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What is anemia?

Anemia is a general term for having too few red blood cells in the blood. Red blood cells carry oxygen and nutrients through the bloodstream to the body’s cells. The most important element of red blood cells is called hemoglobin. Hemoglobin is a protein that carries oxygen in the blood from the lungs to the body’s cells. Anemia occurs when the body is making too few healthy red blood cells; the body is losing blood (hemorrhage); or the body is destroying circulating red blood cells.

Anemia is a common blood disorder, affecting more than three million people in the United States (Source: Women's Health). Anemia can occur in all age groups and populations, but it primarily affects women of childbearing age because of the loss of blood during menstruation.

Anemia is a potentially serious condition that can be caused by a wide variety of diseases, disorders and conditions. These include:

Common symptoms of anemia include hypotension (low blood pressure) and unusually pale skin (pallor). Many symptoms of anemia are due to a reduced amount of hemoglobin. This results in inadequate delivery of oxygen to the body’s cells and symptoms that include:

Anemia and its symptoms can occur suddenly, such as when it is caused by hemorrhage, or anemia can develop gradually, such as in pernicious anemia (vitamin B 12 deficiency).

Treatment of anemia involves diagnosing and treating its underlying cause. Some conditions can be successfully treated and cured, while others may require more intensive treatment. Treatment also depends on your age, general health status, medical history, and other factors. In some severe cases, treatment may include a blood transfusion.

Complications of severe anemia can be serious and life threatening. Complications can include shock and stroke. Underlying diseases, disorders or conditions of anemia can also cause critical complications. Seek prompt medical care if you have symptoms of anemia, such as mild dizziness or weakness, or if you have a low energy level and tire easily. Prompt diagnosis and treatment of anemia and its underlying cause reduces the risk of serious complications.

Seek immediate medical care (call 911) if you, or someone you are with, has an unusual change in alertness, shortness of breath, chest pain, or bleeding symptoms, such as bleeding heavily from the rectum, bloody stools, or vomiting blood.

What are the symptoms of anemia?

The symptoms of anemia are caused by an abnormally low number of red blood cells in the blood. Red blood cells contain the protein hemoglobin, which is vital to carrying oxygen to the body’s cells. Many symptoms of anemia are due to a general lack of oxygen that is available to the cells.

Your symptoms may also be caused by low blood pressure (hypotension), which is due to reduced blood volume. Blood volume will be low if anemia develops quickly, as in blood loss from hemorrhage.

Symptoms of anemia can be mild to severe and vary depending on the underlying cause.

Symptoms of mild to moderate anemia that develop slowly

When anemia is mild or develops slowly, symptoms may not be noticeable at first because the body may be able to adjust to a slow decline in red blood cells. Symptoms can also be mild or vague. Symptoms can include:

  • Difficulties with memory and concentration

  • Fatigue

  • Feeling mildly light-headed

  • Feeling unusually cold

  • Low energy level

  • Mild shortness of breath with exertion that goes away with rest

  • Pale skin

  • Sluggishness

  • Tiring easily

Serious symptoms of severe or rapid-onset anemia that might indicate a life-threatening condition

When anemia is severe or develops quickly, symptoms are more serious because the body cannot adjust to the rapid decrease in blood pressure and the rapid decline in oxygen that is delivered to the cells. This can result in shock and death if not treated immediately. Seek immediate medical care (call 911) if you, or someone you are with, have any of the following symptoms:

  • Black, tarry stools (melena)

  • Bluish coloration of the lips or fingernails

  • Chest pain, chest tightness, chest pressure, and palpitations due to a lack of oxygen delivered to the heart

  • Cold, clammy skin and extreme pallor (pale skin)

  • Heavy, uncontrolled bleeding or hemorrhage

  • Rapid heart rate (tachycardia)

  • Respiratory or breathing problems, such as shortness of breath, difficulty breathing, labored breathing, wheezing, not breathing, or choking

  • Vertigo (severe dizziness) and syncope (fainting) caused by a lack of oxygen in the brain

  • Vomiting blood

When is a fall a symptom of an underlying problem?

Anemia and falls are very common and closely linked in older adults and the elderly. Anemia can cause dizziness, difficulty concentrating, confusion, and other problems that make it difficult to maintain balance during everyday activities. However, older adults and the elderly may become accustomed to these symptoms over time and not realize there is an underlying problem, even after falling.

In fact, falling may be the first sign that an older adult has anemia or another serious underlying medical condition. Falling can also cause injuries, such as a fractured hip, that can lead to bleeding and cause or worsen anemia.

Seek prompt medical care if you, or an older adult you know, have fallen, even if there appears to be no injuries. Prompt diagnosis and treatment of underlying anemia can reduce the risk of additional falls and injuries and other serious complications.

What causes anemia?

Anemia is an abnormal condition in which there is a low number of red blood cells in the blood. Anemia can be caused by a variety of diseases, disorders and conditions.

Bleeding and hemorrhage

Bleeding is the most common cause of anemia. Severe, uncontrolled bleeding (hemorrhage), such as bleeding from ruptured esophageal varices, can rapidly lead to life-threatening anemia. Small amounts of repeated bleeding, such as bloody stools due to ulcerative colitis, can lead to anemia over time. Conditions that cause bleeding or hemorrhage include:

Other causes of anemia

  • Alcoholism

  • Chemotherapy and medications for HIV/AIDS

  • Chronic diseases, such as cancer, celiac disease, and kidney disease, which can hinder the body’s production of red blood cells

  • Hemolytic anemia or sickle cell disease, in which the body destroys old red blood cells faster than it produces new ones

  • Iron deficiency anemia and thalassemia, which cause a deficiency of hemoglobin in the red blood cells

  • Pregnancy

  • Vitamin B12 deficiency (such as pernicious anemia), aplastic anemia, or a low level of the hormone erythropoietin, which impair the body’s normal production of red blood cells

What are the risk factors for anemia?

A number of factors increase the risk for anemia. Risk factors include:

  • Alcoholism
  • Being a woman of childbearing age
  • Certain medications, such as anticancer chemotherapy or drugs for HIV/AIDS
  • Chronic diseases such as cancer, celiac disease, and kidney disease
  • Not eating a well-balanced diet that includes foods high in iron (red meat) and vitamin B (eggs, meats, and whole grains)

    Reducing your risk of anemia

    You can lower your risk of some underlying causes of anemia by:

    • Abstaining from alcohol or drinking in moderation: no more than two drinks per day for a man and one drink per day for a woman
    • Eating a well-balanced diet that includes foods high in iron and vitamin B, such as eggs, red meat, and whole grains
    • Seeking early and regular prenatal care

    How is anemia treated?

    Treatment plans for anemia are individualized to the severity of the condition, the underlying cause, coexisting diseases and complications, the patient’s age, and other factors. Treatment involves a multifaceted plan that addresses the underlying cause, such as iron deficiency or vitamin B 12 deficiency. The underlying cause of these conditions also needs to be diagnosed and treated to reduce the risk of complications.

    Treatment generally includes a well-balanced diet. Iron deficiency anemia and pernicious anemia may also be treated with iron supplements and vitamin B 12 injections, respectively.

    Thalassemia is treated with regular blood transfusions and other procedures.

    Hemorrhage is treated by addressing the underlying cause of the bleeding, such as peptic ulcer. In some cases, excessive hemorrhage (bleeding and blood loss) may be treated with a blood transfusion.

    Sickle cell disease is not curable. The complications of sickle cell crisis are treated with pain medications, supplemental oxygen, and possibly blood transfusion, stem cell transplant or bone marrow transplant.

    What are the possible complications of anemia?

    Untreated anemia or its underlying causes can lead to serious and life-threatening complications. Once the underlying cause is determined, you can help minimize your risk of serious complications by following the treatment plan you and your health care professional design specifically for you. Complications of anemia include:

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    Medical Reviewer: William C. Lloyd III, MD, FACS
    Last Review Date: 2020 Nov 20
    THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
    1. Anemia. Medline Plus, a service of the National Library of Medicine National Institutes of Health.
    2. Anemia. KidsHealth.
    3. What is anemia? National Heart Lung and Blood Institute, National Institutes of Health.