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Excessive hemolysis can cause a low amount of RBCs and lead to hemolytic anemia
Hemolysis refers to the natural destruction of old or damaged red blood cells (RBCs). Typically, RBCs have a lifespan of about 120 days, after which they are broken down by the body and replaced with new RBCs.
In normal conditions, the rate of RBC destruction is matched by the rate of formation of new RBCs. However, excessive hemolysis can cause a low amount of RBCs and lead to hemolytic anemia.
What causes hemolytic anemia?
Genetic causes
- Sickle cell disease (a condition in which a defective hemoglobin, called hemoglobin S, causes RBCs to acquire an abnormal shape)
- Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency (deficiency of the enzyme G-6-PD that ensures that the RBCs function properly and protects them from harmful substances in the blood)
- Red cell membrane disorders such as hereditary spherocytosis, hereditary elliptocytosis, and hereditary poikilocytosis
- Thalassemia (a condition in which the body does not produce enough hemoglobin [the oxygen-carrying pigment in RBCs])
Acquired causes
- Medications such as malaria drugs, sulfa drugs, acetaminophen, antiviral medications, and penicillin
- Infections such as hepatitis, cytomegalovirus, typhoid, and dengue
- Autoimmune disorders (occur due to destruction of the RBCs by the immune system)
- Certain types of cancer such as blood cancer or cancer treatment
- Hypersplenism (enlarged or hyperactive spleen)
- Physical damage to the RBCs due to causes such as defective prosthetic heart valves
- Blood transfusion reactions
Even in people with hereditary cases of hemolytic anemia, certain environmental conditions may act as a trigger for hemolysis. For example, anemia due to G-6-PD deficiency may be triggered by certain medications or infections. Certain foods, particularly fava beans, can trigger hemolysis in susceptible people with the Mediterranean variant of G-6-PD deficiency.
What are symptoms of hemolytic anemia?
Symptoms of hemolytic anemia vary depending on the underlying cause and severity of the condition. They may not always be apparent but can be triggered by a stressful event, medication, or infection (called a hemolytic crisis).
Symptoms of excess hemolysis in the body include:
- Pale skin complexion
- Weakness or fatigue
- Increased heart rate
- Jaundice (yellowish color of the skin and white of eyes)
- Poor exercise tolerance
- Shortness of breath
- Dark urine
- Fever
- Dizziness
- Confusion
- Pain in the abdomen or joints
Blood tests, urinalysis, and bone marrow aspiration or biopsy may be ordered to confirm a diagnosis.