Heme/Onc Pathophys Flashcards
RBC lifespan
120 days
what happens to RBC at end of life?
phagocytized in reticuloendothelial system
what does RBC destruction stimulate?
erythropoiesis
role of hemoglobin
transport vehicle for oxygen
definition of anemia
reduction in the volume (hematocrit) of or concentration (hemoglobin) of RBCs when compared to similar values from a reference population
what is hgb
expression of amount
what is hct
expression of volume
describe the mechanisms of anemia
5 general
- RBCs destroyed early
- ineffective erythropoiesis
- insufficient erythropoiesis
- blood loss
- hemolysis
4 things required for RBC production
- iron
- B12
- folic acid
- erythropoietin
what is the role of erythropoietin?
stimulates RBC production when O2 is low
compensatory response to severe bleeding (acute onset w/ massive volume loss)
- immediate: peripheral vasoconstriction and central vasodilation
- w/ time: systemic small vessel vasodilation
components of systemic small vessel vasodilation
- increased blood flow to increase tissue oxygenation
- decreased systemic vascular resistance
- increase cardiac output, tachycardia, tachypnea
what way will Hgb-O2 dissociation curve shift w/ anemia? why?
- right shift
- enhances O2 release to tissues
2 other compensatory responses for anemia
- increase in plasma volume to enhance tissue perfusion
- stimulation of EPO production
causes of left shift on hgb-O2 curve
6
- low temp
- high pH
- low 2, 3-BPG
- fetal Hb
- methemoglobinemia
- carboxygemoglobinemia
describe the implications of a left shift on hgb-O2 curve
- increased oxygen affinity (stays w/ hgb)
- reduced oxygen delivery to tissues
causes of right shift on hgb-O2 curve
4
- low pH
- increased CO2
- high temp
- high 2,3-BPG
describe the implications of a right shift on hgb-O2 curve
- reduced oxygen affinity (leaves hgb easier)
- increased oxygen delivery to tissues
causes of decreased RBC production
5 primary causes
- marrow failure/suppression (decreased raw materials, RBC defects, blood cancers, chemo)
- renal failure (decreased EPO)
- lack of nutrients (iron, B12, folic acid)
- low levels of hormones which stimulate RBC production
- chronic disease/inflammation
differentials for anemia due to accelerated loss of RBCs
4 categories
- inherited hemolytic anemias (sickle cell, thalassemia major)
- acquired hemolytic anemias (autoimmuno, TTP/HUS, malaria)
- G6PD deficiency
- hereditary spherocytosis
screening recs
- infants at 9-12 mo
- pregnant women
key hx components
8
- hx of medical condition known to result in anemia
- onset of anemia
- ethnicity/country of origin
- mediations/supplements
- use of alcohol, aspirin, NSAIDs
- hx of blood transfusions
- exposure to toxic chemicals
- hx of liver disease
key sx of anemia
10
- DOE, SOB
- fatigue
- weakness
- palpitations
- dizziness
- poor concentration
- HA
- angina/a. fib
- neuropathy
- pica (craving ice)
key signs of anemia
8
- orthostatic vital signs
- jaundice
- lymphadenopathy
- bony tenderness
- petechiae
- pallor
- tachycardic
- melena (FOBT testing)
key labs for anemia
- CBC (Hgb, Hct, MCV, MCH, RDW)
- peripheral blood smear
- reticulocyte count
RBC Indices
what does MCV represent
cell volume (big vs small)
RBC Indices
what does MCHC represent
concentration of Hb in each RBC (pale vs deep red)
RBC Indices
what does MCH represent
Hb content in each RBC
which types of anemia are microcytic?
5
- iron deficiency
- thalassemia
- chronic disease/inflammation
- sideroblastic anemia
- lead posioning
which causes of anemia can be normocytic?
5
- acute blood loss
- chronic disease
- hypersplenism
- bone marrow failure
- hemolysis
which causes of anemia can be macrocytic?
5
- B12 or folic acid deficiency
- hemolysis with reticulocytosis
- chemotherapy
- hypothyroidism
- MDS
define reticulocyte count
the # of immature RBCS released from bone marrow into peripheral circulation
causes of increased reticulocyte count
3
- hemolytic anemia
- acute bleeding
- response to anemia treatment
causes of decreased reticulocyte count
- iron, B-12, folate deficiencies (will be decreased until the nutrient is replaced, then it will be increased)
- decreased erythropoietin
- bone marrow failure
additional labs to order
- vitamin levels
- LDH, bilirubin, haptoglobin
- coomb’s test
- hemoglobin electrophoresis
- serum protein electropheresis (SPEP)
- creatinine
- TSH
- urinalysis
- stool guaiac
- bone marrow biopsy
Iron Deficient Anemia Meds
Ferrous Sulfate
MOA, dosing, mode, adverse rxn
- replaces iron, found in hemoglobin, myoglobic
- dosing: 65mg PO QD
- available as tablets or solutions
- adverse rxns (nausea, darker stools, constipation)
Iron Deficient Anemia Meds
Iron Dextran (INFED)
indications, dosing, mode, adverse rxn
- indications: lack of response to PO iron, chronic kidney disease, IBD
- adverse rxns: anaphylactic rxns, infusion rxns, flushing, pruritis, injection site skin discoloration, arthralgia
- IV
Iron Deficient Anemia Meds
Ferric Carboxymaltose (Injectafer)
MOA, dosing, mode, adverse rxn
- MOA: non-dextran formulation that allows for iron uptake w/out release of free iron
- used in pregnancy (2-3rd trimester)
- dosing: 750mg IV 2x per week (if >50 kg wt); 15mg/kg IV 1x per week (if < 50 kg wt)
- adverse rxns: hypersensitivity, hypertension, hypophosphatemia, skin discoloration
Iron Deficient Anemia Meds
Sodium Ferric Gluconate Complex
MOA, dosing, mode, adverse rxn
- MOA: supplies a source to elemental iron necessary to the function of hemoglobin, myoglobin, and specific enzyme systems
- indications: IDA (hemodialysis pts)
- dosing: 125mg IV every 6 wks
- adverse rxns: hypersensitivity, HTN, nausea, injection site discoloration, muscle cramps
Anemia of Inflammation/Chronic Disease
inflammation causes
- dysregulation of iron homeostasis
- impaired marrow RBC development
- blunted EPO response (CKD)
- increased phagocytosis of RBCs
Sickle Cell Anemia
hydroxyurea (hydrea)
indications, dosage, contraindications, side effects
- unk MOA
- indications: SCA, CML, polycythemia vera, essential thrombocythemia
- 500mg PO
- contraindications: pregnancy
- side effects: myelosuppression, macrocytosis, secondary leukemia, skin cancer, rash, hepatotoxicity, n/v
Hemolytic Anemia
general
anemia due to increased destruction of RBCs to the point that destruction exceeds capacity of bone marrow production
Hemolytic Anemia
what does increased cell turnover result in?
3 things
- increased production response in the bone marrow
- increased requirement for erythropoietin
- increased cell waste products
Hemolytic Anemia
describe intravascular hemolysis
2 components
- hgb released from lysed RBCs binds to haptoglobin which decreases haptoglobin levels
- if lysed hgb does not bind, it will leak into the renal tubules (hemoglobinuria)
- IN blood vessels
Hemolytic Anemia
describe extravascular hemolysis
3 components
- **spleen and liver **macrophages phagocytize RBCs
- no change in haptoglobin
- excess hemolysis in speen leads to hypersplenism and then neutropenia/thrombocytopenia
Hemolytic Anemia
which hemolytic anemias are hereditary and intracorpuscular defects?
- hemoglobinopathies
- enzymopathies
- membrane-cytoskeletal defects
Hemolytic Anemia
which hemolytic anemias are acquired and intracorpuscular defects?
1
- paroxysmal nocturnal hemoglobinuria
Hemolytic Anemia
which hemolytic anemias are hereditary and extracorpuscular defects?
1
- familial HUS
Hemolytic Anemia
which hemolytic anemias are acquired and extracorpuscular?
5
- mechanical destruction
- toxic agents
- drugs
- infection
- autoimmune
Hemolytic Anemia
causes of intravascular hemolysis
- direct trauma
- shear stress
- heat damage
- osmotic lysis following infusion of hypotonic solutions
- lysis from bacterial toxins (clostridial sepsis)
- G6PD deficiency, TTP, DIC
- Transfusion rxn
Hemolytic Anemia
intrinsic causes of extravascular hemolysis
4
- membrane defects
- glycolytic defects
- oxidation vulnerability
- hemoglibinopathies
Hemolytic Anemia
extrinsic causes of extravascular hemolysis
- immune (autoimmune/drug tox)
- microangiopathic (TTP, DIC)
- infection
- hypersplenism
- burns
Hemolytic Anemia
what does coombs positive mean?
- autoimmune, Rh incompatibility
Hemolytic Anemia
what does neg coombs test mean?
- intrinsic RBC disease (sickle cell, thalassemia, hereditary spherocytosis, G6PD deficiency)
- extrinsic RBC disease (microangiopathic hemolytic anemia, TTP, DIC, prosthetic valve hemolysis, splenic sequestration)
Hemolytic Anemia
differentiate Indirect and direct coombs?
- indirect: seeing if the plasma has the antibodies
- direct: seeing if the blood has the antibodies (if abx clump together = pos test = they do have abx on RBCs)
Hemolytic Anemia
autoimmune hemolytic anemia acute tx? refractory?
3
- prednisone
- rituximab
- immunoglobulin
Hemolytic Anemia
prednisone
MOA, class, dosing, pregnancy
- MOA: decreases inflammation by suppression of leukocytes and decreased capillary permeability; suppresses the immune system
- Class: corticosteroid
- Dosing: by weight/disease; given PO
- Pregnancy: crosses the placenta
Hemolytic Anemia
prednisone adverse reactions
6
- facial erythema
- flushing/diaphoresis
- fluid retention
- HA
- impaired wound healing
- increased LFTs
Hemolytic Anemia
any dosing greater than 1 wk requires?
tapering
Hemolytic Anemia
Rituximab
MOA, class, indications, dosing
- MOA: eliminates B cells via apoptosis, antibody dependent cytotoxicity and complement mediated cytotoxicity
- Class: monoclonal antibody
- Indications: initiate therapy with glucocorticoids w/ no improvement
- Dosing: 375 mg/m^2 IV weekly for 4 wks
Hemolytic Anemia
Rituximab- Adverse Effects
3
- infusion reaction
- long term immunosuppression
- reactivation of Hep B
Hemolytic Anemia
what pre infusion meds should be given for Rituximab
3
- acetaminophen
- anti-histamines (benadryl)
- methylprednisolone 100mg IV
Hemolytic Anemia
Immunoglobulin
MOA, dosing, pregnancy, adverse rxns
- MOA: interferes with cell receptors within the reticuloendothelial system; provides passive immunity
- Dosing: varies, can be subQ or IV
- pregnancy: crosses placenta
- Adverse: hypersensitivity rxns
G6PD Deficiency
which are oxidative meds to avoid?
7
- dapsone
- methylene blue
- phenazopyridine
- primathoprim/sulfamethoxazole
- sulfadiazine
- pegloticase
- quinolones
Paroxysmal Nocturnal Hemoglobinuria (PNH)
which meds to treat?
eculizumab
Paroxysmal Nocturnal Hemoglobinuria (PNH)
Eculizumab
MOA, Dosing, Adverse effects, pregnancy
- MOA: IgG antibody that binds to complement proteins which blocks formation of membrace attack complex (MAC) to stabilize hemoglobin
- Dosage: IV infusion Q2 wks for life
- Adverse Effects: infusion rxn, HTN, HA, skin rash, renal insufficiency, fever, increased susceptibility to meningitis
- Pregnancy: crosses placenta
Hereditary Hemochromatosis
describe effects of gene mutation on iron and hepcidin
3 components
- mutation of HFE gene causes dysregulation of hepcidin
- increased iron absorption (low hepcidin, high iron), up to 2-4mg daily
- increased iron deposition in different organs
Aplastic Anemia
meds to tx
3
- erythropoietic growth factors
- myeloid growth factors
- blood product transfusions
Aplastic Anemia
Erythropoietic Stimulating Agents
Med Names, MOA, BBB, Dosing
- Epoetin or darbepoetin
- MOA: induces erythropoiesis by stimulating progenitor cells; induces release of reticulocytes from the bone marrow into blood to mature to RBCs
- BBB: increases risk of death, mI, strok, venous thromboembolism, thombosis of vascular access
- Dosage: wt based; SubQ
Aplastic Anemia
erythropoietic stimulating agents
pregnancy, adverse effects, contraindications
- Pregnancy: does not cross
- Adverse: HTN, n/v, fever, thrombosis
- contra: HF patients
Aplastic Anemia
how long until effect of erythropoietic stimulating agents ?
reticulocyte counts increase w/in 10 days
Aplastic Anemia
myeloid growth factors AKA
granulocyte colony stimulating factor
Aplastic Anemia
which meds are myeloid growth factors?
2
- filgastrim
- sargramostim
Aplastic Anemia
Myeloid Growth Factors
MOA, Dose, Adverse, Pregnancy
- MOA: granulocyte colony stimulating factor activates neutrophils to increase migration and cytotoxicity
- Dose: varies; IV or SubQ
- Adverse Rxns: chest pains, splenic rupture, arthralgia, fever
- Preg: crosses placenta
Aplastic Anemia
Antithymocyte Globulin
Drug Name, MOA, Dosing, Pregnancy, Adverse Rxns
- Equine anti-thymocyte globulin (ATG)
- MOA: suppresses killer T cells; induces hematologic response in aplastic anemia
- Dosing: wt based
- pregnancy: crosses placenta
- Adverse: many, do test dose first
Aplastic Anemia
Cyclosporine
Drug Class, MOA, Dosing, Preg
- Calcineurin Inhibitor
- MOA: inhibits production and release of interleukin II
- Dosing: wt; PO or IV
- Preg: crosses placenta
Aplastic Anemia
Cyclosporine
adverse, notes
- Adverse: HTN, nephrotoxicity, tremors
- Notes: monitor cyclosporine levels, avoid grapefruit juice
Myelodysplastic Syndrome (MDS)
meds for MDS?
3 categories
- lenalidomide
- azacitidine or decitabine
- growth factors
Myelodysplastic Syndrome (MDS)
Lenalidomide
Class, use w/ , Dose, side effects
- Class: vascular endothelial growth factor (VEGF) inhibitor
- Use w/ dexamethasone
- Side effects: neutropenia, thrombocytopenia, venous thrombosis
Myelodysplastic Syndrome (MDS)
Azacitidine
MOA, Dosing, use w/, side effects, goal
- MOA: anti-metabolite which inhibits DNA hypomethylation
- Dosing: 75 mg/m
- Use w/ dexamethasone
- Side Effects: pancytopenia, renal failure, interstitial lung disease, rash
- goal: improve overall survival, delay conversion to AML
what vaxxes must pts have before splenectomy?
- Pneumococcus
- H. flu B (HIB)
- Meningococcal
Leukemia
general- what is leukemia
malignancy of the blood
Leukemia
what is the cell of origin for myelogenous leukemias?
granulocytes
Leukemia
which cells are granulocytes?
- neutrophils
- eosinophils
- basophils
Leukemia
lymphocytic leukemias originate from which cells?
lymphocyte lineages
Leukemia
what type of cells dominate acute leukemias
- high proportion of immature, nonfunctional cells
- ex: blast cells
Leukemia
what type of cells dominate chronic leukemias
- higher proportion of mature cells w/ reduced function