Anemia Iron Deficiency Megaloblastic By Dr. Zahoor

Anemia What is Anemia? Anemia is present when there is decrease in hemoglobin (Hb) in the blood below the reference level for the age and sex

Normal Values for Peripheral Blood

Classification of Anemia Classification of Anemia based on MCV (Mean Cell Volume). There are 3 major types: Microcytic Hypochromic Anemia with low MCV Normocytic Normochromic anemia with normal MCV Macrocytic anemia with high MCV

CLINICAL FEATURES Symptoms (these are non specific) Fatigue, headache, faintness Breathlessness Palpitation Angina Intermittent claudication Signs Pallor Tachycardia Systolic flow murmer Cardiac Failure

Anemia Specific signs are seen in different type of Anemia Koilonychia – spoon shaped nails seen in long standing iron deficiency anemia Jaundice – found in hemolytic anemia Leg ulcers – seen in sickle cell disease Bone deformities – seen in thalassaemia major

INVESTIGATION When hemoglobin is low, then always evaluate with red cell indices (MCV, MCH, MCHC) WBC count Platelet count Reticulocyte count (it indicates bone marrow activity) Blood film to see red cell morphology e.g. microcytic, macrocytic

INVESTIGATION Bone marrow – To see the cellularity of marrow – Type of erythropoiesis e.g. normoblastic or megloblastic – Any infiltration e.g. presence of cancer cells – Iron stores – Special test for further diagnosis e.g. immunological, cytogenetic, microbiological culture

Classification of Anemia Based On MCV (Mean Corpuscular Volume) Microcytic Anemia Red cell appearance – small cell (microcyte) Indices – low MCV < 80fL Diagnosis – Iron deficiency – Thalassaemia – Anemia of Chronic Disease – Sideroblastic anemia

Classification of Anemia Based On MCV (Mean Corpuscular Volume) Macrocytic Anemia Red cell appearance – large cells (macrocyte) Indices – high MCV > 96 fL 1. Appearance of bone marrow – megloblastic Diagnosis – vitamin B12 or Folate deficiency 2. If appearance of bone marrow – normoblastic but macrocytosis in the peripheral blood Diagnosis – Alcohol – Increased reticulocyte e.g. haemolysis – Liver disease – Hypothyroidism – Drug therapy e.g. Azathioprine

Classification of Anemia Based On MCV (Mean Corpuscular Volume) Normal size RBC Red cell appearance – normal cells Indices – normal MCV Diagnosis – Acute blood loss – Haemolytic anemia – Anemia of chronic disease – Chronic kidney disease – Auto immune rheumatic disease – Endocrine disease

We will discuss Microcytic Hypochromic (Iron Deficiency) Anemia

MICROCYTIC HYPOCHROMIC ANEMIA IRON DEFICIENCY Iron Deficiency is the most common cause of anemia in the World, affecting 30% of World’s population Iron is absorbed in upper small intestine in Fe2+ form Why microcytic (iron deficiency anemia) is common? Because of limited ability to absorb iron, and loss of iron due to hemorrhage

IRON We will discuss important points regarding Iron: Dietary intake The average daily diet contains 15-20mg of iron, normally only 10% of this is absorbed Iron is absorbed in proximal intestine, specially duodenum Iron is present in ferric form in the diet, it is reduced to ferrous form by brush border (small intestine)

IRON Iron Transport Iron is transported in the plasma bound to transferrin (beta globulin that is synthesized in the liver) Most of the iron bound to transferrin comes from macrophages in the Recticulo -Endothelial system and not from Iron absorbed by the intestine

IRON Iron Stores About two third of total body iron is in the circulation as hemoglobin Iron is stored in recticuloendothelial cells, Hepatocyte and skeletal muscle cells About two third of iron is stored as ferritin and one third as haemosiderin Ferritin is water soluble and easily mobilized Haemosiderin is insoluble, found in macrophages in the bone marrow, liver and spleen

IRON Requirements Daily requirement is 1mg Each day 0.5-1mg of iron is lost in the faeces, urine and sweat Menstruating women lose 30-40ml of blood per month, an average of 0.5-0.7mg of iron per day Blood loss through menstruation in excess of 100ml will usually result in iron deficiency Demand of iron also increases during growth and pregnancy

IRON DEFICIENCY ANEMIA Iron deficiency anemia occurs, when there is less iron available for Hb synthesis The causes are - Blood loss - Increased demand such as growth and pregnancy - Decreased absorption e.g. post gastrectomy - Poor intake – Diet which contains vegetable predominantly

IRON DEFICIENCY ANEMIA Clinical Features Symptoms - Fatigue, headache, faintness - Palpitation - Breathlessness - Angina - Intermittent claudication

IRON DEFICIENCY ANEMIA Clinical Features In long standing iron deficiency anemia, well known clinical features are - Brittle nails - Spoon shaped nails (Koilonychia) - Atrophy of papillae of the tongue - Angular stomatitis - Brittle hair IMPORTANT – Plummer-Vinson or Paterson-Brown-Kelly Syndrome It is presence of Iron deficiency anemia, Dysphagia and glossitis

IRON DEFICIENCY ANEMIA Investigations Blood film shows RBC – microcytic MCV < 80fL and hypochromic MCH < 27 pg There are poikilocytosis (variation in shape) and anisocytosis (variation in size). Target cells are seen Microcytic hypochromic cells, Poikilocytosis and Anisocytosis is seen

IRON DEFICIENCY ANEMIA Investigations (cont) Serum iron and iron binding capacity Serum iron is low and total iron binding capacity (TIBC) is increased Serum ferritin Serum ferritin is low (serum ferritin level tells us about the amount of stored iron) Serum soluble transferrin receptors Number of transferrin receptors increases in iron deficiency anemia It is done by immunoassay

DIFFERENTIAL DIAGNOSIS Differential Diagnosis of Microcytic Hypochromic Anemia Iron Deficiency Anemia – iron stores (ferritin) is low Thalassaemia – iron stores are normal Sideroblastic Anemia – iron stores are raised Anemia of Chronic Disease – iron stores are normal or raised

Microcytic Anemia: the differential diagnosis

TREATMENT Find and treat the underlying cause e.g. diet, blood loss due to peptic ulcer, hemorrhoids Oral iron – ferrous sulphate 200mg three times daily (it provides 180mg ferrous iron), it is best absorbed when patient is fasting – Oral iron is given for 6 months to correct hemoglobin level and replenish the iron stores Parenteral iron – Given by slow IV infusion of low molecular weight iron dextrin (test dose is required) – It is given when patient is intolerant to oral preparation e.g. severe malabsorption

ANEMIA OF CHRONIC DISEASE In hospital patients, common type of Anemia is the anemia of chronic disease, occurs in patient with TB, inflammatory bowel disease, rheumatoid arthritis, SLE, Malignant disease Cause - Decrease release of iron from bone marrow to developing erthythroblast - Decreased response to erythropoietin - Decrease RBC survival Investigation - Decreased serum iron, decreased TIBC - Serum ferritin is normal or raised - Patient do not respond to iron therapy and treatment is for underlying cause

SIDEROBLASTIC ANEMIA It maybe inherited or acquired It may be transmitted as X-linked disease by female It is characterized by microcytic hypochromic cells in peripheral blood and excess iron and ring sideroblast in bone marrow Presence of ring sideroblast in bone marrow is diagnostic feature of Sideroblastic anemia, ring is due to accumulation of iron in the mitochondria of erythroblast. They can be seen with Perl's stain Causes Myeloid leukaemia, lead toxicity, alcohol abuse

Bone marrow showing sideroblast stained with Perl’s Prussian blue Sideroblastic Anemia Bone marrow showing sideroblast stained with Perl’s Prussian blue

NORMOCYTIC ANEMIA Normocytic Normochromic anemia is seen in Anemia of chronic disease Endocrine disorders e.g. Hypopituitarism, hypothyroidism, Hypoadrenalism Some hematological disorders e.g. Aplastic anemia and some hemolytic anemia In acute blood loss

MACROCYTIC ANEMIA They are divided into two types based on bone marrow findings: Megaloblastic Non Megaloblastic Megaloblastic Anemia: It is characterized by erythroblast, present in the bone marrow (Erythroblast are premature RBC, they occur due to defective DNA synthesis) Megaloblast are large cell and have large immature nuclei

Megaloblasts in Bone Marrow:

MACROCYTIC ANEMIA Megaloblastic Anemia: What is the cause of megaloblastic anemia? Vitamin B12 deficiency or abnormal Vit. B12 metabolism Folic acid deficiency or abnormal folate metabolism Drugs interfering with DNA synthesis eg. Hydroxyurea, azathioprine, Zidovudin (AZT), Myelodysplasia

MACROCYTIC ANEMIA Megaloblastic Anemia: Hematological findings: Anemia is present MCV > 96fl Peripheral blood film shows oval macrocytes with hypersegmented polymorph with six or more lobes in nucleus If severe there may be leukopenia and thrombocytopenia

Macrocytes and a hyper segmented neutrophil (arrowed) on a peripheral blood film

MACROCYTIC ANEMIA Megaloblastic Anemia: Biochemical basis of megaloblastic anemia: Biochemical problem is Vit. B12 & Folate deficiency causing block in DNA synthesis We will talk about Vit. B12 & Folic Acid Vit. B12: Daily requirement 2.4 microgram/day It is found in meat, fish, eggs and milk It is not found in plants It is not usually destroyed by cooking Average daily diet contains 5 – 30 mcg of which 2 – 3 mcg are absorbed Average adult stores are 2 – 3 mg mainly in the liver therefore it may take 2 years after absorption failure before vit B12 deficiency develops

MACROCYTIC ANEMIA Vit. B12: Vit B12 Deficiency: Absorption and transport: Vit B12 is bound to Intrinsic factor in the stomach (Intrinsic Factor is secreted by Parietal cells of stomach) Combination of Vit B12 and Intrinsic factor, it is carried to the ilium, Vit B12 enters the ilial cells and intrinsic factor remains in lumen and is excreted. After absorption of Vit B12 is transported to bone marrow by glycoprotein Transcobalamine II (TC II) Vit B12 Deficiency: Causes : Low intake – vegetarian diet Impaired absorption Stomach – pernicious anemia, Gastrectomy Small bowel – ileal disease or resection, bacterial overgrowth, tropical sprue, fish- tapeworm

MACROCYTIC ANEMIA Treatment –Vit B12 deficiency: Hydroxocobalamine 1000mcg can be given IM to total of 5-6 mg over the course of 3 weeks then 1000mcg every 3 months for rest of life Alternate oral vit B12, 2 mg per day, as 1 -2% of oral dose is absorbed by diffusion and does not require Intrinsic factor

MACROCYTIC ANEMIA Pernicious Anemia (PA): It is an autoimmune disorder in which there is atrophic gastritis, with loss of parietal cells in the gastric mucosa therefore failure of Intrinsic factor production and vit B12 absorption Pathogenesis of PA: Commonly in elderly, age over 60 years, blood group A Female > Male Association with other autoimmune disease e.g thyroid disease, Addison's, Vitiligo Parietal cell antibodies are present in 90 % and intrinsic factor antibody found in 50% of patients

MACROCYTIC ANEMIA Folic acid: Folic acid monoglutamate is not itself present in nature but occurs as polyglutamate Folate are present in the food as polyglutamate Dietary intake: Minimum daily requirement is 100 mcg Folate is found in green vegetables, e.g spinach, Brocolli and also in liver and kidney Cooking causes loss of 60-90% of folate

MACROCYTIC ANEMIA Folic acid: Causes of folate deficiency: Physiological – pregnancy, lactation Poor intake – poor social condition, starvation, ↑alcohol consumption, GIT diseases eg. Partial gastrectomy, coeliac disease. Crohn's disease Antifolate drugs e.g.. Phenytoin (Anticonvulsant), Methotrexate, trimethoprin Pathological – hemolysis, malignant disease, hemodialysis or peritoneal dialysis Small bowel diseases causing malabsorption

MACROCYTIC ANEMIA Folic acid: Folate reserves are low about 10 mg therefore diet deficient in folate causes folate deficiency anemia in about 4 months Folic acid supplementation in mother during first 12 weeks of pregnancy reduces the incidence of neural tube defect Clinical features: Patient may be asymptomatic or present with anemia of underlying cause Glossitis can occur In folic acid deficiency peripheral neuropathy does not occur (occurs in B12 deficiency)

MACROCYTIC ANEMIA Folic acid: Investigations: Serum and red cell folate are assessed by radioisotope dilution or immunological methods RBC folate is better measure Normal serum folate is 4-18 mcg/liter (5-63nmol/lit) Normal RBC folate 160-640 mcg/liter

MACROCYTIC ANEMIA Treatment -Folic acid deficiency: Folate 5 mg per day for 4 months to replace body stores Treat underlying cause Prophylactic folic acid 400mcg per day is given to all women planning a pregnancy and throughout the pregnancy

MACROCYTIC ANEMIA Macrocytosis without Megaloblastic changes: Raised MCV with macrocytosis but normobalstic bone marrow Physiological causes – pregnancy, new born, Pathological causes – Alcohol excess Liver disease Reticulocytosis Hypothyroidism Sideroblastic anemia Drugs – Azathioprine, Important: In all these conditions normal level of Vit B12 and folic acid are found – then why there is macrocytosis? May be due to increase lipid deposition in RBC membrane

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