Pediatrics 5th year, 3rd lecture/contin. (Dr. Jamal)


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The lecture has been given on Oct. 17th, 2010 by Dr. Jamal.

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Pediatrics 5th year, 3rd lecture/contin. (Dr. Jamal)

  1. 1. Sickle Cell anemia This is a qualitative hemoglobinopathy as its caused by substitution of valine amino acid for glutamic acid. This Hb (HbS) alters its solubility at a low O2 tension becoming more liable to crystallise & lead to sickling of the red cells. The resultant sickle – shaped R.C. tend to impact in the capillaries and cause hemolysis and some times infarcts in different body organs. Heterozygotes are called sickle trait while homozygotes have sickle disease. Even homozygous forms do not cause problem during neonatal period when Hb-F predominates. S.C. anemia is far more common among black people than among others. Clinical picture: This includes progressive anemia and slight jaundice. Occasional headache, arthritis, osteopathy of bones especially metacarpals and phalanges may be noticed. Spleen is moderately enlarged during infancy and early childhood, as it gets shrinked and loses its functions (auto-splenectomy) since childhood, as a result of repeated thrombosis. Skin ulceration of the legs, nocturnal enuresis, growth retardation and folic acid deficiency may occur. S.C. patients are particularly susceptible to suffer pneumococcal, H. influenza or salmonella infections. Biliary stones may cause obstructive jaundice. Various forms of crises may occur such as hemolytic, sequestration, megaloblastic, aplastic and painful crisis. This later form of crisis is caused by infarction in the bones, joints, spleen or lungs and is precipitated by infection, hypoxia, dehydration or cold. Papillary necrosis of the kidneys may cause hematuria and renal failure. Diagnosis: - Genetic counseling is carried out in some communities in which the disease is common.
  2. 2. - Prenatal diagnosis is possible from fetal R.C. or liquor fibroblasts, in cases when both parents are heterozygous. - Increased R.C. resistance to osmotic lysis (the reverse to congenital spherocytosis). - +ve sickling test. - Hb- electrophoresis: • At birth: presence of an abnormal Hb in addition to HbF. • From 6 months: Increased proportion of this abnormal Hb (HbS) with some HbF but no HbA. Management: - Pneumococcal vaccine and prophylactic pencillin from early infancy. - Vigorous treatment of infections. - Analgesics for pain crisis. - Avoid and treat hypoxia. - Avoid deydration and cold expsure. - Blood transfusion when indicated. - Hydroxyurea increases Hb-F, by which effect it decreases both the painful crisis requirement for blood transfusion. - Bone marrow transplantation can be curative.
  3. 3. Aplastic Anemia or Hypoplastic Anemia B.M. depression causing reduction in the number of the various blood cells R.C., W.C and platelets. Only one component of blood cells may be involved but more commonly all 3 Components are decreased causing pancytopenia. Types: I. Congenital : 1. Fanconi anemai, chrarcterised by presence of multiple congenital malformations such as intellectual impairment, microcephaly, short stature, thumb and radius defects, café-au-lait spots & renal anomalies. 2. Pure red cell anemia (Blackfan – Diamond syndrome). 3. Schwachman- Diamond Syndrome (Exocrine pancreatic insufficiency +Neutropenia). 4. TAR Syndrome (Thrombocytopenia + Absent Radius). II. Acquired aplastic anemia: may be caused by: 1. Viral infections as HIV, EBV or HB. 2. Bone marrow infiltration by malignant infiltration as in leukemia or involvement in storage diseases as in Niemann – Pick & Gauchers disease. 3. Bone marrow replacement by bone as in osteopetrosis (marble bone disease). 4. Irradiation. 5. Drugs & chemicals as chloramphenicol, antimetabolites, phenylbutazone & benzine.
  4. 4. Clinically the picture depends on one hand on the type of cells involved and on the other hand on the severity of the condition. So there may be anemia, infections and bleeding tendency. Management: - Stop exposure to the possible cause. - Steroid + Androgen. - BMT is curative in successful cases. - Cyclosporin +Anti thymocyte globulin+ steroid. - Packed R.C., platelets and antibiotics when required.