Quiz 4: Hematopathology Flashcards
Anemia is characterized by low oxygen transport capacity of the blood due to … (4)
blood loss, impaired RBC production, increased RBC destruction, a combination of all these things
Anemia can be due to what 2 categories?
Excessive blood loss (hemorrhage or hemolysis) or failure of blood production
Decreased oxygenation of the renal JGA cells triggers the production of what?
EPO
With acute blood loss, … blood loss allows for recycling of the Fe contained in the blood
internal
Immediately after acute blood loss, peripheral smear usually appears…
normal– normal size (normocytic), normal color (normochormic)
What is polychromasia?
RBC’s are released prematurely, leading to bone marrow stress.
Reticulocytes are usually (smaller/larger) than mature RBCs
larger
Chronic blood loss causes anemia only if… (2)
rate of loss exceeds the capacity of the marrow to restore adequate numbers of RBCs; iron stores are depleted such that inadequate hemoglobin is available.
Chronic blood loss is usually due to what (3) organ systems?
GI, Gyn, GU
What is a hemolytic anemia?
RBCs are prematurely destroyed
Hemolytic anemias are characterized by… (3)
shortened RBC life span, Hgb breakdown products accumulate, increase in BM erythropoiesis
What organ is the site of RBC destruction in the majority of hemolytic anemias?
Spleen
What are the 2 types of hemolytic anemais?
Intravascular (within the blood vessels); extravascular (hemolysis in the spleen)
A peripheral blood smear with numerous fragmented RBCs– “helmet” cells or “schistocytes” is indicative of what?
intravascular hemolysis
Intravascular hemolysis is a result of:
mechanical trauma, antibody fixation, toxic injury to the RBCs
What are 2 examples of extravascular hemolysis?
sickle cell anemia and hereditary spherocytosis
In extrinsic hemolytic anemias, Abs are usually what class?
IgG
Intrinsic hemolytic anemias are … while intrinsic hemolytic anemias are …
acquired; congenital
Intrinsic hemolytic anemiaas are divided into what 3 groups?
abnormal hemoglobin, abnormal RBC metabolism, abnormal hemoglobin synthesis
What condition is the prototype of abnormal hemoglobin disorders?
Sickle cell anemia
sickle cells are formed dt
low pH, low oxygen tension
why does sickling occur more readily in acidic tissues?
low pH reduces oxygen’s affinity for hemoglobin
What is MCHC?
Mean corpuscular hemoglobin concentration– concentration of Hgb per cell.
Intracellular dehydration (increases/decreases) MCHC, facilitating sickling and vascular occulsion
increases
What is AIHA?
Autoimmunie hemolytic anemias
What test(s) are used to diagnose AIHA?
Coombs and indirect Coombs antiglobulin
What is the most common form of AIHA?
Warm Ab AIHA
AIHA is (extrinsic/intrinsic)
extrinsic
Half of warm Ab AIHA are… and half are …
idopathic; secondary to SLE, Rx, or neoplastic dzs ie lymphoma
What is Cold Agglutinin AIHA caused by?
IgM Abs that bind and agglutinate RBCs at low temps (0-4C)
Peripheral smears of extrinsic hemolytic anemias resulting from RBC trauma show…
schistocytes, burr cells, helmet cells
What 2 conditions are the only conditions that cause major clinical problems associated with hemolysis?
TTP and HUS
what are (5) anemias of diminished erythropoiesis?
Megaloblastic anemia, iron deficiency anemia, anemia of chronic dz, anemia of renal failure, marrow stem cell failure
What are the keynotes of megaloblastic anemia?
Impaired DNA synthesis and distinctive morphological changes in the blood and bone marrow
What are the 4 most common causes of megaloblastic anemia?
B-12 deficiency; Folic acid deficiency; hyperthyroidism, pregnancy, disseminated cancer; inadequate diet and alcoholism
what is the morphology of megaloblastic anemia?
increased RBC size, increased MCV, normochromia, anisocytosis; hypersegmented nuclei of neuts and eos.; low reticulocytes, nucleated RBC’s;hypercellular marrow with increased numbers of all types myeloid precursors
Coabalamine and folate are coenzymes required for the synthesis of what?
thymidine
Reduced thymidine results in what?
DNA synthesis is diminished and macrocytosis and ineffective erythropoiesis in erythroid precursors
In megaloblastic anemias, what is unaffected so cytoplasmic maturation is normal, leading to nuclear/cytoplasmic asynchrony?
RNA synthesis
Pernicious anemia is a chronic illness of impaired absorption of vit B-12 dt a lack of what?
Intrinsic factor
Adult form of pernicious anemia is a result of what?
auto-reactive T-cell response
An autoreactive T-cell response initiates what?
Gastric mucosal injury, triggering formation of autoantibodies, which then cause gastric mucosal destruction
There are 3 types of ab’s found in pernicious anemia. Type I does what?
Blocks binding of B-12 to IF
There are 3 types of ab’s found in pernicious anemia. Type II does what?
prevents binding of IF-B-12 complex to its ileal receptor
There are 3 types of ab’s found in pernicious anemia. Type III does what?
Binds to the proton pump are are found in up to 50% of elderly pts with chronic gastritis
Which ab’s occur in 90% of pts with pernicious anemia compared to only 5% of healthy adults?
Anti-parietal cell ab’s
Pts with pernicious anemia have a 2 to 3 fold increase incidence of what?
gastric carcinoma
Pernicious anemia often coexists with what other anemia? Why?
Iron deficiency; achorhydria prevents solubilization of dietary ferric iron from foodstuffs
How is pernicious anemia diagnosed?
endoscopy directed biopsy of gastric mucosa showing depleted parietal cells
Neurological symptoms and findings may be present in the absence of anemia dt B-12 deficiency in which patients?
Patients taking folate or on a high folate diet
What are the primary diagnostic features of B-12 deficiency?
low serum or RBC B-12 level; low hgb, hct, RBC counts; MCV elevated; decreased wbc and platelet count; increased serum homocysteine and methylmalonic acid levels; mild jaundice; inability to absorb B-12 supplements
Continual dietary supply of what vitamin is needed because it is not stored in the body in large amounts?
Folic acid
Which medications interfere with the absorption of folic acid?
dilantin, lithium, sulfasalazine, oral contraceptives
RBCs in folate deficiency are abnormally (large/small) in the blood
large (megalocytes)
RBCs in folate deficiency are abnormally (large/small) in the bone marrow
large (megaloblasts)
What are the primary diagnostic findings of folate deficiency?
RBS abnormally large in blood and bone marrow (megalocytes, megaloblasts); hypersegmented neuts; decreased folate levels in serum or RBC; elevate homocysteine in serum
What are 3 primary causes of folate deficiency?
decreaesd intake, increased requirements, impaired use
Unlike B-12 deficiency, folate deficient pts do NOT exhibit what?
neurologic complications associated with myelin loss in nerves of the posterior column
What might mask the diagnosis of combined B-12 and folic acid deficiency?
pt with folic acid replacement
What is the most common nutritional disorder in the world?
Iron deficiency anemia
What are 4 causes of iron deficient anemia?
dietary lack, impaired absorption, increased requirement, chronic blood loss
Dietary lack of iron is most common where?
Developing world.
Why is the lack of iron most common in the developing world?
Vegetarian diet
Dietary lack of iron occurs most often in what populations?
Elderly, infants, children, poor
Impaired absorption of iron is found in what conditions?
Celiac dz, chronic diarrhea, other czs of malabsorption
What are 3 examples of dietary substances that inhibit the absorption of nonheme iron?
phytates, tannins, phosphates
What form of iron comes from animal products?
Heme form
What is the most common cause of iron deficiency anemia in the western world?
chronic blood loss
Iron deficiency induces a … and … anemia
microcytic, hypochromic
When does iron deficiency anemia appear?
iron stores are completely depleted, low serum iron, low serum ferritin, low transferrin saturation
What does the PB of iron deficiency anemia look like?
microcytic, hypochromic RBCs with central zone of pallor and poikilocytosis– small, elongated red cells aka pencil, cigar cells, or elliptocytes
What is diagnostically significant in iron deficient anemia?
disappearance of stainable iron from mononuclear phagocytic cells in the marrow
What are the 3 C’s of anemia of chronic disease?
Chronic infections, connective tissue disease, cancer
ACD (unlike IDA) is characterized by what?
Low iron levels and low TIBC, with normal or even elevated ferratin levels
ACD generally presents as…
normocytic, normochromic anemia
Aplastic anemia is a BM failure syndrome characterized by what 2 things?
PB Pancytopenia, BM hypoplasia
What is the morphology of aplastic anemia?
BM is largely devoid of hematopoietic elements, shows largely fat cells, fibrous stroma, scattered or clustered foci of lymphocytes and plasma cells remain
What is aplastic anemia?
failure of the pluripotent stem cells to produce RBCs, WBCs, and mgakaryocytes
What are the major causes of morbidity and mortality from aplastic anemia?
Infection and bleeding
With aplastic anemia, thrombocytopenia may present as…
mucosal and gingival bleeding or petechial rashes
With aplastic anemia, neutropenia may manifest as…
overt infections, recurrent infections, or mouth and pharyngeal ulcerations
WBC disorders are classified into what 2 categories?
Proliferative and leukopenias
What are the 2 types of proliferative WBC disorders?
reactive and neoplastic
Leukopenia is an (increase/decrease) in leukocytes?
decrease
Proliferative WBC disorders are an (increase/decrease) in leukocytes?
increase
Which type of proliferative WBC disorders are less common and more clinically important?
neoplastic
Leukopenia is usually dt a decrease in what?
Neutrophils
What is agranulocytosis?
marked reduction in neutrophil count with increased susceptibility to infections
What is the pathogenesis of neutropenia?
Decreased/ineffective neutro production; removal of neutros from circulation
Decreased production of leukocytes can be caused by: (4)
Suppression of myeloid stem cells (aplastic anemia, infiltrative marrow d/o’s –tumors, granulomatous dz); Drug suppression of granulocytic precursors; Defective precursors in marrow (megaloblastic anemia, myelodysplastic syndromes); Genetic defects (Kostmann syndrome)
Increased removal of neutrophils can be caused by: (3)
Immune mediated injury (SLE, drugs); Splenic sequestration (increased destruction dt enlargement of the spleen); Increased peripheral utilization (overwhelming infxns)
Which myeloid stem cell can go on to become a WBC?
myeloblast
