anemia Flashcards
what is anemia? what are the three underlying causes?
Anemia, which is defined as a reduction in the oxygen- carrying capacity of the blood, usually is associated with a decreased number of circulating RBCs or an abnormal- ity in the Hb contained within the RBCs. Anemia is not a disease but rather a symptom complex that may result from one of three underlying causes:
(1) decreased pro- duction of RBCs (iron de ciency, pernicious anemia, folate de ciency),
(2) blood loss, or
(3) increased rate of destruction of circulating RBCs (hypersplenism, autoim- mune destruction).
where does erythopoiesis occur? what is hemoglobin? what is the sensor for blood oxygenation? if low what does it release?
About 1% of the circulating erythrocyte mass is gener- ated by the bone marrow each day. Precursors of RBCs are reticulocytes, which account for 1% of the total RBC count. The normal RBC is about 33% hemoglobin by volume. Hemoglobin (Hb), the oxygen-carrying mol- ecule of erythrocytes, consists of two pairs of globin chains (i.e., α plus β, δ, or γ) that form a shell around four oxygen-binding heme groups. Oxygen demand (hypoxia) serves as the stimulus for erythropoiesis. The kidney serves as the primary sensor for determining the level of oxygenation. If the level is low, the kidney releases erythropoietin, a hormone that stimulates the bone marrow to release RBCs. About 95% of erythropoietin is produced by cor- tical cells in the kidney. The other 5% is produced by the liver.6,7
types of anemia?
iron deficiency anemia (lack of iron, or absorption of iron), folate dificiency anemia (vitamin b12 and folic acid are needed for RBC formation and growth within bone marrow, folate not stored in body in large amounts so continual dietary supply is needed from fruits and leafy vegetables, some drugs and alcohol inhibit absorption, pregnancy is a risk factor) and pernicious anemia (deficiency of intrisnic factor which is secreted by the stomach parietal cells that is necessary for absorption of vitamin B12), hemolytic anemia (caused by immune attack, extrinsick factors (infection, splenomegaly, drugs, eclampsia), disorders of the RBC membrane, enzymopathies, and hemoglobinopathies), hemolytic anemia (glucose-6-phosphate dehydrogenase deficiency an enzyme that helps the RBC to turn carbohydrates into energy), sickle cell anemia, aplastic anemia (occurs when the bone marrow is unable to produce adequate numbers of RBCs, white blood cells, and platelets), renal disease (if significant renal damage occurs, lack of production of erythropoietin, which stimulates RBC production by the bone marrow, will occur).
what are some tests?
The screening tests done prior to surgery include:
Complete (overall health, variety of diseases/leukemia/infection), and differential (percentage of each type of white blood cells, neutrophils, lymphocytes, monocytes, eosinophils, and basophils. ) blood counts. s
-A smear for cell morphological study
-Determination of Hb or hematocrit
-Sickledex test
-Platelet count
-Complete blood count and differential includes: Hb level, hematocrit and RBC indicies, total white blood cell count and platelet count. These are obtained to determine whether there is a possibility of bone marrow defect and to inspect neutrophils.
- Mean corpuscular volume (MCV)
-Mean corpuscular hemoglobin
-Mean corpuscular hemoglobin concentration (MCHC)
-Red cell distribution width (RDW)
-The dentist must evaluate the patients test, determine if blood transfusions for severe anaemia or if complications can be expected. The tests can also provide information on the origin or type of anaemia or potential underlying problems which lead to the anaemia (peptic ulcer or carcinoma). Infections can also lead to increased rate of hemolysis (rupture or destruction of blood cells).
-May also consider serum iron levels.
What is iron deficiency anemia in men most commonly due to?
-It is most likely due to a GI disorder such a peptic ulcer, hiatal hernia with linear erosions, colonic vascular ectasia, colonic polyps, and chron’s disease. These can lead to chronic bleeding. Unlikely due to dietary factors but always a possibility.
what woudl a blood smear look like for iron deficiency anemic patient?
Iron deficiency anemia is a microcytic anemia which would show RBCs that are small and show marked hypochromic central pallor (pale in colour). They will show variability in their shape and size.
