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Dr Olufemi-Aworinde KJ FMCPath, FWACP
Senior Lecturer/Consultant Haematologist
Department of Haematology and Blood Transfusion.
Bowen University, Iwo
Outline Introduction / definition
Classifications
Physiologic adaptation
Clinical features
Laboratory Investigations
Introduction and definition Anaemia is Greek word meaning “Lack of blood”
It is one of the most common haematological conditions worldwide, especially in developing world, both in children and adults
It is defined as a fall in haemoglobin concentration of at least 2 standard deviation below the accepted mean for sex , age and environment(high altitude).
The WHO DEFINITION OF ANAEMIA
It is based on hemoglobin at sea level in g/l
At 6months to 5 years : < 110g/L
At 5years-11 years: < 115 g/L
Non pregnant women (15 and above: <120g/L
Pregnant women: 110g/L
Men (15years and above): 130g/L
Classifications of Anaemias This will ensure a systematic and rational approach to
the evaluation of anaemia.
Guarantees a timely and accurate diagnosis hence saving time and unnecessary cost .
Classification is based on morphology, pathphysiology, severity
Morphological classification
Simple , widely accepted and is based on the red cell indices: Microcytic/(Hypochromic) anaemia: MCV ⬇ , MCH ⬇ (<80fl)
e.g. Fe-def anaemia, Thalassaemia.
Normocytic anaemia: Normal sized RBC, Normal MCV e.g. Anaemia of chronic illness, haemorrhage
Macrocytic anaemia: MCV ( >100fl)
e.g. Megaloblastic anaemias, chronic liver disease, Alcohol, AIHA, Aplastic anaemia
Dimorphic picture: Two populations of red cells – microcytes &
macrocytes as seen in combined Iron and folic acid def
Red cell indices are indices of blood that are calculated and provide information about the red blood cells.
MCV- Mean Corpuscular /Cell Volume. This is a measure of the average volume of a red blood cell
MCV= PCV/RBC X 10 (Fl) normal value –; 80-100 fl MCH –Mean Corpuscular /Cell Haemoglobin. This is the
average mass of Hb per red blood cell in a sample of blood. Normal value is 27-33 pg
MCH= Hb/RBC X 10 (pg) MCHC- Mean cell haemoglobin concentration. This is the
average concentration of Hb in a given volume of packed red cells. Normal value is 30-35 g/dl
MCHC =Hb /PCV X 100 (g/dl)
Pathophysiologic classification Takes into account the cause of the anaemia and its sub
classifications are as follows
Anaemia due to Blood loss (haemorrhage)
Anaemia due to Decreased production (ineffective erythropoiesis)
Anaemia due to Increased destruction (haemolysis)
A)Blood loss (haemorrhage)
Haemorrhage –Acute or chronic
Redistribution – e.g. splenic sequestration
B. Decreased Production (Ineffective Erythropoiesis) Deficiency of substance required for Hb and red cell
formation, iron, folic acid, Vit B12, Copper pyridoxine,
riboflavin, ascorbic acid, protein.
1) Acquired: Bone marrow failure e.g. Aplastic anaemia, infiltration with
malignant cells or drug induced Nutritional e.g. megaloblastic anaemias, Fe-def. anaemia, etc Functional e.g. anaemia of chronic illness, HIV/AIDS
2) Hereditary: Bone marrow failure e.g. Fanconi anaemia, Diamond-Blackfan
syndrome Congenital intrinsic factor deficiency Homocystinuria (Megaloblastic Anaemia) Haemoglobinopathies e.g. Thalassaemia
C) Increased destruction (haemolysis) 1) Acquired:
Mechanical e.g. parasitic infection (malaria), microangiopathy (DIC)
Antibody mediated –AIHA, Transfusion reactions Redistribution – hypersplenism RBC membrane defects – Acquired acanthosis etc Chemical injury – e.g. Scorpion and snake venoms Physical injury – e.g. Radiation
2) Hereditary: Haemoglobinopathy e.g. Sickle cell anaemia, thal RBC membrane disorders e.g. hereditary spherocytosis RBC enzyme defect e.g. G-6-PD def, Pyruvate kinase Porphyrias
CLASSIFICATION BY SEVERITY Mild: 100g/L to 109g/L
Moderate : 70g/L to 99g/L
Severe: less than 70 g/L
PHYSIOLOGIC ADAPTATION Hypoxia leads to these compensatory effects
1. Pasteur's effect
2. Bohr’s Effect
Increased 2,3 DPG
Increased cardiac output
Increased EPO production
Bohr effect- this is decreased affinity of Hb for oxygen caused by an increase of carbon dioxide
Pasteur effect- -decrease in the rate of glycolysis and suppression of lactate accumulation by tissues in the presence of oxygen.
2,3 DPG- controls the ease with which Hb releases oxygen to tissue. Increase 2,3 DPG decreases oxygen affinity and vice versa.
Clinical features Anaemia may be asymptomatic in chronic, compensated
anaemia
In most people, signs and symptoms may be mild or vague and may be due to the anaemia or the underlying cause.
Most commonly, people with anemia report non-specific symptoms such as
feeling of weakness or fatigue
general malaise
poor concentration
shortness of breath
dyspnoea on exertion.
In very severe anemia, the body may compensate for the lack of oxygen carrying capability of the blood by increasing cardiac output. The patient may have symptoms and signs such as - palpitations,
angina (if preexisting heart disease is present),
Bilateral pedal oedema, suggesting heart failure
Signs includes pallor, koilonychias (Fe-def), jaundice ( haemolytic anaemia), bone deformities (Thalassaemia), leg ulcers (SCA).
Clinical features of anaemia
Clinical features of anaemia
Laboratory investigations These tests are the most fundamental tests in the
investigation of anaemia
FBC with red cell indices
Peripheral blood smear
Reticulocyte count
They are essential initial investigations in anaemia and will direct the physicians on which path to follow
Reticulocyte count
Both absolute count and percentage - need for corrected reticulocyte count Corrected Retic count = Retic count% x Hct Normal Hct Normal range for corrected retic count in adults 0.5%-1.5% Reticulocytosis – an increase in reticulocyte count
Haemolysis SCA AIHA Acute blood loss Enzymopathy Membrane disorder
Reticulocytopaenia – a decrease in reticulocyte count Fe-def Marrow infiltration Megaloblastic anaemia Sideroblastic anaemia Congenital Dyserythropoietic Anaemia Anaemia of chronic disease
Peripheral blood smear/film Important to confirm all data from automated haematology
analyzers through microscopy.
Look at the peripheral blood smear for: Nucleated red cells
Rouleaux formation
Agglutinated RBCs
Hypersegemented neutrophils
Macrocytes with ovalocytes – Megaloblastic anaemia
Target cells – SCA, Chronic liver dx
Fragmented RBC (Schistocytes) – DIC,HUS
Spherocytes – AIHA
Heinz bodies
Malaria parasite
Approach to Differential Diagnosis of Anaemia Corrected Retic count < 2% Corrected Retic Count > 2%
Low MCV – Iron Def
Normal MCV - Anaemia of Chronic Disease
High MCV - Folate Def
- B12 Def
- MDS
Further tests- PB Smear
Iron studies, Serum Folate, B12, EPO levels, BM exam
Check for haemolytic anaemia
PB Smear
Hb Electrophoresis
Direct Antiglobulin test
Thick Film
Osmotic fragility
G6PD Assay