Pathgen 5.1 Blood Disorders

Objectives 1. Interpret the morphology of blood cells and their functions. 2. Review the pathology of hemolysis 3. Debate the causes and typical findings in Hereditary Spherocytosis 4. Inventory the broad categories of hemoglobinopathies and the effect that genetic mutations have on globin...

Objectives 1. Interpret the morphology of blood cells and their functions. 2. Review the pathology of hemolysis 3. Debate the causes and typical findings in Hereditary Spherocytosis 4. Inventory the broad categories of hemoglobinopathies and the effect that genetic mutations have on globin proteins in each category. 5. Review the pathology of Glucose 6 Phosphate Dehydrogenase (G6PD) Deficiency 6. Contrast Anemias of diminished erythropoiesis, Iron Deficiency Anemia, Anemia of Chronic Disease, Megaloblastic Anemia, and Aplastic Anemia. 7. Review the characteristics of polycythemia. 8. Contrast leukopenia and leukocytosis and relate the possible causes of these conditions. 9. Differentiate leukemia and lymphoma and apply the classification and presentation of these diseases. 10. Distinguish between Hodgkin's lymphoma and Non-Hodgkin's lymphoma. 11. Analyze multiple myeloma, inventory the most common sites involved by this disease, and interpret three laboratory findings. 12. Inventory three congenital bleeding disorders and relate their pathogenesis. Three types of blood disorders Red Cells White Cells Clotting Platelets Factors Roadmap Red Cell Disease Morphology of RBC and Lab tests Including brief discussion of blood loss Hemolytic disease White Blood Cell Disease Blood Cancers Bleeding Disorders Red Cell Disease Red Cell Disease 3 ways you can have an issue 1. Loose your RBC’s  bleeding 2. Kill your RBC’s  hemolysis 3. Stop making RBC’s  decreased production Anemia Acute: shortness of breath, organ failure, shock Chronic Pallor, fatigue, presyncope  syncope Severe and congenital: growth retardation, bone deformities due to reactive marrow hyperplasia Overview of RBC Morphology: Blood- Tests (IO:1) The growth factor responsible for making new RBC’s is erythropoietin (EPO) Red cells can be measured many ways Hgb/Hematocrit both measure the Hg directly MCV – “mean corpuscular volume” Helps distinguish the size type of disease, which is really useful Reticulocyte count – measures the young cells Helps distinguish between hemolytic and agenerative anemia We can also measure iron several ways Iron level, iron binding capacity, ferritin Overview of RBC Morphology: Blood- Tests (IO:1) Bilirubin Conjugated and uncongigated bili Helpful in differentiating hemolytic anemia Folate and B12 Macrocytic anemia Hemoglobin electrophoresis Distinguishes type of hemoglobin abnormality Coombs test Anti-body mediated hemolytic anemia  Overview of RBC Morphology: Blood- Tests (IO:1) Hemoglobin is relative This is one lab you should always measure the change of “anemia is in the eye of the blood-holder” Meaning, some people run high or low, but what matters is an abrupt change When onset of anemia is slow: 02 deficit leads to increased cardiac output, respiratory rate and “red cell 2,3-diphosphoglycerate (DPG), which enhances the release of 02 from hemoglobin o the fThis adaptive change helps compensate for chronic anemia! PG b inds t o ent 2,3-D compartm al centr r, the i n te trame glob hemo nges its ha this c a t i d on an se rm confo es 02 relea a s incre Overview of RBC Morphology: Blood- Tests (IO:1) More than 20% blood loss leads to shock and is often fatal But... At first your hemoglobin will not read as low, this is because, although you’ve got less blood in your body, the concentration of Hgb in the blood is normal throughout Over the next few days, hemodilution begins and the full effect of anemia will evince itself A similar effect occurs in trauma once IV fluids are given to trauma patient Initial Hgb upon arrival will be normal  Chronic blood loss and iron Chronic blood loss gradually depletes iron stores Because you can’t make proper Hgb without iron, chronic anemia of underproduction occurs Chronic bleed will demonstrate the following Low serum iron – b/c you don’t have iron High TIBC – because the body is “trying” to grab on to more iron Low ferritin – because this is the body’s major storage protein for iron One of the best measures of iron Important implication of high ferritin: think anemia of chronic disease Hemolysis: Lab Review (IO:2) RBC’s live 120 days – in RBC destruction, the life span is shortened Remember that RBC’s are being lysed when they die This leads to the release of unconjugated bilirubin The bili wasn’t able to be conjugated through normal delivery to the liver Hemolysis  low 02  increased EPO  increased reticulocytes being made Therefore, check the reticulocyte count; it will be high in this disease Hemolysis: Classification (IO:2) May be classified as intravascular or extravascular in its cause Extravascular hemolysis This is caused by defects that destroy the RBCs with phagocytes – often this happens in the spleen The spleen requires that cells be able to change their shape in order to move through it. When they cannot, they get stuck. Called “sequestration” A process by which the spleen traps cells with diminished deformability and feeds them to macrophages Findings include Hyperbilirubinemia and jaundice Late-stage, gallstones and cholelithiasis Sometimes splenomegaly Pathway: RBC houses Hgb  Hgb breaks down inside cell releasing bili as byproduct + disease causes RBC to not be pliant  RBCs stuck in spleen  spleen houses macrophages for just such a purpose  degradation of RBCs lets unconjugated bili into bloodstream  over time, jaundice and gallstones can occur, as can splenomegaly Hemolysis: Classification Continued (IO:2) Intravascular hemolysis Direct insult to RBC that bursts it in the blood stream Turbulence from defective heart valve, complement destruction, some toxins to give a few examples Hg is released into the blood, passes into the urine Some Hg is processed into hemosiderin which builds in the kidney and then lost in urine as well Both intravascular and extravascular Increased unconjugated bilirubin Decreased haptoglobin This is a plasma protein that binds free hemoglobin and removes it from circulation; therefore, its levels will fall (it is being used up) when RBCs are being destroyed, as it is in both cases Hereditary Spherocytosis IO: 03 Hereditary Spherocytosis (IO:3) Autosomal dominant trait Leads to intrinsic defect in RBC membrane that leads to spherical, non- deformable cell  sequestration and destruction in the spleen Mutations in ankyrin or spectrin proteins, both structural cell membrane proteins This causes blebs to form at the membrane surface which are then shed Little by little, bits of cytoplasm are released until the surface to volume ratio is decreased, forming a sphere These spherical RBCs are then destroyed by macrophages in the spleen Hereditary Spherocytosis (IO:3) Clinical features are anemia, splenomegaly, and jaundice Usually anemia is moderate, though patients are prone to infection with parvovirus B19 which causes aplastic crisis Treatment is splenectomy which improves the anemia Hemoglobinopathies Sickle Cell, Alpha and Beta Thalassemia Sickle Cell Single amino acid substitution leading to valine in place of glutamate at 6th amino acid position on the beta hemoglobin This causes all HgA (Hg“Adult”) to be turned to HgS (Hg “Sickled”) in homozygotes (only ½ of the proteins are mutated in heterozygotes) Under hypoxic conditions, cells with this mutation undergo sickled structural change, which is irreversible Each sickle-forming episode leads to influx of calcium which leads to K and H20 loss and damages membrane skeleton Sickled cells hemolyze easily and become stuck in microvasculature Fetal vs Adult Hemoglobin Adult (HgA) Fetal (HgF) Combination of alpha- Combination of gamma- globin and beta-globin globin and alpha-globin By six months of age, gamma-globin is gradually replaced with beta-globin Sickle Cell Symptoms In the womb we have HgF (fetal) instead of HgA (adult). HgF persists in the blood stream until 6 months of age  onset 6 mo Splenomegaly Vasoocclusive crises in body characterized by pain! Hand-foot syndrome Infarct in bones in said regions Acute chest syndrome Sluggish blood flow to inflamed lung  hypoxia Stroke Proliferative retinopathy 2nd to vasoocclusions in the eye  vision loss and blindness Thalassemias Thalassemias Disorders associated with an imbalance in the production of alpha or beta globin Causes the formation of hemoglobin molecules with an abnormal number of alpha or beta globins These alternate hemoglobins do not bind oxygen efficiently and can be lethal Thalassemias Alpha thalassemia Reduced or absent synthesis of alpha globin Most common cause is deletion(s) of one or both alpha globin genes There are two different genes for alpha globin, and thus 4 alleles Beta thalassemia Reduced or absent synthesis of beta globin Most common cause is single-base pair substitutions that result in proteins that have either reduced activity, altered activity, or no activity at all One gene with two alleles Alpha Thalassemia Normal Hemoglobin Destruction of 1,2,3, or 4 alleles that code for alpha- globin Once three or more alpha-globin chains are lost, the cell experiences a vitally low amount of alpha-globin, so the remaining beta-globin pairs into a tetramer This leads to formation of its own tetramer beta-4 in adults, and gamma-4 in infants Infants will build up tetramers of gamma-globin until 6 months of age Both these tetramers have high affinity for oxygen, so they won’t let it go Hb H (4) disease – A moderately severe hemolytic anemia develops because of the gradual precipitation of the Hg H in the erythrocyte. This leads to the formation of inclusions in the mature red blood cell, and the removal of these inclusions by the spleen damages the cells, leading to their premature destruction. Hydrops fetalis, Hb Bart’s (4) – Infants suffer from severe intrauterine hypoxia and are born with massive generalized fluid accumulation This causes infant death Alpha Thalassemia Beta Thalassemia Can either be heterozygous or homozygous for this disease Decreased -globin production leads to in imbalance in globin synthesis and the precipitation of the excess  chains Alpha chains don’t form their own tetramers... They accumulate in the cell and form a Heinz Body (denatured Hgb seen in photo) This in turn leads to damage of the red cell membrane Finally, patients suffer from iron overload due to dietary intake which cannot be accommodated by functional RBCs Beta Thalassemia Carriers of one -thalassemia allele are clinically well and have thalassemia minor Hypochromic, microcytic red blood cells May have a slight anemia that can be misdiagnosed initially as iron deficiency Why? In regions of the world where -thalassemia is common (malaria belt) individuals may be homozygous recessive or compound heterozygotes for two different -thalassemia alleles and have thalassemia major Characterized by severe anemia and the need for lifelong medical management Beta Thalassemia Major A child with untreated - thalassemia major Prominent cheekbones and protrusion of upper jaw result from expansion of marrow cavity in bones of skull and face G6PD IO:5 G6PD Glucose-6-Phosphate Dehydrogenase Deficiency X-linked recessive mutation in G6PD gene G6PD is an enzyme that processes glucose, which results in production of NADPH NADPH protects red blood cells from the harmful effects of reactive oxygen species G6PD deficiency produces no symptoms until patients are exposed to environmental factors that increase oxidant stress (e.g., infectious agents, certain drugs and food, severe stress) Hemolytic anemia 1 in 10 Black males G6PD Drugs Chlorpropamide – anti-diabetic Dapsone – antibiotic with anti-inflammatory properties Fluoroquinolones – “floxacins” antibiotics Nitrofurantoin – antibiotic Sulfa drugs Antimalarial – “quines” Chemicals and foods Fava beans Henna Naphthalene (moth balls) G6PD 3-5 days after exposure Peripheral blood smear shows RBC with precipitates of denatured globin (Heinz bodies) with splenic macrophages that have “plucked out” these inclusions “bite cells” Anemia of Decreased Production IO:6 Anemias of Diminished Erythropoiesis Iron Deficiency Anemia Anemia of Chronic Inflammation Megaloblastic Anemia Aplastic Anemia Iron Deficiency Anemia The most common cause of anemia Inadequate intake (or loss) of iron results in insufficient hemoglobin synthesis Caused mainly by nutritional deficiency in developing countries In Western World, main cause is blood loss (e.g., ulcers, colon cancer, hemorrhoids, menorrhagia) Diagnostic criteria Hypochromic and microcytic red cells Iron levels low Transferrin saturation low Total iron-binding capacity HIGH Ferritin low Asymptomatic in most cases In severe cases: weakness, listlessness, pallor In chronic cases: spooning of the nails or pica Anemia of Chronic Disease Most common anemia in hospitalized patients: Chronic microbial infections Chronic immune disorders Neoplasms Inflammatory cytokines increases hepatic hepcidin Hepcidin blocks iron from being added to RBCs Additionally, chronic inflammation blunts EPO synthesis Iron is being stored away and not put into RBC’s Ferritin will be high Cause is unclear – perhaps to inhibit growth of iron-dependent organisms Anemia of Chronic Disease So Iron is involved, but how? Iron is actually being stored so ferritin is high Therefore, iron is not desired so TIBC is low The MCV remains normal and the cells are not hypochromic Administration of EPO can improve anemia, but treatment of underlying disease is curative Megaloblastic: Folate and B12 Building blocks of DNA: Nucleotides ACTG T = thiamine Thiamine comes from Thymidine, which is a precursor of thiamine (combined with a ribose sugar) and is then converted to thiamine Thiamine cannot ultimately be produced without folate and B12 DNA cannot be replicated when these compounds are deficient, and DNA is eventually damaged The body then experiences increased production of large, red blood cell precursor cells, called megaloblasts Megaloblastic: Folate Deficiency Due to inadequate dietary intake It’s ubiquitous, but destroyed by 10-15 minutes of cooking When levels fall, DNA cannot be replicated and is damaged  megaloblastic anemia High risk for this disease in those with poor nutrition and those with increased metabolic demand – pregnant women Clinical features Weakness and fatigue Diagnosis made with MCV, blood smear, folate level Megaloblastic: B12 Deficiency Also called “Cobalamin” Pepsin and other gastric juices release B12 from food Intrinsic factor is secreted from parietal cells in the mucosa of gastric fundus Intrinsic factor binds to B12 in the stomach and passes to the distal ilium There it is absorbed into enterocytes B12 is then transferred to liver and body cells We have enough B12 stored in the liver for 5 years! Megaloblastic: B12 Deficiency Two primary causes One is dietary – not consuming enough B12 The second is known as “pernicious anemia” This results from auto-immune attack on gastric mucosa, suppressing intrinsic factor When this is the cause, repletion with oral B12 will do no good, because it cannot be absorbed Further secondary cause: GI disorders which effect absorption, such as Chron’s disease can cause it Gastric bypass can cause it Suppression of pepcin by PPI (pepsin is only active with low pH) Megaloblastic: B12 Deficiency Clinical symptoms Fatigue, malaise Beefy red tongue (late) – megaloblastic changes in oropharyngeal epithelium Spinal cord disease – B12 anemia is accompanied by neurologic symptoms Numbness, tingling or burning in feet or hands Unsteadiness of gait and diminished proprioception Its pathology is intertwined with folate, in that it affects DNA synthesis and leads to macrocytic anemia The anemia may be improved even with the administration of folate, but the neurological symptoms will not, and may even worsen Aplastic Anemia Bone marrow failure and pancytopenia caused by suppression of multipotent myeloid stem cells Half of cases are idiopathic Remaining half caused by exposure to myelotoxic agents (e.g., toxins, radiation, hypersensitivity to drugs or viruses) Bone marrow hypocellular with fat replacement Autoreactive T cells may be the reason for marrow failure Anemia, thrombocytopenia, neutropenia Slowly progressive, weakness, pallor, dyspnea Increased RBC Production Polycythemia (IO:7) Polycythemia (erythrocytosis) is the result of an abnormal increase in red blood cell number Primary polycythemia (polycythemia vera) Clonal proliferation of myeloid stem cells Uncontrolled production of red blood cells and an increased total red blood cell mass Secondary polycythemia Increased red blood cell volume owing to erythroid bone marrow hyperplasia caused by erythropoietin Usually caused by prolonged hypoxia Living at high altitudes, anoxia secondary to chronic lung disease, congenital heart disease, renal carcinoma Polycythemia vera (IO:7) Symptoms: hypertension, dark red or flushed face, headaches, puritis, visual problems, neurologic symptoms, splenomegaly, hypercellular bone marrow Increased risk of deep vein thrombosis (DVT), heart attack, stroke, leukemia Leukocyte Disorders IO:8  Technically Benign: But often secondary to other disease Leukopenia – white cell count below normal Leukocytosis – white cell count above normal Leukocytic Malignant Disorders: Leukemia – arising from white cell precursors in bone marrow, in periphery (acute and chronic) 2 types - Lymphoid stem cells - Myeloid stem cells Lymphoma – arising from white cells in lymph nodes (Non-Hodgkin’s and Hodgkin’s) Multiple myeloma – malignant plasma cells arising in bone marrow Leukopenia Reduction in WBC count to below normal May be seen in sepsis May be due to neutropenia Chemotherapy – decrease in production Increased destruction – drugs, infection, sequestration in the spleen Leukocytosis Often due to inflammatory response Infection Slight rise may be seen in catecholamine-induced demargination which is stress-induced In extremely high numbers, suspect leukemia Leukocytosis  Acute self-limited disease caused by Epstein Barr virus Symptoms: fever, sore throat, and lymphadenitis, splenomegaly Lymphocytosis of activated CD8+ T cells can also see w/ CMV infection and can only be distinguished by serology Infectious Pathogenesis Mononucleosi Latent infected B cells are activated and proliferate Host T cell ( atypical CD8+ mononuclear) response controls the s proliferation of EBV-infected B cells (and thus the spread of the virus) Diagnosis Presence of atypical lymphocytes in peripheral blood Positive hetorophil reaction (monospot) Risnig EBV antibody titer Risks Some EBV infected B cells escape immune response, thus placing patients at high risk for B cell proliferations like lymphoma  Acute self-limited disease caused by Epstein Barr virus Symptoms: fever, sore throat, and lymphadenitis, splenomegaly Lymphocytosis of activated CD8+ T cells can also see w/ CMV infection and can only be distinguished by serology Infectious Pathogenesis Mononucleosi Latent infected B cells are activated and proliferate Host T cell ( atypical CD8+ mononuclear) response controls the s proliferation of EBV-infected B cells (and thus the spread of the virus) Diagnosis Presence of atypical lymphocytes in peripheral blood Positive hetorophil reaction (monospot) Risnig EBV antibody titer Risks Some EBV infected B cells escape immune response, thus placing patients at high risk for B cell proliferations like lymphoma Cat-Scratch Disease Self limiting lymphadenitis Caused by Bartonella hensale 90% are younger than 18 Results in regional lymphadenopathy (most common axilla and neck) Neoplastic Proliferations of White Cells Leukemias, Lymphomas, & Multiple Myelomas (IO:9, 10, 11) Leukemias Bone marrow is infiltrated with malignant cells Clonal expansion of neoplastic stem cells with genetic changes specific to each disease Failure of maturation Suppression of normal hematopoiesis Peripheral blood contains an increased number of immature blood cells Complications include anemia, recurrent infections, and uncontrollable bleeding Myeloblast vs. Lymphoblast Myeloblast Lymphoblast Precursor for myelocytes Precursor of lymphocytes Can differentiate into Can differentiate into granulocytes: lymphocytes Basophils B cells Eosinophils T cells Neutrophils  Leukemia Overview AML Acute  blast cells Myelogenous  neutrophils Leukemia  blood cancer Look for “blast crisis” Rapid proliferation of immature cells  Leukemia Overview ALL Acute  blast cells Lymphocytic  lymphocytes Leukemia  blood cancer Occurs in kids Treatable with chemo Leukemia Overview CML Chronic  mature cells Myelogenous  neutrophils Leukemia  blood cancer High amounts of WBC on CBC Philadelphia chromosome Oncotic fusion of BCR and ABL gene regions May also have “blast crisis” Leukemia Overview CLL Chronic  Mature cells Lymphocytic  lymphocytes Leukemia  blood cancer Disease of the very elderly, 80s Very high WBC count on CBC Slow growing Often not treated if over 65  Hodgkin’s Overview Contiguous spread B symptoms Fever/chills, night sweats, weight loss Nontender LAD Reed Sternberg Cells Large, abnormal lymphocytes, often with multiple nuclei Nonhogkin’s Overview Hematogenous Spread Usually no B sx Nontender LAD NO reed Sternberg cells Lymphoma Lymphoma Lymphoma Lymphoma Bleeding Disorders DIC, ITP, TTP/HUS, vWD, & Hemophilia (IO:12)  Syndrome in which systemic activation of the coagulation leads to consumption of coagulation factors and platelets Disseminated Can be dominated by Intravascular bleeding, vascular Coagulation occlusion and tissue hypoxemia, or both (DIC) Common triggers: sepsis, major trauma, certain cancers, obstetric complications  Caused by autoantibodies against platelet antigens Idiopathic Thrombocytopen ic Purpura May be triggered by drugs, (ITP) infections, or lymphomas, or may indeed be idiopathic  TTP: Caused by acquired or inherited deficiencies of ADAMTS 13, a mutation that inhibits platelet function through vW Thrombotic factor. Causes large platelet aggregation Thrombocytopeni and micro clots. This leads to over use of platelets and then c Purpura (TTP) bleeding. & Hemolytic uremic syndrome: Caused by Hemolytic Uremic deficiencies of complement regulatory Syndrome (HUS) proteins  triggered frequently by infection, in particular E Coli Initiates platelet activation platelet aggregation  thrombocytopenia Also causes and red blood cell destruction  TTP: Caused by acquired or inherited deficiencies of ADAMTS 13, a mutation that inhibits platelet function through vW Thrombotic factor. Causes large platelet aggregation Thrombocytopeni and micro clots. This leads to overuse of platelets and then c Purpura (TTP) bleeding. & Hemolytic uremic syndrome: Caused by Hemolytic Uremic deficiencies of complement regulatory Syndrome (HUS) proteins  triggered frequently by infection, in particular E Coli Initiates platelet activation platelet aggregation  thrombocytopenia Both manifest with thrombocytopenia, Also causes and red blood cell destruction microangiopathic hemolytic anemia, and renal failure; fever and CNS involvement are more typical of TTP.  Autosomal dominant disorder caused by mutations in vWF, a large protein that promotes the adhesion of platelets to subendothelial collagen. von Impairment of vWF function  decreased platelet aggregation Willebrand Disease Typically causes a mild to moderate bleeding disorder resembling that associated with thrombocytopenia.  Hemophilia A: Most common cause of hereditary bleeding. X-linked disorder caused by mutations in factor VIII. Affected males typically present with Hemophilia severe bleeding into soft tissues and joints have a prolonged PTT. Hemophilia B: X-linked disorder caused by mutations in coagulation factor IX. Clinically identical to hemophilia A. Thank you! Nussbaum, R. L., McInnes, R. R., Williard, H. F., Thompson, J. S., & Thompson, M. W. (2007). Genetics in medicine. Estados Unidos: Saunders. Robbins, S. L., Aster, J. C., Perkins, J. A., Abbas, A. K., & Kumar, V. (2018). Robbins basic pathology. Philadelphia: Elsevier. Smarter decisions. better care. (2020, December 09). Retrieved February 03, 2021, from https://www.uptodate.com/home 2021, J. (n.d.). Drugs & diseases. Retrieved February 03, 2021, from https://reference.medscape.com/ Onlinemeded