Hemolytic anemia

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at December 4, 2016
StartDiseasesHemolytic anemia

Hemolytic anemia is a condition which arises when red blood cells are destroyed earlier than their normal lifespan at a rate higher than they can be replaced in the bone marrow. Causes of this condition are diverse and can be inherited or acquired due to autoimmune diseases, side effects from medication, infections, and others. Mild cases may present no symptoms, but if they are present, early symptoms include fatigue, skin paleness, and weakness, and the condition can be chronic and become severe if not treated promptly. 

Contents

Definition & Facts

Hemolytic anemia occurs when red blood cells die faster than new ones can be produced in the bone marrow. The typical lifespan of a red blood cell is 120 days, but with hemolytic anemia the lifespan is reduced and the bone marrow cannot produce enough to replace them and meet the body’s needs. Red blood cells carry oxygen throughout the body and remove carbon dioxide, so a reduction in red blood cells affects the body’s ability to function properly.

There are two types of hemolytic anemia: extrinsic (acquired) and intrinsic (inherited). The extrinsic type is also known as autoimmune hemolytic anemia and develops when healthy red blood cells are trapped and destroyed by the spleen or from destruction of red blood cells due to infection, tumors, autoimmune disorders, leukemia, lymphoma, or side effects from medications.

The intrinsic type of hemolytic anemia is often inherited and occurs when the body produces defective cells, like in individuals with sickle-cell anemia and thalassemia. The severity of the anemia depends upon the extent of red blood cell destruction and whether it has occurred gradually or abruptly.

Mild hemolytic anemia can be asymptomatic, and resolve itself without symptoms or treatment. More severe forms can be life-threatening if not treated and can cause angina (pain caused by low blood supply to the heart) and cardiopulmonary decompensation (a worsening of symptoms related to heart failure).

Symptoms & Complaints

Since there are a variety of causes which can lead to this condition, symptoms are also diverse, vary from person to person, and depend on the severity of the condition. The onset of symptoms can occur slowly or suddenly, and in mild cases, there may be no symptoms at all.

One of the most common symptoms of hemolytic anemia is fatigue, which results from reduced oxygen levels in the blood. This can also lead to heart-related symptoms because the heart has to work harder to move oxygenated blood throughout the body.

These can include cardiac arrhythmia (irregular heartbeat), heart murmur, enlarged heart (cardiomegaly), angina, and heart failure. Other common symptoms include headache, fever, coldness of the hands and feet, confusion, paleness of the skin, and weakness.

Less common symptoms which are a sign of the condition worsening include jaundice (yellowing of skin and the whites of the eyes), sore tongue, brittle nails, lightheadedness, dark urine, and enlarged spleen (splenomegaly) or enlarged liver (hepatomegaly).

If the hemolytic anemia is severe, it can cause certain conditions like heart disease and lung disease to worsen.

Causes

Hemolytic anemia can be caused by various diseases, as a side effect of certain medications, or inherited. Some causes include enlarged spleen, infections, leukemia, lymphoma, hepatitis, tumors, lupus, typhoid fever, and genetic disorders like sickle-cell anemia.

Causes related to immune system disorders result in red blood cell destruction when the immune system creates antibodies to attack red blood cells when it misidentifies them as foreign substances. The condition can also be drug-induced. Some common medications which can cause this include acetaminophen, antibiotics such as penicillin, and ibuprofen.

Receiving a blood transfusion of the wrong blood type can also be the cause a reaction resulting in severe hemolytic anemia, as the new, incompatible blood cells are destroyed by the immune system. This type of reaction requires immediate treatment. The condition can also be temporary and is treatable if the underlying cause can be identified. 

Diagnosis & Tests

Diagnosis is made based on medical history, family history, physical examination, and laboratory tests. Various diagnostic tests can be used to detect hemolytic anemia and more specialized tests can identify the cause.

One of the common tests used to detect anemia is a complete blood count (CBC) test to determine the number of blood cells present and identify lowered hemoglobin or hematocrit levels which can be a sign of anemia. Other blood tests are used to define the type and severity of the anemia. Urine tests and bone marrow tests may also be conducted.

Treatment & Therapy

Treatment depends on the underlying cause of the condition, age, and health of the patient. It is usually treated or controlled successfully once the cause is corrected. If the condition is inherited it may require ongoing treatment. Mild hemolytic anemia may require no treatment while more severe cases can be fatal if not treated properly.

Treatment can include blood transfusions, medication, surgery to remove the spleen (splenectomy) which may be enlarged and removing more red blood cells than normal, bone marrow transplants, and lifestyle changes.

These treatments are used to reduce or stop the premature destruction of red blood cells, increase red blood cell counts, and treat the underlying cause of the anemia. Blood transfusions are most commonly used when the condition is severe or life-threatening.

If the cause lies in the immune system, immunosuppresive drugs may be used to prevent the immune system from attacking red blood cells. Mortality rates are low, but increase in older patients and those with cardiovascular diseases.

Prevention & Prophylaxis

Inherited forms of hemolytic anemia cannot be prevented. Some forms can be prevented by reducing exposure to medications which may trigger it. In chronic hemolytic anemia, red blood cells can be reduced by cold weather, so avoiding exposure to the cold can reduce infections and breakdown of blood cells.

Other lifestyle changes which can reduce the risk of infections and red blood cell loss include staying away from sick people, washing the hands often, avoiding food that is undercooked, good dental hygiene, and yearly flu shots. Reactions caused by improper blood type transfusions can be prevented through careful blood type matching.