Lecture 1 general aspects of Anaemia.pptx

Describe the general aspect , symptoms and signs of anaemia

1. Lecture 1 Red Cell Diseases General Aspects of anaemia Haematology Dept

2. Anaemia Anaemia is defined as a reduction in the haemoglobin concentration of the blood. Reduction of haemoglobin is usually accompanied by a fall in red cell count and packed cell volume (PCV)

3. The Hb values would be less than 13.5 g/dL in adult males and less than 11.5 g/dL in adult females . From the age of 1 year to puberty, less than 11.0 g/dL indicates anaemia. As newborn infants have a high haemoglobin level, 14.0 g/dL is taken as the lower limit at birth

4. Clinical features of anaemia The major adaptations to anaemia are in the cardiovascular system (with increased stroke volume and tachycardia) and in the haemoglobin 0 2 dissociation curve. The presence or absence of clinical features depends on: 1 Speed of onset 2 Severity 3 Age 4 Haemoglobin 0 2 dissociation curve

5. Symptoms Shortness of breath particularly on exercise weakness Lethargy palpitation headaches. In older subjects, symptoms of cardiac failure, angina pectoris or confusion may be present.

6. Signs These may be divided into general and specific. General signs include pallor of mucous membranes and skin when Hb is less than9-10 g/dL A hyperdynamic circulation may be present with tachycardia In elderly, features of congestive heart failure may be present.

7. Specific signs are associated with particular types of anaemia - koilonychia 'spoon nails' with iron deficiency - jaundice with haemolytic anaemia , - leg ulcers with sickle cell, - bone deformities with thalassaemia major

8. Classification of anaemia Generally, anemias are classified either morphologically or according to pathophysiological cause. Morphological Classification The most useful classification is that based on red cell indices and divides the anaemia into - Microcytic hypochromic - Normocytic Normochromic - Macrocytic

9. A microcytic hypochromic anemia implies an MCV of less than 80 fL with reduced MCHC and MCH. In this blood picture, the red cells are microcytic and smaller and lack Hgb, having an area of central pallor much greater than third the RBC. Normocytic Normochromic implies normal RBCs indices A macrocytic anemia implies an MCV of greater than 100 fL.

10. Laboratory finding useful in anaemia - The red cell indices - Leucocyte and platelet counts - Reticulocyte count Blood film picture Bone marrow examination The red cell indices MCV, MCH and MCHC are very useful because it will indicate the type of anaemia, other RBCs parameter are also important e.g. RDW

11. Leucocyte and platelet counts Measurement of these helps to distinguish 'pure ‘ anaemia from 'pancytopenia' (decrease in red cells, White cells and platelets) which suggests a more general marrow failure (e.g. caused by marrow hypoplasia or infiltration) or general destruction of cells (e.g. hypersplenism). Also in anaemias caused by haemolysis or haemorrhage, the neutrophil and platelet count are often raised.

12. Reticulocyte count The normal percentage is 0.5-2.5%. Reticulocytes raised when Hb decreased If the reticulocyte count is not raised in an anaemic patient this suggests impaired erythropoiesis .

13. Blood film picture It is important to examine the blood film in anaemia. Abnormal red cell morphology or red cell inclusions may suggest a particular diagnosis. 'dimorphic' appearance can be discovered from blood film In case of anaemia due to leukaemia abnormal leucocytes may be visible in the film

14. During the blood film examination the white cell differential count is performed, platelet number and morphology are assessed and the presence or absence of abnormal cells (e.g. normoblasts, granulocyte precursors or blast cells) is noted

15. Bone marrow examination This may be performed by aspiration or trephine biopsy During bone marrow aspiration a needle is inserted into the marrow and a liquid sample of marrow is sucked into a syringe. This is then spread on a slide for microscopy and stained by the usual Romanowsky stains.

16. A great deal of morphological information can be obtained by examining aspirate slides. The proportion of the different cell lines assessed {myeloid: erythroid ratio}, normal is (3-4:1) The cellularity of the marrow can also be viewed The detail of the developing cells can be examined and the presence of cells foreign to the marrow (e.g. secondary carcinoma) observed. An iron stain can be performed

17. A trephine biopsy provides a solid core of bone including marrow and is examined as a histological section after fixation in formalin, decalcification and sectioning. It is less valuable than aspiration when you want to examine the cells detail but provides a general view of the marrow from which overall marrow architecture, cellularity and presence of fibrosis or abnormal infiltrates can be reliably determined.

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