hematology

HEMATOLOGY: ANEMIAS

OBJECTIVES

  • The student will:
    • Understand common lab values related to anemia disorders.
    • Understand diagnostics related to anemia disorders.
    • Understand and discuss common assessment findings related to anemia.
    • Understand and discuss nursing care associated with anemia disorders.
    • Understand and discuss common treatments for anemia disorders.

RED BLOOD CELLS AND OXYGEN TRANSPORT

  • Function of Red Blood Cells (RBCs):

    1. Oxygen transportation from the lungs.
    2. Oxygen bonding occurs with hemoglobin.
    3. Oxygen is released to tissue cells.

  • Regulation of Erythropoiesis:

    • Normal oxygen levels in the body are essential.
    • Low oxygen levels:
    • Reduced oxygen-carrying capacity of the blood, which can be caused by:
      • Hypoxia.
      • Decreased O$_2$ availability to the blood.
      • Increased O$_2$ demand from tissues.
    • Response:
    • Kidneys secrete the hormone erythropoietin (EPO) that:
      • Stimulates enhanced erythropoiesis in the bone marrow.
      • Results in increased RBC count and oxygen-carrying capacity of the blood.

ANEMIA

  • Definition:
    • A deficiency in the number of RBCs or erythrocytes.
    • A deficiency in the quality or quantity of hemoglobin.
    • A deficiency in the volume of packed RBCs (hematocrit).
    • It is not a specific disease but a manifestation of a pathologic process requiring further investigation to determine the specific cause.

CAUSES OF ANEMIA

  • Decreased RBC Production:
  • Blood Loss:
  • Increased RBC Destruction:
    • Factors affecting these causes include trauma, liver disease, nutrient deficiencies (Iron, B$_{12}$, Folic acid), and GI ulcers.

CLINICAL FINDINGS

  • Classification of Anemia Severity by Hemoglobin (Hgb):
    • Mild: Hgb 10 to 12 g/dL.
    • Symptoms: Mild fatigue, exertional dyspnea, heart palpitations, tachycardia with activity.
    • Moderate: Hgb 6 to 10 g/dL.
    • Symptoms: Fatigue at rest, headache, dizziness (orthostatic hypotension), significant pallor.
    • Severe or Quick: Hgb < 6 g/dL.
    • Symptoms: Tachycardia at rest, tachypnea and dyspnea at rest, cold to touch, hypotension.
    • General findings: Low RBCs, hemoglobin, and hematocrit levels.

NUTRITIONAL DEFICIENCY ANEMIA

Vitamin B$_{12}$ (Cobalamin)
  • Roles of Vitamin B$_{12}$:
    • Essential for neurological development.
    • Crucial for RBC and WBC production.
    • Supports healthy nerve cell function.
Pernicious Anemia
  • Characteristics:
    • Typically begins in middle age or later (usually after age 40).
    • Characterized by a lack of intrinsic factor (IF), a protein secreted by gastric mucosa, required for B$_{12}$ absorption.
    • Requires B$_{12}$ injections; may have other secondary causes, such as:
    • GI surgeries, Crohn’s, celiac disease, gastritis, and H. pylori infections.
    • Excessive alcohol or hot tea consumption.
    • Long-term use of proton-pump inhibitors (e.g., Esomeprazole, Lansoprazole).
    • Long-term H2-blockers (e.g., Famotidine).
    • Vegetarian diets.
Findings in B$_{12}$ Anemia
  • Symptoms: Gradual onset of anemia symptoms, paresthesia (numbness/tingling), muscle weakness, poor balance (ataxia), memory impairment.
  • Oral Findings: Smooth, red, beefy tongue (glossitis) and sores at the side of the mouth.
Diagnostics for B$_{12}$ Anemia
  • Characterized as megaloblastic/macrocytic anemia.
  • Increased mean corpuscular volume (MCV), often exceeding 110 fL.
  • Low Hgb, hematocrit, and RBC counts.
  • Decreased vitamin B$_{12}$ level (<200 pg/mL).
  • Positive intrinsic factor antibody test indicates pernicious anemia.
Treatment and Nursing Care for Pernicious Anemia
  • Requires IM injections of B$_{12}$ weekly until levels normalize, then monthly for life.
  • Encourage dietary intake of B$_{12}$ from as many sources as possible.
Folic Acid Deficiency
  • Causes:
    • Dietary deficiency (e.g., leafy greens, citrus fruits).
    • Malabsorption syndromes (e.g., Celiac disease, Crohn’s).
    • Medications that interfere with absorption (e.g., Metformin, Phenytoin).
    • Excessive alcohol use.
    • Increased requirements (e.g., pregnancy).
Clinical Manifestations of Folic Acid Deficiency
  • Similar to B$_{12}$ deficiency but no neurological symptoms.
Diagnostics for Folic Acid Deficiency
  • Decreased folate levels (normal 5 to 25 ng/mL).
  • Symptoms may include smooth, red tongue, and oral sores.
Treatment of Folic Acid Deficiency
  • Folic acid replacement through supplements or dietary adjustments including:
    • Leafy greens, asparagus, broccoli, papaya, oranges, and various legumes and nuts.

IRON DEFICIENCY ANEMIA

Role of Iron
  • Necessary for various bodily functions, primarily oxygen transport.
Causes of Iron Deficiency Anemia
  • Most common in women and older adults due to:
    • Poor dietary intake or absorption.
    • Bleeding (GI blood loss, trauma).
    • Increased need (e.g., pregnancy, heavy menstruation).
  • Medications that may lead to bleeding or decreased absorption (e.g., anti-platelet drugs, anticoagulants such as Clopidogrel, NSAIDs, and Aspirin).
Clinical Manifestations of Iron Deficiency Anemia
  • Symptoms include fatigue, pallor, shortness of breath (SOA), paresthesia, cheilitis/glossitis, cravings for non-nutritive substances (PICA), cold intolerance, and koilonychia (spoon nails).
Diagnostics for Iron Deficiency Anemia
  • History and physical examination, CBC showing decreased iron levels:
    • Men: 65-176 mcg/dL.
    • Women: 50-170 mcg/dL.
  • Occult blood test to identify bleeding.
Treatment of Iron Deficiency Anemia
  • Dietary Sources of Iron:
    • Haem iron from animal sources: Red meat, fish, eggs.
    • Non-haem iron from plant sources: Tofu, legumes, spinach, nuts.
Treatment of Mild Iron Deficiency
  • Oral iron replacement for 3 to 6 months on an empty stomach for optimal absorption (Vitamin C enhances this).
  • May interfere with certain antibiotics and cause GI side effects (e.g., heartburn, constipation).
Treatment of Severe Iron Deficiency
  • IV iron treatment with an initial test dose to monitor for anaphylaxis.
  • Nursing care includes monitoring vital signs, oxygen status, and administering emergency medications (e.g., epinephrine).

ANEMIA RELATED TO BLOOD LOSS

Types of Blood Loss

  • Acute:

    • Sudden loss of blood volume with acute symptoms reflecting the degree of loss (e.g., tachycardia, hypotension).

  • Chronic:

    • Slow blood loss may lead to vague symptoms (e.g., fatigue, lethargy).
Acute Blood Loss Manifests by Percentage and Volume:
  • 10% (500 mL): Asymptomatic or mild symptoms.
  • 20% (1000 mL): Tachycardia with activity.
  • 30% (1500 mL): Postural hypotension and tachycardia during exercise.
  • 40% (2000 mL): Symptoms at rest including decreased BP and tachycardia.
  • 50% (2500 mL): Signs of shock.
CASE STUDY: MRS. HARRIS
  • A 78-year-old female presents with shortness of breath worsening over several days. PMH includes hip arthroplasty and medications including anticoagulants.
  • Assessment findings indicate potential blood loss including pale oral mucosa and skin petechiae. CBC shows Hgb at 7 mg/dL, triggering admission for treatment.
Treatment of Blood Loss
  • Fluid replacement with isotonic fluids (e.g., 0.9% NS).
  • Transfusion of packed RBCs as necessary.
Nursing Care
  • Monitor vital signs, blood work (CBC, PT/aPTT, INR), and devices like tubes and dressings.
  • Monitor treatment response closely.

APLASTIC ANEMIA

  • Characterized by pancytopenia (decrease in all blood cell types) leading to severe complications like bleeding and infections.
Clinical Manifestations
  • Symptoms include fatigue, dyspnea, tachycardia, petechiae, and flu-like symptoms.
Diagnostics
  • Laboratory studies confirm pancytopenia. Bone marrow biopsy reveals hypocellular marrow with increased fat content.
Nursing Care for Aplastic Anemia
  • Management focuses on identifying and removing causative agents and providing supportive care. Monitor for complications like bleeding and infection.

SICKLE CELL ANEMIA

  • An inherited group of disorders characterized by abnormal hemoglobin leading to sickling of RBCs, predominantly affecting African Americans.
Pathophysiology
  • Triggers for Sickle Cell Crisis:
    • Hypoxia, stress, dehydration, high altitude, and blood loss.
  • Sickle cells can lead to vaso-occlusion and potential organ failure.
Clinical Manifestations and Diagnostics in Sickle Cell Crisis
  • Symptoms include pain, edema, elevated vital signs, decreased oxygen saturation, and supportive diagnostics (CBC, peripheral blood smear, and imaging where necessary).
Treatment and Nursing Care for Sickle Cell Crisis
  • Oxygen therapy to reverse sickling and decrease pain, along with hydration strategies and pain management using IV narcotics.
Complications of Sickle Cell Disease
  • Risk for thrombosis, hemorrhage, acute chest syndrome, and multiple organ systems may be involved.
Acute Chest Syndrome in Sickle Cell Disease
  • A life-threatening complication where sickle-shaped RBCs block blood vessels in the lungs, leading to varied respiratory symptoms.
Treatment and Nursing Care of Acute Chest Syndrome
  • Manage IV fluids cautiously, provide oxygen therapy, and consider antibiotics and bronchodilators as necessary.

LEARNING CHECK QUESTIONS

  1. Identify appropriate dietary recommendations for managing iron-deficiency anemia.
  2. Recognize medications that may contribute to Vitamin B$_{12}$ deficiency (e.g., Famotidine).
  3. Assess nursing priorities for patients receiving IV iron therapy and managing sickle cell crisis.