Dr. Jeff Hersh explains what causes anemia and options on how it can be treated

Dr. Jeff Hersh
·4 min read

Q: What causes anemia, and is a blood transfusion the only treatment?

A: Red blood cells are a critical component of our blood. They are "loaded" with oxygen in the lungs, and then along with the rest of the blood are pumped by the heart to carry and deliver this oxygen to the body’s cells. Oxygen is needed by the body’s cells to react with glucose (the main sugar the cells use) to make adenosine triphosphate, the specific energy source used and stored at the cellular level.

If there are insufficient red blood cells (this is anemia), then not enough oxygen can be supplied to the body’s cells, and hence they will not have sufficient energy to function normally. Symptoms of anemia may include tiredness/weakness (especially with exertion where increased energy is needed), shortness of breath (anemia triggers your body to look for more oxygen), other non-specific symptoms (lightheadedness, headache, feeling a rapid heartbeat, bone/joint/other pain, cold hands/feet, others), and/or other symptoms (for example, growth problems in children).

Dr. Jeff Hersh
Dr. Jeff Hersh

Red blood cells normally survive an average of about 120 days, becoming damaged (their oxygen-carrying capacity becomes compromised) as they age. These damaged red blood cells are cleared from the blood, primarily in the spleen but also by the liver and by other mechanisms. About 5 million red blood cells (a volume of about one microliter; there are about 5,000 microliters in a teaspoon) are cleared from the blood every second, with this same number of red blood cells created in the bone marrow each second to replace them, yielding a reasonably steady number of them in our blood.

Anemia is common, affecting more than 1 in 20 people. There are three major pathways for our red blood cell count to become low:

  • Loss of blood from the blood stream:

    • Acute bleeding, for example from a significant injury, whether from external loss of blood (such as from a severed artery from trauma) or from internal bleeding (such as from a gunshot wound causing bleeding into someone’s abdomen/pelvis/chest/other locations).More chronic blood loss, such as gastrointestinal bleeding from an ulcer, gynecological bleeding and many others. Of course, some chronic conditions can have an acute flare-up of large bleeding.

    • Other causes.

  • Increased destruction of red blood cells in the blood stream (hemolysis):

    • Diseases/conditions that cause red blood cells to rupture, such as a reaction to severe infection/sepsis and certain immune disorders.Certain genetic conditions causing the red blood cells to be fragile/abnormal (for example, sickle cell anemia).

    • Other causes.

  • Compromise of the bone marrow preventing adequate red blood cells to be made:

    • Such as from the bone marrow being infiltrated by cancer/other, side effects from chemotherapy, other conditions inhibiting the bone marrow’s normal function.Inadequate "ingredients" to be able to make red blood cells such as from iron deficiency or vitamin B12 deficiency.Certain toxins (such as lead poisoning).Certain congenital conditions (for example, thalassemia).Interruption of some of the normal endocrine system signals that stimulate red blood cell production (such as from kidney disease or thyroid disease).

    • Other causes.

The hematocrit is the ratio of the total volume of blood to the total volume of red blood cells, and is measured as part of a complete blood count. This is the primary test done to determine if a patient has anemia. The size, shape and other characteristics of the red blood cells often provide clues to a possible etiology of the anemia. Other blood tests may be done as indicated to look for potential causes (for example, certain blood tests to look for hemolysis, nutrient deficiencies or to check organ/endocrine function), and even a bone marrow biopsy may be needed for some patients.

Treatment for the underlying cause of anemia is essentially always indicated, and may include iron/vitamin supplementation, medications/treatments for underlying diseases/conditions, treatments for active bleeding (including treatments for trauma, GI bleeding, etc.) or hemolysis treatments.

Most cases of anemia are not so severe, nor causing worrisome enough symptoms to require a transfusion. In certain hemolysis patients, blood transfusions may be intentionally avoided so as not to "fuel the fire" (i.e., transfuse more red blood cells to be hemolyzed, potentially causing other issues due to consequences of these destroyed red blood cells).

However, severe symptomatic anemia requiring a blood transfusion is not uncommon. For example, certain trauma patients, newborns with certain medical issues, people with large acute bleeding conditions, someone with severely compromised BM production (certain cancer patients, others) and many others require blood transfusions as part of their treatment. Someone in the U.S. requires a blood transfusion every two seconds; over 12 million units of blood are needed to transfuse more than 4.5 million Americans every year.

From this, we see there is a huge need for people who are able (about 40% of the population are medically healthy enough and without contraindications) to donate blood and/or blood components (for example, platelets). But unfortunately, only about 10% of people actually donate annually. Please consider contacting the Red Cross (https://www.redcrossblood.org/give.html/find-drive) to find a blood drive near you so you can arrange to give the gift of life.

Jeff Hersh, Ph.D., M.D., can be reached at DrHersh@juno.com.

This article originally appeared on MetroWest Daily News: Dr. Jeff Hersh explains anemia, what treatments are available