Iron Deficiency Anaemia (PDF)

HONG KONG METROPOLITAN UNIVERSITY MLS 3009SEF Haematology & Transfusion Science I H.LEE Iron Deficiency Anaemia 27-1-2025 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 1...

HONG KONG METROPOLITAN UNIVERSITY MLS 3009SEF Haematology & Transfusion Science I H.LEE Iron Deficiency Anaemia 27-1-2025 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 1  Anaemia Morphologic classification of Anaemia Uses erythrocyte indices (MCV) for classification : 1. Macrocytic, Normochromic - Causes: Folate or B12 deficiency, liver disease, alcoholism 2. Normocytic, Normochromic - Causes: bone marrow failure, haemolytic anaemia, chronic renal failure, leukaemia, metastatic malignancy 3. Microcytic, Hypochromic - Most common anaemia - Causes: iron deficiency, sideroblastic anemia, thalassemia, chronic diseases 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 2  Diagnosis of Anaemia Clinical history Physical signs such as pallor, fatigue, weakness, dizziness and dyspnea(shortness of breath) Laboratory tests CBC Examination of the blood smear Reticulocyte - measures effectiveness of erythropoiesis Iron studies - iron, total iron-binding capacity (TIBC), ferritin Vitamin B12 and folate Erythropoietin level Bone marrow examination – smear and trephine biopsy 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 3  Iron Metabolism Primary function – Oxygen transport and storage Distribution – Types of iron-containing compounds Functional, assisting in enzymatic and metabolic functions Transportation or storage – Location RBCs- majority Macrophages of spleen & liver- where destruction of RBC occurs, liberating iron Hepatocytes and enterocytes- storage of iron 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 4  Iron Metabolism Loss of iron – Secretions of urine, bile , sweat and exfoliation of intestinal epithelial cells of GI tract Regulation of iron – Delicate balance between loss and absorption 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 5  Iron Regulation Human iron is regulated at two different levels: 1. First, the systemic iron levels are balanced by the controlled absorption of dietary iron by enterocytes interior cells of the intestines, and the uncontrolled loss of iron from epithelial sloughing, sweat, injuries and blood loss. A male adult needs ~1mg/day absorbed from diet. 2. Second, systemic iron recycling and loss processes. 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 6  Iron Re-cycling - Most of the iron in the body is hoarded and recycled by the reticuloendothelial (RE) system, which breaks down aged red blood cells. - Red cells are broken down in the macrophages of the RE system and their iron is subsequently released into the plasma. - According to overall body iron status, some iron is stored in the RE cells as hemosiderin and ferritin in the ferric form and is mobilized after reduction to the ferrous form with vitamin C. 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 7  Iron Absorption - Normally, only 5-10% is absorbed and can be increased to 20-30% in iron deficiency or pregnancy but, even in these situations, most dietary iron remains unabsorbed. - The human body's rate of iron absorption appears to respond to a variety of interdependent factors: i. Total Iron stores, ii. Activity of the bone marrow i.e. the extent to which the bone marrow is producing new red blood cells, iii. Concentration of hemoglobin in the blood, and the oxygen content of the blood. iv. The body also absorbs less iron during times of inflammation, in order to deprive bacteria of iron 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 8  Iron Metabolism About 1/3 of iron is stored in the liver, spleen Iron is transported in plasma bound to a transferrin which is synthesized in the liver, has a half-life of 8-10 days, and is capable of binding two atoms of iron per molecule. It is re-utilized after it has given up its iron. Approximately 95% of iron is complexed with transferrin. Once the physiologic needs of iron in the bone marrow are met, iron is deposited in the tissues, specifically the liver for storage. Ferritin and hemosiderin are the largest non-heme iron stores in the body. Storage iron serves as a quick supply in cases of increased iron loss through bleeding. 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 9  Iron Metabolism Iron is transported from the duodenum into mucosal cells in the ferrous form where it is converted to the ferric form. Iron may combine with apoferritin to form ferritin or cross into the plasma Iron is transported in plasma bound to a transferrin which is synthesized in the liver, has a half-life of 8-10 days, and is capable of binding two atoms of iron per molecule. It is re-utilized after it has given up its iron. Approximately 95% of iron is complexed with transferrin. 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 10  Iron Metabolism The majority of the transferrin bound iron is delivered to the bone marrow where it binds to specific transferrin receptors on the normoblasts as ferrous form. Once the physiologic needs of iron in the bone marrow are met, iron is deposited in the tissues, specifically the liver for storage. The iron may bound to apoferritin as Ferritin, therefore, low ferritin level is presence in iron deficiency status In excess absorption of iron as ferritin, the iron are deposited as hemosiderin. Ferritin and hemosiderin are the largest non-heme iron stores in the body. Storage iron serves as a quick supply in cases of increased iron loss through bleeding. 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 11 www.Studygorgi.com 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 12  Iron Deficiency Anemia (IDA) Iron Deficiency Anemia (IDA) – This is the most common form of anemia. – Normal adult man iron requirement is ~1.0 mg/day. – IDA occurs when the iron stores in the body are inadequate to preserve homeostasis Symptoms: - Fatigue lethargy and dizziness - Pallor of mucous membranes - Koilonychias (spooning of nails) 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 13  Iron Deficiency Anemia (IDA) Causes of IDA – Dietary – Blood Loss – Hemodialysis – Malabsorption Notes: Type of iron : Non-heme iron (Ferric): in vegetables and grains not easily absorbed Heme iron (ferrous) : in red meat and readily absorbed 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 14  3 Stages of IDA Stage 1 – Decrease in storage iron (ferritin decrease) – No anemia – RBC morphology normal – RDW can be elevated Stage 2 – Decrease in iron for erythropoiesis – No anemia or hypochromia i.e. normochromic – RBC slightly microcytic Stage 3 – Decrease in Blood Hb – Decrease in peripheral tissue oxygen delivery – Microcytic, hypochromic anemia 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 15  IDA 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 16  Laboratory Findings Increased - RDW Decreased – RBC, Hb, Hct, MCV, MCH, MCHC Normal to decreased – Reticulocyte Chemistry – Decrease in serum iron and ferritin – Increased TIBC 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 17  Laboratory Findings Peripheral blood smear – Anisocytosis – Microcytic-hypochromic in late stage – Poikilocytosis e.g. elliptocytes, teardrops – Presence of nRBC – If IDA is caused by bleeding, leukocytosis and thrombocytosis are possible. In bone marrow, sideroblasts are absent or reduced and there is mild to moderate erythroid hyperplasia. Notes: IDA is a type of ineffective erythropoiesis due to the decreased 27/1/2025 Henry Lee ability of Erythrocytes to make haemoglobin MLS 3009SEF Iron Deficiency Anaemia 18  Anemia’s Associated with Abnormal Heme Synthesis Abnormal Heme Synthesis : Sideroblastic Anemia Lead Poisoning Porphyrias 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 19  Sideroblastic Anaemia First step in heme synthesis is affected, the formation of ALA (amino levuilinate synthase) Characterized by: – Increase in total body iron – Presence of ringed sideroblasts in bone marrow – Hypochromic anemia 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 20  Sideroblastic Anaemia ScienceDirect.com 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 21  Sideroblastic Anaemia Classification – Hereditary X-linked recessive gene defect. – Acquired 2 Forms – Idiopathic – Secondary type » Certain therapeutic drugs (eg TB drug) » Chronic transfusions (for aplastic anemia, leukemia, thalassemia) » Alcoholism and food fads » Use of iron utensils or increased iron in water 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 22  Sideroblastic Anaemia Mechanism – Adequate iron but it can not be incorporated into hemoglobin synthesis. – Iron enters mitochrondria , but accumulates leading to formation of ringed sideroblasts – Eventually, mitochrondria rupture due to excess iron 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 23  Lead Poisoning Lead poisoning is one of the most common causes of sideroblastic anemia Lead interferes with iron storage in the mitochondria Lead damages the activity of enzymes used for heme synthesis Basophilic stippling pronounced 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 24  Basophilic stippling CellWiki 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 25  Laboratory Findings Peripheral blood – Pappenheimer bodies – Hypochromic, normochromic RBCs – Normal to increased platelets Chemistry – Increased serum iron, ferritin – Decreased TIBC 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 26  Pappenheimer bodies ASH Image Bank 27/1/2025 Henry Lee MLS 3009SEF Iron Deficiency Anaemia 27