Anemia Overview and Pathophysiology

Study Notes

Anemia is a deficiency in red blood cells (RBCs), hemoglobin, or packed RBC volume (hematocrit).
It's a sign of an underlying disorder, not a specific disease.
It's the most common hematologic condition.

Reduced RBC count can be due to three factors:
- Impaired RBC production (e.g., aplastic anemia, nutritional deficiencies)
- Increased RBC destruction (e.g., hemolytic anemia, sickle cell anemia)
- Massive or chronic blood loss
Some anemias are related to genetic problems.

Dietary deficiencies: Iron, folic acid, and vitamin B12 are essential for healthy RBC production; deficiencies lead to anemia.
- Pernicious anemia is caused by a lack of intrinsic factor in stomach secretions, which is needed for vitamin B12 absorption.
Hemolysis: Destruction (lysis) of RBCs leads to hemolytic anemia. This can be congenital or due to toxins.
Other causes: Thalassemia is a hereditary anemia common in Southeast Asia, Africa, Italy, and the Mediterranean islands where hemoglobin synthesis is abnormal. Chronic disease can also cause anemia.

Hemoglobin (Hgb) levels are used to gauge anemia severity.
- Mild anemia (Hgb 10-12 g/dL) may be asymptomatic.
- Moderate anemia (Hgb 6-10 g/dL) can cause general anemia symptoms.
- Severe anemia (Hgb < 6 g/dL) shows more pronounced symptoms.
Symptoms include:
- Mild tachycardia (increased heart rate) with exertion
- Fatigue
- Dyspnea (shortness of breath)
- Chest pain
- Muscle pain
- Pale skin, cold extremities
- Yellowing of the eyes
- Low blood pressure
- Rapid or irregular heartbeat

Complete Blood Count (CBC): Measures RBCs and WBCs per cubic millimeter.
Hemoglobin and hematocrit levels: Used to diagnose the presence and severity of anemia, as they indicate a decrease from normal levels.
Serum iron, ferritin, and total iron-binding capacity: Diagnose iron-deficiency anemia.
Serum folate: Diagnoses folic acid deficiency anemia.
Bone marrow biopsy and analysis may also be needed.

Hypo-proliferative anemia: Defective RBC production.
- Causes:
  - Marrow damage due to medications (e.g., chloramphenicol, benzene).
  - Lack of factors needed for RBC formation.
  - Decreased erythropoietin production (e.g., renal dysfunction).
  - Cancer/inflammation. Specific examples include deficiencies in:
    - Iron
    - Vitamin B12
    - Folate
Bleeding anemia: RBC loss.
- Causes:
  - Gastrointestinal tract bleeding
  - Menorrhagia (heavy menstrual bleeding)
  - Epistaxis (nosebleeds)
  - Trauma
Hemolytic anemia: RBC destruction.
- Causes:
  - Hypersplenism
  - Drug-induced anemia
  - Autoimmune anemia
  - Sickle cell anemia: Abnormal RBC shape, causing them to get stuck in small blood vessels.
  - Thalassemia: Impaired hemoglobin production.

Bleeding (e.g., ulcers, gastritis, inflammatory bowel disease, gastrointestinal tumors, excessive menstrual bleeding)
Pregnancy with inadequate iron intake
Chronic alcoholism (GI tract blood loss)
Inadequate iron stores or intake (vegetarian diets)
Iron malabsorption (e.g., after gastrectomy, celiac disease)

May be asymptomatic initially in early stages.
Symptoms of anemia may develop as the disease becomes chronic, including:
- Smooth, sore tongue
- Brittle nails
- Ulcers on the corners of the mouth
These symptoms often resolve with iron replacement therapy.

Laboratory investigations include:
- CBC
- Hemoglobin values
- Hematocrit
- Ferritin level
Endoscopy/colonoscopy may be needed to detect gastrointestinal bleeding.
Bone marrow biopsy may be done.

Medical management:
- Oral iron supplements (e.g., ferrous sulfate, ferrous gluconate).
- Intravenous or intramuscular iron dextrin in cases of poor absorption or intolerance to oral supplements.
Nursing management:
- Dietary education
- Nutritional counseling for patients with diets lacking iron
- Taking iron supplements on an empty stomach and with vitamin C
- Tips for preventing constipation from iron supplements
- Using a straw to prevent staining of teeth

What happens when a person has anemia?
- The blood does not have enough red blood cells.
What is the most common cause of anemia?
- Too little iron in the body.
Which of these groups is most likely to have anemia?
- Women
How does anemia affect the body?
- The blood doesn't deliver enough oxygen to the body.
Which of these are signs of anemia?
- Pale gums, dark circles under the eyes, and bleeding.
How does iron-deficiency anemia affect children and teens?
- More fatigue; irritability.
Anemia can contribute to what in older adults?
- More falls