HLTH 201: Ch. 23 - Disorders of Red Blood Cells

what is one adult hemoglobin composed of?

two alpha chains, two beta chains

how many iron containing heme groups is on a red blood cell?

4

How many oxygen molecules can be transported by one hemoglobin molecule?

4

what component of hemoglobin does oxygen bind to?

heme group

What is iron bound to in the blood?

transferrin

what is iron stored as inside of cells?

ferritin

What is erythropoiesis?

production of red blood cells

what is erythropoietin released by?

kidneys

What does erythropoietin stimulate?

red blood cell production in bone marrow

how long is the life span of a rbc?

120 days

what organs phagocytize RBCs?

liver, spleen, bone marrow, lymph nodes

what is hemoglobin broken down into?

globin and heme

What is globin broken down into?

amino acids and reused for protein synthesis

What is heme broken down into?

iron (recycled) and bilirubin

What happens to bilirubin?

processed by liver and excreted through bile, feces, urine

what happens if bilirubin is not processed by the liver?

binds to fat in skin and sclera of eyes causing jaundice

What is anemia?

reduction in oxygen carrying capacity of blood

what are the general signs and symptoms of anemia?

pallor, dyspnea, tachycardia, fatigue, decreased regeneration of epithelial tissue, low hematocrit

What is hemolytic anemia?

premature destruction of RBCs (before 120 days)

how do the RBCs look in hemolytic anemia?

normal

why does hemolytic anemia case hyperactive bone marrow?

premature destruction of RBCs causes bone marrow to increase RBC production to compensate for the lost RBCs

what are the genetic forms of hemolytic anemia?

Sickle cell anemia, thalassemias

What is sickle cell anemia?

Genetic disorder causing hemoglobin S instead of hemoglobin A. Causes RBCs to get stuck in capillaries and cause blockages and decreasing blood flow to tissues

when do sickle cells appear sickled?

once RBC gives up oxygen

what can cause RBCs to appear sickled?

anything that increases oxygen demands of the body

when do clinical signs of sickle cell anemia appear?

8-10 weeks of age (still have fetal hemoglobin)

what are the signs and symptoms of sickle cell anemia?

tachycardia, splenomegaly (spleen working ot to remove damaged RBCs), vascular occlusion and infarction

what is the treatment for sickle cell anemia?

Hydroxyurea

what does hydroxyurea do for patients with sickle cell anemia?

stimulates the production of fetal hemoglobin (fetal hemoglobin doesn't sickle when deoxygenated)

What is thalassemia?

decreased synthesis of globin chains of hemoglobin

What is alpha thalassemia?

RBC missing an alpha chain

What is beta thalassemia?

RBC missing a beta chain

When doing a blood smear, what would a patient with thalassemia's RBCs look like?

microcytic (missing globin chains), hypochromatic (not enough oxygen: pale)

what are the signs and symptoms of thalassemia?

general signs of anemia, increased hemolysis, heart failure, splenomegaly, hepatomegaly

why does thalassemia cause heart failure?

heart is working harder to pump blood

why does thalassemia cause splenomegaly and hepatomegaly?

spleen is removing the damaged cells. Liver processes the damaged cells. Spleen and liver are working overtime

what diagnostic tests should be done to diagnose someone with thalassemia?

blood smear (shows microcytic and hypochromatic RBCs), genetic tests

what treatments are done for thalassemia?

blood transfusions

what are acquired hemolytic anemias caused by?

drugs, chemicals, toxins, venoms, infections

what are the types of anemias caused by deficient RBC production?

iron deficiency anemia, megaloblastic anemia, aplastic anemia, chronic disease anemia

What is iron deficiency anemia caused by?

low iron intake, increased iron demands (pregnancy), chronic blood loss (menstruation), impaired iron absorption

when doing a blood smear for a patient with iron deficient anemia, how will their RBCs appear?

microcytic and hypocrhomatic

what are signs and symptoms of iron deficient anemia?

pallor, fatigue, cold intolerance, palpitations (heart beats to deliver more oxygen to tissues), delayed wound healing (tissue needs oxygen to heal)

which diagnostic tests are indicative of iron deficient anemia?

low hemoglobin, low serum ferritin and iron, microcytic and hypochromiatic RBCs

what are treatments for iron deficient anemia?

treating underly problem, iron supplements

What is megaloblastic anemia?

large, immature red blood cells

what are the types of megaloblastic anemia?

vitamin B12 deficiency anemia (pernicious anemia), folic acid deficiency anemia

What is Vit B12/pernicious anemia?

destruction of parietal cells in the stomach, leading to loss of intrinsic factor and thus inability to take up vitamin B12 (intrinsic factor is needed to absorb B12)

what do the RBCs of a patient with Vit B12/pernicious anemia look like?

megaloblastic, contains nucleus fragments (released too soon)

what are causes of vitamin b12 deficiency?

chronic gastritis (destruction of gastric mucosa), gastrectomy (removing stomach), ileal resection (ileum is where b12 is absorbed), gastric bypass surgery

what are the signs and symptoms of Vitamin b12 deficient anemia?

general anemia s/s, neurological signs: paresthesia's, demyelination (b12 is needed to maintain myelin sheaths)

what will diagnostic tests show in a patient with vitamin b12 deficient anemia?

large and immature RBCs, low serum vitamin b12, antibodies against parietal cells and intrinsic factor

what is the treatment for vitamin b12 deficient anemia?

vitamin b12 injections

what is folic acid deficient anemia caused by?

malabsorption of folic acid

which megaloblastic anemia will a patient show neurological signs and symptoms?

Vitamin b12 deficient anemia

what will the RBCs look life in folic acid deficient anemia?

megaloblastic, immature, nucleated

What is aplastic anemia?

destruction of bone marrow causing decreased production of RBC, WBC, platelets

what do the RBCs look like in aplastic anemia?

normal

what will a bone marrow biopsy show in a patient with aplastic anemia?

hypocellular bone marrow with increased fatty tissue

what are the causes of aplastic anemia?

idopathic (not knowing cause), radiation, chemicals, drugs that damage bone marrow

what are the signs and symptoms of aplastic anemia?

general anemia s/s, leukopenia (multiple infections due to low WBC), thrombocytopenia (platelet plug cannot form due to low platelets), ecchymosis, petechiae

what will diagnostic tests show for a patient with aplastic anemia?

bone marrow biopsy showing hypocellular bone marrow and increased fatty tissue

what are the treatments for aplastic anemia?

treating underlying cause, bone marrow transplant, blood transfusions

What is polycythemia?

increased number of RBCs and hematocrit greater than 50%

what are the types of polycythemia?

primary polycythemia (polycythemia vera), secondary polycythemia

what is primary polycythemia caused by?

neoplastic disorder that increases production of RBCs, granulocytes, and platelets

why does polycythemia vera cause increased hematocrit?

increased production of RBC, granulocytes, and platelets increases viscosity of blood

what are the signs and symptoms of polycythemia vera?

increased blood volume and viscosity, hypertension, hypercellular bone marrow

how do you treat polycythemia vera?

radiation, phlebotomy

what is secondary polycythemia caused by?

increased erythropoietin

what will a diagnostic test show in a patient with secondary polycythemia?

increased RBC (due to inc erythropoietin)

what are the causes of secondary polycythemia?

chronic hypoxia: heart failure (less oxygen to tissues), COPD (impaired gas exchange), high altitude

why does chronic hypoxia cause secondary polycythemia?

stimulates kidneys to release erythropoietin (increases RBC to oxygenate)

what are the treatments for secondary polycythemia?

supplemental oxygen

what is the normal bilirubin level in neonates?

below 15 mg/dL

how do you treat hyperbilirubinemia in neonates?

putting infant under UV lights to break down bilirubin