Bone Marrow Disorders

Bone marrow disorders are a group of conditions that affect the bone marrow’s ability to produce healthy blood cells. Bone marrow, a spongy tissue found in bones, is responsible for producing red blood cells, white blood cells, and platelets, which are essential for oxygen transport, immune function, and blood clotting, respectively.

What is Bone Marrow ?

Bone marrow is the only site of blood production after birth. Bones are made up of cortex and marrow. The cortex is a solid layer of compact bone, and the marrow is a honeycomb of spongy bone that forms the medullary cavity and contains the bone marrow. Marrow is a soft fatty tissue found inside the sternum (center of the chest), pelvis (hip bone), and femur (thigh bone). The fibrous tissue of the marrow supports hematopoietic stem cells, which are “primitive” undifferentiated cells. Hematopoietic stem cells can differentiate (change, specialize, and multiply) to become a particular type of mature blood cell. These include erythrocytes, granulocytes, macrophages, monocytes, mast cells, megakaryocytes, and lymphoid cells. Normally, only mature cells are released from the bone marrow and enter the bloodstream.

Types of Bone Marrow Disorders:

• Anemia: Insufficient production of red blood cells, often caused by iron deficiency, vitamin deficiency, or chronic disease.
• Leukemia: A type of cancer that affects white blood cells, causing abnormal production and function.
• Aplastic anemia: A rare disease in which the bone marrow does not make enough blood cells.
• Myelodysplastic syndromes (MDS): A group of disorders caused by malformed or dysfunctional blood cells.
• Polycythemia vera: Overproduction of red blood cells, which can cause thickening of the blood and complications.
• Multiple myeloma: Cancer that affects plasma cells, a type of white blood cell responsible for producing antibodies.
• Myelofibrosis: A condition in which bone marrow tissue is replaced by scar tissue, causing anemia, fatigue, and an enlarged spleen.

Other disorders include:

• Plasma cell disorders, a group of conditions associated with overproduction of a clone of B cells and its antibody protein, including multiple myeloma, primary amyloidosis, and “monoclonal gammopathy of undetermined significance” (MGUS).
• Lymphomas and other non-hematologic cancers that spread to the bone marrow and affect cell production.
• Anemias caused by deficiencies (e.g. iron deficiencies) and/or hemoglobinopathies that result in abnormal hemoglobin production.
• Anemias caused by a deficiency or malfunction of the cytokine erythropoietin, a protein produced by the kidneys that stimulates red blood cell production.

Major Bone Marrow Problems:

Bone marrow diseases can cause an abnormality in the production of mature blood cells or their immature precursors or predecessors. The main types of bone marrow problems include:

• Increased production of one type of cell: This fills the bone marrow with one type of cell and decreases the production of other types of cells.
• Increase in one cell line because the cells do not die normally
• Production of immature cells that do not mature or function properly
• Production of fragile cells that die easily or production of fewer cells
• Increased growth of the network of supporting fibrous tissues leading to the formation of abnormal cells and a decrease in the number of cells
• Lack of iron which hinders the formation of red blood cells
• Spread of other diseases to the bone marrow

Signs and Symptoms of Bone Marrow Disorders:

Symptoms of bone marrow disorders can be severe and life-threatening, or very subtle. Some chronic diseases may be discovered during a routine physical exam, while other acute diseases can come on quickly and be life-threatening.

Symptoms in both cases include:

• Fever
• Weakness, fatigue, and paleness due to anemia
• Weight loss
• Swelling of the lymph nodes, liver, spleen, kidneys, and testicles
• Bleeding and bruising
• Night sweats
• Bone and joint pain
• Frequent infections
• Headache, vomiting, confusion, and seizures

What causes bone marrow failure?

Genetic mutations cause inherited bone marrow failure. One or both of your biological parents may carry a gene that they passed on to you, or you may develop a new mutation that causes it.

Causes of acquired bone marrow failure include:

• Autoimmune disorders.
• Certain types of cancer, such as granular lymphocytic leukemia (GLY), lymphoma, and multiple myeloma.
• Chemicals, such as those found in insecticides and pesticides.
• Chemotherapy and radiation therapy.
• Medications, such as antibiotics and rheumatoid arthritis.
• Myelodysplastic syndrome (myelodysplasia).
• Paroxysmal nocturnal hemoglobinuria, a disorder acquired when red blood cells break down too quickly.
• Viral infections, such as cytomegalovirus, Epstein-Barr virus, hepatitis, HIV, and parvovirus B19.

Sometimes doctors don’t know the cause of acquired (idiopathic) bone marrow failure.

Dagnosis of Bone Merrow Disorders:

A health care professional will first ask you questions about your symptoms, your medical history, and your family medical history. He or she will also perform a physical exam.

1. Your doctor will perform a complete blood count (CBC), which looks at your levels of red blood cells, white blood cells, and platelets. If you have a FMB, these rates will be low.

Depending on the disease your doctor suspects, he or she may also perform tests such as:

2. A bone marrow biopsy.
3. An MRI or positron emission tomography (PET) scan.
4. Blood tests to check for iron, vitamin B12, folate, or copper deficiency.
5. An ultrasound to look for hepatomegaly (liver enlargement), an enlarged spleen, or swollen lymph nodes.

To rule out acquired bone marrow failure, your doctor may:

• Stop some of your medications.
• Screen for other diseases such as hepatitis or pregnancy.
• Screen for infections.

Your doctor may also suggest genetic testing. This test can detect changes in genes that cause bone marrow failure syndrome.

Treatment of Bone Marrow Disorders:

Treatment for bone marrow disorders depends on the specific condition and its severity. Here are some common treatment options:

• Stem cell transplant: This procedure involves replacing damaged or diseased bone marrow with healthy stem cells from a donor.
• Immunosuppressive therapy: Drugs may be used to suppress the activity of the immune system in bone marrow disorders related to autoimmune diseases.
• Targeted therapies: These drugs specifically target abnormal cells, preventing damage to healthy cells.
• Splenectomy: In some cases, removal of the spleen (splenectomy) may be recommended to manage conditions such as autoimmune hemolytic anemia.
• Supportive care: This includes treatments to manage symptoms, such as blood transfusions, antibiotics, and pain management.