Benign Heme Flashcards
Ataxia Telangiectasia
- rare, neurodegenerative, inherited disease
- impairs cerebellum, causing difficulty with movement and coordination.
- weakens the immune system, causing a predisposition to infection.
- prevents repair of broken DNA, increasing the risk of cancer (especially lymphoma/leukemia)
- sx appear in early childhood when children begin to walk
- caused by a defect in the ATM gene (manages cell’s response to multiple forms of stress including double-strand breaks in DNA)
Bloom Syndrome
Ashkenazi Jewish population
diabetes mellitus
decreased fertility
MDS
Down Syndrome
- overall risk of cancer is not changed, risk of leukemia and testicular cancer is increased and risk of solid cancers is reduced
- leukemia is 10 to 15x more common in Downs:
*ALL is 20x more common
*megakaryoblastic AML leukemia is 500 times more common
- TAM affects 3–10% of infants, resolves without treatment
- After TAM, 20 to 30% risk of developing ALL
HIV marrow findings
ALIP commonly seen (NOT dysplasia) increased plasma cells
Measured CBC parameters
Hgb RBC MCV RDW
Hemolyzed sample- what is still valid
Hgb (after all RBC lysis is the first step in the cyanmethemoglobin method for measuring Hgb)
3 methods automated instruments use to perform cell counts
- Impedance (size) 2. Optical (forward vs light scatter) 3. Combo of these
RBC count
Measures using Coulter principle: cells travel one by one through an aperture across which a current is flowing causing a momentary increase in impedance/electrical resistance V=IR I is constant, R is the increases resistance caused by a red cell, V momentary increase in voltage is interpreted as a single cell which is simultaneously counted/sized Particles measuring 36-360 fL are counted as red cells (includes WBC but their contribution is negligible)
Calculated CBC parameters
Hct MCH MCHC
Hct calculation
Hct= (MCV x RBC)/10
MCH calculation
MCH= (Hb/RBC) x 10
MCHC
MCHC= (Hb/Hct) x 100
Neoplastic causes of increased RBCs
RCC HCC Hemangioblastoma
WBC count
Lyse RBCs then count all particles >36 fL using Coulter principle (plt usually less than 36 fL)
WBC interferences
platelet clumps micromegakaryocytes nRBCs
Platelet count
Particles between 2-20 fL are counted as platelets using Coulter principle
How to fix platelet clumping/satellitism
Recollect sample in sodium citrate New platelet count should be multiplied by 1.1 to correct for dilution factor associated with this anticoagulant
Acanthocytes
- Abetalipoproteinemia
- Severe burns
- Liver dz
- Post-splenectomy
- McLeod phenotype (Kell null)
Fine basophilic stippling
Seen in reticulocytes as artifact of slow air drying
Coarse basophilic stippling
Ribosomal RNA aggregates, indicative of abnormal hemoglobin synthesis (lead poisoning, thalassemia)
Bite cells
Due to removal of Heinz bodies by splenic macrophages (suggestive of G6PD deficiency or drug induced oxidant hemolysis)
Burr cells
Usually artifactual; seen in uremia and pyruvate kinase deficiency
Cabot rings
Remnant of nuclear DNA; remnants of spindle fibers that form during mitosis (seen post splenectomy or in megaloblastic anemia)
Elliptocytes
Seen in iron deficiency anemia and hereditary elliptocytosis
Heinz bodies
Ppt hemoglobin, requires supravital dye to visualize (seen in G6PD deficiency and with unstable forms of Hgb)
Howell-Jolly bodies
Remnant of nuclear DNA (seen in post splenectomy, in hemolytic anemia, or in megaloblastic anemia)
Hypochromia
Seen in iron deficiency anemia, thalassemia, and sideroblastic anemia
Macrocytes
Seen with increased erythropoiesis (due to increased reticulocytes), megaloblastic anemia (oval macrocytes), and liver disease (round macrocytes)
Microcytes
Seen in iron deficiency anemia, thalessemia, and sideroblastic anemia
Pappenheimer bodies
Iron containing mitochondria (seen in sideroblastic anemia and post splenectomy)
Pencil cells
Hypochromic variants of elliptocytes that have long axis at least three times the length of the short axis (classic for Fe deficiency but also seen in anemia of chronic disease and beta thalassemia minor
Polychromasia
Due to residual ribosomal material
Sickle cells
Seen in sickling hemoglobinopathies (NOT seen in sickle cell trait)
Spherocytes
Seen in hereditary spherocytosis and immunohemolytic anemia
Stomatocytes
Usually artifact; may be seen in alcoholism, hereditary stomatocytosis, or Rh null phenotype
Target cells
Liver disease, HbC, SC disease, HbE, post splenectomy, thalassemia
Teardrop cells (dacrocytes)
Myelophthisic dz, splenic dysfunction
Dohle bodies
Thought to be remnants of rough ER, possibly agglutinated ribosomes
Toxic granulation
Prominent primary granules; seen in sepsis and GM-CSF (Neupogen) therapy
Prolymphocytes
Larger than lymphocytes (2x) with a moderate amount of cytoplasm, round nuclei (occasionally irregular), immature chromatin, and prominent central nucleolus
LGL
May be T or NK phenotype; very common to be increased post transplant
Manual retic count
Use supravital stain (eg new methylene blue)
Automated retic count
RNA binding dyes that can be detected by fluorescence (but Coulter still uses detection of light scatter after staining with new methylene blue)
Immature retic fraction
Cells with the highest fluorescence intensity (highest RNA content)
Retic count
% retics (# per 100 RBCs)
Corrected retic count (CRC)
(retic%)(hct/45) -takes into account normal RBC production for a given hematocrit
Reticulocyte production index (RPI)
CRC/correction factor -1.0 for hct 40-45 -1.5 for hct 35-39 -2.0 for hct 25-34 -2.5 for hct 15-24 -3.0 for hct
For how long do reticulocytes circulate?
Usually present in blood for 24 hours before they extrude residual RNA and become erythrocytes; if released early from marrow, immature retics may persist in PB for 2-3 days (RPI corrects for presence of immature retics)
RPI less than 2
failure of BM RBC production (hypo proliferative anemia)
RPI>3
marrow hyperproliferation or appropriate response to anemia
Constitutional aplastic anemia
Fanconi anemia Dyskeratosis congenita Diamond-Blackfan anemia Congenital amegakaryocytic thrombocytopenia Schwachman-Diamond syndrome Severe congenital neutropenia (Kostman syndrome)
Acquired aplastic anemia
-PNH -Idiopathic: (theory: destruction of CD34+ progenitor cells through apoptotic mechanisms stimulated by cytokine released from activated BM cytotoxic T cells) -Secondary to drugs (cytotoxic drugs, chloramphenicol, gold), radiation, toxins (benzen), infections (parvovirus), neoplasms (thymoma), pregnancy
Constitutional red cell aplasia
Diamond-Blackfan anemia
Acquired red cell aplasia
P-parvovirus infection I- idiopathic T- transient erythroblastopenia of childhood (most likely due to antecedent viral infection) A- antierythropoietin ab induced red cell aplasia (occurs in some patients receiving recombinant epo) S- sustained pure red cell aplasi (secondary to neoplasms such as T cell LGL leukemia, immune d/o, chronic viral infections, and drugs)
Fanconi anemia genetics
-AR (rarely X-liked recessive) -13 genes on many different chromosomes (one being BRCA2) -cells characteristically show abnormally high frequency of spontaneous chromosomal breakage and hypersensitivity to DNA cross-linking agents such as diepoxybutane (DEB) and mitomycin C
Fanconi anemia diagnostic test
increased chromosomal breakage seen in FA cells compared to normal controls after exposure to DEB or mitomycin C (AKA the DEB/MMC stress test)
Fanconi anemia clinical
-progressive BM failure (aplastic anemia with pancytopenia) and increased risk of malignancy (AML- often with monocytic features, solid tumors like cutaneous malignancies, HCC, gastric carcinoma) -cafe au lait spots, microcephaly, hypoplastic thumbs, absent radius, scoliosis, MR, horseshoe kidney, duodenal atresia, cardiac defects, neurologic abnormalities (1/3 no abnormalities) -present toward end of 1st decade -anabolic steroids (oxymetholone) produce useful trilineage hematopoietic response in 50-70%, but most become refractory -tx HSCT
Dyskeratosis congenita genetics
-X-linked recessive (80% cases), but AD and AR subtypes are recognized -DKC1 gene on Xq28 -genomic instability d/o similar to Fanconi anemia (however, no increased chromosomal breakage)
Dyskeratosis congenita clinical
Inherited BM failure syndrome characterized by mucocutaneous triad (mostly males): 1. abnormal skin pigmentation 2. nail dystrophy 3. oral leukoplakia -skin and nail changes appear first, usually by age 10 -BM failure by age 20 -like Fanconi anemia, main cause of death is BM failure -other causes of death include pulmonary complications and malignancy -again, like FA, anabolic steroids (oxymetholone) produce useful trilineage hematopoietic response in 50-70% -tx HSCT
Schwanchman-Diamond syndrome genetics
-AR, 90% due to mutation of SBDS gene (chr 7q11) -results in deficiency of SBDS protein (can see loss by IHC) -protein plays regulatory role in RNA metabolism in nucleolus by stabilizing mitotic spindle -can see an isochromosome 7q
Schwanchman-Diamond syndrome clinical
-2nd most common cause of pancreatic insufficiency in childhood after CF -exocrine pancreatic insufficiency (86%), BM failure-mostly as neutropenia (98%), anemia (42%), pancytopenia (19%), skeletal abnormalities (50% particularly metaphyseal dysostosis), growth retardation (56%), and increased risk of MDS/AML (30%) -tx with pancreatic enzymes and G-CSF -main cause of death infection/bleeding -at risk for complications from HSCT
Diamond-Blackfan anemia genetics
-DBA1 gene AKA RPS19 - encodes ribosomal protein S19 and is NOT a regulator of erythropoiesis rather is a ubiquitous ribosomal protein -AD with incomplete penetrance -heterozygosity for mutations of gene (genetic heterogeneity of DBA)
Diamond-Blackfan anemia clinical
-presents in early infancy (around 8 weeks) with sx of anemia -hallmark is selective decrease in erythroid precursors and normochromic macrocytic anemia -craniofacial, thumb, cardiac, and urogenital malformations -modest increase in MDS/AML/osteosarcoma -tx with corticosteroids and transfusions; HSCT
Diamond-Blackfan vs Shwachman-Diamond vs Fanconi Anemia
DB: pure RBC aplasia SD: neutropenia FA: pancytopenia
Diamond-Blackfan anemia lab tests
-elevated erythrocyte deaminase activity and elevated fetal hemoglobin (HbF) -i ag overexpressed on RBCs
Diamond-Blackfan: hematologic diagnostic criteria
- normochromic, macrocytic anemia developing in early childhood 2. reticulocytopenia 3. normocellular BM with marked selective deficiency of eyrthroid precursors (erythroblasts
Reticulocytes on supravital stain
clumped ribosomal RNA (not dots-those are Heinz bodies)
Babesiosis vs Malaria
- On right, RBC contains 4 small, red-purple dots (tetrad)
- On left, 2 RBCs contain trophozoites (ring forms), which closely resemble P. falciparum
- RBCs may show single chromatic dot or two or more chromatic masses; occasionally 4 ring forms in tetrad => maltese cross
- 4 visible dots is diagnostic and not seen in malaria; can also see extraeythrocytic forms which are not seen in malaria
- in malaria, RBCs are enlarged/ovoid vs babesia they are normal
- noncyclic fever and hemolysis
- coinfection with Lyme dz and flavivirus
Causes of basophilia
- allergic/hypersensitivity reactions
- inflammatory d/o (collagen vascular dz, RA, UC)
- endocrinopathy (DM)
- chronic renal failure
- infections (influenza, chicken pox)
- neoplasms (CML)
Chediak-Higashi Syndrome pathogenesis
AR
- PMNs impaired mobility (defective chemotaxis) and defective granulation
- primary defect in intracellular granules:
*leads to WBC death in marrow resulting in neutropenia and thrombocytopenia
*defective granules in grans, lymphs, and NK cells alter immune fx with resultant severe pyogenic infections
*abnormal melanin containing granules result in eye/skin hypopigmentation
- all WBCs contain large cytoplasmic granules (due to fusion of lysosomes)
- cytoplasmic inclusions contain both primary (MPO+) and secondary granules
Chediak-Higashi Syndrome clinical
- severe recurrent bacteria infections
- partial oculocutaneous albinism
- many develop EBV associated hemophagocytic syndrome (“accelerated phase”) or EBV induced lymphoproliferative d/o
- pts die in childhood
- tx HSCT
Congenital Dyserythropoietic Anemia general
-rare disorders characterized by profound morphologic abnormalities of erythroid elements and ineffective erythropoiesis
- some cases are AR
- all pts have anemia with marked anisopoikilocytosis, reticulocytopenia, marrow erythroid hyperplasia
CDA Type I
- erythroid precursors show megaloblastic changes with internuclear chromatin bridges
- occasional binucleate forms seen
CDA Type II
**The most common type**
- characterized by bi- and multinucleated erythroid precursors (usually 2-7 nuclei)
- positive acidified serum test (Ham’s test) due to an abnormal RBC antigen; lysis occurs in heterologoys serum only, in contrast to PNH in which lysis occurs in both autologous and heterologous serum
- also referred to as “hereditary erythroblastic multinuclearity with positive acidified serum” HEMPAS
- RBCs have very high density of i (recall Diamond-Blackfan too)
Causes of reactive eosinophilia
- allerigic/atopic disorders
- medications (L-tryptophan linked to eosinophilia-myalgia syndrome)
- parasites (must invade tissue to produce eosinophilia)
- cutaneous disorders (eczema, atopic dermatits, bullous pemphigoid)
- inflammatory disorders (IBD, collagen vascular dz, sarcoid, celiac)
- pulmonary disorders (Loeffler syndrome, CF, Churg-Strauss)
- neoplasms (T cell lymphoproliferative d/o, HL, LCH)
CDA Type III
-pronounced multinucleateion with up to 12 nuclei present in some erythroid precursors (“gigantoblasts”)
Eosinophil function
Release of secondary granules:
*major basic protein
*peroxidase
*arylsulfatase
*histamine oxidase
*eosinophil cationic protein
- modulate immediate hypersensitivity rxn
- destroy parasites
Erythrocyte Cytoskeleton
- Two isoforms of spectrin, and , form a loosely wound helix. Two helices are linked end to end to form a tetramer, which has binding sites for several other proteins, including other spectrin molecules.
- The spectrin tetramers are organized into a meshwork that is fixed to the membrane by the protein ankyrin.
- Ankyrin is itself connected to a transmembrane protein called Band 3 (AE1, anion exchanger).
- Band 4.2 (palladin) is thought to function to stabilize the link between ankyrin and Band 3.
- Spectrin is also linked to the transmembrane protein glycophorin C by the protein known as Band 4.1.
- Thus the meshwork is anchored to the membrane at multiple sites.
- Band 4.1 stabilizes the association of spectrin with actin, as does the protein adducin.
- Actin subunits form short microfilaments consisting of actin and tropomyosin.
- The protein tropomodulin is also associated with filamentous actin.
Chromogenic Factor Xa Assay
- useful in monitoring warfarin in presence of a LA or DTI
- utilizes an activator of factor X and peptide substrate for factor Xa that is coupled to a chromogenic marker
- cleavage of peptide by factor Xa releases the marker and yields a colored product, the intensity of which is directly proportional to factor X levels