Introduction to Anaemia BMS326 Clinical Haematology I Murray Adams Learning Objectives • After completing this lecture, you should be able to: 1. Describe and categorise causes of anaemia 2. Describe and differentiate laboratory tests used in the diagnosis of anaemia 3. Apply correct haematological terminology in describing the pathophysiology and laboratory diagnosis of anaemia 2 3 Overview • Definition • Classification • General aspects of anaemia • Laboratory investigations (general) • This lecture will provide a foundation for the first half of BMS326 Anaemia is defined as a significant decrease in the haemoglobin concentration of blood, below the normal for the age and sex of the patient RBC usually decreased PCV usually decreased Compare laboratory result of parameters to reference intervals (Refer to BMS326 Clinical Haematology practical manual) Anaemia: Definition 4 Anaemia: Introduction • Anaemia is not a specific disease • Reflects an underlying disorder or disease • Important to diagnose exact cause of anaemia • RCC and PCV are usually decreased • Prevalence is higher in females • Low socioeconomic groups • Anaemia results from: • RBC loss/destruction > BM RBC production • Impaired BM RBC production 5 • Patient History • Physical Examination • Laboratory Testing: • FBC • Blood films: peripheral blood and BM • Specific tests: Haem & Biochem • Systems of classification: • Morphological • Aetiological (functional) Anaemia: Diagnosis 6 Morphological Classification • Based on the appearance of RBC's in blood film • “ - cytic ” = size • “ - chromic” = colour • “ poikilocytosis ” = shape • Normocytic/normochromic anaemia (MCV 80 - 100 fL ) • Macrocytic anaemia (MCV > 100 fL ) • Microcytic anaemia (MCV < 80 fL ) 7 • Morphological assessment not sufficient • Persistent anaemia may be due to one or more pathophysiological mechanisms involving: • Proliferation defects • Maturation defects • Survival defects • Abnormal blood loss (acute vs chronic) • Note : increased plasma volume i.e. haemodilution Aetiological Classification 8 • ↓proliferation, maturation & release rates of RBCs • Insufficient erythropoietin production • Bone marrow damage • Stem cell damage • Liver disease, renal disease • Normocytic/normochromic anaemia (usually) Proliferation Defects 9 Abnormal nuclear or cytoplasmic development Cytoplasmic Defects Abnormal Hb production Nuclear Defects Affect all cell lines e.g. Megaloblastic Anaemia e.g. Iron Deficiency Anaemia Maturation Defects 10 • Premature loss/destruction of RBC's • Haemolysis • Schistocytes, spherocytes • Normocytic/normochromic anaemia (usually) • For example: haemolytic anaemias Survival Defects 11 • Due to: • Haemorrhage • Accidents/injuries • Underlying disorders • Internal bleeding • External bleeding NB Causes of anaemia may be multi - factorial Acute and Chronic Blood Loss 12 • Laboratory investigation of anaemia occurs after: • Evaluation of patient history • Physical examination • Incidence higher: • Females • Age (> 65 years) • Children susceptible via diet (malnutrition) • Genetic and regional factors (Mediterranean/SE Asia) • Pregnancy (increased requirement for Fe/ Folate ) Laboratory Investigation 13 Laboratory Tests • Full Blood Count (FBC) • Peripheral Blood Examination • Bone Marrow Examination • Reticulocyte count 14 https://www.sysmex.com/us/en/Company/News/XN - SpecialEdition2012/Pages/XN.aspx • Hb , RCC, PCV • Red cell indices i.e. MCV, MCH, MCHC • RDW (red cell distribution width): • %CV of RBC volume distribution • Normal range: 11.5 - 14.5% • Reticulocyte count: • Reflects effective BM activity • Normal range: 0.2 - 2.0% Full Blood Count 15 • Morphological classification of anaemia • Review BMS218 Haematology • Examples in disease states: • Anisocytosis • Poikilocytosis • Polychromasia • RBC inclusions Peripheral Blood Examination Rodak 5 th Ed. Page 287 16 • What type of anaemia is present? • Normocytic normochromic • Microcytic normochromic • Microcytic hypochromic • Macrocytic normochromic Peripheral Blood Examination 17 18 Rodak 5 th Ed. Page 292 • Fragments • Cellularity: • Represents proliferation & maturation rates of cells • Normal bone marrow (50 % cells : 50 % adipose/fat ) • Hypercellular (> 70% cellularity e.g. leukaemia) • Hypocellular (< 30% cellularity e.g. myelodysplasia ) • M:E Ratio • Cytoplasmic and nuclear maturation • PBR stain - iron stores Bone Marrow Examination 19 • Iron Studies • Serum bilirubin • Vitamin B 12 assay • Folate assay • Direct antiglobulin test • What you will need to know: • Principles and applications of a range of laboratory tests used for the investigation and diagnosis of anaemia Other Tests 20