hematology

Objective

To know different hematological diseases. To study the pathology of different hematological disorders.

Anaemia

Definition :defined as a hemoglobin concentration in the blood less than 130 g/l .in adult males (NR 130-170g/L) and less than 120 g/l(NR 120-150g/L) in adult females.

Morphological classification

Normochromic Normocytic Anaemias Hypochromic Microcytic Anaemias Normochromic Macrocytic Anaemias Dimorphic Anaemias

Aetiological Classification

1) Anaemia of inadequate red cell production : ( Low Retics )Stem cell Failure ( Hypoplastic ) Building units deficiency ( Iron, B12, folate……etc deficiencies ) Marrow infiltration ( Leukamias, marrow deposits, fibrosis & macrophage filtration ) Dyserythropoiesis ( Thalass., CDA & MDS )

2) Anaemias of excessive red cell destruction (Haemolytic Anaemias) (High retics) A) Intrinsic red cell defects : I. Membrane defects : ( H.S , H.O & PNH ) . II. Hb-Synthesis defects : (Haemoglobinpathies ) III. Metabolic defects : ( Enzymopathies )

B) Extrinsic red cell defects : Immune red cell destruction : Autoimmune : Warm & Cold antibody types Alloimmune : Incompatible blood trans . & HDN Drug related immune haemolysis


Non- immune haemolysis : Infections : Malaria , haemorrhagic fever, gas gangrene …. Etc .Chemicals : Oxidants Physical agents : Burns , Mechanical haemolysis : MAHA , Cardiac haemolysis & March Hb-uria

3.Blood loss

Iron Deficiency (ID)

A reduced iron supply to the erythron can be absolute due to reduced body iron leading to IDA or functional due to defective iron utilization such as anaemia associated with chronic illnesses.

Causes of IDA

Dietary deficiency of Iron (important only when associated with other causes) may arise due to poverty, religious trends and among vegetarians. Malabsorption of iron : this occurs in gluten enteropathy and after gastrectomy. Increased demands: Infancy aggravated by prematurity, infections and delayed mixed feeding. Adolescence Pregnancy : emberyo requirements is around 300 mg + 500 mg . Blood loss: this is the most important cause of IDA, in females it is most commonly from the genital tract while in males from GIT usually.

Absorption

Duodenum . Jejunum .

Iron absorption Favoured by

Increased haem iron Increased animal food Ferrous iron salt Gastric acid PH Vit C Iron deficiency Haemorrhage Ineffective erytropoiesis Pregnancy and hypoxia


Iron absorption reduced by Decreased haem iron Ferric salt Alkalis Tannate in tea Iron overload Inflammatory disorders

Haematological features:

Reduction in all red cell indices ( Hb, PCV, MCV, MCH & MCHC ) Peripheral blood: Hypochromia + microcytosis with mild to moderate anisopoikilocytosis Platelets are usually increased but may be normal, WBCs are normal usually.

Bone marrow

BM is usually hypercellular Normoblastic erythroid hyperplasia, normoblasts show shaggy outlines and vacuolated cytoplasm with pyknotic nuclei. Other haematopoietic cells are normal. Absent marrow iron both in erythroid cells and macrophages with iron stain.

Diagnisis of IDA

In most cases: Clinical data. Typical red cell morphology Reduced serum iron &increased TIBC Reduced transferrin saturation S. Ferritin B.M iron assessment (Iron stain)

Iron requirement

Vary with age and sex .Its highest in pregnancy and adolescent . Adult male: 0.5 – 1 mg /day Female : Menopause: 0.5-1 mg/d Menstruation: 1-2 mg/d Pregnancy: 1.5-3 mg/dFemale (12- 15 y ): 1.6-2.6 mg/dChild: 1.1 mg /d