Approach to Anemia PG CME

Transcription

1 Approach to Anemia PG CME Vikram Mathews Haematology Department Christian Medical College Vellore

2 Definition of Anemia Beutler et al. Blood 2006.

3 Definition of Anemia WHO definition of anemia (40 years old) Adult male <13g% Adult female <12g% Adult pregnant female <11g% Beutler et al. Blood 2006.

4 Definition of Anemia Databases analyzed: Third US National Health and Nutrition Examination Survey [ NHANES-III ] Scripps-Kaiser database

5 Definition of Anemia Beutler et al. Blood 2006.

6 At Birth Day 3 1 month 2 months 3 6 months 1 yr 2 6 yrs 6 12 yrs RBC x 10 6 /dl 6 ± ± ± ± ± ± ± ± 0.6 Hb gm/dl 18 ± 4 18 ± 3 14 ± ± ± ± ± ± 2 MCV fl 110 ± ± ± ± ± 8 78 ± 6 81 ± 6 86 ± 9 WBC 18,000 ± ± ± ± ± ± ± ± 4000 ANC (9000) (4000) (6000) (3000) (3500) (4000) (4750) (5000) ALC (5500) (5000) (9500) (7000) (8000) (7250) (7500) (3000)

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8 Briefly address: - Reticulocyte count - Coulter principle - Generation of red cell indices

9 Reticulocyte Count Expressed frequently as percentage of RBC s Normal % (RBC 5,000,000/mcl) Absolute 25,000 75,000/mcl The reticulocyte count is the key to answer the question whether it is a production problem or a loss problem Corrected Retic count = Obs/Exp Hb x Retic count

10 Reticulocyte Count Normal Hb 12g% RBC count 5,000,000/mcl Retic % 1% Absolute Reticulocyte count 50,000/mcl Severe anemia Hb 6g% RBC count 2,000,000/mcl Retic % 2% Absolute Reticulocyte count 40,000/mcl Corrected Retic count 6/12 x 2 = 1%

11 Reticulocyte Count (reticluocyte maturation time) - Additional correction for prolonged survival in peripheral blood often twice the normal duration of 1 day hence x 0.5 (Reticulocyte production index) RPI=Retic% x (Obs / Exp Hb:HCT) x (1/RMT) - Limitations of reticulocyte count - High CV - Poor inter-laboratory comparison

12 The Coulter Principle

13 A red cell passes through RBC aperture Red Blood Cell Sensing Zone Ohm s law: Voltage = Current X resistance Oscilloscope

14 Hgb Measurement In Beckman Coulter Instruments Hb Cuvette HGB Lamp ADC Signal Processor Derivation Absorbance= log 10 ( VR / Vs ) Where VR = Reference voltage Vs = Sample voltage Sample HGB Sensor & PRE-AMP

15 RED CELL INDICES RED CELL INDICES MCV (fl)= PCV 0.45 = 90fl Normal range: fl MCV (fl)= PCV 0.45 = 90fl Normal range: fl RBC count/l 5 x 10 RBC count/l 5 x MCH (pg) = Hb/L 150 = 30pg Normal range: pg MCH (pg) = Hb/L 150 = 30pg Normal range: pg RBC count/l 5 x 10 RBC count/l 5 x MCHC (g/l) = Hb (g/l) MCHC (g/l) = Hb (g/l) 150 = 33.3g/l Normal range: g/l 150 = 33.3g/l Normal range: g/l PCV (%) PCV (%) Reference ranges from Dacie and Lewis Practical Haematology Reference ranges from Dacie and Lewis Practical Haematology

16 RBC Distribution Width (RDW) Normal Values As CV 12.8±1.2% As SD 42.5±3.5fl

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18 Clinical Features Anemia results in decrease in oxygen carrying capacity Symptoms depend on: Degree of anemia Rate of fall in hemoglobin Capacity to compensate Increase cardiac output Tachycardia Increased stroke volume Peripheral resistance Change in O2 dissociation curve 2,3 DPG Other co-morbid conditions

19 Clinical Features of Anemia TIREDNESS / EXERTIONAL DYSPNOEA PALPITATIONS HEADACHE PALLOR TACHYCARDIA HYPERPNOEA HYPERDYNAMIC CIRCULATION FEVER FEATURES OF HYPOXIA

20 History: - DURATION OF SYMPTOMS - ONSET & PROGRESSION - BLOOD LOSS IF ANY TRANSFUSIONS - FREQUENCY - DATE OF LAST TRANSFUSION - OTHER TREATMENT RECEIVED - EXPOSURE TO DRUGS AND CHEMICALS - DEVELOPMENTAL HISTORY IN CHILDREN - FAMILY HISTORY - OTHER ASSOCIATED SYMPTOMS IF ANY - INFECTIONS - BLEEDING - OTHER SYSTEMS REVIEW

21 1. Reticulocyte count in diagnosis of anemia Decreased production Increased peripheral destruction

22 2. Morphology approach based on alteration of red cell size best indicated by the MCV along with the reticulocyte response Classification of Anemia based on red cell size Microcytic Normocytic Macrocytic

23 Microcytic Hypochromic Anemia LOW/ ABSENT IRON DEFICIENCY - S.Iron /TIBC - S.Ferritin - BM Iron Stores LOOK FOR CAUSE Increased loss Hemorrhage GI tract Kidney Uterus Other IRON STORES Decreased intake Increased regq-mnt Nutritional Pregnancy Lactation Other NORMAL / INCREASED 1. THALASSEMIA α / β - Hb A2/F - HbH Stain - Globin Chain Analysis 2. HEMOGLOBINOPATHY(Few) - Hb Electrophoresis 3. SIDEROBLASTIC ANEMIA - Siderocytes - Sideroblasts 4. CHRONIC DISEASE - Diagnosis of Exclusion

24 Iron deficiency Causes of GI Blood Loss ESOPHAGEAL WEB VARICES, REFLUX CARCINOMA DUODENAL ULCER AMOEBIASIS CARCINOMA TUBERCULOSIS CHRON S ULCER, CARCINOMA LEIOMYOMA GASTRITIS POLYPS, MECKEL S AV MALFORMATION CARCINOMA ULCERATIVE COLITIS HAEMORRHOIDS Normal Iron deficiency Low MCV Serum Fe S Ferritin Thalassemia minor

25 Serum Iron : /- 50 mgm/dl Iron Binding : /-30 mgm/dl Capacity % Saturation : 10.2% 35 +/- 15% Serum Ferritin: 4 M ng/ml F ng/ml

26 Thalassemia / haemoglobinapthy: - appropriate clinical setting - low MCV - low RDW - normal / increased ferritin Peripheral smear Hb electrophoresis HPLC Mutation analysis

27 Anemia of Chronic Disease: Acute infections Chronic infections Tuberculosis Infective endocarditis Chronic urinary tract infection Chronic fungal infection Chronic inflammatory disorders Osteoarthritis Rheumatoid disease Collagen vascular disease Polymyalgia rheumatica Acute and chronic hepatitis Decubitus ulcer Malignancy Metastatic carcinoma Hematologic malignancies Leukemia Lymphoma Myeloma Proteinenergy malnutrition

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29 SERUM IRON Serum Iron and IBC NORMAL IRON IRON ANAEMIA OF DEFICIENCY OVERLOAD CHRONIC DISEASE

30 Differentiating from iron deficiency anemia - Important since ACD does not respond to iron supplements

31 Bone marrow - Peripheral smear - History

32 Hereditary Spherocytosis Sickle cell anemia Aplastic Bone Marrow Leukemia Bone Marrow MAHA Heinz Bodies - G6PD deficiency - Other enzymopathies - Thalassemia AIHA - AUTOAGGLUTINATION

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35 Vitamin B12 Total Body content 2-5 mg RDA-5-7 mcg/day Takes 3-4 years to deplete stores Folic Acid Total Body content mg RDA- 50 mcg Stores can be rapidly depleted.

36 Folate Deficiency Metabolic Block Pyrimethamine Methotrexate Decreased Intake Increased Requirement Growth Pregnancy Lactation Haemolysis B12 Deficiency Pancreatic disease Diseases of the small intestine Mal-absorption Bacterial overgrowth Metabolic Block Decreased Intake Pure vegetarians TC II deficiency Gastrectomy Pernicious anemia Diseases of the terminal ileum

37 Megaloblastic Anaemia Clinical Features Anaemia with icterus Macrocytosis, hypersegmented neutrophils, pancytopaenia Raised indirect bilirubin, LDH Hypercellular marrow with megaloblastic changes

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39 Pathophysiology of megaloblastic anemia 1.B 12 and folate deficiencies result in defective DNA synthesis. 2.This results in an abnormal cell maturation process 3.Megaloblastic cells die in the bone marrow. (apoptosis through p53)

40 Laboratory evaluation Suspect when MCV raised LDH raised Raised Indirect Bilirubin Peripheral smear Macrocytosis Hypersegmented neutrophils Pancytopenia Bone Marrow examination Serum B12 assay Serum and red cell folate assays

41 Serum B12 and Folate Reference ranges Serum B 12 : pg/ml Serum Folate: 3-16 ng/ml Lower limit for B 12 deficiency not well defined In untreated patients with folate deficiency levels are usually <1.0 ng/ml Other tests may be needed in borderline cases Serum methyl malonic acid Serum homocysteine

42 MMA and thcys are now considered GOLD STD for diagnosis of Vitamin B12 Deficiency. (98% and 96% sensitivity respectively- Savage- Am J Med 1994) These tests are used in patients with-(1) Borderline Cobalamin and Folate Deficiency. (2) In conditions which increase or decrease levels. (3) Both Cbl and Folate are low( MMA= Cbl def) (4) When there are low Serum levels.

43 Approach to a Patient with Hemolytic Anemia

44 Clinical Signs of hemolysis Chronic long standing from childhood Skeletal Abnormalities» Frontal Bossing» Maxillary prominence» Harrison s sulcus» Genu valgum Jaundice with acholuric urine Hepatosplenomegaly Chronic leg ulcers

45 Laboratory indices of hemolysis Raised reticulocyte count, polychromasia Raised serum bilirubin indirect fraction Increased urine urobilinogen Raised LDH Intravascular hemolysis Urine hemoglobin Plasma hemoglobin Decreased serum haptoglobin Methhemalbumin

46 HEMOLYTIC ANEMIA COOMBS TEST IMMUNE + - NON IMMUNE WARM Antibody Primary idiopathic Secondary Lymphoprolifer Connective tissue Drugs Hapten Immune complex COLD Antibody Primary idiopathic Secondary Lymphoprolifer Infections Mycoplasma Inf Mono PCH Syphillis Post viral CONGENITAL Hemoglobinopathy Thal major Hb E disease Enzymopathy G6PD def Membranopathy Her spherocytosis ACQUIRED PNH MAHA Venoms Infections Drugs / Chemicals

47 Laboratory tests required to establish the cause of hemolysis Congenital Blood Picture Sickle prep, Hb H prep, Electrophoresis/HPLC Osmotic fragility Unstable Hb, Heinz body G6PD, PK Acquired Coomb s test Tests for PNH

48 With a rational approach it is possible to determine the cause of anemia and then plan appropriate treatment