What is and what is myelosuppression? – Causes, Treatments and Alternative Therapies

Definition: it is a decrease in the production of blood cells.

Normal blood contains a large number of cells, including red blood cells to carry oxygen and white blood cells to fight infections.

The blood also contains platelets, small fragments of cells that initiate blood clotting. These cells and fragments are made in the bone marrow, a reddish substance found in the centers of some bones.

Healthy bone marrow produces a large number of red blood cells, white blood cells and platelets every day to replace those that are worn out. In myelosuppression, the bone marrow makes very few of these cells.

Myelosuppression is defined as a decrease in the ability of the bone marrow to produce blood cells. It occurs most commonly with cancer as a side effect of chemotherapy, but there are other causes as well.

A decrease in the number of red blood cells, called anemia, is very common in patients with cancer. A drop in the number of white blood cells is often a problem during chemotherapy.

A type of white blood cell, called a neutrophil, is usually affected more severely. A decrease in these cells is called neutropenia .

Because neutrophils are responsible for defending the body against bacteria, neutropenia increases the chance of infection.

The thrombocytopenia , a decreased number of platelets in the blood, is rare; Platelet numbers become low enough to cause problems in less than 10% of cancer patients.

Myelosuppression is a painless condition, but decreases in important blood cells can result in fatigue, an increased risk of infection or excessive bleeding.

The consequences vary from mild to life threatening, depending on how low the number of blood cells falls.

Causes

The most common cause of myelosuppression is cancer treatment. Many of the drugs used in chemotherapy temporarily suppress the bone marrow.

The therapeutic X-rays that reach the bone marrow are also destructive. Cancer cells can also cause myelosuppression. Some cancers invade the bone marrow and expel the cells that are normally there.

Others can suppress the bone marrow without invasion. Nutritional deficiencies, common in cancer patients, also slow down the production of blood cells, as do viruses and some non-chemotherapeutic drugs.

Myelosuppression usually begins seven to ten days after an injury to the bone marrow. However, the bone marrow usually returns to normal in the coming weeks.

Less frequently, cumulative damage can occur. Occasionally, irreversible damage causes permanent myelosuppression.

Chemotherapy or very intense radiation can destroy all the cells in the bone marrow.

There are several ways in which the bone marrow can be interrupted so that it does not produce blood cells:

Damage to stem cells – The most common cause of myelosuppression is due to medications that slow down the ability of stem cells and specialized descendants to divide and multiply.

All our blood cells are continuously being replenished. Medications such as chemotherapy drugs cause the suppression of drug-induced bone marrow.

Bone marrow replacement – The bone marrow may be “expelled” by things such as blood cancers or metastatic cancer so that there is no “space” for the normal manufacture of blood cells.

Bone marrow failure – Instead of being suppressed by a medication, the bone marrow can be destroyed by various toxins and chemicals.

When this is the case, stopping the medication will not result in the bone marrow again doing its job of making blood cells.

Treatment

Myelosuppression is not always treated, especially if it is mild.

If myelosuppression is the result of chemotherapy or radiation therapy, cancer treatments can be stopped, delayed or reduced to give the bone marrow the chance to recover.

This may mean that the full dose of the treatment is not received.

Red blood cells or platelets can be replaced by transfusions, red blood cells or platelets. These treatments can be very effective in the short term.

However, the transfused cells are short-lived and it may be necessary to repeat the treatment.

There is a small chance of a transfusion reaction and a slight risk of infection by a virus carried in the blood. White blood cell transfusions are ineffective and rarely occur.

Injections of growth factors can also be effective. Growth factors are chemicals, which are found naturally in the body, which stimulate the bone marrow to produce blood cells.

Each type of growth factor affects specific blood cells.

Several are being manufactured as drugs. They include erythropoietin, granulocyte colony stimulating factor (G-CSF or filgrastim), granulocyte-macrophage colony stimulating factor (GM-CSF or sargramostim) and interleukin 11 (oprelvekin).

Erythropoietin injections stimulate the production of red blood cells. They can decrease the need for a transfusion and improve the quality of life.

This medication has few side effects if the kidneys are healthy, but it may not be effective if the body is already making enough natural erythropoietin.

G-CSF and GM-CSF can accelerate the return of neutrophils. Its side effects include bone pain, fevers, rashes, muscle aches and nausea.

Interleukin 11 can increase the number of platelets. Its side effects may include fluid retention, fast heartbeat, red eyes and shortness of breath. Growth factors are expensive and several injections are usually needed.

Alternative and complementary therapies

Supportive therapy can help minimize the effects of myelosuppression. If nutrition is a contributing factor, iron or vitamin supplements can be beneficial.

Antibiotics can help prevent infections. Some patients find that mild exercise and pleasant distractions help with fatigue.

Is myelosuppression the same as immunosuppression?

You may wonder if immunosuppression and myelosuppression are the same. In the context of myelosuppression, the production of white blood cells decreases, so there will be immunosuppression.

But immunosuppression does not always mean myelosuppression. For example, a drug (or other process) can suppress white blood cells or other particular parts of the immune system, but not affect red blood cells or platelets.