Hematology Exam 2
RBC band 3 protein reduction
test where eosin-5'-maleimide dye binds to band 3 on intact RBCs, fluorescence detected in flow cytometry to determine if band 3 deficient (hereditary spherocytosis)
THF
tetrahydrofolate
all dividing cells
the defective DNA synthesis in megaloblastic anemia affects ___
HPSC transplant
treatment with the best success rate in young patients with AA
abetalipoproteinemia
(hereditary acanthocytosis) -rare autosomal recessive disorder (MTTP) characterized by fat/fat soluble vitamin malabsorption, progressive ataxia, neuropathy, retinitis pigmentosa, acanthocytes -no chylomicrons/VLDL/LDL in plasma->triglycerides/cholesterol ↓, ↑ sphingomyelin->acanthocytes -mild hemolysis, N RBC, prolonged PT/PTT
B12 deficiency
-secondary deficiency usually caused by a deficiency of intrinsic factor which is necessary for absorption -causes neurological symptoms (neuropathy, abnormal gait, memory loss, mood changes)
hereditary elliptocytosis
-autosomal dominant protein dysfunction (spectrin/protein 4.1/Band 3) that disrupts the horizontal linkages of RBC cytoskeleton and weakens membrane stability->elliptocytes and possibly hemolysis -low Hgb, high RETC, C
causes of acquired aplastic anemia
-70% idiopathic -drugs (chloramphenicol antibiotic) -chemicals (benzene derivatives, pesticides -ionizing radiation -infection (EBV, TB, HIV)
AA diagnostic criteria
-BM cellularity <25% (>75% fat) -absolute granulocyte count <0.5x10^3uL -PLTB <20x10^3uL -corrected RETC <1%
Transient erythroblastopenia of childhood (TEC)
-acquired acute self limiting form of pure red cell aplasia in <10yo after viral infection -pallor, NN anemia, RBC hypoplasia in BM -may need transfusion but usually resolves in 2-8w without treatment
Fanconi anemia
-autosomal recessive disorder with chromosomes that break easily, often develops into aplastic anemia -ashkenazi and afrikaner descent -predisposition for leukemia, physical deformities of bones/kidneys/GI/heart/head/stature/eyes/ears, skin hyperpigmentation -pancytopenia, macrocytic, HbF↑
secondary causes of AA
-drugs (chloramphenicol antibiotic) -chemicals (benzene derivatives, pesticides) -ionizing radiation -infections (EBV, TB, hepatitis, HIV, parvo) -PNH, pregnancy, autoimmune
folate
-general term for any form of folic acid, circulates in the blood predominantly as 5-methyl THF -found in egges, milk, yeast, liver, mushrooms, leafy veggies -absorbed in proximal jejunum
hereditary spherocytosis
-most common cause of hemolytic anemia from membrane abnormality -autosomal dominant defects of ankryn, spectrin, protein 4.2, or band 3 that disrupt vertical interactions (ANK1) -loss of lipid membrane over time->spherocyte culled by spleen -anemia, splenomegaly, jaundice, hemolysis (↑ bilirubin ↑LDH), usually moderate form with Hgb >8, RETC 6-10%, ↑ MCHC
megaloblastic anemia
-ovalocytic macrocytic anemia caused by impaired thymidine/DNA synthesis->nuclear maturation defect->ineffective erythropoiesis with hemolysis in BM -95% from the lack of folate/B12, other causes=chemotherapy, methionine synthase reductase deficiency, myelodysplastic syndromes, congenital dyserythropoeitic anemia
diamond-blackfan anemia
-rare autosomal progressive RBC aplasia caused by structural ribosome protein mutation (RPS19 gene) -diagnosed in first year of life: physical defects of hand/heart/head/eye/ear/cleft palate/kidney, cataracts/glaucoma, pallor, arrhythmia, SOB, fatigue, malignancy -macrocytic, reticulocytopenic, HbF↑, erythrocyte adenosine deaminase↑, genetic test +
hereditary pyropoikilocytosis
-rare autosomal recessive severe subtype of hereditary elliptocytosis due to qualitative/quantitative spectrin defects -african descent, severe hemolytic anemia and anisopoikilocytosis from infancy, resembles burn injury to cells, hyperbilirubinemia, gallstones, splenomegaly, thermal sensitivity -low Hgb, low MCV, budding, fragments, microspherocytes, elliptocytes
Schwachman-Diamond syndrome
-rare hereditary disorder that often develops into aplastic anemia caused by abnormality in ribosome maturation -pancreatic insufficiency, impaired BM function, skeletal abnormalities, malignancy↑, GI malabsorption -pancytopenia, ↑fecal fat, genetic test +
Dyskeratosis congenita
-rare hereditary disorder that often develops into aplastic anemia caused by shortened telomeres -skin pigmentation, dystrophic nails, oral leukoplakia, pulmonary fibrosis -pancytopenia, HbF↑, flow cytometry FISH detects short telomeres
B12
-vitamin required for DNA synthesis and neurological function -present in most animal products (milk, meat, eggs), digested in stomach by haptocorrin, released by intrinsic factor in the duodenum, then transported by transcobalamin to cells -stored in liver, heart, kidneys
megaloblastic triad
3 characteristic symptoms of megaloblastic anemia: -macroovalocytes -hypersegmented neutrophils -howell jolly bodies
congenital aplastic anemia
3 types of ___: -Fanconi anemia -Dyskeratosis congenita -Schwachman-Diamond syndrome
5-methyl THF to THF
B12 is a cofactor used in the conversion of
B12 deficiency treatment
B12 supplements/dietary changes in mild cases, B12 injections in severe cases with resistant absorption to bypass digestive tract, lifelong monthly injections in pernicious anemia
anti-parietal cell Abs
Abs found in 90% of pernicious anemia patients, also found in gastritis/thyroiditis
hypersegmentation
CBC WBC finding most indicative of megaloblastic anemia
WBC and PLT count
CBC parameters that differentiate Fanconi and Diamond-Blackfan anemia (low in FA, N in DBA)
HS vs AIHA
HS: DAT -, homogenous spherocytes AIHA: DAT +, heterogenous spherocytes
nuclear cytoplasmic asynchrony
Nucleus and cytoplasm mature at different rates, immature nucleus with mature cytoplasm seen in megaloblastic anemia
aplastic anemia treatment
RBC/PLT infusions, antibiotics, HSCT, immunosuppression, high mortality without treatment
gel electrophoresis
SDS-PAGE used to detect abnormal proteins
osmotic fragility
Screening test for hereditary spherocytosis where RBCs are incubated in hypotonic NaCl to measure RBC hemolysis resistance sphereocytes have low surface to volume ratio->increased fragility target cells have decreased fragility
megaloblastic anemia lab results
Smear: macrocytic normochromic anemia, pancytopenia, anisocytosis, oval macrocytes, howell jolly bodies, NRBCs, cabot rings, dacryocytes, schistocytes, basophilic stippling, hypersegmented neutrophils
TEC vs DBA
TEC: mostly deficient in mature normoblasts DBA: HbF ↑, erythrocyte adenosine deaminase ↑, iron/ferritin ↑, deficient in all normoblasts
DBA (diamond-blackfan anemia)
a 3mo with pallor/fatigue, low RBC, low Hgb/HCT, normal WBC/PLT, ↑ EPO, erythroid hypoplasia, and RPS19 mutation would be Dx with:
FA (fanconi anemia)
a 5yo with malformed thumbs, microcephaly, prolonged bleeding, fatigure, persistent infections, and ↑ chromosome breakage would be Dx with:
extrinsic abnormality
acquired RBC membrane defect when RBC is damaged by chemical/mechanical/physical agent (immune system, hemolysis, infection, drug/chemical)
spurr cell anemia
acquired hemolytic anemia from severe liver disease->free cholesterol
40+
age with the highest risk of pernicious anemia
cobalamin
aka B12
Most common causes of macrocytosis
alcoholism, B12/folate deficiency, liver disease, drugs, reticulocytosis, MDS
pancytopenia
all 3 cell lines decreased in peripheral blood (RBC+WBC+PLT)
membrane defect anemia
anemia caused by abnormalities with the RBC itself ex. hereditary spherocytosis, hereditary pyropoikilocytosis, hereditary stomatocytosis, hereditary acanthocytosis, paroxysmal nocturnal hemoglobinuria
hypoproliferative anemia
anemia caused by decreased erythropoiesis
intravascular hemolysis lab results
serum indirect bilirubin ⬆ haptoglobin ⬇ hemopexin ⬇ hemoglobinemia + hemoglobinuria + hemosiderinuria + urine bilirubin N urine urobilinogen N/⬆ LDH ⬆⬆ PB smear schistocytes
extravascular hemolysis lab results
serum indirect bilirubin ⬆⬆ haptoglobin N/⬇ hemopexin N/⬇ hemoglobinemia - hemoglobinuria - hemosiderinuria - urine bilirubin N urine urobilinogen ⬆⬆⬆ LDH N/⬆ PB smear spherocytes
pernicious anemia
autoimmune disease seen in >40yo Northern European women caused by absence of intrinsic factor secondary to GI damage->B12 cannot be absorbed because of lack of parietal cells
intrinsic factor
stomach parietal cell secretion that binds to B12 to resist digestion in the stomach and release the vitamin to the intestinal enterocytes
hepatosplenomegaly
symptom usually absent in aplastic anemia
unknown causes
aplastic anemia is most often caused by
liver disease
can cause macrocytic anemia without megaloblastosis
fatigue, infection, bleeding
clinical consequences of pancytopenia
BM exam
confirmatory test performed with aplastic anemia is suspected
folate deficiency
deficiency usually caused by a lack of dietary intake
xerocyte
dehydrated RBC
DNA
folate and B12 work together in the production of
peripheral proteins (skeleton)
form a lattice network that functions as a cellular cytoskeleton of RBC membrane ex. spectrin, ankryin, protein 4.1/4.2
southeast asian ovalocytosis
form of hereditary elliptocytosis with abnormal band 3 protein and mild hemolysis->rounded ovalocytes and stomatocytes
IF
glycoprotein needed for B12 to be absorbed from food into the intestinal mucosa
megaloblastic erythroid precursors
have loose/open/webby chromatin
Congenital Dyserythropoietic Anemia
hereditary macrocytic aplastic anemia with abnormal ineffective erythropoiesis, BM is normo/hypercellular but peripheral blood has pancytopenia
anti-intrinsic factor Abs
highly specific Abs to pernicious anemia found in60% of patients, 2 types: blocking and binding
megaloblastic anemia bone marrow
hypercellular with increased giant erythroid precursors and decreased M:E ratio->cell death and pancytopenia
megaloblastic anemia clinical history
impaired DNA metabolism affects all rapidly dividing cells, insidious onset since deficiency takes years to develop, fatigure, SOB, syncope, yellow/waxy pallor, glossitis, weight loss, GI issues
integral proteins (transmembrane)
important for attaching skeletal protein network to lipid bilayer of RBC membrane ex. glycophorins, band 3, AE1
low methylmalonic acid
inconsistent finding with elevated IF blocking ABs, neutrophil hypersegmentation, macrocytes, and low B12
homocysteine
intermediate in folate/B12 metabolism, increased in both folate deficiency and B12 deficiency
methylmalonic acid
intermediate in folate/B12 metabolism, normal in folate deficiency, increased in B12 deficiency
Urinary formiminoglutamic acid
intermediate in metabolism of histidine to glutamic acid, deficiency of folate blocks the metabolism->increase of this intermediate
acanthocyte
irregular RBC shape from altered lipid content
spherocyte
irregular RBC shape from decreased surface to volume ratio
echinocyte
irregular RBC shape from increased area of outer bilayer relative to inner bilayer
stomatocyte
irregular RBC shape from increased inner bilayer relative to outer bilayer
codocyte
irregular RBC shape from increased surface to volume ratio
elliptocyte
irregular RBC shape from membrane instability caused by altered horizontal protein interactions
schistocyte
irregular RBC shape from membrane instability or damage caused by severely altered horizontal protein interactions
hemolytic anemia symptoms
jaundice, gallstones, dark/red urine (hematuria), pallor, fatigue, SOB, cardiac symptoms, thinning of cortical bone, hepatosplenomegaly
round macrocytes
key feature of nonmegaloblastic macrocytosis
high MCV
lab finding consistent with a diagnosis of megaloblastic anemia
increased
levels of MMA and homocysteine with B12 deficiency
pernicious anemia lab results
low serum B12, high serum gastrin, anti-intrinsic factor and anti-parietal cell Abs, high methylmalonic acid, high homocysteine
chromosome breakage analysis (diepoxybutane-induced chromosome breakage)
lymphocytes cultured with DEB/MMC Dna crosslinking agent to find chromosomal breaks, test used to diagnose fanconi anemia
Band 3 (anion exchange protein 1)
major RBC integral protein
spectrin
major RBC peripheral protein
horizontal interactions
membrane interactions parallel to the plane of the RBC membrane disruption of these interactions->poikilocytes
vertical interactions
membrane interactions perpendicular to the plane of the RBC membrane disruption of these interactions->spherocytes
folate functions
needed for embryogenesis, growth, pregnancy, lactation
fatty acid
neurological symptoms are prevalent in B12 deficiency because of defective ___ degradation
hypoplastic BM
number of hematopoietic cells in BM is decreased
gastrin
peptide hormone that stimulates the secretion of gastric acid by the parietal cells to aid in motility/digestion, elevated in pernicious anemia due to body trying to compensate for lack of parietal cells
haptocorrin
protein secreted by the salivary glands that binds to the acid-sensitive vitamin B12 and protects it in the stomach
schilling test
radioactively labeled B12 used to test for pernicious anemia to see if B12 is not being absorbed or not being consumed enough
pure red cell aplasia
rare acquired (autoimmune, infections, drugs, malignancy) or congenital (diamond-blackfan) disorder with only erythroid progenitor cells decreased in BM->severe NN anemia + term-81reticulocytopenia, normal WBC/PLT
dehydrated hereditary stomatocytosis
rare autosomal dominant hemolytic anemia due to RBC membrane defect (PIEZO1) making cells lose intracellular K+->crenate->splenic culling, jaundice, splenomegaly -low Hgb, low MCV, target cells, stomatocytes, burr cells, xerocytes
overhydrated hereditary stomatocytosis
rare autosomal dominant hemolytic anemia due to RBC membrane defect making RBC hyperpermeable to cations->intracellular cations increase->cell swells->stomatocytes and splenic culling -neonatal jaundice, gallstones, splenomegaly, Rh null -stomatocytes, high MCV, low MCHC, ↑ RETC, ↑ bilirubin ↑LDH
aplastic anemia
rare disease with a deficiency of all formed elements of blood from failure of BM to generate blood cells -asian descent, 15-25yo or >60yo, pallor, fatigue, dizziness, SOB/cardiac symptoms, bruising/petechiae, infections -hypocellular "dry tap" BM, pancytopenia, Hgb <7, NN/Macrocytic, relative lymphocytosis -usually idiopathic, may be acquired/hereditary
serum B12
reflection of B12 vitamin stores
red cell folate
reflects folate available when RBC was maturing in the BM, showing net folate level over last few months best indicator of folate level
serum folate
reflects folate intake over the last several days
nonmegaloblastic anemia
round macrocytic anemia caused by an increase in membrane lipids, seen in hepatic conditions (alcoholism, liver disease)
neurological
type of symptoms that distinguishes pernicious anemia from folic acid deficiency (pernicious anemia +, FA deficiency -)