Test 4 review sheet Flashcards
hereditary spherocytosis is highest in people of ?
Northern European ancestry
Hereditary spherocytosis
membrane protein deficiencies that result in an unsupported red cell membrane
spherocytes in hereditary spherocytosis
rigid and not as deformable as the normal biconcave red cell
What does the spleen do to correct the spherocytes in hereditary spherocytosis?
sequesters these abnormal red cells, where they become further damaged and are selectively removed by macrophages
direct antiglobulin test
detects antibodies present on the red blood cell (RBC) membrane
If the antiglobulin test is negative?
antibodies won’t be present and thus be a sign of hereditary spherocytosis
Tests for hereditary spherocytosis
Direct antiglobulin test
Osmosis fragility
Red cell morphology
reticulocyte count
Results of test if hereditary spherocytosis is present
Direct antiglobulin test: negative
Osmosis fragility: increased
Red cell morphology: spherocytes present
reticulocyte count: increased
aplastic crisis.
a temporary shutdown of red cell production due to a drop in hemoglobin from a viral infection
What is the difference between immune hemolytic anemias (with spherocytes) and hereditary spherocytosis
Direct antiglobulin test:
Positive for IHA and negative for HS
What happens to MCHC in hereditary spherocytosis?
increased, probably for cellular dehydration from cells with low levels of water and potassium
What temperatures can affect osmotic fragility?
incubaton at 37 degrees C for 24 hours increases fragility
Why does temperature affect osmotic fragility?
red cells become metabolically deprived and tend to lose membrane surface because of their relative membrane instability
What happens after a splenectomy?
anemia is usually corrected and reticulocyte counts return to high-normal
Consequences of a splenectomy?
appearance of Howell-Jolly bodies
siderocytes
target cells in red cells
What won’t a splenectomy change?
Spherocytes in peripheral blood
Hereditary elliptocytosis treatments
Splenectomy, though if severe a transfusion before the procedure
Aspect of Hereditary elliptocytosis
RBCs appear more elliptical
Where can burr cells (Echinocytes) be observed
Patients with kidney problems and newborns
Acanthocytes can be seen where?
abetalipoproteinemia
liver disease
McLeod blood groups
Which group has G6PD A deficiency?
African American males
G6PD A gene is linked to?
The gene is X linked, so that female subjects are carriers and generally do not have clinical problems
G6PD A are clinically normal unless
exposed to an oxidant drug, This can result in acute hemolysis
Bite cells and polychromasia can be seen through?
Wright stain
Heinz bodies can’t be seen under a?
Wright Stain
What is higher in reticulocytes than older RBCs?
G6PD, Because reticulocytes are increased after a hemolytic episode, their presence can give a normal result in the screening test for G6PD
Pyruvate kinas
the most common enzyme deficiency in the glycolytic pathway
the most common red cell morphologic findings in PK deficiency
Polychromasia and echinocytes
diagnosis of PK deficiency
performing an assay for the enzyme
Red cells in paroxysmal nocturnal hemoglobinuria are abnormally sensitive
to complement, which is activated on their surface and results in premature destruction of the red cells
Hemosiderin
present and a useful diagnostic tool in paroxysmal nocturnal hemoglobinuria
What occurs during paroxysmal nocturnal hemoglobinuria
CD55 decrease
Hemolysis when blood is acidic
Platelets and WBCs are decreased
What tool is good for diagnosis paroxysmal nocturnal hemoglobinuria?
Flow cytometer, though has been replaced by sucrose hemolysis and Ham
What can hereditary spherocytosis be inherited as?
an autosomal dominant trait, although autosomal recessive forms exist
G6PD gene
has the greatest degree of variability in the human genome; this results in multiple clinical variants
Mainly found on the X Chromosome
G6PD B vs G6PD A
G6PD A contains one mutation so that its electrophoretic pattern is different, but it is a benign change
G6PD is needed for what?
regenerate reduced glutathione in the red cell
Reduced glutathione
essential to generate nicotinamide adenine dinucleotide phosphate, which is necessary to prevent oxidative damage to the red cell
Paroxysmal nocturnal hemoglobinuria is what kind of disease?
An acquired disease that can be shown to be clonal in nature
What are surface proteins of paroxysmal nocturnal hemoglobinuria linked to
GPI, which link it to the membrane
PIGA gene
Located on the X chromosome, , which is mutated in paroxysmal nocturnal hemoglobinuria
examples of microangiopathic hemolytic anemia (MAHA)s
Thrombotic thrombocytopenia purpura
hemolytic uremic syndrome
DIC
causes immune thrombocytopenia purpura
An antibody against platelets
MAHA is characterized by what?
red cell fragmentation; schistocytes are thus seen in the blood
What happens when RBCs are forced into the fibrin?
they are fragmented, as pass through fibrin deposits that have been abnormally formed inside the lumen of blood vessels
How else might RBCs fragment?
turbulence of red cells as they pass over damaged endothelial cells that line the blood vessels
What can result in MAHA?
infections (sepsis)
obstetrics complications
cancer
Exercise-induced hemoglobinuria occurs when?
individuals after repeated forceful effect of the feet on hard surfaces. Hence the name march hemoglobinuria
How many people are killed by malaria?
more than 1 million people per year
Plasmodium falciparum
Most serious form of malaria, has banana shaped gametocytes
How doe clinicians diagnose malaria
Blood films
What can 3rd degree burn patients develope?
severe acute hemolytic anemia
Cell morphology of severe acute hemolytic anemia
globular fragmentation
budding
microspherocytes
When does acute hemolytic anemia begin to subside
24 hours after the injury before they are removed from circulation.
What is prominent in hemolytic uremic syndrome?
Renal failure
What can decrease malaria infection of RBCs
Heterozygosity (Genetic variability) for Hb S
RBCs lacking the Duffy phenotype
Rh-negative genotype
hereditary spherocytosis
P. falciparum can infect what type of RBCs
RBCs in all stages of development
What does thin and thick blood films
Thick: concentrate the parasites and are ideal for initial screening
Thin: determination of the percent of parasitemia, speciation, and staging
patients with thrombotic thrombocytopenic purpura typically have?
A severe deficiency of von Willebrand factor (VWF)–cleaving protease
Rh hemolytic disease of the newborn are typically found in?
Mothers with no prenatal care, however mother’s antibody titer does not predict the severity of hemolytic disease
IgG autoantibodies causes?
Red cell destruction in warm-reactive autoimmune hemolytic anemia
IgG-sensitized red blood cells are resolved by?
The macrophages in the spleen which remove them from circulation
direct antiglobulin test
tests that distinguishes warm autoimmune hemolytic anemia from hereditary spherocytosis
direct antiglobulin test results
Negative: hereditary spherocytosis
Positive: warm autoimmune hemolytic anemia
Cold-reactive autoimmune hemolytic anemia
secondary after infections with organisms such as M. pneumoniae and Epstein Barr Virus
What happens when blood agglutination is on a blood film
blood should be warmed to 37C for 15 minutes and the automated analysis of the specimen repeated while the blood is warm
What antibody is not associated with excess red cell destruction?
IgE antibodies
cause RBC destruction
. Drugs
IgM autoantibodies
IgG alloantibodies
largest number of deaths
ABO blood type errors from patient misidentification
What can cause an immediate infusion reaction?
ABO incompatibility, is most often the result of human error
Erythroblastosis results in?
ABO or anti-D, occurs as a result of a maternal-fetal incompatibility
A delayed hemolytic transfusion reaction occurs?
as a result of undetected alloantibodies, where the level of antibody was below the level of sensitivity at the time of transfusion
When only complement is present on the membrane
anti-C3b/C3d, a cold agglutinin is most likely present, thus agglutination would be seen at room temp.
In infants whose mothers make an IgG anti-A or anti-B at a low level isn’t really bad because
Most ABO antibodies are IgM and do not cross the placenta because of their large size
Evans syndrome
When thrombocytopenia and a warm-reactive autoimmune hemolytic anemia are found together, usually in children
Wiskott-Aldrich syndrome
X-linked and is caused by a mutation in a gene that encodes a protein called WASp
Wiskott-Aldrich syndrome results
low levels or absence of WASp, and affected individuals have immunodeficiency, eczema, and thrombocytopenia
Hereditary spherocytosis can arise from what?
defects in proteins that provide vertical support for the membrane
Hereditary elliptocytosis can result from
defects in cytoskeletal proteins that provide horizontal
support for the membrane
Donath-Landsteiner antibody can be found
on paroxysmal cold hemoglobinuria
What is Donath-Landsteiner antibody directed towards?
This antibody is directed against the P blood group antigen
What is Donath-Landsteiner antibody associated with?
associated with tertiary or congenital syphilis and is found after some viral infections
