Hematology

HEMATOLOGIC DISORDERS: ANEMIA

Objectives

• Independently review the anatomy, physiology, and functions of the hematologic system.
• Identify the etiology, pathophysiology, clinical manifestations, and collaborative care of patients with hematologic problems.

Blood Composition

• Plasma (55% of blood)
    - Water: 91%
    - Proteins (7%):
      - Albumin: 58%
      - Globulin: 38%
      - Fibrinogen: 2%
    - Other solutes: 2% (ions, nutrients, waste products, gases)
• Formed Elements (45% of blood):
    - Leukocytes (White Blood Cells): 4-11 x 10^3/µL
      - Neutrophils: 50%-70%
      - Lymphocytes: 20%-40%
      - Monocytes: 4%-8%
      - Eosinophils: 2%-4%
      - Basophils: 0%-2%
    - Erythrocytes (Red Blood Cells): 4-6 x 10^6/µL
    - Platelets: 150,000-400,000 per µL

Anemia

• Definition: A deficiency in the number of erythrocytes (red blood cells).
• Causes of Anemia:
    - Blood Loss
    - Impaired Production
    - Increased Destruction of Erythrocytes

Hemoglobin (Hgb)

• Function: Hemoglobin is the vehicle for O2 and CO2 transport.
• Normal Hgb Levels (indicating normal RBC size and amount of Hgb present):
    - Male: 14-18 g/dL
    - Female: 12-16 g/dL
• Diagnostic Test: Order 5-7 mL blood in a lavender top tube.
• Abnormal Hgb Levels:
    - ↓ Hgb may indicate anemia.
    - Effects of Blood Volume:
      - ↓ with overhydration.
      - ↑ with dehydration.
• Hematocrit (Hct): Normally 3× level of Hgb.
    - Male: 42-52%
    - Female: 37-47%
    - Newborn: 44-64%

Clinical Manifestations of Anemia

• Severity of Anemia:
    - Mild (Hgb 10-12 g/dL):
      - Integument: None
      - Eyes: None
      - Mouth: None
      - Cardiovascular: Palpitations
      - Pulmonary: Exertional dyspnea
      - Neurologic: None
      - General: None or mild fatigue
    - Moderate (Hgb 6-10 g/dL):
      - Increased palpitations, “bounding pulse”
      - Increased dyspnea
      - Fatigue
    - Severe (Hgb <6 g/dL):
      - Integument: Pallor, jaundice, pruritus
      - Eyes: Icteric conjunctiva and sclera
      - Mouth: Glossitis, smooth tongue
      - Cardiovascular: Tachycardia, heart failure, angina
      - Pulmonary: Tachypnea, orthopnea, dyspnea at rest
      - Neurologic: Headache, vertigo, irritability, impaired thought processes
      - Gastrointestinal: Anorexia, hepatomegaly, splenomegaly
      - Musculoskeletal: Bone pain

Anemia Classification

• Morphologic Classification: Based on size and color of RBCs.
• Etiology: Causes of anemia grouped according to origin.
• Relationship Table:
    - Normocytic, normochromic (normal size and color): MCV 80-100 fL, MCH 27-34 pg
      - Causes: Acute blood loss, hemolysis, chronic kidney disease, cancers.
    - Microcytic, hypochromic (small size, pale color): MCV

Types of Anemias

Iron Deficiency Anemia

• Commonality: One of the most prevalent chronic hematologic disorders.
• Etiologies:
    - Inadequate dietary intake
    - Malabsorption
    - Blood loss
    - Hemolysis
    - Cancer
• Collaborative Care:
    - Diagnostic:
      - History and physical examination
      - Hct, Hb, RBC count, morphology
      - Reticulocyte count
      - Serum iron levels
      - Serum ferritin
      - Serum transferrin
      - Total iron-binding capacity (TIBC)
      - Stool examination for occult blood
    - Treatment:
      - Identify and treat underlying cause.
      - Iron supplementation: Ferrous sulfate, gluconate, iron dextran.
      - Nutritional therapy.
      - Transfusion of packed RBCs as needed.

Megaloblastic Anemias

• Characteristics: Large blood cells.
• Types: Cobalamin (B12) deficiency and folic acid deficiency.
• Cobalamin (B12) Deficiency Etiology:
    - Absence of intrinsic factor (IF)
    - Gastric lining secreted by parietal cells, needed for absorption of B12.
    - Causes include GI surgery and long-term H2 receptor blockers.
• Clinical Manifestations:
    - General anemia symptoms
    - Neuromuscular: Weakness, paresthesias.
    - Diagnosis: CBC, Serum folate, and B12 levels.
    - Treatment involves parenteral B12 administration.

Folic Acid Deficiency

• Characteristics: Cause of megaloblastic anemia.
• Common Causes:
    - Poor nutrition
    - Malabsorption syndromes
    - Drug use
    - Alcohol abuse
• Clinical Manifestations:
    - Similar to cobalamin deficiency, but without neurologic issues.
    - Treated via dietary replacement therapy.

Anemia of Chronic Disease

• Characteristics: Underproduction of RBCs.
• Causes include end-stage renal disease and chronic inflammation.
• Indicates: ↓ Erythropoietin levels.
• Findings:
    - ↑ Serum ferritin
    - ↑ Iron stores
    - Normal folate and B12 levels.
• Treatment: Focus on underlying cause; seldom requires blood transfusions.

Aplastic Anemia

• Characteristics: Body stops producing RBCs, WBCs, and platelets (Pancytopenia).
• Etiologies include congenital alterations and acquired causes (radiation, chemicals, infections).
• Treatment: Erythropoietin and blood transfusions as necessary.

Blood Loss Anemia

Acute Blood Loss

• Characteristics: Sudden hemorrhage, trauma, surgical complications.
• Clinical Manifestations: Hypovolemic shock, reduced plasma volume, decreased O₂ availability.
• Management: Replace blood volume, identify and stop bleeding, correct RBC loss.

Chronic Blood Loss

• Characteristics: Gradual reduction in iron stores.
• Common Causes: Bleeding ulcers, hemorrhoids, menstrual postmenopausal loss.
• Management: Identify source, stop bleeding, potential use of iron supplements.

Epoetin Alfa (Procrit)

• Use: Synthetic erythropoietin, increases Hct and Hb.
• Indications: Treats anemia associated with renal failure and chemotherapy.
• Cautions: Watch for hypertension, headache, nausea; monitor serum iron levels.

Sickle Cell Anemia

• Characteristics: Genetic, inherited autosomal recessive disorder.
• Cause: Hemoglobin S (HbS) causes the RBCs to sickle under low oxygen levels.
• Clinical Manifestations: Typically asymptomatic except during crisis; symptoms include pain, swelling, pallor, fatigue.
• Sickle Cell Crisis:
    - Blockage of blood vessels
    - Symptoms: Acute chest pain, hypoxia, fever, pain, splenomegaly.
    - Treatment includes hydration, oxygen, pain relief.

Diagnosis of Sickle Cell Anemia

• Tests:
    - Peripheral blood smear
    - Sickling test
    - Hemoglobin electrophoresis
    - DNA testing

Hemochromatosis

• Definition: Autosomal recessive disease with increased iron absorption.
• Goal of Treatment: Remove excess iron from the body and minimize symptoms.

Polycythemia

• Definition: Increased production of RBCs leading to impaired circulation.
• Treatment Objective: Reduce blood volume/viscosity and bone marrow activity.
• Phlebotomy is the main treatment method.

Problems of Hemostasis

Thrombocytopenia

• Understanding the Condition: Discussed in the cancer unit; review concepts in text.

Management and Nursing Considerations

• Avoid Injury: High risk scenario.
• Medications to Avoid: Aspirin, NSAIDs, etc., that increase bleeding risk.

Hemophilia

• Characteristics: Inherited blood disorder with symptoms including:
    - Intracranial hemorrhages
    - Prolonged nosebleeds
• Treatment: IV administration of deficient clotting factor.

Neutropenia

• Review: Discussed in cancer unit; responsible for independent study.

Blood Component Therapy

• Transfusion Guidelines:
    - Verify client allergies and previous transfusion reactions.
    - Administer within 30 minutes of receiving from the blood bank.
    - Use a large gauge needle (18G or 20G) with saline.
• Monitoring for Reactions:
    - Key signs include chills, flushing, fever, low back pain, hypotension.

Disseminated Intravascular Coagulation (DIC)

• Description: Secondary coagulation disorder with underlying vascular damage.
• Causes: Shock, hemolytic processes, sepsis, obstetric complications.
• Clinical Manifestations: Thrombocytopenia, prolonged bleeding, hypotension, organ dysfunction.
• Treatment: Correct underlying issues, transfusions, consider heparin under specific conditions.