work-up of anemia
CBC
retic count - young blood cell, in 24hrs it matures to a RBC
polychromasia present - basophilic immature RBCs, 2-3d before they become a mature RBC (so even younger than reticulocytes)
- another correction needed - (corrected retic count)/2
rule of 3: 3Hb = HCT
every unit of packed RBCs transfused = increase Hb by 1, HCT by 3%
Fe deficiency anemia
most common cause of anemia WW
increased in RDW - why?
- you dont develop microcytic anemia overnight - Fe-deficiency starts with normocytic anemia and progresses to microcytic anemia
Tests:
serum Fe - nl 100
ferretin - ferritin is found in organs, very small amount circulating in the blood. Also represents the amount of Fe stored in bone marrow.
transferrin - carries Fe to macrophages in bone marrow
percent saturation - serum Fe/TIBC
what you would see: low serum Fe, high TIBC, low percent saturation, serum ferretin is low
causes - prematurity (not gaining Fe from mom), bleeding Meckel’s diverticulum (most common cause of Fe deficiency in a newborn, child), menorrhagia (woman under 50), PUD (duodenal ulcer, in men under 50), colon cancer (folks over 50)
Plummer-Vinson syndrome - Fe-def anemia, esophageal webs, dysphagia
target cells
markers for alcoholics (alters cholesterol content of membrane) and hemoglobinopathies
microcytic anemia
increased central pallor - because all microcytic anemias have low Hb
when RBC is developing in the marrow - Hb concentration determines the number of cell divisions
- if Hb synthesis is decreased –> signal to marrow to INCREASE division
Hb synthesis: heme + globin
- heme = Fe + protoporphyrin
Fe-deficiency, thalassemias, sideroblastic anemias
anemia of chronic disease
normocytic anemia –> can become microcytic
inflammation - body responds like there is an infection
Fe remains trapped in bone marrow macrophages - transferrin cant pick up this Fe and take it to the RBCs
- also decreased Fe absorption from gut
Fe studies - low serum Fe, low TIBC, low percent sat, high serum ferritin
sideroblastic anemias (rare)
heme synthesis:
causes
Fe stains with Prussian blue stain = Pappenheimer bodies
Fe studies:
increased Fe, increased ferritin, normal/decreased TIBC
a-thalassemia
Asian populations and Black population
microcytic anemia
2 gene deletions - minor
3 gene deletions - HbH (4 beta chains)
- also a hemolytic component to this
4 gene deletions - hydrops fetalis (edema in 2+ fetal compartments), HbBarts (4 gammas)
note HbH and HbBarts ~ myoglobin - extremely high affinity for O2
b-thalassemia
Black, Greek, Italian
AR
mutations - splicing defects, promoters, stop codons
b minor (mild): due to splicing defects --> decreased HbA, increased HbA2 (greater than 3.5%) and HbF - heterozygote
b0 (homozygote) = Cooley’s anemia - require constant transfusions, will die from Fe overload
HbS/B heterozygote - mild sickle cell disease, because of reduced b-globin production
bd thalassemia - electrophoresis will show HbF (hereditary persistence of HbF), asymptomatic
- low b, low d, normal a, normal y
Fe overload
Fe high, ferritin high, low transferrin, low TIBC, high percent saturation
B12 and folate
macrocytic anemia, hypersegmented neutrophils
deficiency –> problem making deoxythymidine phosphate
folate deficiency is more common - alcoholics and preggos
B12 takes the methyl group off methyl-THF
hematopoietic cells are made outside the sinusoids - need to squeeze through and enter the sinusoids to get into the blood, BUT they are too big
Schilling’s test - localizes B12 deficiency
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orotic aciduria (AR) - cant convert orotic acid –> UMP (pyrimidine synthesis pathway)
- NO hyperammonemia
- presentation: kids with failure to thrive, developmental delay, and megaloblastic anemia
- treat with UMP to bypass the mutated enzyme
normocytic anemia
1) Corrected retic count < 2%
early Fe deficiency
- Fe deficiency but NO anemia - low serum ferritin, next Fe decreases, TIBC increases, percent decreases –> normocytic anemia –> microcytic anemia
- first low storage, then compensatory mechanisms kick in
other causes - anemia of chronic disease, blood loss for less than 1 week, aplastic anemia (chloramphenicol, indomethacin, phenylbutasone, thyroid-related drugs, hepatitis C, radiation)
2) Corrected retic count > 3%
hemolysis
- autoimmune hemolytic anemias (IgG mediated, warm autoimmune anemia) - EXTRAvascular hemolysis
- spherocytes and sickle cell RBCs will be removed extravascularly (they cant get out of the sinusoids of the spleen)
- Howell-Jolly bodies - piece of nucleus, macrophage will try to ingest this body –> also extravascular hemolysis
phagocytosis of RBCs –> UCB –> jaundice
intravascular hemolysis - if RBC gets sheared (valve defects
hemolytic anemia
INTRINSIC defect of RBC, nothing wrong with bone marrow (corrected retic count is greater than 3%)
MAD:
Membrane defect (spherocytosis, paroxysmal nocturnal Hb-uria)
- spherocytosis (spectrin, ankyrin, band 3 mutations, AD) - defective binding of RBC cytoskeleton to membrane –> spherocytes –> RBCs cant get out of spleen –> splenomegaly, gallstones. Spherocytes are smaller! - so they have increased MCHC. Osmotic fragility test in hypertonic saline. Treat with splenectomy.
- paroxysmal nocturnal Hb-uria - complement-decay accelerating factor absence - protein on RBC cell surfaces that inhibits C3 convertases. Nocturnal because complement sits on RBCs during respiratory acidosis, which occurs when we sleep.
- increased incidence of acute leukemias - defect is in PIGA gene of multipotent hematopoietic stem cells. Gene defect means GPI anchor (necessary to anchor CD55 and CD95) is not made).
- triad: coombs negative hemolytic anemia, pancytopenia, venous thrombosis
- CD55/59 negative RBCs non flow cytometry
- treat with eculizumab - terminal complement inhibitor
Abnormal Hb
HbS: valine is nonpolar –> sickling
- note if you have sickle cell trait, you will not have sickle cells in your peripheral blood - RBC will sickle if it has 60% or more HbS
- microscopic hematuria - get a sickle cell screen, esp in black population
- splenomegaly –> autoinfarct at age 18 or 19 (brown!, fibrosed, atrophied spleen), spleen has stopped working at 2 yo
- Howell-Jolly body is a sign that the spleen is not working - a piece of nucleus in the RBC, if the spleen was working, the macrophage would have plucked out this nucleus
- S. pneumo sepsis - cant get pneumovax until 2 years of age
- H. flu is the next most common cause - penicillin prophylaxis
- N. menin, Salmonella, GBS are other encapsulated bac
- first vaso-occlusive crisis occurs around 6-9 months of age - HbS as accumulated at this point (ex of vaso-occlusive crisis is if pt comes in with scleral icterus and tenderness over bones)
- splenic sequestration crisis - marked Hb decrease, rapidly enlarging spleen
- renal papillary necrosis - decreased PO2 in papilla and microhematuria (medullary infarcts)
- decreased life-expectancy, normocytic anemia with increased retics
- treat with hydroxyurea (increases HbF) and hydration
- Gardos channel blockers - this channel allows K and water to leave, if you block it –> prevent sickle cell dehydration
HbC: glutamic acid to lysine
- crystals inside RBCs and target cells
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Deficient enzyme:
G6PD deficiency - XR, primaquine, dapsone (leprosy), Heinz bodies (denatured Hb), bite cells
- seen in blacks, greeks, italians
- can cause prolonged neonatal jaundice, but mild anemia, in newborn
Pyruvate kinase deficiency (AR, last step of glycolysis) –> decreased ATP –> rigid RBCs –> extravascular hemolysis
- increased 2,3-BPG... - hemolytic anemia in a newborn
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EXTRINSIC
- IgG = warm reacting antibodies - most common cause is lupus, also seen in lupus and CLL
- IgG and C3b on the surface of RBCs
- direct Coombs - directly detect antibodies on RBCs (v.s. indirect Coombs - screens for IgG in serum)
- IgM = cold reacting antibodies - seen in CLL, M. pneumo, mono
- second most common cause is penicillin - piece of penicillin attaches to RBCs
- can get IgG antibodies against this chunk of penicillin = type 2 HSR
- methyldopa - can be given to pregnant women with HTN (hydralyzine can also be given –> drug induced-lupus, second to procainamide)
- methyldopa screws up your Rh antigens - you make IgG against your Rh antigens –> autoimmune hemolytic anemia
- immune complex - quinidine-IgM complex circulates in blood stream
- IC sits on an RBC - attracts complement –> intravascular hemolysis
- microangiopathic hemolytic anemia - schistocytes
- most common cause is aortic stenosis –> chronic intravascular hemolysis –> losing a lot of Hb in urine –> can get secondary Fe-deficiency anemia
- other causes - DIC, TTP/HUS, SLE, HELLP, malignant HTN
- infections - malaria, Babesia
malaria
plasmodium falciparum - ring forms of trophozoites and banana-shaped gametocytes
fever spikes when RBCs rupture
leukemoid reaction
site of immune response activation, note 2 follicles are the active ones
looks like leukemia - but benign
- can distinguish from ALL because there is no anemia and no thrombocytopenia
Tb, sepsis >30,000-50,000 neutrophils in periphery
lymphocytic leukocytosis
- pertussis - bacteria produces lymphocytosis promoting factor (prevents lymphocytes from leaving blood and entering LNs)
lupus
thrombocytopenia and hemolytic anemia = type 2 HSR
other symptoms are related to IC
pt on creatine supplements
pt will have extremely high creatinine levels, but BUN is normal
polycythemia
RBC mass (mass of RBCs in circulation, unchanged with plasma volume) v.s. RBC count (concentration in blood, will increase if you are dehydrated)
relative polcythemia - decrease in plasma volume, RBC mass is unchanged
absolute polycythemia
- appropriate increases - tissue hypoxia
inappropriate absolute polycythemia
myeloproliferative disorders - stem cell has lost regulation (nothing can inhibit it)
1) polycythemia vera
- H - hyperviscosity –> increased peripheral resistance, increased risk of thrombosis (Budd-chiari - hepatic vein thrombosis), phlebotomy to reduce viscosity and to create Fe deficient
- Budd-Chiari syndrome - liver infarction
- H - hypervolemia - plasma volume increases to match increased RBC mass (unique to this polycythemia)
- H - hyperhistaminemia - RBCs, white cells, mast cells, basophils are increased
- scenario: I itch all over when I take a hot shower - temperature changes cause mast cell degranulation –> generalized itching. Pt will also have ruddy/red face, headaches (all due to vasodilation due to histamine).
- side note - only bile salt deposition in skin can produce generalized itching
- classic symptom is erythromelalgia - blood clots in extremities –> severe, burning pain and red-blue discoloration
- Hyperuricemia - nucleated hematopoietic cells are elevated… (urate nephropathy - have to put chemo pts on allopurinol)
- treat with phlebotomy, hydroxyurea
2) CML - 9;22 Bcr-Abl
- tyrosine kinase (and PDGF mutations play a role)
- leukocytosis
- treat with imatinib
- splenomegaly! - enlarging spleen suggests accelerated phase of disease –> transformation to AML* or ALL thereafter
3) myelofibrosis (agnogenic myeloid dysplasia) - spleen will be huge (can cause early satiety)
- megakaryocytes –> stimulate fibroblast proliferation –> fibroses bone marrow
- 10% of cells stay in marrow (rest have moved to the spleen) - when these cells move through fibrosed marrow = tear-drop cells
- early stages = marrow is hypercellular, late stages = pancytopenia
- blood cells in spleen (there is no reticulin gate to prevent immature blood cells from leaving) –> blasts and nucleated RBCs on smear
4) essential thrombocythemia (least common)
- hemorrhagic and thrombotic symptoms (easy bruising, microangiopathic occlusion)
except for CML, others have JAK2/STAT gain-of-function mutations
- treat with ruxolitinib = JAK2 inhibitor (approved for primary myelofibrosis)
……..
5) myelodysplastic syndrome (pre-leukemia)
leukemia
malignancy of stem cells in marrow, can met anywhere - generalized LAD, HSM
myelodysplastic syndrome - cytopenias with hypercellular bone marrow (cells cant get out of bone marrow)
lymphoblasts are TdT+, PAS pos
myeloblasts = Auer rods
- Auer rods stain for peroxidase
age will tell you leukemia
0-14 years = ALL
- B-ALL is most common - C10, CD19, CALA antigen positive (in general B cell markers are more reliable)
- T-ALL - CD1, CD2, CD5, present with large mediastinal mass
15-39: AML
40-49: AML and CML
60+: CLL
- hypogammaglobulinemia - neoplastic B cells cant transform into plasma cells
CML is the most cause of leukemia regardless of age
most common cause of generalized, non-tender LAD in pt over 60 - METs to LN
hairy cell leukemia
rare, adult males - chronic leukemia
B cell neoplasm that infiltrates bone marrow and red pulp of spleen –> pancytopenia
TRAP (tartrate-resistant acid phosphatase) stain positive, cells have spikes
massive splenomegaly (red pulp), drug tap with bone marrow aspiration --> bone marrow is fibrosed, LAD absent (-note this can look like myelofibrosis)
cladribine - adenosine deaminase inhibitor
LNs
non-tender LAD
1) mets - most common
2) primary lymphoma
germinal follicles - form when macrophages deliver antigen to B cells –> B cells are dividing –> plasma cells that make antibodies
= reactive LAD, benign
tumors:
- follicular lymphoma - most common non-Hodgkins B-cell lymphoma
-14;18 - apoptosis gene was knocked off
- small cleaved cells (centrocytes) and large noncleaved cells (centroblasts)
Bruttons agammaglobulinemia
- germinal follicle would be absent
DiGeorge
- no paratrabecular region or germinal follicle - T cell country
histiocytosis - sinusoids
SCID - due to adenine deaminase deficiency
- would only have sinusoids/histiocytes
Langerhans cell histiocytosis
scenario: kid with rash, non-tender LAD, monomorphic cells, CD1 positive
- CD1 = histiocytes, also S100 positive (mesodermal)
- Birbeck granule in histiocyte - tennis racket
(remember C. tetani spore also looks like a tennis racket)
- may have eos granulomas that affect the skull and bones
- kid comes in with fracture - red herring is osteosarcoma
- Letterer-Siwe disease - malignant - skin rash and cystic skeletal defects (recurrent otitis media) in an infant
- Hand-Schuller-Christian disease - malignant - scalp rash, lytic skull defects, DI, and exopthalmos
tissues that cancer cant invade
cartilage and elastic tissue - cancer cells cant invade these tissues
Burkitt’s lymphoma
EBV, 8;14, c-myc oncogene translocation
starry-sky appearance - stars are normal, benign macrophages
mycosis fungoides
chronic leukemia - neoplastic cell = CD4 T cell, adults
skin and lymph nodes (?) involved
–> aggregates of neoplastic T cells in epidermis = Pautrier microabscesses
Sezary syndrome - malignant cells are now in peripheral blood
- lymphocytes with cerebriform nuclei
Hodgkins
non-tender generalized LAD
bimodal age distribution
overall prognosis is better than that of non-Hodgkins
owl-eyes = RS cells, CD15 adn CD30 positive
1) nodular sclerosing Hodgkins - more common in young adult women
- 2 hard, non-painful nodes - in anterior mediastinum and in a node above the diaphragm
2) lymphocyte-rich = best prognosis
3) mixed cellularity - eos!
4) lymphocyte depleted- worst prognosis, elderly, HIV