Hematology Exam 3 (Fall 2023)
PNH: Special tests Immunophenotype analysis of RBC's in PNH
•Confirmatory test •Utilize antibodies, directed against GPI-anchored proteins (such as CD59)
decreased EPO production
•Cytokines, primarily those produced by macrophages during inflammation, contribute to ACD by inhibiting erythropoiesis (inhibitory cytokines - they inhibit EPO)
etiology of megaloblastic
-Deficiency of vitamin B12 (cobalamin) -Deficiency of folic acid (folate)
Acquired Hemolytic Anemias: Non-Immune hemolytic anemias
-Diseases -Intracellular organisms -Chemicals, venoms and drugs -Burns
laboratory diagnosis of aplastic anemia: blood picture
- Normochromic, normocytic anemia - Pancytopenia (due to bone marrow failure) is typical (decrease in all cell lines) - Although initially only 1 or 2 cell lines may be decreaed - Normal RDW
are porphyrias rare or common?
- They are RARE! - Disease affected the royal families of England and Scotland
etiology of acquired aplastic anemia
-(common) -Idiopathic (unknown cause) - roughly 70% of cases some are secondary to (these external things get into bone marrow and mess up bone marrow architecture) •Toxic chemicals (agriculture) •Radiation •Drugs (chemotheraputic) •Infectious agents (vial - hepatitis)
Patients with Pyruvate Kinase Deficiency symptoms
- Jaundice - Splenomegaly - High incidence of gall stones
lead poisoning aka how are people exposed to lead?
- is a significant public health concern - Lead poisoning also known as plumbism •How are people exposed to lead? -Adults work with leaded compounds (inhalation) -Children and adults living in older homes due to lead based paint (produced prior to 1978)
3 causes of iron deficiency anemia
-1. Decreased intake of iron •Inadequate iron intake -Vegetarian, infancy, pregnancy -2. Increased need for iron •Pregnant and lactating women •Growing children and teens -3. Increased loss of iron •Menstruation •Chronic blood loss -GI tract bleed -Slow loss through urinary tract (renal stones) -Heavy menstration •Intravascular hemolytic processes
Electrophoresis on cellulose acetate at pH 8.4 (alkaline) shows:
-85-100% Hgb S -<15% HgbF (increased amount of F) -HgbA2 is normal -Absence of Hgb A
Hereditary Elliptocytosis (HE)- clinical findings
-90% of patients show no signs of hemolysis -Anemia is not characteristic
PNH: Stem cell mutation
-A mutation of the phosphatidylinositol glycan gene -This mutation prevents the assembly of a fatty-acid tail, known as a glycosyl-phosphatidylinositol (GPI) anchor, a necessary step in surface attachment of some proteins -When proteins with this GPI anchor are diminished or absent, which are crucial in protecting blood cells from inappropriate complement destruction, PNH erythrocytes, are easily lysed by complement..
sickle cell anemia: Hemoglobin Mutation
-A single nucleotide change that results in glutamic acid (GLU) being replaced by valine (VAL) at the 7th position of the beta chain •Glutamic acid = Hemoglobin A (normal) •Valine = Hemoglobin S (sickle) -Results in production of hemoglobin S and no production of hgb A
what is DAT aka/detection of?
-AKA direct Coomb's test •Is used to detect these antibodies or complement proteins that are bound to the surface of red blood cells [•The direct Coombs' test is used to determine whether RBC-binding antibody (IgG) or complement (C3) is present on RBC membranes. The patient's RBCs are incubated with antibodies to human IgG and C3. If IgG or C3 is bound to RBC membranes, agglutination occurs-a positive result.]
note on EPO-- EPO usage as a therapeutic agent
-Administered erythropoietin produces the same effect as a transfusion of red blood cells, but can be given chronically without the risks of repeated transfusions -Can be beneficial in many types of anemia due to diseases that interfere with RBC production -Epogen and Procrit are 2 US brands (stimulates the bone marrow to make red cells)
molecular assays for thalassemia
-Allow for screening several mutations
WAIHA laboratory diagnosis
-Anemia varies from mild to severe -Spherocytes -Reticulocytosis (5-10%) and increased polychromasia -Increased unconjugated bilirubin, -Positive DAT (direct Coombs' test)
Anemia of Chronic Renal Disease etiology
-Anemias caused by chronic renal disease -In US 800,000 adults with chronic renal disease have a Hgb less than 11g/dL
treatment for ACD
-Anything that diminishes the underlying inflammatory process will improve the anemia -Typically anemia is mild so treatment is not needed -Therapeutic EPO
Hydroxyurea (Droxia, Hydrea)
-Approved by the FDA in 1998 and is now available for adult patients with SCD -This prescription drug was normally used to treat cancer -When taken daily, reduces the frequency of painful crises and may reduce the need for blood transfusions -Still investigating long-term use of this drug -It works by stimulating production of Hgb F which helps prevent the formation of sickle cells •The presence of other hemoglobins in the red blood cell, such as hemoglobin F, hemoglobin A, hemoglobin C, and hemoglobin O, has an anti-sickling effect on the polymerization of hemoglobin S. •Hemoglobin F has the most profound anti-sickling effect
Acquired Hemolytic Anemias: Immune hemolytic anemias
-Autoimmnune 1. Warm autoimmune hemolytic anemia 2. Cold autoimmune hemolytic anemia 3. Paroxysmal cold hemoglobinuria 4. Drug-induced 5. Alloimmune -Transfusion reaction -Hemolytic disease of the newborn (HDN)
treatment of CAIHA
-Avoid exposure to cold -Move to warmer climates- Drugs and splenectomy is not effective
Experimental Treatments: sickle cell anemia
-Because sickle cell anemia is caused by a defective gene, researchers are exploring whether inserting a normal gene into the bone marrow of people with sickle cell anemia will result in the production of normal hemoglobin -Scientists are also exploring the possibility of turning off the defective gene while reactivating another gene responsible for the production of fetal hemoglobin
Pathogenesis of aplastic anemias (what is impaired)
-Bone marrow failure due to depletion of bm cells and replacement of bm with fat= bm is Hypocellular Results in •Bone marrow no longer producing an adequate number of precursor blood cells = pancytopenia (decrease in all cell lines)
PNH: clinical findings age/urine
-Can occur at any age - occurs most often in adults -Reddish-brown urine
DIC (Disseminated intravascular coagulation) characterized by/accompanies
-Characterized by •RBC fragmentation due to fibrin strands present in pb •Thrombocytopenia of varying degrees always observed •Hemolysis is usually not severe -Accompanies many systemic disorders such as obstetric complications, snakebite, heatstroke
etiology of ACD (anemia of chronic disease)
-Chronic inflammation may be a better term because inflammation appears to the the unifying factor among the conditions -Anemia associated with chronic diseases such as -rheumatoid arthritis -systemic lupus erythematosus (SLE) -tuberculosis (TB) -HIV -malignancies -chronic urinary tract infection
what is complement
-Composed of at least 20 proteins responsible for a variety of biologic activities •Abbreviated C1, C2, C3, etc. -Normally circulate inactive -If complement attaches to the RBC membrane and are activated, the cell can be hemolyzed (intravascular hemolysis)
PCH: laboratory diagnosis
-DAT weak positive for complement -Reticuolocytosis -Spherocytes -Hemoglobinuria and hemoglobinemia -Serum bilirubin elevated
Hereditary Elliptocytosis (HE) membrane defect caused by results in
-Defect in membrane protein resulting in membrane instability--Deficiency of alpha-spectrin or beta-spectrin are common •Results in oval or elliptical RBCs
Anemia of Chronic Renal Disease pathogenesis
-Deficiency of EPO production by the kidneys
what are porphyrias basic disease characteristic/acquired or hereditary
-Diseases characterized by impaired production of heme 1. May be acquired -Lead poisoning is an example 2. Hereditary -Porphyria is most often used to refer to the hereditary conditions
Immune complex formation
-Drug combines with protein in the plasma (antigenic complex) -Stimulates antibody production -Drug/antibody complex attaches to RBC -Activates complement -Intravascular hemolysis
WAIHA- antibody
-Due to Warm Reactive Antibody •Antibody will react and induce hemolysis at 37 degrees Celsius •Usually the warm-reactive antibody is IgG •Detected using the DAT
Pernicious Anemia (PA) cause
-Due to deficiency of vitamin B12 -Specific cause of this deficiency= Autoimmune destruction of Intrinsic Factor secreting gastric cells- causes a loss of intrinsic factor (loss caused by a autoimmune disease) -Feature of the automimmune response to PA is the production of antibodies to IF (this is how to determine that this is the cause)
hemolysis is the premature destruction of RBCs...where does this occur
-Extravascular -Intravascular
laboratory diagnosis of anemia of chronic disease- iron studies:
-Ferritin - normal to increased -Serum iron - decreased -TIBC - decreased -% transferrin saturation - decreased
what is increased in intravascular hemolysis?
-Free hemoglobin in plasma -Hemoglobinuria -Hemosiderinuria
Enzyme Defects
-G6PD Deficiency (extravascular hemolysis) -Pyruvate Kinase Deficiency (extravascular hemolysis)
why is it called megaloblastic
-Giant and abnormal appearing erythroid precursors in the bone marrow of this anemia (erythroblast, pronormoblast, orthochromic normoblast)
sideroblastic anemias main issue/interferes with/status of iron
-Group of anemias in which heme synthesis is impaired -Diseases that interfere with the production of adequate amounts of heme produces anemia -Iron is abundant
Adult hemoglobins:
-HbA is 2 alpha chains and 2 beta chains -HbA2 is 2 alpha chains and 2 delta chains -HbF is 2 alpha and 2 gamma
Hemoglobin electrophoresis: thalessemia
-Hemoglobin A is usually decreased -Elevated HgbA2 and HgbF in β-thalassemia -Decreased HgbA2 and HgbF in α-thalassemia
Laboratory Findings: beta thalassemia intermedia hemoglobin electrophoresis (adult)
-Hemoglobin A2: 5-10% -Hemoglobin F: 30-75% -Hemoglobin A: Remainder
Hemoglobin electrophoresis (in adults): beta thalassemia major
-Hemoglobin A: Absent or nearly absent -Hemoglobin F: Majority -Hemoglobin A2: Typically increased
Laboratory Findings: thalassemia minor--hemoglobin electrophoresis
-Hemoglobin A: Majority -Hemoglobin A2: Increased (3-7%) -Hemoglobin F: Normal or increased
Hemoglobin H Disease: Hemoglobin electrophoresis (adult)
-Hemoglobin H 30-50% H -Hemoglobin A2 decreased (1.5%) -Hemoglobin F normal -Hemoglobin A - remainder
Globin defects
-Hemoglobinopathies -Thalassemias
Acquired Hemolytic Anemias: Immune Hemolytic Anemias(IHA) Alloimmune Hemolytic Anemia introduction
-Hemolytic anemia induced by immunization of an individual with erythrocyte antigens on the infused cells of another individual -Patient's RBCs lack the antigen present on infused cells -Transfused antigens are recognized as foreign and induce recipient (patient) to form antibodies [Alloantibodies are antibodies produced in one individual in response to the antigens of another from another person] This type of immunologic destruction of RBCs is seen in •Transfusion reactions •Hemolytic disease of the newborn
membrane defects
-Hereditary Spherocytosis (extravascular hemolysis) -Hereditary Elliptocytosis (extravascular hemolysis)
Normal Adult hemoglobin %
-Hgb A (>95%) -Hgb A2 (<3.5%) -Hgb F (<1-2%)
PCH treatments
-If associated with infections, the anemia terminates upon recovery from infection -Transfusion if anemia is severe -Avoid exposure to cold
IgM antibodies agglutinate cells
-IgM pentamer has a possible span of 35nm, therefore it can overcome electrostatic forces separating RBCs and cause them to agglutinate -Maximum span of IgG is about 14nm and it cannot reach antigens on two separate RBCs to cause agglutination
Thalassemia leads to
-Imbalanced globin chain synthesis -Decreased production of normal hemoglobin -Synthesis of abnormal hemoglobins -Ineffective erythropoiesis -Chronic hemolysis
Hemolytic Transfusion Reactions: Treatment
-In immediate, prompt action is necessary •Stop transfusion •Efforts to prevent shock, maintain renal circulation -In delayed •Treatment usually not required
what is increased in extravascular hemolysis?
-Increase in unconjugated bilirubin in serum -Increased urobilinogen in urine and stool
hemoglobinopathies: Sickle Cell Trait who has it? (method of inheritance)
-Inherited -Heterozygous form HgbAS •Hgb S from one parent •Hgb A from the other parent
Hereditary hemolytic anemias are
-Intrinsic hemolytic anemias •Intrinsic meaning defects within the red cell (refers to an abnormality of the erythrocyte itself) •Almost all intrinsic defects are hereditary •Usually extravascular hemolysis
paradox of ACD (anemia of chronic disease): pathogenesis
-Iron is abundant in the body stores yet... -Serum iron is low (sideropenia) •Resulting in: -Erythropoeisis is iron deficient therefore decreased production of RBCs
to determine cause of megaloblastic anemias (questions to ask)--to determine cause for treatment:
-Is it vitamin B12 deficiency? -if yes...what is causing the deficiency? -Is it pernicious anemia? -Is it folic acid deficiency? -What is causing the deficiency?
Iron Deficiency Anemia: Etiology of IDA
-It is inadequate stores of iron for hemoglobin ***Worldwide most common anemia
Hemoglobin E Disease: hemoglobin mutation and symptoms
-Lysine is substituted for glutamic acid at the 26th position on beta chain •Symptoms- Asymptomatic
what are some symptoms of vit b12 deficiency
-Memory loss -Numbness -Tingling in toes and fingers -Loss of balance -Impairment of walking -"Megaloblastic madness"
epidemiology: at high risk
-Menstruating women -Growing children -Infants (cows milk not a good source of Fe) -Senior citizens (not eat balanced diet) -Pregnant women
acquired form of sideroblastic anemias causes
-More common than hereditary forms -Idiopathic or secondary to an underlying disease or toxin -Most common causes of acquired form are: 1. Heavy metals especially lead- Lead poisoning 2. Alcohol
hereditary form of sideroblastic anemias
-Most common hereditary form is due to defective sex linked recessive gene •Carrier females •Affected males -Most commonly appears in young adulthood
treatment for Pyruvate Kinase Deficiency
-No specific therapy -Splenectomy -Blood transfusions
laboratory diagnosis of megaloblastic anemia: blood picture
-Normochromic, macrocytic anemia (***MCV commonly greater than 120 fL, MCHC normal because Hgb production unaffected) -Pancytopenia (decrease in all cell lines) -Elevated RDW (have large cells already, bm is making normal cells-- variation in size is present) -Oval macrocytes -Hypersegmented neutrophils***** (HALLMARK TRAIT) -Poikilocytosis (variation in shapes--Dacryocytes, schistocytes, microspherocytes) -Nucleated RBCs, Howell-Jolly bodies, basophilic stippling, and cabot rings may be present -Reticulocyte count is low--Cells die during division in bone marrow never enter peripheral blood
Anemia Associated with Renal Disease: blood picture
-Normochromic, normocytic anemia -Normal RDW -Poikilocytosis -Retics - normal or decreasedNormocytic, Normochromic, Iron deficiency develops overtime, Echinocytes
blood picture for myelophthisic anemia
-Normochromic, normocytic anemia -Pancytopenia (due to infiltration of abnormal cells into the bone marrow) -Moderate to marked poikilocytosis
Acquired Hemolytic Anemias: Immune Hemolytic Anemias(IHA) lab findings
-Normocytic, normochromic anemia -With spherocytes, schistocytes, and polychromatophilia -Reticulocytosis -Positive direct antiglobulin test (DAT)
TTP (Thrombotic Thrombocytopenic Purpura) what is it/characterized by
-Not a single disease but a syndrome of diverse mechanisms and etiologies Syndrome characterized by •Hemolytic anemia with RBC fragmentation •Fever •Thrombocytopenia •Neurological dysfunction Progressive renal failure
Alpha Thalassemia Minor: treatment/prognosis
-Not required -normal life span
Delayed transfusion reaction hemolysis?
-Occuring 2 to 14 days after transfusion -Underlying cause: Antibodies other than ABO Often Kidd system -Hemolysis: Extravascular - RBCs are coated with IgG antibodies and removed via splenic macrophages
Acquired Hemolytic Anemias: Membrane Defects
-Paroxysmal nocturnal hemoglobinuria
Normal destruction of aged RBCs --Protoporphyrin
-Protoporphyrin (heme ring) is broken down into bilirubin •This form of bilirubin is called indirect or unconjugated bilirubin (non water soluble) (1) •Bilirubin is secreted into plasma where it circulates bound to albumin until it reaches liver (2) •Liver conjugates it with 2 glucose molecules making it conjugated or direct bilirubin (3) •From liver it is secreted as bile and is dumped into GI tract (4) •In GI tract bacteria converts bilirubin to urobilinogen (5) •Majority excreted in stool (6) -Some is urobilinogen is naturally reabsorbed and goes back into the liver this time to be excreted as urine urobilinogen because it is water soluble (7)
CAIHA: Laboratory Diagnosis
-RBC polychromasia and reticulocytosis -Usually with less spherocytosis. -Autoagglutination of RBCs -Positive DAT -Increased unconjugated bilirubin -IgM antibodies agglutinate cells
Special Tests for HS: osmotic fragility
-RBCs are incubated in varying concentrations of hypotonic sodium chlroide solutions -Because of their decreased surface-area-to-volume ratio, spherocytes are unable to expand as much as normal discoid shaped cells can -Very little fluid needs to be absorbed before the cells hemolyze -Lysis of HS erythrocytes, therefore begins at higher NaCL concentrations than normal cells •Osmotic fragility test results-Are graphed to show the degree of fragility in comparison to the normal state (determining the concentration where hemolysis takes place, see slide 45)
Acquired Hemolytic Anemias Immune Hemolytic Anemias(IHA): Autoimmune Hemolytic Anemia
-Results in autoantibodies (antibodies from self) against their own RBC antigens •Antidodies bind to the RBC surface -Usually secondary condition due to an altered state of immunity •Such as Systemic Lupus Erythematosus (SLE), chronic lymphocytic leukemia (CLL), lymphoma, immunodeficiency disorders
Treatment G6PD Deficiency
-Self limited -Avoid exposure to oxidant drugs and food -In hemolytic episodes= Supportive therapy of blood transfusions, treatment of infections
when should iron studies be done how should they be used
-Should be drawn fasting and early in the morning •Iron levels drop throughout the day •Iron absorbed from a meal can falsely elevate results -Iron studies should be used collectively
what are porphyrias?
-Single deficiencies of most enzymes in the synthetic pathway for heme -When enzyme is missing, the products from earlier stages in the pathway accumulate in the blood and is excreted in urine or feces, allowing for their assay for diagnosis
Hemolytic anemias can be classified according to the
-Source of the defect causing the hemolysis (intrinsic or extrinsic to the RBC) -Mode of onset (inherited or acquired) -Location of hemolysis (intravascular or extravascular)
PNH treatment
-Supportive-Transfusions, antibiotics -Bone marrow transplant •Published reports document that 35% of PNH patients die within 5 years of diagnosis
•Polymerization is time dependent
-Takes roughly 2-4 minutes for the development of polymerization and formation of crescent shaped cells -Majority of cells do not sickle because they reach the lungs and are reoxygenated before significant polymerization and cell distortion occurs
Myelophthisic anemia
-Term used to signify marrow replacement or infiltration by fibrotic or neoplastic (cancerous) cells (bone marrow replaced by fibrotic cells) ^^Abnormal replacement reduces normal hematopoiesis and disrupts marrow architecture
note on EPO: synthetic erythropoietin production
-The gene which encodes erythropoietin production was cloned in 1985 and has been successfully implanted in guinea pigs in order to produce artificial erythropoietin in the form of Epoetin
Normal RBC oxygen delivery
-The hemoglobin molecule picks up oxygen in the lungs (oxyhemoglobin) and releases it when the red cells reach tissues (deoxyhemoglobin) -Throughout this process normal red cells maintain a basic disc shape
Anemia Associated with Renal Disease treatment
-Theraputic EPO -Kidney transplant
Bone marrow transplant
-This procedure replaces bone marrow affected by sickle cell anemia with healthy bone marrow from a donor who doesn't have the disease -It can be a cure, but it's difficult to find suitable donors -Currently, the procedure is recommended only for people who have significant symptoms and problems from sickle cell anemia
2 groups of sideroblastic anemias
-Those that are inherited -Those that are acquired
treatment for HE
-Typically not needed -Splenectomy
Treatment: hemoglobin e disease
-Usually no treatment necessary
CAIHA cold agglutinin
-When present, an anticoagulated blood specimen visibly agglutinates at room temperature •When warmed to 37°C, agglutination disappears Blood from patients with cold agglutinins must be warmed to 37°C for 15 minutes before analyzed -Otherwise RBC indices are grossly elevated, RBC count decreased -These abnormal results are the first indication of the presence of unsuspected cold agglutinins
Sickled RBCs
-When sickle hemoglobin releases oxygen in the peripheral tissues -The coils of the hemoglobin molecules themselves becomes sticky and tend to stick together
G6PD Deficiency-- enzyme defect
-enzyme defect of the hexose monophosphate pathway -10% of glucose is metabolized this way -Essential for maintaining adequate glutathione (GSH). Protects against oxidant damage. Maintains Hgb -Either the red blood cells do not make enough of the enzyme or the G6PD produced is altered and cannot function properly
enzyme defect: Pyruvate Kinase (PK) Deficiency
-enzyme deficiency of the glycolytic pathway -90% of glucose is metabolize here -Needed for active transport of cations (NA,K, Ca). Maintains membrane deformability -Deficiency in PK, decreases ATP (energy for red cells to move comes from the glycolytic pathway)
Hemolytic Transfusion Reactions= Immediate transfusion reaction Symptoms:
-fever -chills -back pain -nausea -vomiting -hypotension -pain at site of infusion
Glucose-6-phosphate dehydrogenase Deficiency (G6PD) etiology
-hereditary hemolytic anemia- enzyme defect •Etiology -X linked recessive (Sex linked) disorder. •Males with X linked G6PD def. is affected •Occurs most frequently in the Mediterranean area, Africa, and China •Most common inherited enzyme deficiency
diagnostic test for ida
-iron studies 1. Ferritin decreased -Decreased in all stages and is usually the first indication of developing IDA 2. Serum iron decreased 3. TIBC increased -Rises because the body tries to capture as much iron as possible 4. Percent saturation (%Sat) -Is the percent of transferrin saturated with iron will be decreased
symptoms of sideroblastic anemias
-nausea -vomiting -headaches -abdominal cramping -seizures
beta thalassemia intermedia treatment and prognosis
-possibly blood transfusions -most have a normal life span
Mutations can affect one or more α-genes resulting in four clinical severities
1. All four α-genes are deleted produces no α-chains, condition referred to as hydrops fetalis 2. 3 of the 4 α-genes are deleted, the disorder is known as Hemoglobin H disease 3. 2 of the 4 α-genes are deleted, the disorder is known as α-thalassemia minor 4. 1 of the 4 α-genes is deleted, known as silent carrier-No symptoms
Categories of alpha thalassemia
1. Alpha thalassemia minor (trait) 2. HbH disease 3. hydrops fetalis or Alpha thalassemia major
Malaria begins as
1. It begins as a ring stage and grows into later or more mature stages 2. The spleen tries to pit out the parasite from the infected RBC, this usually results in destroying the RBC -At first only the parasitized RBCs are destroyed but after several days nonparasitized cells become spherical and are destroyed (result of immunologic factors)
Laboratory Diagnosis of G6PD Deficiency
1. Anemia is absent and peripheral blood findings are normal except during hemolytic attacks 2. Clinical presentation during hemolytic episode or attack: -Normochromic, normocytic anemia -"Bite cells" due to spleen pitting- Bite cells have a chunk of the cell removed from one side 3. Positive Heinz body test- only are seen on supravitial stain 4. Reticulocytosis 5. Increased unconjugated bilirubin 6. Hemoglobinuria (hemoglobin in the urine) 7. Hemoglobinemia (presence of hemoglobin in plasma) 8. Quantitative assays of G6PD enzyme can be performed 9. ^But screening tests for G6PD are usually adequate
PNH: Laboratory findings:
1. Anemia mild to severe •Usually normocytic, normochromic •May become microcytic, hypochromic as iron deficiency develops 2. Pancytopenia 3. Neutropenia 4. Reticulocytosis-Mild to moderately elevated 5. 25% of patients will have the hallmark reddish urine upon rising from sleep (hemoglobinuria) ->Nocturnal hemoglobinuria -Cause of sleep hemoglobinemia and hemoglobinuria uncertain -Possibly by the lowering blood ph during sleep, facilitates complement 6. Hemosiderinuria
Erythropoietic protoporphyria (EPP) cause/sign
1. Autosomal dominant disease -Abnormal gene from one parent needed 2. Missing enzyme-Ferrocheletase 3. Creates buildup of Protoporphyrin Signs: -Less severe photosensitivity to sunlight
Congenital erythropoietic porphyria (CEP) cause/signs
1. Autosomal recessive disease -Two copies of abnormal gene needed >> 2. Missing enzyme- Uroporphyrinogen III cosynthetase 3. Creates buildup of Uroporphyrin I and coproporphyrin I Signs: -Excess porphyrins in the skin create an extreme photosensitivity to sunlight
Categories of Beta thalassemia
1. Beta thalassemia minor -Mild anemia 2. Beta thalassemia major -Severe anemia 3. Beta thalassemia intermedia- Symptoms of severity between the other two
lab diagnosis of sideroblastic anemias: blood picture
1. Blood Picture -Usually normochromic, normocytic anemia •Can be microcytic, hypochromic with chronic exposure 2. RDW normal 3. ***Basophilic stippling*** (lead retards breakdown of RNA) 4. Pappenheimer bodies or siderotic granules (iron deposits) 5. Bone marrow -Has adequate iron supplies -Ringed sideroblasts are specific finding for heme enzyme abnormalities ---Ringed sideroblasts are formed from an accumulation of iron in the mitochondria that will encircle the erythroblast nucleus
stages 1
1. Body's reserve is sufficient to maintain transport and functional compartments •So RBC development is normal 2. Iron stores are becoming depleted •Decrease in serum ferritin •Serum iron, TIBC and % saturation - normal 3. No anemia •RBC development is normal •So blood picture normal - no symptoms -RDW can be abnormal in non-anemic patients.
types of erythropoietic porphyrias
1. Congenital erythropoietic porphyria (CEP) -About 130 cases reported 2. Erythropoietic protoporphyria (EPP) -About 300 cases reported
what are some clinical signs and symptoms of Folic Acid Deficiency
1. Depression, psychosis 2. During pregnancy the fetus is affected by neural tube defects like spina bifida
what causes lack of vitamin b12
1. Dietary deficiency •Seen in strict vegetarians who do not eat meat, eggs, dairy products (vegans) 2. Increased need during pregnancy, lactation and growth 3. Impaired absorption of vit.B12
what causes deficiency of folic acid
1. Dietary deficiency- Sources leafy green vegetable, dried beans, liver, beef, some fruits (especially oranges) (common issue) 2. Increased need with pregnancy and growth 3. Impaired absorption (usually due to intestinal disease) 4. Impaired utilization due to drugs -Antiepileptic drugs impair folic acid metabolism 5. Excessive loss of folic acid with renal dialysis (Normally a small amount of folate is lost through the kidneys)
Drug-Induced Hemolytic Anemia: •Few hypotheses for the actual mechanism of hemolysis
1. Drug adsorption 2. Immune complex formation
treatment for sideroblastic anemias
1. Eliminate exposure to lead -In severe cases, salts of ethylenediamine tetraacetic acid are used to chelate (combine) the lead present so that it can be excreted in urine 2. Remove drug or toxin
stage 2
1. Exhaustion of the storage pool of iron 2. Deficient erythropoiesis •Insufficient iron to insert into protoporphyrin ring to form heme •Results - zinc complexes with protoporphyrin (because iron is lacking) 3. Hgb will begin to drop 4. Ferritin still low 5. Serum iron will be low 6. TIBC of transferrin will rise •Iron-starved cells try to capture as much available iron as possible 7. % saturation will be low
screening tests for G6PD
1. Fluorescent spot test -Whole blood added to mixture -Drop of mixture placed on filter paper and examined under UV light for florescence -Lack of fluorescence indicates G6PD deficiency
3 disorders with severe MAHA are
1. HUS 2. TTP 3. DIC
lab diagnosis of sideroblastic anemias: bone marrow
1. Has adequate iron supplies 2. Ringed sideroblasts are specific finding for heme enzyme abnormalities -Ringed sideroblasts are formed from an accumulation of iron in the mitochondria that will encircle the erythroblast nucleus -Excess iron appears in the mitochondria of developing RBCs forming a ring around the nucleus called ringed sideroblasts (see slide 62)
lab findings sickle cell trait
1. Hematologic parameters are normal -No drepanocytes -Normal pb smear, possibly target cells 2. Solubility test is positive 3. Electrophoresis is definitive -Hb A1 50-65% -HbS 35-45% -HbF normal HbA2 normal
Hemolytic Transfusion Reactions: Immediate transfusion reaction laboratory findings
1. Hemoglobinemia -Compare patient's pretransfusion plasma against posttransfusion plasma - hemolyzed plasma in post 2. Positive DAT
What causes the sideropenia? (pathogenesis)
1. Increased hepcidin 2. Decreased EPO production
HDN treatment
1. Intrauterine transfusion •Correct fetal anemia 2. Phototherapy •Slowly lowers elevated bilirubin levels •Fluorescent light exposure- Breaks down bilirubin into a form that can be eliminated 3. Exchange transfusion •When bilirubin levels are extremely high (toxic levels)
Hereditary Hemolytic Anemias Outline
1. Membrane Defects -Hereditary Spherocytosis (extravascular hemolysis) -Hereditary Elliptocytosis (extravascular hemolysis) 2. Enzyme Defects -G6PD Deficiency (extravascular hemolysis) -Pyruvate Kinase Deficiency (extravascular hemolysis) 3. Globin defects (next lecture topic) -Hemoglobinopathies -Thalassemias
other tests for lab diagnosis of megaloblastic anemias
1. Methylmalonic acid (MMA) •Increased excretion of MMA in the urine indirectly indicates decreases in vitamin B12 concentration 2. Antibody assays for intrinsic factor 3. Schilling's test (don't use this but be aware that it exists)--associated with megaloblastic anemia
HUS (Hemolytic-Uremic Syndrome) what is it/characterized by
1. Multi-system disorder 2. Characterized by triad of clinical findings •Hemolytic anemia with RBC fragmentation (schistocytes) •Thrombocytopenia •Acute nephropathy (renal damage), including renal failure
Myelophthisic Anemia pathogenesis
1. Normal bm replaced with abnormal cells (neoplastic cells) = bone marrow failure 2. BM is infiltrated stem cells can no longer renew or differentiate in sufficient quantities
Laboratory Diagnosis of HS confirmatory test?
1. Normochromic, normocytic 2. Anemia may be present (mild) 3. Moderate to many spherocytes 4. Elevated MCHC (due to slight dehydration of these cells) 5. Reticulocytosis (usually more than 8%) 6. Increased osmotic fragility-Confirmatory test ***
Possible Signs of Hemolytic Anemia
1. Normochromic, normocytic anemia 2. Jaundice --yellowing of skin and eye due to deposits of bilirubin (due to erythrocyte destruction) --Rate of hemolysis and bilirubin production exceeds livers ability to conjugate it and excrete it 3. elevated indirect or unconjugated bilirubin 4. Gallstones consisting of bilirubin 5. Dark or red urine due to excretion of plasma hemoglobin 6. Elevated retic count "usually" = reticulocytosis (polychromasia on pb) 7. Splenomegaly 8. Schistocytes or spherocytes (usually) *Clinical findings depend on degree of hemolysis and compensation
Pyruvate Kinase Deficiency: lab results
1. Normochromic, normocytic anemia -Hemoglobin levels of 6-12 g/dL 2. Reticulocytosis= 2-15% 3. Quantitative assay for PK (reduced) 4. Elevated indirect bilirubin 5. Negative Heinz body test
Immediate transfusion reaction
1. Occuring within 24 hours (acute) -Underlying cause: Usually ABO antibodies (ABO incompatibility) 2. Hemolysis: •Intravascular due to complete activation of complement cascade •Usually mediated by IgM
Severe clinical signs and symptoms (in addition to generic anemia signs) (iron deficient anemia)
1. Pica syndrome: craving unnature items -Crushed ice -Dirt/clay -Starch 3. Sore tongue (glossitis) 4. Cracks at the corners of the mouth 5. Spooning of the fingernails (koilonychia)
WAIHA: Treatment
1. Prednisone •Improved the management of and reduced mortality •Used to produce immunosuppression 2. Splenectomy
Pathophysiology: sickle cell anemia
1. Production of hemoglobin S -Due to mutation 2. And the production of sickled RBCs -Deoxyhemoglobin S molecules have a tendency to polymerize into rigid aggregates 3. Normal RBC oxygen delivery 4. Sickled RBCs 5. -And form long rods or polymers in the red cell -Rigid polymers distort the cell, therefore it assumes a crescent shape 6. Polymerization if reversible upon reoxygenation - goes back to discoid shape 7. Polymerization is time dependent
Three categories of HDN
1. Rh (D) caused by anti-D 2. ABO caused by anti-A, anti-B and/or anti-A,B 3. Other caused by alloantibodies to other blood blood group system antigens •More than 95% of HDN cases are due to either anti-D or ABO system antibodies
other Treatment for beta thalassemia major
1. Splenectomy -Attempt to decrease hemolysis 2. Bone marrow transplants -Not widely used 3. Drugs to treat leukemia have been used
laboratory diagnosis- megaloblastic anemias: chemistry tests
1. Total and indirect bilirubin may be elevated -Bilirubin is derived from the breakdown of hemoglobin in the spleen and bone marrow causes>> lactate dehydrogenase 2. Lactate Dehydrogenase (LD) -Enzyme found in erythrocytes, elevated during destruction of erythrocytes 3. Serum folate and vitamin B12
Myelophthisic Anemia: etiology
1. Tumors and malignant diseases--Prostate, breast, stomach cancer 2. Nonmalignant diseases such as TB
Prognosis of beta thalassemia major
1. Untreated patients -Die within 1st or 2nd decade of life 2. Treated patients -Extend life until 3rd or 4th decade
•3 Forms: Autoimmune Hemolytic Anemia (AIHA)
1. Warm autoimmune hemolytic anemia 2. Cold autoimmune hemolytic anemia 3. Paroxysmal cold hemoglobinuria
specialized testing for ida
1. ZPP (zinc protoporphyrin) 2. BM will display iron deficiency
Substitution of G for A Deletion of G Insertion of A
1. makes amino acid Isoleucine (Ile) instead of valine (Val) 2. makes amino acid phenylalanine (Phe) instead of Val 3. - makes serine (Ser) instead of Val
groups of hereditary hemolytic anemias
1. membrane defects 2. enzyme defects 3. globin defects
Acquired Hemolytic Anemias different groups
1. non immune hemolytic anemias 2. immune hemolytic anemias 3. membrane defects
Most important thalassemias
1.Alpha thalassemia •Results from a decreased or absent production of α-globin chains 2.Beta thalassemia -Results from a decreased or absent production of β-globin chains
what are the 3 types of immune hemolysis
1.Autoimmnune (AIHA) 2.Drug-induced 3.Alloimmune
lab diagnosis of iron deficient anemia
3 categories -Screening -Diagnostic -Specialized
screening for ida
CBC -Hypochromic, microcytic anemia -Hgb decreases -Elevated RDW (bone marrow is trying to compensate--- there are small and large cells)
Microangiopathic Hemolytic Anemia (MAHAs)
A group of clinical disorders characterized by 1. RBC fragmentation in the circulation resulting in intravascular hemolysis •Fragmentation occurs as RBCs pass through fibrin (clot) deposits inside small blood vessels •They fragment by the force of the flowing blood
Diagnosis of Thalassemia (lab)
CBC -Hypochromic, microcytic anemia -Target cells are usually present •Reticulocytosis often •Hgb H inclusions- Can be visualized with Brillant cresyl blue stain
Hemolytic Disease of the Newborn (HDN)
Alloimmune disease associated with increased RBC destruction during fetal and neonatal life caused by feto-maternal blood group incompatibility -Mother produces an antibody to the fetal antigen she lacks -For example an Rh (D) negative woman may develop an alloantibody to a D-positive fetus
Beta Thalassemia Major
AKA Cooley's anemia -After Thomas Cooley who offered the first clinical description of thalassemia is 1925 •Caused by homozygous inheritance of abnormal β-genes •Resulting in marked reduction or absence of β-chain synthesis
1st step in determining the cause of megaloblastic anemia
Assay the amount of folate (folic acid) or vitamin B12 in the body? (to determine the cause) Vit.B12 or folate will be decreased: •If folate deficient - stop at this point (due to diet, pregnant, growth, drugs, dialysis, disease) •If vit.B12 - stop at this point if the patient is vegetarian, vegan, pregnant or growing otherwise go to step 2
Pathogenesis:
Development of the disease
CAIHA
Due to cold Reactive Antibody -Antibody that will react and induce hemolysis at lower temperatures <32°C -Usually IgM antibodies
Acquired hemolytic anemias are
Extrinsic hemolytic anemias •Extrinsic defects are caused by the action of external agents upon the normal RBCs (antagonist in the cell's environment that causes injury to the erythrocyte) •Hemolysis may be extravascular or intravascular
Symptoms of hemoglobin c disease
Hemoglobin C disease is usually asymptomatic -Splenomegaly -Symptoms due to anemia
Confirmatory Testing for sickle cell anemia
Hemoglobin Electrophoresis -Confirmatory -Alkaline hemoglobin electrophoresis -Acidic hemoglobin electrophoresis
Definitive diagnosis of hemoglobin c disease
Hemoglobin electrophoresis •On cellulose acetate, HbC migrates with HbA2 •On citrate agar, it migrates alone ->90% HbC -HbF is <7%
Hemoglobin Mutation: hemoglobin sc disease
Hemoglobin mutation -Glutamic acid is replaced by valine at 7th position = Hgb S -Glutamic acid is replaced by lysine at 6th position = Hgb C
what is the hallmark trait of megaloblastic anemia
Hypersegmented neutrophils
step 2 of determining the cause of megaloblastic anemias If vit.B12 is decreased, determine whether if it is due to what to do?
If vit.B12 is decreased, determine whether if it is due to IF deficiency how^^->>>>> 1. Measure IF antibodies or 2. Schilling's test •Not commonly used in the US •Used to determine if malabsorption of vit.B12 due to lack of IF
Malaria what is it/animal/invades
Infection of RBCs by malarial parasites is one of the most common causes of hemolytic anemia worldwide -These parasites are injected into the human host via Anopheles mosquito -Parasite invade circulating RBCs and are nourished by the cell's content
Pathogenesis of G6PD Deficiency leads to
Leads to erythrocyte injury and hemolysis -Hemoglobin is oxidized to methemoglobin which precipitates in the form of Heinz bodies (inclusions) that adhere to membrane of RBC -Heinz bodies removed from RBC by splenic macrophages, producing bite cells and blister cells... -With progressive membrane loss, spherocytes become formed - become trapped and hemolyzed in the spleen (extravascular hemolysis) -Precipitates of denatured hemoglobin (Heinz bodies) can damage the RBC membrane -This damage can be severe enough for the cell to hemolyze in circulation (Intravascular hemolysis)
What is Hgb electrophoresis? process
Method of identifying hemoglobins based of differences in their electrical charges •Hemoglobin carries an electrical charge •The type (net positive, net negative) and strength of charge depend upon both the amino acid sequence hemoglobin molecule and the pH of the surrounding medium -This process involves subjecting hemoglobin components from dissolved red blood cells to an electric field -The components then move away from each other at different rates, and when separated form a series of distinctly pigmented bands -The bands are then compared with those of a normal sample -Each band can be further assessed as a percentage of the total hemoglobin, thus indicating the severity of any abnormality
Laboratory Diagnosis of anemia of chronic disease
Mild anemia -Hgb usually 9-11 g/dL Blood Picture -Normochromic, normocytic---Can be hypochromic, microcytic in long-standing cases(about 1/3 of patients) -RDW is usually normal -Retics - normal or decreased
Gene Mutations for hemoglobinopathies
Mutations alter the structure of a particular globin chain -More than 900 abnormal hemoglobins have been discovered -These abnormalities commonly affect adult hemoglobin (beta chain of hemoglobin A) -Most mutations in hemoglobin produce no problem
what is the most common form of megaloblastic anemia?
Pernicious Anemia (PA)
what is the principle of the schilling test
Principle - that once absorbed, a portion of any oral dose of vit.B12 that is not used by the body ultimately will be excreted in the urine -If the vitamin is not detected in the urine, malabsorption is confirmed •2 phases to the test
BM will display iron deficiency
Prussian blue can be used to stain bm for hemosiderin -Hemosiderin is a storage form of iron -Less physiologically accessible than ferritin -Ferritin and hemosiderin are found in liver, bone marrow and spleen Reveal an absence of hemosiderin
Acquired Hemolytic Anemias: Non-Immune Hemolytic Anemias (Diseases Intracellular organisms Chemicals, venoms and drugs Burns) basic introduction
RBCs that have normal hemoglobin structure, enzymes and membranes can be prematurely destroyed by factors extrinsic to the cell -Destruction an be immune mediated via antibodies and/or complement -Nonimmune factors can also cause either extravascular or intravascular hemolysis
Other hemoglobinopathies
Rare hemoglobinopathies -Hemoglobin C-Harlem -Hemoglobin D -Hemoglobin G -Hemoglobin O-Arab
CAIHA- hemolysis
Results from the binding and activation of complement by IgM •IgM binds complement in vivo while the individual is in a cold environment •After warming the antibody dissociates from the cell but the complement remains either causing direct cell lysis (intravascular) or initiating extravascular hemolysis
inheritance of hemoglobin c disease
Same as seen in SCA
Clinical Symptoms beta thalassemia
Severity depend upon category -Chronic anemia -Splenomegaly -Bone malformations - due to chronic anemia the bm expands to try to compensate causing deformities of the bone
Screening Test for sickle cell anemia
Solubility screening test for HgbS -SickleDex or SickleChex 1. Cells are lysed by saponin 2. Released hgb is deoxygenated by sodium dithionite 3. Hgb A forms clear red solution but Hgb S polymerizes to form cloudy solution
Membrane Defect in HS: spherocytes
Spherocytes are cleared by the spleen more rapidly -Lack of deformability and reduced cellular flexibility means they cannot squeeze through the sieve-like slits of the spleen -Therefore they are trapped in the harsh environment of the splenic cords -In this stressful environment the spherocytes quickly run out of ATP - macrophages destroy these metabolically stressed cells (spherocytes are a target for macrophages)
what is the treatment for HS
Splenectomy After splenectomy will see •Spherocytes (functional) •Post splenectomy inclusions-Howell-jolly bodies, target cells, siderocytes
Special tests: PNH Sugar water test
Sugar water test (sucrose hemolysis test) •Screening test •Patient's blood is incubated with sucrose solution - sucrose provides medium that promotes the binding of complement to RBCs - PNH cells show hemolysis in this medium
treatment for megaloblastic anemias
Supplement missing vitamin 1. B12 shots/oral-- Vitamin B12 can be administered intramuscularly to bypass the need for IF in patients with PA 2. Oral folate 3. Iron supplement usually given to support rapid cell production
Trait versus Disease
TRAIT: •If an individual is homozygous for the gene coding for a structural β-globin mutant, meaning no Hgb A is produced, and the term disease or anemia is used •If one of the genes coding for the β-chain is normal and the other β-gene codes for a structural variant, then both Hgb A and the abnormal hemoglobin are produced, and the word trait is used to describe the heterozygous disorder DISEASE: •For example: An individual with one gene for sickle hemoglobin (HbS) and the other gene for sickle hemoglobin (HbS) will have sickle cell disease •Disease has symptoms •Referred to as homozygous form (Hgb SS)
What Is a Hemolytic Anemia?
Term hemolytic anemia refers to conditions in which there is increased destruction of RBCs causing the BM to respond by accelerating production -Erythropoiesis is normal, the lifespan of RBCs is greatly decreased -Hemolytic anemia occurs when RBC survival is so short that anemia develops despite a vigorous erythropoietic response
what happens to irreversible sickled rbcs
These irreversibly sickled RBCs are removed by phagocytes in the spleen or livers -Hemolytic anemia -Extravascular hemolysis
Treatment for beta thalassemia major (main)
Transfusion dependent at early age -Regular transfusion program to keep hemoglobin 7-10 g/dL However, regular blood transfusions creates excessive iron load and burden •Can lead to organ toxicity = death •No physiologic way to excrete large amounts of iron •Chelating drug (desferrioxamine) to reduce the iron accumulation
etiology of hereditary aplastic anemia
Two inherited diseases associated with aplastic anemia: 1. Fanconi's Anemia 2. Dyskeratosis Congenita -Extremely rare -Skin Pigmentation -Nail Degeneration
G6PD deficiency in normal conditions:
Under normal circumstances, G6PD deficiency usually does not cause problems for most until exposed to one of these: 1. Infections 2. Oxidant drugs (antimalarials-chloroquine) 3. Fava beans (grown in Mediterranean area) (favism) •All of the above increase the amount of oxidative stress on the body's red blood cells ===leading to hemolytic attack
WAIHA: Hemolysis
Usually extravascular hemolysis •IgG attaches to erythrocyte membrane antigens •After binding the splenic macrophages pits the antigen-antibody complex, fragmenting the cell membrane •Eventually the cell looses enough membrane to become a spherocyte and phagocytized by splenic macrophages
laboratory diagnosis: what is the confirmatory test to identify the megaloblastic appearance of cells? what should you be looking at in the bm?
bone marrow: 1. Immature RBCs -Nuclear-cytoplasm asynchrony in which the cytoplasm appears to be progressing as normal (increasing pinkness as hemoglobin accumulates) but the nucleus appears younger than expected for the degree of maturity of the cytoplasm 2. WBCs also affected -Appear larger - giant metamyelocytes
what is serum ferritin useful for
distinguishing from IDA
epidemiology
distribution in populations
Inheritance of beta thalassemia
each child has: -25 percent chance of inheriting two normal genes (no anemia) -50 percent chance of inheriting one altered gene and one normal gene (beta thalassemia trait) -or a 25 percent chance of inheriting two altered genes (beta thalassemia intermedia or major)
HDN is the disease of characterized by
fetus and newborn •Hemolytic anemia -Greatest risk to infant in the first 24 hours •Unconjugated bilirubinemia -Greatest risk after 24 hours •Extramedullary hematopoiesis
stage 3
full-blown anemia 1. Since depleted iron stores and diminished iron transport, developing RBCs are unable to develop normally (if at all) 2. Patients just starting to develop generic anemic symptoms 3. H&H are low --Microcytic, hypochromic 4. Ferritin extremely low 5. Serum iron low 6. TIBC of transferrin is high 7. % saturation is low
types of hemolytic anemias
hereditary vs acquired
hemoglobinopathies are
inherited disorders •If a mutation produces an abnormal hemoglobin gene in a person, the gene will be passed on to his or her children. •In hemoglobinopathies the distinction is made between the disease state and the trait or carrier state
Another sign that the kidney has filtered a significant amount of hemoglobin
is the presence of hemosiderin in the urine (hemosiderinuria) -Hb is reabsorbed into renal tubular cells where Fe is converted to hemosiderin
drugs that cause Drug-Induced Hemolytic Anemia
more than 100 drugs -Antimicrobials -Nonsteroidal anti-inflammatory drugs -Antineoplastic drugs -Diuretics -Antidiabetic
what are heinz bodies
precipitates of denatured hemoglobin
what is the hallmark sign of ACD? what causes this?
sideropenia -Increased hepcidin -decreased epo •Hepcidin is produced in response to inflammatory cytokines •Produced by hepatocytes to regulate body iron levels, particularly the absorption of iron in the intestine and release of iron from macrophages •Hepicidin blocks iron uptake in the duodenum and release from macrophages (in spleen) for recycling purposes -Thereby decreasing delivery of iron to RBC precursors.
Etiology
the cause of the disease
most frequent cause of sickle cell anemia hospitalization cause
vaso-occulusive crisis Crises can by triggered by: -Infection, dehydration, but frequently occur without any known cause •Occlusions accompanied by pain, low-grade fever, organ dysfunction and tissue necrosis •Episodes generally last 4-5 days and subside spontaneously •Recurrent episodes can lead chronic organ damage
What is a Hemoglobinopathy?
•Clinical diseases that result from a genetically determined abnormality of the structure or synthesis of the hemoglobin molecule •The abnormality is associated with the globin chains; the heme portion of the molecule is normal
how is absorption of vit b12 impaired
• Failure to separate vit.B12 from haptocorrin (transport protein needed to transport vit.B12 to small intestine) • Lack of IF - required to bind to IF in order to be absorbed by the cells in the small intestine) - due to IF gastic cells lost due to gastrectomy - ***common •Malabsorption caused by conditions such as inflammatory bowel disease •Competition for available vitamin B12 - fish tapeworm Diphyllobothrium latum is able to use vitB12 thus rendering the vitamin unavailable for absorption
Intravascular hemolysis
• the destruction of defective RBCs as they circulate -In intravascular hemolysis, RBCs lyse in circulation releasing hemoglobin into the plasma. -The fragmented RBCs are called schistocytes
The globin abnormality can either be
•1. a qualitative defect in the globin chain (structural abnormality) •Incorrectly functioning globin -Resulting in a hemoglobinopathy 2. Or the abnormality can be due to a quantitative defect in globin synthesis •Too few globins synthesized Resulting in thalassemia
hemoglobinopathies: Hemoglobin E Disease prevalence
•2nd most prevalent hemoglobinopathy worldwide •Prevalent in Southeast Asia-Occurs infrequently in African Americans and Caucasians
Globin chains? genes
•6 different globin chains produced in normal individuals during development and into adulthood 1.alpha α 2.beta β 3.delta δ 4.gamma γ 5.zeta ζ epsilon ε •They combine to form the different forms of hemoglobin •Controlled by genes on chromosomes 11 and 16
Hemoglobinopathies: Sickle cell anemia aka commonality
•AKA Hemoglobin SS, sickle cell disease (SCD), SCA •Worldwide, the most common symptomatic hemoglobinopathy
Alpha Thalassemia Major
•AKA Hydrops fetalis •Deletion of all 4 α -genes -No alpha globin chains are being produced
anemia of chronic disease (ACD) aka
•AKA chronic inflammation, chronic infection •Common anemia amongst hospital patients
Cold Autoimmune Hemolytic Anemia
•AKA cold agglutinin disease •Comprises 16-30% of AIHA's •Chronic hemolytic anemia •Patients are usually 50 or older
PNH: abnormal stem cell clone produces...
•Abnormal stem cell clone produces RBCs, platelets and neutrophils that bind abnormally large amounts of complement and that are abnormally sensitive to complement lysis •This can potentially result in thrombosis, end organ damage, and increased mortality
•Five major classes of immunoglobulin (antibodies) -Gamma (IgG), alpha (IgA), mu (IgM), epsilon (IgE), or delta (IgD) what makes up Igs?
•All immunoglobin molecules are made up of a basic four-chain polypeptide unit that consists of two heavy chains and two light chains
how to prevent complications with sickle cell anemia
•All newborn babies should be placed on daily penicillin to prevent serious infections •All of the childhood immunizations should be given plus the pneumococcal vaccine •Taking the vitamin folic acid daily to help make new RBCs •Daily penicillin until age six to prevent serious infection •Drinking plenty of water daily •Avoiding too hot or too cold temperatures •Avoiding over exertion and stress •Getting plenty of rest •Getting regular check-ups
Clinical Findings in HS
•Anemia •Jaundice (because of hemolysis) •Splenomegaly (see spleen issue because of hemolysis)
Symptoms of thalassemia
•Anemia •Splenomegaly •Hepatomegaly •Infections •Bone deformities-Bone marrow expansion
Hemolytic Transfusion Reactions: antibodies... types:
•Antibodies produced in transfusion reactions cause immunologic destruction of donor cells but do not react with the RBCs of the person making the antibody -Two types of transfusion reactions 1. Immediate 2. Delayed
PCH antibody reacts when
•Antibody that will react and induce hemolysis at lower temperatures 15°C or below •Characterized by massive acute hemolysis and hemoglobinuria -Massive hemolysis occurs after exposure to cold
Acquired Hemolytic Anemias: Immune Hemolytic Anemias(IHA)
•Antibody-coated RBCs are removed extravascularly by macrophages and in severe cases through intravascular complement lysis
Hemoglobin E Trait
•Asymptomatic •Hematologic parameters are normal -Slight microcytosis Hemoglobin electrophoresis -35-45% Hgb E -Remainder is Hgb A, with normal A2 and F
Hemoglobin C Trait: hematologic abnormalities %s
•Asymptomatic •No hematologic abnormalities -Except target cells •About 60-70% of the hemoglobin is Hgb A and 30-40% is Hgb C
hereditary etiology: fanconi's anemia (FA)
•Autosomal recessive disorder •1 in 350,000 North America •Congenital abnormalities (bone & organ malformations, mental retardation) •Aplastic anemia occurs in 90% of fanconi's anemia patients
inheritance of alpha thalassemia slide 138 (etiology)
•Based on the previous slide, each child has a 25 percent chance of inheriting: - two missing genes and two normal genes (thalassemia trait), -three missing genes and one normal gene (hemoglobin H disease), -four normal genes (no anemia), -or one missing gene and three normal genes (silent carrier).
Thalassemias and Malaria
•Believed that thalassemias might enhance resistance to malaria (plasmodium falciparum) •Small advantage Theory -Malarial parasites cannot acquire sufficient nutrients from the digestion of hemoglobin in thalassemic cells
Venom
•Brown recluse spider injects a venom that leads to severe hemolytic anemia with local pain, necrosis and ulceration at the site of the bite •Venom contains enzymes that act directly on the RBC membrane and produce lysis •Venom from certain snakes (pit viper and copra) can produce the same effects
Laboratory Diagnosis: sickle cell anemia
•CBC/Retic count •Screening test-Solubility test •Confirmatory test-Hemoglobin electrophoresis •Normochromic, normocytic anemia •Reticulocytosis -10-20% is typical •NRBCs •Poikilocytosis in crisis -Drepanocytes, target cells, schistocytes, ovalocytes
beta thalassemia major Clinical findings
•Detected in early childhood as the gamma to beta switch takes place Observed in infants -Irritability -Pallor -Failure to thrive -Diarrhea Fever
pathogenesis of iron deficiency anemia
•Develops slowly over time as the various iron compartments become depleted -3 Stages of iron depletion
Pathophysiology: Alpha Thalassemia Major
•Disorder incompatible with life •Hemoglobin produced cannot supply tissue with sufficient oxygen to sustain life •Infant, if born, dies of hypoxia and congestive heart failure •Fetus is stillborn or dies shortly after birth
Pathophysiology: Hemoglobin H Disease
•Dramatic decrease in α-chain synthesis results in decrease in the assembly of Hgb A, Hgb A2, and Hgb F •Hemoglobin H is formed -Unstable and tends to precipitate inside RBCs -Chronic hemolytic anemia
Beta Thalassemia Major: pathophysiology
•Dramatic reduction or absence of Hemoglobin A •Non- β-containing hemoglobins, hgb A2 and F, are increased in partial compensation for decreased hgb A •Free excess α chains precipitate within the cell, damaging the membrane, leading to chronic hemolysis
Drug adsorption
•Drug binds to proteins on RBC membrane •Antibodies are produced against the drug •Hemolysis is extravascular and mediated by splenic macrophages
Membrane Defect in HS-- cause
•Due to deficiency of cell membrane protein= spectrin and/or ankyrin protein deficiency Results in loss of membrane (this is how it becomes a spherocyte) -Shedding of lipid bi-layer--RBCs progressively lose unsupported lipid membrane because of local disconnection of the skeleton and bilayer -Results in decreased surface to volume ratio -Changing the morphology from discoid to spherocyte see slide 40 [loss of membrane=loss of surface area=loss of deformability]
what causes extravascular hemolysis is extra or intra vascular more common what happens to everything
•Due to increased RBC destruction •More common than intravascular (90% occurs as extravascular) -Globin is returned to amino acid pool -Iron is separated and stored -Protoporphyrin (heme ring) is broken down into bilirubin •Indirect or unconjugated bilirubin (1) is secreted into plasma where it circulates bound to albumin until it reaches liver (2) •Liver conjugates it with 2 glucose molecules making it conjugated or direct bilirubin (3) then it is secreted as bile and is dumped into GI tract (4) •In GI tract bacteria converts bilirubin to urobilinogen (5), majority excreted in stool (6), some is excreted as urine urobilinogen (7)
EPO other use...don't need to know for exam
•EPO has been extensively used as an, a doping drug, in some sports, particularly cycling and long-distance running, •Because higher amounts of red blood cells can increase the oxygen carrying capacity of the blood and improve endurance
Pathogenesis of PK Deficiency
•Erythrocyte's inability to maintain normal ATP levels results in alterations of the RBC membrane •Leads to deformability or rigid cells that are removed in the spleen and liver (cells moving slow, allows macrophages to catch up and eat them)
clinical findings of sickle cell anemia
•First signs appear at 6 months of age when the concentration of Hgb S predominates over Hgb F -Result from hemolytic anemia -Infection -Jaundice
sickle cell anemia: Epidemiology
•Found most commonly in persons of African ancestry -Tropical Africa, Mediterranean areas, Middle East, India, Nepal
What is G6PD used to do? what happens if they build up?
•G6PD is necessary to reduce cellular oxidants •If oxidants build up they are harmful to the cell •Leads to erythrocyte injury and hemolysis-> leads to anemia
Hemoglobin Mutation in hemoglobin c disease
•Globin variant with lysine replacing glutamic acid at the 6th position of the beta chain Results in decreased solubility for deoxygenated hemoglobin results in -Formation of intracellular hexagonal crystals (Hemoglobin C crystals) -Hemoglobin F inhibits the formation of crystals
Embryonic hemoglobins:
•Hb Gower 1 is 2 zeta and 2 epsilon •Hb Gower 2 is 2 alpha and 2 epsilon •Portland is 2 zeta and 2 gamma
Complications associated with SCA
•Heart problems (murmurs) •Strokes-A stroke can occur if sickle cells block blood flow to an area of your brain •Gallstones •Kidney failure •Retinopathy (affects retina of the eye)-Tiny blood vessels that supply your eyes can get blocked by sickle cells
Thalassemia versus Hemoglobinopathy
•Hemoglobinopathies result from point mutation in the globin gene, resulting in hemoglobin containing chains produced at normal levels but are structurally abnormal •Thalassemias result from deletional and nondeletional mutations in globin genes that reduce or eliminate synthesis of the corresponding globin chain = inadequate amounts of normal hemoglobin & reduced oxygen capacity of blood
PCH what causes hemolysis
•Hemolysis caused by complement-binding IgG antibody known as the Donath-Landsteiner antibody 1. IgG antibody reacts with RBCs in capillaries at temperatures less than 20°C 2. Upon warming, the antibody disperses from the RBC, but complement components on the RBC membrane are activated, causing cell lysis (intravascular)
what happens to red blood cells in hemolytic anemia? describe type of cells that are seen what is hemolysis
•Hemolytic anemia is a disorder in which the red blood cells are destroyed faster than the bone marrow can produce them. •Group of normocytic, normochromic anemias in which the erythrocyte is prematurely destroyed •Premature destruction is referred to as hemolysis
Non-Immune hemolysis why do they develop/examples
•Hemolytic anemias can develop from non-immune defects (mechanical hemolysis) •These non-immune defects are diverse: pregnancy, certain diseases, organ transplants, toxins, drugs, organisms, thermal injury -For example •Diseases: HUS, TTP, DIC (intravascular hemolysis) •Malaria (extravascular hemolysis) •Venoms (intravascular hemolysis) •Burns (intravascular hemolysis)
Hereditary Spherocytosis (HS) etiology
•Hereditary hemolytic anemia due to RBC membrane defect •Etiology - inherited -Among whites, it is the most commonly inherited anemia
Hereditary Elliptocytosis (HE) caused by/etiology
•Hereditary hemolytic anemia due to RBC membrane defect •Worldwide, the incidence is 1 case per 2000-4000 individuals-Although true incidence unknown because many patients are asymptomatic •Etiology-Inherited
children and lead poisoning: health problems
•Hyperactivity •Low IQ •Concentration disorders •Hearing loss •Impaired growth and development kids eat paint chips
schilling test- phase 1 interpretation
•If IF is present in the patient's stomach and absorption is normal , the labeled vitB12 will be absorbed and vit.B12 will be detected in the urine (due to flushing dose this is now excess to be excreted in the urine) = you can conclude IF must be present if absorption is normal (stop at phase 1) •If absorption is impaired the labeled vit.B12 will pass directly through the small intestine and is excreted in stool therefore vit.B12 will not be present in urine (go to phase 2)
how is sickle cell anemia inherited
•If both parents have sickle cell trait: -25% chance normal hemoglobin (AA) -50% chance child that has sickle cell trait (AS) -25 % chance child with sickle cell disease (SS) •Inherited as an autosomal recessive condition
treatment of aplastic anemia
•If causative agent is suspected it should be discontinued (radiation, chemo...) •Transfusions of RBCs, platelets and leukocytes- Why? because of pancytopenia •Bone marrow transplant •Stem cell transplants--Using cells collected from bone marrow
schilling test phase 2- interpretation
•If vit.B12 is present in the urine, the diagnosis of PA (deficiency of IF) is confirmed because the addition of IF corrected the malabsorption •If vit.B12 is not present in the urine, the vit.B12 was not absorbed due to other causes (not IF deficiency)
pathogenesis of sideroblastic anemias
•Impairs heme synthesis (interferes with one of the stages required in making heme) -once ingested lead passes through the blood to the bone marrow, where it accumulates in the mitochondria of erythroblasts and inhibits cellular enzymes involved in heme synthesis -Mutations that affect the formation of ALA result in lead poisoning •Mutations in subsequent steps result in metabolic disorders called porphyrias
Hemoglobin Electrophoresis
•Important to understand that different amino acid substitutions may cause identical changes in net charge of the molecule •Thus two different mutant hemoglobins may have identical electrophoretic mobility •By varying the medium and pH of the procedure you may identify the significant hemoglobin -Cellulose acetate pH 8.4 -Citrate agar pH 6.0-6.2
Pathogenesis of Hereditary spherocytosis
•In HS a large portion of RBCs are spherocytes •Spleen sequesters and destroys spherocytes ->ANEMIA
Prognosis: sickle cell anemia
•In the past, sickle-cell patients often died from organ failure between ages 20 and 40 •Today patients can live into their 50s or beyond. •Causes of death include organ failure and infection
treatment (iron deficiency anemia)
•Iron supplements -Oral, taken on empty stomach to maximize absorption (Ferrous sulfate - type of iron) •Eliminate source of loss if GI bleed, renal stones, etc...
what is PNH?
•It is an acquired membrane abnormality that causes increased susceptibility of blood cell to complement -Intravascular hemolytic anemia= Results from an RBC membrane defect that increases its susceptibility to complement •Stem cell mutation
Simple Hemoglobin Electrophoresis
•Lanes 1 and 5 are hemoglobin standards •Lane 2 is a normal adult (Hgb A) •Lane 3 is a normal neonate (Hgb A & F) •Lane 4 is a homozygous HbS individual (Hgb S) •Lanes 6 and 8 are heterozygous sickle individuals (Hgb A & S) Lane 7 is a SC disease individual (Hgb S &
Alpha Thalassemia Minor
•Measurable decrease in production of α-containing hemoglobin occurs, the unaffected globin genes are able to compensate
Laboratory Findings: Hemoglobin H Disease
•Microcytic, hypochromic anemia -Hgb 8-10g/dL •Reticulocytosis-5-10% •Poikilocytosis - target cells, bizarre shapes •Nucleated RBCs
Laboratory Findings: Alpha Thalassemia Minor hemoglobin electrophoresis
•Microcytic, hypochromic anemia -MCV 60-70fL •Few target cells •Hemoglobin electrophoresis (adult) -Normal
Laboratory Findings: beta thalassemia minor
•Mild hemolytic anemia-Hgb around 10-13g/dL •Hypochromic, microcytic •Slight poikilocytosis-Target cells, elliptocytes, basophilic stippling
Laboratory Findings: hemoglobin E disease
•Mild microcytic, hypochromic anemia-Has thalassemia-like characteristics •Target cells •Electrophoresis definitive -HbE 90% or more -Remainder is Hgb A2 and Hgb F
beta thalassemia intermedia lab findings
•Moderate microcytic hypochromic anemia •Hemoglobin ranging from 7-10 g/dL •Poikilocytosis-Target cells are predominant •Basophilic stippling and NRBCs are present
geographic distribution of beta thalassemia
•More common in populations from Mediterranean regions -Also occurs in Middle East and Southeast Asia
Pyruvate Kinase Deficiency severity
•More severe than HS
Warm Autoimmune Hemolytic Anemia (WAIHA)
•Most common -About 70% of immune hemolytic cases •Most common-About 70% of immune hemolytic cases
Hemoglobinopathies: Hemoglobin SC Disease- inheritance pattern
•Most common double heterozygous syndrome -Two different amino acid substitutions are found on each β-globin chains -No normal beta chains, therefore no hgb A
Pyruvate Kinase (PK) Deficiency common in/ what type
•Most common in individual of Northern European ancestry •Hereditary hemolytic anemia due to enzyme defect
Vaso-occlusive Crisis
•Sickle cell crisis or vaso-occlusive crisis -Sickled cells have difficulty squeezing through small capillaries - they tend to aggregate in microvasculature •If blockage is severe it can lead to lack of oxygen and cause local tissue necrosis
what causes beta thalassemias
•Most defects are due to point mutations in regions of the DNA that control β-gene expression -Can affect gene expression ranging from minor reductions in β-globin production to complete absence of synthesis •If you have one altered gene, you're a carrier-Condition is called beta thalassemia minor or beta thalassemia trait •If both genes are altered, you will have beta thalassemia intermedia or beta thalassemia major
Electrophoresis--Hgb S and Hgb C both apparent on electrophoresis %
•Nearly equal amounts of HbS and HbC (about 45%) •HbF is <7% •No HbA is found due to absence of normal beta chains
Normal Destruction of RBCs what happens to hemoglobin
•Normal destruction (catabolism) of aged RBCs (not increased destruction): -Hemoglobin is degraded into the following: •Globin is returned to amino acid pool •Iron is separated and stored •Protoporphyrin (heme ring) is broken down into bilirubin
Pathophysiology of thalessemia
•Normally, equal amounts of α- and β-chains are synthesized by the maturing RBC In thalassemia, synthesis of one of these chains is decreased or absent -Resulting in an excess of the other chain -If the α-chain is affected, there is an excess of β-chains -If the β-chain is affected, there is an excess of α-chains
Laboratory Diagnosis of HE
•Normochromic, normocytic •No anemia, no hemolysis- In 90% of patients •Elliptocytes= typically more than 25%
laboratory findings of hemoglobin c disease
•Normochromic, normocytic anemia •Target cells •Hgb C crystals •Reticulocytosis
Laboratory Findings: hemoglobin sc disease
•Normocytic, normochromic anemia •Reticulocytosis •Target cells •Few sickle cells •Hemoglobin SC crystals •Solubility test positive •Electrophoresis: Hgb S and Hgb C both apparent on electrophoresis
Iron Deficiency Anemia when do symptoms appear? when do abnormal CBC results appear
•Numerous individuals may be iron deficient while appearing normal •Symptoms do not appear until stage 3 •Abnormal CBC results do not appear until stage 3
Beta Thalassemia Minor clinical findings
•One normal β-gene and one abnormal β-gene -Normal gene directs synthesis of sufficient amounts of β-chains to synthesize enough Hgb A Clinical Findings Asymptomatic
Beta Thalassemias
•Only two β-globin genes, one located on each chromosome 11 •Beta thalassemia is the result of several different types of molecular defects -More than 180 mutations result in partial to complete absence of β-gene expression -But only 20 mutations account for 80% of the diagnosed β-thalassemias
Diagnosis of Thalassemia (things to consider)
•Patient's family history •Race/ethnic background •General anemia symptoms
Clinical Findings: Alpha Thalassemia Minor
•Patients are asymptomatic with a mild anemia
Burn Victims
•Patients with 3rd degree burns may have severe acute hemolytic anemia •Direct thermal damage to RBCs circulating in the involved skin/tissue leads to hemolysis-Direct effect of heat on spectrin - causes loss of elasticity and deformability •Thermal injury damages RBCs leading to many morphological changes including schistocytes, spherocytes and acanthocytes
alpha thalassemia Affected Individuals
•People of Mediterranean, Asian and African ancestry
schilling test-- phase 1
•Phase 1 - Answers the question "Is there malabsorption of vit.B12?" 1. Patient given oral dose of radio-labeled vitamin B12 2. Several hours later a IM injection of non-labeled vit.B12 is given "flushing dose" - gives the body excess of vit.B12 (to saturate the body wuith B12) •This is given to saturate the liver with vit.B12 so that the labeled vit.B12 is now free to be excreted in the urine now urine sample is collected
schilling test- phase 2
•Phase 2 - is the malabsorption due to IF deficiency? -Oral dose of radio-labeled vit.B12 with IF -Flushing dose given -Test urine for vit.B12
Delayed transfusion reaction: laboratory findings
•Positive DAT
hemoglobin c disease and anemia
•RBCs with crystals become rigid and are trapped and destroyed in the spleen-Hemolytic anemia - extravascular hemolysis •Mild to moderate hemolytic anemia
Paroxysmal Cold Hemoglobinuria
•Rare acute form of cold generated hemolysis •Can occur at any age - but common in children= Cause of 30-40% of all AIHA in children •Often associated with viral infection= Epstein-Barr virus, cytomegalovirus, measles, mumps
etiology of aplastic anemia
•Rare but potentially fatal bone marrow failure syndrome •May be acquired or inherited
Acquired Hemolytic Anemias Membrane Defect: Paroxysmal Nocturnal Hemoglobinuria
•Rare-Affects approximately 8,000 to 10,000 people in North America and Western Europe •Hemolytic anemia •Acquired
how common is drug-induced hemolytic anemia
•Relatively uncommon acquired condition that is precipitated by certain drugs -Drug itself does not cause RBC injury -And not all individuals taking the drug develop immune hemolytic anemia
beta thalassemia major: Laboratory Diagnosis
•Severe hemolytic anemia •Hgb around 2-4g/dL •Extremely Hypochromic, microcytic-MCV <67fL •Marked poikilocytosis-Target cells, tear drop, elliptocytes, schistocytes basophilic stippling, NRBCs
PCH: what happens when patient is exposed to cold
•Short time after exposed to cold, patient develops pain in the back and legs, abdominal cramps, headahces, chills and fever •Hemoglobinemia and hemoglobinuria appear as symptoms develop
Sickle Cell Anemia and Malaria
•Sickle cell anemia appears to offer some protection to plamodium falciparum Theory -Malarial parasites live within RBC -Parasite utilizes the oxygen within the RBC -Reduced oxygen tension causes the RBC to sickle -These sickled cells are phagocytized in the spleen •Destruction of these RBCs decreases the number of malarial organisms and increases the time for immunity to develop
can sickled rbcs return to normal discoid shape
•Sickled RBCs can return to normal discoid shape upon reoxygenation, however with repeated cycling of sickling the RBC membrane becomes leaky and rigid -Becoming irreversible sickled -Regardless of whether oxygenated or deoxygenated
Exchange Transfusion
•Slowly the infant's blood is withdrawn, and the fresh, pre-warmed blood or plasma is injected •Lowers bilirubin Treats anemia
Hemoglobin H Disease
•Symptomatic but nonfatal type •Occurs when 3 of the 4 α-chains are deleted
Clinical Features: hemoglobin sc disease
•Symptoms do not occur until teenage years Patients will have: 1.Formation of aggregates of intracellular HgbSC crystals -Leads to anemia 2.And they are prone to sickling -May have some vaso-occlusive complications -Leads to anemia 3. Mild hemolytic anemia -Severity between SA and SS 4. Splenomegaly
Beta Thalassemia Intermedia clinical findings
•Term used to describe patients who are able to maintain a hgb of 7g/dL or greater without transfusion Clinical findings -Severity between severe major and mild minor
Treatment for hemoglobin sc disease prognosis
•Therapy similar to SCA •Prognosis-Live longer than patients with SCA
hemoglobinopathies: hemoglobin c disease prevalence/populations/homozygous vs heterozygous
•Third most prevalent hemoglobin variant worldwide •Seen in the same populations as HgbS -Found predominantly in West African blacks in whom the incidence of the trait can reach 17-28% of the population •Homozygous state is symptomatic (HgbCC) •Heterozygous state (HbAC) is asymptomatic
see slide 31***
•Top picture - normal RBC- discoid shape to RBCs (oxygenated and deoxygenated) •Bottom picture - the blue cell indicates a deoxygenated RBC and notice how the yellow polymers (of deoxyhemoglobin S molecules) have now formed into long rods causing the RBC to change shape
Treatment: sickle cell anemia
•Treatment is usually aimed at avoiding crises, relieving symptoms and preventing complications. -Treatments may include medications to reduce pain and prevent complications, blood transfusions and supplemental oxygen •Hydroxyurea (Droxia, Hydrea) •Bone marrow transplant
Alpha Thalassemia etiology
•Two α-genes are located on each of the two chromosome 16 structures, totaling four α-genes •Mutations can affect one or more α-genes resulting in four clinical severities •Mutations are due to large deletions in the alpha-globin gene that removes the alpha globin gene or part of it
Sickle Cell Trait symptoms? severity?
•Typically do not experience symptoms of the disease -Hgb A constitutes more than 50% of the total hemoglobin in these patients Not as severe as SCA -The presence of Hgb A interferes with the process of Hgb S polymerization, preventing sickling under most physiologic condition
Delayed transfusion reaction Symptoms
•Uncommon •If present, malaise, unexplained fever, possible hemoglobinuria
treatment for hemoglobin c diseae
•Usually not necessary
Acquired Hemolytic Anemias: Immune Hemolytic Anemias(IHA)-Drug-Induced Hemolytic Anemia
•Usually self limiting but severe, Even fatal cases •Easily treated by drug termination •Prevention- Avoidance of the drug
vitamin b12 absorption simplified
•Vit.B12 is bound to transport protein called haptocorrin •In small intestine vit.B12 is released from haptocorrin by trypsin •Vit.B12 must now bind to intrinsic factor (IF). IF is produced by gastric cells-Vit. B12 must bind to IF to be absorbed by the intestines
Acquired Hemolytic Anemias: Immune Hemolytic Anemias(IHA) introduction
•When RBCs are destroyed prematurely by an immune mediated process (antibody and/or complement), the disorder is refered to as immune hemolytic anemia -Damage to the RBCs is the result of an immunologic event occurring on the surface of the RBCs
pathogenesis of megaloblastic anemias
•When either folic acid or vitamin B12 is missing DNA synthesis will be impaired -Because vitamin B12 and folic acid are vitamins necessary as coenzymes for nucleic acid synthesis -Causing DNA to be nonfunctional and the DNA replication process to be incomplete (cell division is halted) -Affects hematopoietic cells and other dividing cells of the body and results in demyelinization of nerves = anemia due to large degree of ineffective erythropoiesis resulting from disrupted DNA synthesis
-ZPP (zinc protoporphyrin) when is zinc protoporphyrin also elevated
•When iron is not available for incorporation into heme, zinc gets incorporated instead •Concentration of ZPP increases in iron deficient erythropoiesis -ZPP increased •Correlates inversely with ferritin concentration but is more cost effective •Since it cannot transport oxygen, ZPP serves no useful purpose in the RBCs that contain it •Also elevated in lead poisoning
what happens in Intravascular Hemolysis
•When the RBC is hemolyzed free hemoglobin is released into plasma •Free hemoglobin is bound to the plasma protein haptoglobin -Normal concentration of hemoglobin in plasma is less than 5mg/dL -In severe intravascular hemolysis, synthesis of haptoglobin may not be sufficient to replace that being used so free hemoglobin accumulates in the plasma -This is known as hemoglobinemia (hemoglobin in plasma) •Haptoglobin levels are influenced by several factors so the haptoglobin level cannot be used to differentiate intravascular vs extravascular -Free hemoglobin is removed by the liver, some will go to the kidneys. Usually free hemoglobin in reabsorped in the kidney (recycled and reused) but when there is an excess (more than kidneys can handle) free hemoglobin will appear in the urine = hemoglobinuria
laboratory diagnosis and ACD-- ZPP?
•ZPP levels also increased -Due to iron-deficient erythropoiesis
Excess β-chains
•can combine to form hemoglobin H (Hgb H) -Hgb H is unstable and poor transport of oxygen
Thalassemia
•constitutes a family of congenital disorders in which mutations in one or more of the globin genes of hemoglobin cause decreased or absent synthesis of the corresponding globin chains •Almost 400 unique mutations have been described •Simply thalassemias are quantitative disorders of hemoglobin synthesis that produce reduced amounts of normal hemoglobin
Qualitatively abnormal hemoglobin molecules result from
•genetic mutations in the coding region of a globin gene -Resulting in amino acid deletions or substitutions in the globin protein chain (see next slide)
Excess α-chains
•precipitate within the cell - and binds to the cell membrane cause membrane damage and decreased RBC flexibility -They are removed by the spleen Chronic extravascular hemolysis
Extravascular hemolysis
•the rbc is destroyed outside the blood vessels (spleen, liver, bone marrow) -In extravascular hemolysis RBCs are phagocytized by macrophages in the spleen and liver - Extravascular hemolysis is characterized by spherocytes
Citrate agar gel electrophoresis (acidic - pH 6.0) useful for
•useful in separating HgbD and HgbG from HgbS -In alkaline electrophoresis HgbG and D will migrate with Hgb S but on acidic it migrates with Hgb A
