Hematologic Disorders: Anemias Study NotesPathoPharmacology 1

See Basic physiology Review--Hematology

Blood Composition

Plasma = aqueous component = 92%Solids = 9%--Plasma Proteins:

Albumin (53%): volume, pH & lyte balance, transport Globulin (43%): antibody formation Fibrinogen: clotting Enzymes

--Organic Components: Fats, glucose, nitrogenous products--Inorganic Components: electrolytes

Types of Blood Cells

White Blood Cells: (Leucocytes) inflammation & infection Platelets: (Thrombocytes) Clotting Red Blood Cells: (Erythrocytes) transport of O2 & CO2

Hematopoeisis:

All blood cells formed in bone marrow from pluripotential stem cell Differentiates into 5 types of “blast” cells which then produce all RBC, WBC, and platelets Marrow Stem cells continuously replace old blood cells & respond to acute needs Decrease in bone marrow function leads to decrease in all blood cells What do these terms mean and what are the clinical implications (ie what is the person at increased risk for?)

o Leucopenia: increased infectiono Thrombocytopenia: Deficiency of platelets in the blood. This causes bleeding into the tissues, bruising, and slow blood clotting

after injury.

o Erythropenia: bleedingo Pancytopenia: reduction in white blood cells, red blood cells and platelet count

RBC Life Cycle

Bone marrow production RBCs : Erythropoeitin: hormone formed in kidneys--stimulates RBC production in bone marrow by erythroblasts due to

low O2 Requires Iron, Folic Acid, Vit. B12, copper & proteins Reticulocytes: “Baby” RBCs released from bone marrow, soft & pliable, become mature RBCs in days RBCs Live 120 days Aging RBCs: become stiff & hard, broken down by spleen, liver, bone marrow and lymph nodes Hgb is recycled: globulins - amino acids; heme--Iron reused, rest goes to bile

Diagnostic Tests: Lab Studies of RBCs

1. RBC count: number of RBCs,

low--Anemias High--polycythemia

2. RBC Indices--Morphology: size, shape & color of RBCs --Helps to differentiate types of Anemia

MCV = mean cell volume = Size

Normocytic= normal size Microcytic = smaller RBCs Macrocytic = larger RBCs Anistocytic--variations in size

MCHC = mean cell Hb concentration = amt. Hb

Normochromic Hypochromic = pale, low Hgb Polychromasia: variations in color Siderocytes: contain granules of iron

Morphology variations

Poikilocytic--variations in shape Spherocytes--increased diameter (not biconcave) Sickle cells--change shape to sickle when deoxygenated

3. Hemoglobin:

usually ~12-16 gms

Electrophoresis--to determine % of different types of hemoglobin

Hb A: normal adult Hb Hb F: Fetal Hb Hb S: Sickle Cell Hb Hb Memphis

4. Hematocrit: % of blood volume that is RBCs --usually ~ 37-50%--low HCT = anemia--need to interpret in terms of overall fluid balance since is a % of blood volume-- if blood volume low or high changes interpretation of Hct

5. Reticulocyte count = bone marrow activity in making new RBCs, usually 1-2%

¡Low retic count—vitamin def or bone marrow suppression¡High retic count– hemolytic anemia or blood loss

6. Bone Marrow Aspiration & Biopsy

Purpose: Analysis of bone marrow function, diagnosis of bone marrow or blood cell malignancies Needle aspiration or biopsy from sternum or iliac crest

AnemiasPathophysiology: --Decrease in RBCs, Hb, Hct from many causes, results in decreased O2 delivery to tissues

General Signs & Symptoms of Anemia:

--Pallor: Vasoconstriction & low Hb--Tachycardia, murmur, Angina, Heart Failure--Dyspnea, Fatigue, Hypotension--Headache, dizziness, faintness, tinnitus

Appearance and severity of signs and symptoms depend on:1. Personal characteristics: *Age, underlying disease, severity of anemia, activity level

2. Effectiveness of compensatory mechanisms: * Increased cardiac output & respirations * increase in plasma volume by shifting fluid into blood * redistribution of blood to vital organs, less to skin

3. Speed of onset: *Acute onset: rapidly see S & S w/ >30% loss of RBCs *Chronic onset: compensatory mechanisms may prevent S & S even w/ 50% loss--except on exertion

Causes of Anemia-- Increased RBC loss, Increased RBC destruction, Decreased RBC production

I. Increased RBC Loss:

A. Hemorrhage:

Acute trauma Chronic--ulcers, polyps, cancer

II Increased RBC Destruction: Hemolysis:

1. Hemoglobinopathies --Anemia due to Abnormal Hemoglobin:

a. Sickle Cell Anemia: --inherited disease resulting in alteration in globin fraction of Hb: replacement of amino acid valine with glutamic acid = HbS --results in change in shape of RBC--sickling--microvascular occlusion and hemolytic anemia

Heterozygous inheritance = Sickle Cell Trait (40% Hb = HbS, few symptoms) Homozygous inheritance = Sickle Cell Disease (all Hb = HbS, many symptoms and often death)

Most common genetic disease in USA

Affects mainly African Americans: 1 in 375 w/ disease, 9-10% w/ Traitalso affects those of Mediterranean, Italian, Indian, and Arab descent

Pathophysiology:--Abnormal Hb S sickles when deoxygenated-- click here to see slide--occurs in infections, illnesses w/ hypoxia, acidosis, dcehydration, exertion--Sickled cells occlude microvasculature causing ischemia and infarction --common sites: abdomen, chest, joints --chronic organ damage from ischemia or infarction to spleen, kidney, liver, heart, retina --acute chest syndrome: atypical pneumonia after pulm infarct --Stroke: most serious and often fatal complication

--Sickling is reversible, but after several episodes, cells are fragile and break--Hemolyzed cells are removed by Monocyte-Macrophage system--Decreases RBC life span to 10 - 15 days--Bilirubin from hemolyzed cells increases--causes jaundice & bile gallstones

Lab studies: --low Hb, Hct, RBC count --increased reticulocyte count, bilirubin and uric acid--May see erythroblasts-- Bone marrow hyperplastic

Signs & Symptoms: due to vascular occlusion--Babies are asymptomatic until 5-6 months (due to HbF)--Then increased risk severe bacterial infection due to spleen activity (few antibodies; need spleen to remove bacteria)--Swollen painful inflamed hands and feet, knees, back--Failure to thrive, decreased growth & development--Anemia: tachycardia, CHF--renal and pulmonary impairment--Cerebral occlusions--- stroke

Sickle Cell Crisis: requires immediate medical intervention1. Vaso-Occlusive crisis: most prevalent and causes above S/S2. Splenic Sequestration: massive spenomegaly, hypovolemic shock3. Aplastic crisis: markedly decreased RBCs, Hb

Nursing care:

neonatal screening for sickle cell:--leads to early identification nursing care is geared toward prevention of crises and therefore decreased symptoms

--includes daily prophylactic administration of penicillin until child is 6 Bone marrow transplantation is new treatment for SC cure, proving to be effective See Maternal-Child Nursing course for details of nursing interventions…..

Excellent web resources:

Emory University Sickle Cell article Human Genome Project Sickle Cell site

"Bobby Blood Cell" teaching guide aimed at children with SC

b.) Thalassemia- absent or defective synthesis of the alpha and beta chains

2. Acquired hemolysis--Extrinsic causes

Immune mechanisms (blood transfusion reaction) Infection (malarial, clostridal) Drugs (quinidine, penicillin, methyldopa) Liver or kidney disease Toxins (chemical, venoms)

III. Decreased or defective RBC production: A. Aplastic Anemia:

Stem Cell disorder causes Pancytopenia: insufficient numbers of RBC, WBC, plts RBC Studies show: low reticulocyte count, normochromic, normocytic RBCs Bone marrow biopsy: Hypoplasia

Causes: congenital, idiopathic, or secondary to drugs (antibiotics, antineoplastics, anticonvulsants), radiation therapy, chemicals (organic solvents, insecticides)

Signs & Symptoms: o Leukopenia-- increased infectionso Erythropenia--Anemia symptomso Thrombocytopenia—Bleeding

Treatment: -Supportive until bone marrow recovers-Prevent bleeding and infection (main causes of death)

Medications: Bone Marrow Stimulating Medications:

1. Erythropoeitin (Epogen, Procrit):

o Used for:o Common AEso Nursing implications

2. Granulocyte Colony Stimulating Factor, Filgastrin (Neupogen): a. Used for:b. Common AEsc. Nursing implications

-Surgical: Bone marrow transplant

B. Microcytic Anemia: Iron Deficiency Anemia

-Microcytic, hypochromic anemia -Normal amount of RBC , low Hb, normal or low reticulocyte count-Major cause of Anemia worldwide due to low iron intake, persistent blood loss, or decreased iron absorption (duodenum, jejunum)

Treatment:

Fix underlying cause: (Surgery?)Diet modifications: increase IronMedications: Iron supplements po or IV/IM

Iron Medications1. Oral: Ferrous Sulfate, Ferrous Gluconate--dose according to how much elemental iron supplied (12-20%); only ~10-15% iron is absorbedCommon AEs: GI--nausea, anorexia, dark tarry stoolsNursing Implications: Give with meals to decrease GI irritationContraindicated w/ peptic ulcer disease or inflammatory bowel disease

2. Parenteral: Iron Dextran, Imferon--Given IM or IV for clients who cannot tolerate po iron or who need rapid replenishmentCommon AEs & Nursing Implications:-May stain skin when given IM, so give Z-Track to dorsal gluteal w/ long needle -IV preparation must be given diluted & over several hours to avoid anaphylaxismay see tachycardia, hypotension, shock with IM or IV

C. Macrocytic or Megaloblastic Anemias: Vit. B12 or Folate Deficiency

-Macrocytic, normochromic Anemia with a low reticulocyte count, Hct & Hb-Causes: malnutrition, folic acid deficiency, pregnancy, malabsorption, lack of intrinsic factor (Pernicious Anemia), parasites, cancer, chemotherapySymptoms: Anemia symptoms listed above & glossitis, diarrhea, anorexiaTreatment: -treat underlying cause-dietary modifications--increase folate & Vit. B12

Medications--folate and Vit B12 replacement

Common AEs:

Nursing Implications:

D. Anemia of Chronic Disease

Normocytic/Normochromic mild to moderate anemia associated with chronic conditions such as AIDS, RA, acute and chronic hepatitis, chronic renal failure and

malignancies

Polycythemia= Condition of excess blood cells (generally excess RBCs): leads to hyperviscosity & increased blood volume--Relative polycythemia: loss of plasma volume so > in Hct; main cause dehydration--Absolute polycythemia: increase in actual # of cells --Polycythemia Vera: abnormal stem cells: increased RBC, WBC, and plts--secondary Polycythemia: due to other medical conditions such as COPD

Treatment: phlebotomy, chemotherapy, treat cause