid hyperplasia in beta thal??
because we have tons of EPO but we aren’t making a response from marrow
so we have a massive response from ALL bone marrow
even that in the face
What results from extramedullary hematopoesis in beta thalassemia?
hepatosplenomegaly that make nucleated (immature RBC)
lab findings of folate def anemia
Clinical and laboratory findings include
I. Macrocytic RBCs and hypersegmented neutrophils (> 5 lobes, Fig. 5.5) 2. Glossitis
3. decreased serum folate
4. increased serum homocysteine (increases risk for thrombosis)
5. Normal methylmalonic acid
lab findings of b12 def anemia
Vitamin B12 is a cofactor for the conversion of methylmalonic acid to succinyl CoA (important in fatty acid metabolism).
Vitamin B12 deficiency results in increased levels of methylmalonic acid, which impairs spinal cord myelinization.
Damage results in poor proprioception and vibratory sensation (posterior column) and spastic paresis (lateral corticospinal tract).
- decreased serum vitamin B12
- increased serum homocysteine (similar to folate deficiency), which increases risk for thrombosis
- increased methyl malonic acid (unlike folate deficiency)
what can happen to reticulocyte count in anemia????
it can be falsely elevated!!!
RC is corrected by multiplying reticulocyte count by Hct/45.
Corrected count > 3% indicates good marrow response and suggests peripheral destruction.
Corrected count < 3% indicates poor marrow response and suggests underproduction.
Clinical features of extravascular hemolysis
Clinical and laboratory findings include:
anemia with splenomegaly, jaundice due to unconjugated bilirubin, and increased risk for bilirubin gallstones
Marrow hyperplasia with corrected reticulocyte count > 3%
clinical features of intravascular hemolysis
Intravascular hemolysis involves destruction of RBCs within vessels.
1. Clinical and laboratory findings include
i. Hemoglobinemia
ii. Hemoglobinuria
iii. Hemosiderinuria- Renal tubular cells pick up some of the hemoglobin that
is filtered into the urine and break it down into iron, which accumulates as
hemosiderin; tubular cells are eventually shed resulting in hemosiderinuria. iv. Decreased serum haptoglobin
Most common cause of death in adult sickle cell patients?
Acute chest syndrome-
vasa-occlusion in pulmonary microcirculation
i. Presents with chest pain, shortness of breath, and lung infiltrates
ii. Often precipitated by pneumonia
iii. Most common cause of death in adult patients
what is the percentage of HbS in sickle cell trait?
Sickle cell trait is the presence of one mutated and one normal beta chain chain;
results in < 50% HbS in RBCs (HbA is slightly more efficiently produced than HbS)
Generally asymptomatic with no anemia;
RBCs with < 50% HbS do not sickle in
vivo except in the renal medulla.
what is hemoglobin C disease?
Autosomal recessive mutation chain of hemoglobin.
Normal glutamic acid is replaced by lysine.
Less common than sickle cell disease.
Presents with mild anemia due to extravascular hemolysis.
Characteristic HbC crystals are seen in RBCs on blood smear.
What is G6P deficiency?
X-linked recessive disorder resulting in reduced half-life of G6PD; renders cells susceptible to oxidative stress
RBCs are normally exposed to oxidative stress, in particular
Glutathione (an antioxidant) neutralizes H20 2• but becomes oxidized in the process
NADPH, a by-product of G6PD, is needed to regenerate reduced glutathione.
Decreased G6PD –> decreased NADPH –> reduced glutathione –> oxidative injury –> intravascular hemolysis
How does drug-induced hemolytic anemia get started?
Drug may induce production of autoantibodies (e.g., a-methyldopa) that bind self antigens on RBCs
Drug may attach to RBC membrane (e.g., penicillin) with subsequent binding of antibody to drug-membrane complex
Associated with SLE (most common cause), CLL, and certain drugs (classically, penicillin and cephalosporins)
