Hemolytic anemia Fazel Elahi (MD) Oncologist &Hematologist Production of Erythrocytes: Erythropoiesis Erythrocytes (RBCs) Components of Whole Blood Plasma (55% of whole blood) Buffy coat: leukocyctes and platelets (<1% of whole blood) Formed elements Erythrocytes 1 Withdraw blood 2 Centrifuge (45% of whole blood) and place in tube Erythropoietin Mechanism Start Normal blood oxygen levels Stimulus: Hypoxia due to decreased RBC count, decreased availability of O2 to blood, or increased Increases tissue demands for O2 O2-carrying ability of blood Reduces O2 levels in blood Erythropoietin Kidney (and liver to a Enhanced stimulates red smaller extent) releases erythropoiesis bone marrow erythropoietin increases RBC count Structure of Hemoglobin Hemolysis: Any condition characterized by a significantly decreased erythrocyte life span RBC destrution Hemolysis Ineffective erythropoesis hematoma Haemolysis may be predominantly extravascular (i.e. phagocytic uptake) or intravascular (i.e. in the blood stream Definition A haemolytic anaemia is an anaemia resulting from an increased rate of red cell destruction. This results in a shortening of the red cell life span Erythropoiesis in the bone marrow can expand by up to 6-fold to compensate for accelerated red cell destruction, but anaemia results when red cell destruction exceeds erythropoiesis Increased erythropoiesis leads to a reticulocytosis classification Intavascular or Extravascular Inheritance or Aquired Extrinsic or Intrinsic HEMOLYTIC ANEMIA Causes INTRACORPUSCULAR HEMOLYSIS Membrane Abnormalities Metabolic Abnormalities Hemoglobinopathies EXTRACORPUSCULAR HEMOLYSIS Nonimmune Immune Classification The haemolytic anaemias can be classified as inherited or acquired Inherited haemolytic anaemias can be subclassified into I. Haemoglobin defects II. Red cell membrane defects III. Red cell enzyme defects HEMOLYTIC ANEMIA Membrane Defects Microskeletal defects Hereditary spherocytosis Membrane permeability defects Hereditary stomatocytosis Increased sensitivity to complement Paroxysmal nocturnal hemoglobinuria Hereditary hemolyisis Hemoglobinopathy (alfa,beta thal, S,S beta ,C ,SC…..) Membran disorders ( HS ,HE, HPP, STOMATOCYTOSIS …) Enzyme defect: 1-Glycolytic pathway 2-Pentose phosphate pathway 3-Nucleotid metabolism INHERITED HAEMOLYTIC ANAEMIAS HAEMOGLOBIN DEFECTS Thalassaemia Sickle cell anaemia Other haemoglobin defects MEMBRANE DEFECTS Hereditary spherocytosis Other membrane defects ENZYME DEFECTS G6PD deficiency Other enzyme defects All Hereditary etiology of hemolysis have intrinsic defect Only nonhereditary intrinsic defect (PNH) In some of intrinsic defect hemolysis one extrinsic factor cause hemolysis or aggrevated hemolysis (G6PD) Acquired haemolytic anaemias immune or non-immune The entire classification encompasses a very large number of different haemolytic disorders ACQUIRED HAEMOLYTIC ANAEMIAS IMMUNE Auto-immune haemolytic anaemia Allo-immune haemolysis NON-IMMUNE Microangiopathic haemolytic anaemias Infections Drugs and toxins Acquired membrane disorders Mechanical and physical agents Aquired Immunohemolytic Microangiopathic Traumatic Infectious agent Chemical agent Physical agent Spur cell anemia PNH hypophosphATEMIA Vit .E deficency EXTRACORPUSCULAR HEMOLYSIS Nonimmune Mechanical Infectious Chemical Thermal Osmotic Microangiopathic Hemolytic Anemia Causes Vascular abnormalities Thrombotic thrombocytopenic purpura Renal lesions Malignant hypertension Glomerulonephritis Preeclampsia Transplant rejection Vasculitis Polyarteritis nodosa Rocky mountain spotted fever Wegener’s granulomatosis Microangiopathic Hemolytic Anemia Vascular abnormalities AV Fistula Cavernous hemangioma Intravascular coagulation predominant Abruptio placentae Disseminated intravascular coagulation Hemolysis Acute Chronic Acute on chronic Clinical finding Acute haemolysis presents with : Fatigue, Pallor, Jaundice, Fever, Chills, Low back pain, Splenomegaly and Congestive cardiac failure Haemoglobinuria results if the haemolysis is predominantly intravascular Clinical finding Chronic haemolysis : (e.g. thalassemia, sickle cell anaemia etc) Present with pallor, jaundice, splenomegaly and congestive cardiac failure; but in addition there may be gallstones, bony deformities and pathological fractures due to marrow erythroid expansion with thinning of the bone cortex Causes of Intravascular Haemolysis Infection : Malaria, clostridium perfringen sepsis G6PD deficiency Severe auto-immune haemolytic anaemia Paroxysmal nocturnal haemoglobinuria Paroxysmal cold haemoglobinuria Transfusion : ABO mismatched blood, infected blood Burns Cardiac prosthesis Intravascular haemolysis Elevated plasma haemoglobin (haemoglobinaemia) urinary haemoglobin (haemoglobinuria) serum LDH urinary haemosiderin Elevated unconjugated bilirubin and reduced haptoglobins are found in both intra- and extravascular haemolysis Chronic intravascular haemolysis Results in iron deficiency due to the loss of haemoglobin, haemosiderin and ferritin in the urine Extravascular haemolysis Red cells are destroyed by phagocytosis by macrophages in the spleen, liver and bone marrow This uptake system is often referred as the reticulo-endothelial system (R.E.S). In this situation, free haemoglobin is not liberated into the bloodstream Detecting reasons of hemolysis Duration and severity Jundice (acholuric ) Splenomegaly Cholelithiasis (black stone) Leg ulcer Skeletal abnormality Fever , shaking chills Pain ( limb, back,abdominal,headache ) Malaise ,vomiting ,hypotention Shock ,oliguria, aneuria History ( famalial , personal , drugs ) Physical exam lab test : 1- Sign of accelerated RBC destruction 2- Sign of accelerated erythropoesis Normal blood film: There is a slight degree of anisocytosis (variation in cell size). The width of central pallor is less than one- third of the diameter of the cell. Laboratory finding Peripheral blood film Increased red cell destruction e.g. jaundice, unconjugated hyperbilirubinaemia, elevated serum lactate dehydrogenase (LDH), reduced haptoglobins Increased erythropoiesis e.g. reticulocytosis, polychromasia, radiological changes of erythroid hyperplasia in chronic haemolysis The biochemical profile is characteristic of a pre- hepatic jaundice with unconjugated hyperbilirubinaemia and elevated LDH, but normal hepatocellular enzymes There are a relatively small number of causes of intravascular haemolysis Therefore, tests for intravascular haemolysis are useful because the differential diagnosis for haemolysis can be considerably simplified if it can be shown that predominantly intravascular haemolysis is taking place RBC MORPHOLOGY HAEMOLYTIC ANAEMIA Spherocytes hereditary spherocytosis, immune haemolysis, sepsis Fragmentation DIC, artificial heart valves, malignancy, TTP, HUS Agglutination immune haemolysis Target cells liver disease, thalassaemia, haemoglobin C Sickle cells S/S, S/C, S/Thal Blister cells G6PD deficiency Acanthocytes liver disease, pancreatitis, abetalipoproteinaemia Prickle cells pyruvate kinase deficiency post-splenectomy blood film ,nucleated red cells, Howell- Jolly bodies, acanthocytes, target cells, mild to moderate leukocytosis and thrombocytosis This film is from a splenectomised patient who was in chronic renal failure, and therefore also shows burr cells. Reticulocytes are larger than mature red cells and stain purplish with Romanowsky stains (e.g. May Grunwald Giemsa). Reticulocytosis leads to a rise in the MCV (mean cell volume). The reticulocyte count is a simple test that provides a rough guide to the rate of red cell production The reticulocyte count does not neccessarily reflect true erythroid activity because of premature or delayed release of reticulocytes from the marrow and variable rates of reticulocyte maturation in response to different conditions Reticulocyte count (reference range 0. 2 - 2.0%) Number of reticulocytes per litre (10-100 x 109/L) Reticulocyte count: methylene blue stain BMA Erythroid Hyperplasia (haemoglobinaemia): Reddish plasma in severe intravascular haemolysis Urinary haemosiderin May persist for several weeks after an acute haemolytic episode, and may therefore be useful in detecting a bout of recent haemolysis Urinary haemosiderin: Perl's iron stain of urine cellular debris Sign of RBC destruction Uncongugated bilirubin increased Urobilinogen “ “ “ LDH LDH2>LDH1 “ “ “ Haptoglobin deceased GHb glycosylated hemoglobin “ RBC life span (t ½ Cr ) “ Carbon menoxide increased Free haemoglobin binds with high affinity to a serum glycoprotein, haptoglobin and the complex is cleared by the reticulo-endothelial system (R.E.S.), resulting in a low or absent serum haptoglobin. Albumin combines with haem to form methaemalbumin which gives a brown colour to the plasma. Methaemalbumin can be biochemically detected by Schumm's test (LDH) is released from red cells during haemolysis and this contributes to a rise in serum LDH, which is a useful marker for intravascular haemolysis. Massive deposition of free haemoglobin in the renal tubules can cause acute oliguric renal shutdown, a medical emergency, as seen in the haemolytic transfusion reaction. Intravascular hemolysis HEMOGLOBINEMIA HEMOGLOBINURIA HEMISIDRINURIA METHEMOGLOBINEMIA METHEMALBUMINEMIA HEMOPEXIN decreased Urine hemosiderrin Spacific Lab test Antiglobulin (coomb”s ) test Osmotic fragility test Autohemolysis Heat stability test (denaturation procedure ) Heinz body formation Isopropanol precipitation test Sickling