Red Blood Cell Disorders – Pathophysiology

1. Structure and Function of Red Blood Cells:

• Red blood cells (RBCs) are non-nucleated blood cells that are biconcave disc-shaped. Their primary function is to transport oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs.
• RBCs are produced in the bone marrow and fully mature before being released into the peripheral blood.
• The average lifespan of an RBC is 120 days. After this, aged RBCs are destroyed in the liver, spleen, and bone marrow.
• The average number of RBCs in the blood of an adult: 3.8 – 4.2 million/ml of blood.

2. Red Blood Cell Disorders:

Red blood cell disorders are abnormalities in the number and/or quality of red blood cells, affecting the blood’s oxygen-carrying capacity.

2.1. Disorders of Red Blood Cell Count:

• Anemia: A condition where the number of red blood cells in the blood is lower than normal, leading to reduced oxygen delivery to the tissues. Anemia can be caused by various factors, the most common being:
  • Blood loss:
    • Acute blood loss: Hemorrhage due to trauma, acute gastrointestinal bleeding, etc.
    • Chronic blood loss: Bleeding due to conditions like peptic ulcer disease, menorrhagia, bleeding from polyps, etc.
  • Decreased RBC production: Due to deficiencies in nutrients essential for blood production (iron, vitamin B12, folic acid), bone marrow failure, chronic diseases, etc.
  • Increased RBC destruction: Due to autoimmune diseases, infections, G6PD deficiency, etc.
• Polycythemia: A condition where the number of red blood cells in the blood is higher than normal. Common causes include oxygen deficiency, blood disorders, and the use of certain medications.

2.2. Disorders of Red Blood Cell Quality:

• G6PD deficiency: An inherited disorder that causes a deficiency of G6PD enzyme in red blood cells, making them vulnerable to destruction when exposed to oxidizing agents like drugs, foods, etc.
• Hemoglobin (Hb) deficiency: A condition where red blood cells have low Hb levels, reducing their oxygen-carrying capacity. Causes can include iron deficiency, thalassemia, etc.
• Macrocytosis: A condition where red blood cells are larger than normal, commonly seen in anemia due to vitamin B12 or folic acid deficiency.
• Microcytosis: A condition where red blood cells are smaller than normal, often seen in iron deficiency anemia.

Note:

• Red blood cell disorders can cause various symptoms like fatigue, dizziness, lightheadedness, pale skin, rapid heartbeat, shortness of breath, etc.
• Diagnosing red blood cell disorders involves blood tests such as:
  • Red blood cell count (RBC)
  • Hemoglobin (Hb) level
  • Hematocrit (HCT)
  • Mean corpuscular volume (MCV)
  • Mean corpuscular hemoglobin (MCH)
  • Mean corpuscular hemoglobin concentration (MCHC)
• Treatment for red blood cell disorders depends on the underlying cause and severity.

Summary:

• Red blood cells are non-nucleated blood cells that transport oxygen and CO2.
• Red blood cell disorders are abnormalities in the number and/or quality of red blood cells.
• Anemia is a condition with low red blood cell count, while polycythemia is a condition with high red blood cell count.
• G6PD deficiency, Hb deficiency, macrocytosis, and microcytosis are disorders of red blood cell quality.

Recommendations:

• Regular health checkups are recommended to detect any blood abnormalities early.
• Maintain a diet rich in nutrients, especially iron, vitamin B12, and folic acid.
• Avoid oxidizing agents that can harm red blood cells.