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