Red Blood Cell Disorders DR.Leni Lismayanti, SpPK-K Dept of Clinical Pathology RSHS/FKUP Bandung

Reference book: Denise M Harmening. Clinical Hematology and Fundamental of Hemostasis. 5th edition. Philadelphia: FA Davis Co, 2009.

RBC Structure & Function Areas of RBC metabolism important in normal RBC survival and function: RBC membrane Hb structure & function RBC metabolic pathway

RBC Membrane RBC membran proteins: Deformability Permeability RBC membran lipids: Phospholipd Glycolipid cholesterol

RBC membrane

Abnormality That Can Lead to a Change in RBC Morphology Cholesterol accumulation in the RBC membrane (liver disease) Target cells Abetalipoproteinemia with cholesterol accumulation Acanthocytes LCAT deficiency with cholesterol accumulation Hemolysis with RBC fragmentation Decreased phosphorylated spectrin or altered spectrin Bite cells and spherocytes

Hb Structure & Function Hb function: delivery and release of oxygen to the tissue and facilitation of CO2 excretion. Hb synhesis depends on 3 prs: Adequate Iron delivery & supply Adequate synthesis of protophorphyrin Adequate globin synthesis

RBC Metabolic Pathway ATP needs for: Hb function Membrane integrity & deformability RBC volume Adequate amounts of reduced pyridine nucleotides Protection of metabolic enzymes

RBC Senescence & Hemolysis RBC traveles 200-300 miles during 120 day life span  undergo the process of senescence (aging)  metabolic & physical changes. 1% RBC taken out (removed) from circulation by RES/MPS  process: Extravascular hemolysis (90%) Intravascular hemolysis (5-10%)

Extravascular Hemolysis

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RBC Disorders: RBC disorders  morphologic changes Numbers: Decreased (Anemia) Increased (Polycythemia) Structure and function: Hemoglobin RBC membrane Abnormal erythropoiesis  nutritional RBC disorders  morphologic changes

Anemia Inability of the circulating blood pool to supply the tissue with adequate oxygen for proper metabolic function. Clinically d/ based on: HT, SS, PE, Lab. Caused by or associated with underlying disease. Usually associated with decrease Hb & Hct (Lab: + RBC count). Consideration by age, sex and other fact

Classification of Anemia Based on Hb level: Moderate (7-10), severe (<7). BM dynamic: Hypoproliferative Accelerated destruction combination Clinically (caused): RBC indices (normochromic normocytic)

Categories of anemia by causes Blood loss Accelerated destruction Nutritional deficiency BM replacement Infection Toxicity Hematopoietic SC arrest/damage Hereditary/acquired defect idiopathic

Significance of Anemia and Compensatory Mechanism N: 1% of RBC loss daily  BM produce (measured by reticulocyte count  0.5-2.0%). Replacement RBC requires: Adequate functioning SC in BM Normal RBC maturation process Ability to release mature RBC from BM

Proper HB & RBC production requires: Variety of nutritional factors Normal pathway of Bh synthesis In severe anemias  symptoms of functional impairment of several organs (+). Compensatory mechanism  increase 2,3-DPG levels

2,3-DPG Physiologic regulator of: Normal Hb oxygen-carrying capacity Tissue oxygen delivery 2,3-DPG (+)  Hb more readily released oxygen to tissues  depend on: pH & Oxygen level of arterial blood. N individual responds to anemia  elevated EPO  Recombinant EPO  Th/ certain anemia.

Lab Tests in Diagnosis of Anemia Hb Hct (RBC Count) RBC indices Peripheral Blood Smear Reticulocyte Count BM smear/biopsy Treatment of anemia: depends on etiology

Polycythemia Polycythemia Vera (Myeloproliferative disorders). Secondary Hypoxic Polycythemia (Secondary Erythrocytosis). Relative Erythrocytosis.

Manifestations PV SE RE CLINICAL FEATURES Cyanosis Absent Present Maybe present Heart/lung disease Splenomegaly Present in 75% Hepatomegaly Present in 35% LAB FEATURES RBC mass Increased Normal EPO Decreased (rarely N) Increased (rarely N) Arterial O2 saturation Decreased WBC count Increased in 80% Platelet count Increased in 50% NRBCs poikilocytes Often present LAP Increased in 70% BM Hypercell; eryth & myelop ↑; Erythropoiesis ↑ Megakaryocytes ↑; fibrosis Serum vit B12 Increased in 75% Culture studies Autonomous, ery proliferation EPO dep.col.form Not applicable

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RBC Morphology

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