Anaemia

UPDATED ON Tue, 27 Aug, 2024 BY THOMPSON, RN RAEN.

Definition:

Anaemia is defined as a condition characterized by a reduction in the number of circulating red blood cells (RBCs) or a decrease in the haemoglobin concentration, leading to a reduced capacity of the blood to carry oxygen.

Haemoglobin (Hb) levels vary by age and sex. In newborns, Hb levels are approximately 20g/dl but decrease as the child grows. The normal haemoglobin range for adult males is 14-18g/dl, or a packed cell volume (PCV) of 40-50%. For adult females, the normal range is 12-16g/dl, or a PCV of 37-47%.

Classification of Anaemia

Anaemia can be classified based on various factors such as the underlying cause, the size and color of red blood cells, and the mechanism of red blood cell loss. Below are the primary classifications:

Classification by Underlying Cause:

  1. Deficiency Anaemia: Caused by a lack of essential nutrients required for red blood cell production, such as iron, vitamin B12, and folic acid. Examples include Iron Deficiency Anaemia, Vitamin B12 Deficiency Anaemia (Pernicious Anaemia), and Folate Deficiency Anaemia.

  2. Aplastic Anaemia: Results from damage to the bone marrow, leading to reduced production of red blood cells, white blood cells, and platelets. Can be caused by factors such as radiation, chemotherapy, certain drugs, infections, and autoimmune diseases.

  3. Haemolytic Anaemia: Occurs when red blood cells are destroyed faster than they can be produced. Causes include genetic conditions like Sickle Cell Anaemia, Thalassemia, autoimmune diseases, certain infections, and exposure to toxins or certain medications.

  4. Haemorrhagic Anaemia: Results from acute or chronic blood loss, which reduces the number of circulating red blood cells. Common causes include trauma, gastrointestinal bleeding, heavy menstrual bleeding (menorrhagia), and surgery.

  5. Idiopathic Anaemia: The cause of anaemia is unknown or cannot be identified despite investigations.

Classification by Red Blood Cell Size and Color (Morphological Classification):

  1. Microcytic, Hypochromic Anaemia: Characterized by smaller-than-normal red blood cells (microcytic) and reduced hemoglobin content, making them appear pale (hypochromic). Commonly caused by iron deficiency, thalassemia, and chronic diseases.

  2. Normocytic, Normochromic Anaemia: Red blood cells are of normal size (normocytic) and hemoglobin content (normochromic), but the overall number of red blood cells is reduced. Often seen in conditions like chronic diseases (e.g., renal failure, liver disease), acute blood loss, and aplastic anaemia.

  3. Macrocytic, Normochromic Anaemia: Characterized by larger-than-normal red blood cells (macrocytic) with normal hemoglobin content. Common causes include vitamin B12 deficiency, folate deficiency, and certain medications that affect DNA synthesis.

Classification by Mechanism of Red Blood Cell Loss:

  1. Decreased Red Blood Cell Production: This includes anaemias caused by nutritional deficiencies, bone marrow failure, or chronic diseases that interfere with red blood cell production.

  2. Increased Red Blood Cell Destruction (Haemolysis): Anaemias caused by conditions where red blood cells are destroyed faster than they can be produced, such as in haemolytic anaemia.

  3. Blood Loss (Haemorrhage): Anaemia resulting from significant blood loss, either acutely (e.g., from trauma) or chronically (e.g., gastrointestinal bleeding).

Clinical Manifestations:

Clinical symptoms vary depending on the type or cause of anaemia.

  • General fatigue and weakness.
  • Reduced exercise tolerance.
  • Shortness of breath on exertion.
  • Pale skin and mucous membranes.
  • Increased pulse rate and palpitations.
  • Headache, dizziness, and potential fainting episodes.
  • Bruising (ecchymoses) and small red or purple spots on the skin (petechiae).
  • Orthostatic hypotension (a drop in blood pressure upon standing).
  • Jaundice, particularly in haemolytic or megaloblastic anaemia.
  • Neurological symptoms such as paresthesia and ataxia, especially in vitamin B12 deficiency
  • Brittle and ridged nails, commonly seen in iron deficiency.
  • Gastrointestinal symptoms like anorexia, diarrhea, or constipation.
  • Additional complications like angina, splenomegaly (enlarged spleen), or lymphadenopathy (enlarged lymph nodes) may occur.

Nursing Management: Pre-hospital Care

  • Access the scene for hazard
  • Place the patient in a comfortable position.
  • Assess the patient’s airway, breathing, and circulation (ABC) and provide necessary interventions
  • Stop any external bleeding using sterile dressings and bandages.
  • Restrict the patient from unnecessary movement.
  • Encourage the intake of fluids and nourishing foods as tolerated.
  • Transport the patient to an appropriate healthcare facility.

Hospital-Based Care:

  • Receive and admit the patient.
  • Position the patient semi-upright to ease breathing.
  • Connect the patient to a multi-parameter (cardiac) monitor.
  • Reassess the patient's ABC and intervene as needed.
  • Administer oxygen if necessary and monitor vital signs.
  • Assist the doctor in obtaining IV access and blood samples for laboratory investigations such as PCV or Full Blood Count (FBC), Genotype, etc.
  • Ensure bed rest to prevent fatigue and reduce metabolic demand.
  • Obtain a thorough history of recent medication use, as some drugs may depress bone marrow activity, induce haemolysis, or interfere with folate metabolism.
  • Investigate family history for hereditary conditions like sickle cell disease.
  • Conduct a nutritional assessment to identify deficiencies in iron, folate, vitamin B12, or other essential nutrients.
  • Inquire about excessive menstrual flow, other types of vaginal bleeding, and the use of iron supplements during pregnancy.
  • Assess the patient’s socioeconomic status, as children from impoverished families may have a higher risk of anaemia due to nutritional deficiencies.
  • Obtain an accurate history of alcohol consumption, as alcohol can interfere with nutrient absorption and utilization.
  • Check and record pre-transfusion vital signs
  • Administer prescribed pre-transfusion medications.
  • Assist the doctor in setting up and monitoring blood transfusions (refer to chapter one for details on blood transfusion).
  • Identify and treat the underlying cause of anaemia.
  • Involve a nutritionist to help plan and optimize the patient’s diet.
  • Encourage adequate intake of nutritious foods as recommended by the nutritionist.
  • Educate the patient about the effects of alcohol on nutrient absorption and encourage them to limit or avoid alcohol.
  • Involve family members in the care of the patient to enhance compliance with dietary and treatment recommendations.