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 -)