Medical brain notes 15

  Red Cell Shapes Abnormal size is called anisocytosis ( aniso  means unequal). Abnormal shape is called poikilocytosis ( poikilo  means various).  Elliptocytes  may be seen in hereditary elliptocytosis.  Spherocytes  result from decreased erythrocyte membrane, and they may be seen in hereditary spherocytosis and in autoimmune hemolytic anemia.  Target cells  result from increased erythrocyte membrane, and they may be seen inhemoglobinopathies, thalassemia, and liver disease.  Acanthocytes  have irregular spicules on their surfaces; numerous acanthocytes can be seen in abetalipoprotein-emia.  Echinocytes  (burr cells) have smooth undulations on their surface; they may be seen in uremia or more commonly as an artifact. Schistocytes  are erythrocyte fragments (helmet cells are a type of schistocyte); theycan be seen in microangiopathic hemolytic anemias or traumatic hemolysis.  Bitecells  are erythrocytes with...

  ANEMIAS Anemia  is a reduction below normal limits of the total circulating red cell mass. Signsof anemia include palpitations, dizziness, angina, pallor of skin and nails, weakness, claudication, fatigue, and lethargy. ·              Reticulocytes  are immature, larger red cells (macrocytic cells) that are spheri-cal and have a bluish color (polychromasia) due to free ribosomal RNA. Reticulocytes do not have a nucleus; note that any erythrocyte with a nucleus (nRBC) in peripheral blood is abnormal. Reticulocyte maturation to a mature erythrocyte takes about 1 day. The reticulocyte count is the percentage of red immature cells present in peripheral blood (normal 0.5–1.5%). The corrected reticulocyte count takes into consideration the degree of anemia and is calculated as (patient’s hct/45) × (reticulocyte count); the idea behind the calculation is to scale the reticulocyte count by multiplying by the ratio of t...

  Iron Deficiency Anemia Iron physiology.  Functionally available iron is normally found in hemoglobin,myoglobin, and enzymes (catalase and cytochromes). Additionally, ferritin is the physiological storage form (plasma ferritin is normally close to the total body Fe), and hemosiderin (Prussian blue positive) is iron precipitated in tissues in the form of degraded ferritin mixed with lysosomal debris. Iron is transported in the blood stream by transferrin. Transferrin saturation is reported as a percentage; it represents the ratio of the serum iron to the total iron-binding capacity, multiplied by 100. Dietary deficiency of iron is seen in elderly populations, children, and the poor. Increased demand for iron is seen in children and pregnant women. Additionally, iron deficiency can develop because of decreased absorption, either due to general-ized malabsorption or more specifically after gastrectomy (due to decreased acid, which is needed for ferrous absorption) or when there ...

  NORMOCYTIC ANEMIAS Anemias of blood loss. Acute blood loss may cause shock or death. If the patient sur-vives, the resulting hemodilution caused by shift of water from the interstitium will lower the hematocrit. There will be a marked reticulocytosis in 5–7 days. Chronic blood loss, such as from the gastrointestinal tract or from the gynecologic system, may result in iron deficiency anemia. Hemolytic anemias. ·              In  intravascular (IV) hemolysis , release of hemoglobin into the blood causes hemoglobinemia and hemoglobinuria; increased bilirubin from erythrocytes causes jaundice and an increased risk of pigment (bilirubin) gallstones. The hemoglobin may be oxidized to methemoglobin, which causes methemoglo-binemia and methemoglobinuria. Markedly decreased (because they have been used up) hemoglobin-binding proteins in the blood, such as haptoglobin and hemopexin, are characteristic. No splenomegaly is seen...

  MACROCYTIC ANEMIAS   The basic cause of  megaloblastic anemias  is impaired DNA synthesis (delayed mito-ses) without impairment of RNA synthesis; this produces a nuclear-cytoplasmic asynchrony that affects all rapidly proliferating cell lines, including cells of the bone marrow, gastrointestinal tract, and gynecologic system. The erythrocytes are the most obvious rapidly proliferating cells that exhibit these changes, and specifically show megaloblastic maturation, with megaloblasts in bone marrow forming macro-ovalocytes in peripheral blood. Autohemolysis of the affected megaloblasts in bone marrow (ineffective erythropoiesis) will cause increased bilirubin and increased lac-tate dehydrogenase (LDH). White blood cell changes include giant metamyelocytes in bone marrow and hypersegmented neutrophils (>5 lobes) in peripheral blood. Note that platelets are not increased in size. Megaloblastic anemia due to vitamin B 12  (cobalamin) deficiency ·   ...