بنام خدا DEFINITION OF ANEMIA : Anemia may be defined as a reduction in red blood cell mass or blood hemoglobin concentration. It is particularly important to use age and sex adjusted norms when evaluating a pediatric patient for anemia Pathophysiology of anemia Blood loss Hemolytic anemia Impaired red cell formation Acute blood loss Acute blood loss: (Normal spleen, high retic count, normal bilirubin, normal urinalysis) Neonatal problem (fetofetal transfusion, fetomaternal transfusion,…) Hemorrhagic disease of newborn Meckel’s diverticulum, ….. (Spleen, Hb, Retic, Bilirubin, urinalysis ) Hemolytic anemia Hemolysis Shortened lifespan of circulating RBC Sites of Hemolysis – Intravascular– Extravascular-Liver and Spleen Hemolytic anemia 1)Corupuscular (enzyme defect, membrane defect, hemoglobin disorder) 2) Extra corpuscular (immune, non immune) Hemolytic anemia: Corpuscular 1) Enzyme defect: G6PD deficiency, PK deficiency 2) Membrane defect: Spherocytosis, Elliptocytosis 3) Hemoglobin disorder: Normal variant, Functional disorder, Structural problem, Thalassemia Hemolytic anemia: Corpuscular( Enzyme defect): G6PD Deficiency Glucose 6 phosphate dehydrogenase(G6PD) G6PD DEFICIENCY: X-linked disorder The most common enzymatic disorder of red blood cells in humans Affecting 200 to 400 million people Contains 515 amino acids Over 400 variant enzymes have been reported (90 according to specific mutations) Classification of G6PD variants: Class I variants: are rare, have severe enzyme deficiency (less than 10 percent of normal) and have chronic hemolytic anemia(44 variants) Class II variants : have severe enzyme deficiency, but there is usually only intermittent hemolysis (28 variants) Class III variants: have moderate enzyme deficiency (10 to 60 percent of normal) with intermittent hemolysis usually associated with infection or drugs (16 variants) Class IV variants: have no enzyme deficiency or hemolysis (2 variants) Class V variants: have increased enzyme activity Normal wild-type enzymes: G6PD B : is found in most Caucasians, Asians, and a majority of Blacks G6PD A+: is found in 20 to 30 percent of Blacks from Africa Abnormal wild-type variants: G6PD A- variant :is the most common variant associated with mild to moderate hemolysis (class III). It is found in 10 to 15 percent of African-Americans G6PD Mediterranean variant: is the most common abnormal variant found in Caucasians , its catalytic activity is markedly reduced and hemolysis can be severe (class II) G6PD Canton : a variant enzyme seen in Asians; its biochemical properties are very similar to those of G6PD Mediterranean PATHOPHYSIOLOGY OF G6PD DEFICIENCY: The in vivo half-life of enzyme: normal enzyme (G6PD B): 62 days, G6PD A- :13 days, G6PD Mediterranean: in hours Patients with G6PD A- usually have hemolysis that is mild and limited to older deficient erythrocytes (class III). In contrast, red cells of all ages are grossly deficient in G6PD Mediterranean (class II). Clinical sign and symptoms: Intermittent hemolysis Chronic non spherocytic hemolytic anemia Neonatal hyperbilirubinemia Favism Increased infection susceptibility(rare) Hemolytic anemia Membrane defect: Spherocytosis Membrane defect (Spherocytosis): Pathophysiology : A deficiency or abnormality of the erythrocyte membrane structural protein: spectrin , ankyrin, band 3, and protein 4.2. The spherocyte is relatively rigid and non-deformable Membrane defect (Spherocytosis): Clinical presentation: anemia, hyperbilirubinemia, splenomegaly Expansion of the marrow cavities . Laboratory findings reticulocytosis, anemia, hyperbilirubinemia, spherocyte in PBS, Erythroid hyperplasiain BMA, osmotic fragility test, Autohemolysis, Hemolytic anemia: Hemoglobin disorder: Hemolytic anemia: Hemoglobin disorder: Normal variant, Functional disorder, Structural problem, Thalassemia Thalassemia minor: A patient with microcytosis with mild anemia or actually without anemia عوارض کم خونی تغییرات استخوانی بزرگی طحال خون سازی خارج مغز استخوان شکستگی پاتولوژ یک افت سطح هوشی زخم اندام تحتانی توقف رشد عوارض سیستم انعقادی Sickle cell anemia Extracorpuscular Factors: Immune hemolysis : (alloimmune, autoimmune, iso immune) Non immune hemolysis: Extracorpuscular Factors: Non immune hemolysis: Hypersplenism Trauma – malfunctioning prosthetic valves – DIC – TTP , HUS Infection: malaria, clostridium difficile, snake and insect bites Impaired red cell formation: Impaired red cell formation 1)Deficiency (Normal spleen, low retic count, normal bilirubin, normal urinalysis) 2)Bone marrow failure (Normal spleen, low retic count, normal bilirubin, normal urinalysis) 3)Bone marrow infiltration (splenomegaly low retic count, normal bilirubin, normal urinalysis) 1)Deficiency (Normal spleen, low retic count, normal bilirubin, normal urinalysis): Iron deficiency Megaloblastic anemia ( vitamin B12 deficiency, folate deficiency) Others: vitamin C, vitamin B6, protein deficiency, Thyroxine deficiency Iron: Iron is an essential nutrient in humans most common nutritional deficiency in children. iron balance is achieved by control of intestinal absorption درصد جذب آهن در موارد غذایی مختلف علل بروز فقر آهن Clinical manifestation of IDA; Hematological symptoms The most common presentation of IDA is an otherwise asymptomatic, well nourished infant or child who has a mild to moderate microcytic, hypochromic anemia Clinical manifestation of IDA; Non hematological symptoms Neurodevelopmental and Cognitive function Immunity Exercise capacity Pica and pagophagia Thrombosis Epithelial change: dysphagia, esophageal web, atrophic glossitis, spoon nails, blue sclerae DIAGNOSIS serum ferritin serum iron, Total iron-binding capacity, Transferrin saturation serum transferrin receptor, and reticulocyte hemoglobin content Therapeutic trial of iron BM Aspiration 2)Bone marrow failure (Normal spleen, low retic count, normal bilirubin, normal urinalysis): Failure of a single cell line(red cell): 1) Congenital pure red cell anemia (Diamond-Blackfan anemia) 2)Acquired red cell aplasia: a) TEC syndrome b) Aplastic crisis Failure of all cell line: 1)Constitutional (Fanconi’s anemia) 2)Acquired(Aplastic anemia) Fanconi Anemia: Clinical features Incidence is 3/1,000,000 – Heterozygote frequency ~1/300 in U.S. and Europe Median age at diagnosis is 5-7 Median survival is 20-30 yrs. Phenotypic variability occurs even within families 3)Bone marrow infiltration (splenomegaly, low reticulocyte count, normal bilirubin, normal urinalysis) : Malignant: Leukemia, Bone marrow involvement in other cancers Non malignant: Metabolic disease (gaucher’s disease, Niemann-pick), Osteopetrosis