What can go wrong?
A number of diseases or conditions can affect the structure and function of bone marrow. This in turn can affect the production and/or function of any of the mature blood cells or their immature precursors.
Disorders that affect the bone marrow and the blood cells it produces may be very subtle, causing mild or non-specific symptoms over a long period of time, or may be severe and life-threatening. Some chronic conditions may only be discovered during yearly health examinations, when a complete blood count (CBC) is done as a general health check. Acute conditions, on the other hand, can cause serious symptoms related to too many or too few functioning blood cells, revealing that a serious condition is present.
These are few examples of what can go wrong:
- One or more types of cells may begin to overproduce; this crowds out and decreases the production of the other cell types (e.g., polycythemia vera, essential thrombocythemia)
- The bone marrow produces abnormal cells that don't mature or function properly (e.g., leukemias, myelodysplastic syndrome)
- The supporting fibrous tissue network within the bone marrow increases and compresses the cells within the marrow, resulting in abnormally-shaped cells and low numbers of cells (e.g., myelofibrosis)
- The bone marrow is unable to produce one or more types of cells (e.g., aplastic anemia)
- Insufficient amount of nutrients such as iron, vitamin B12, or folate, affects the bone marrow's ability to produce normal red blood cells; those produced may be small (microcytic), large (macrocytic), and/or may have decreased amounts of hemoglobin inside them (hypochromic)
- White blood cells such as abnormal lymphocytes or plasma cells are overproduced (e.g., lymphomas, multiple myeloma)
- Infection of the bone marrow can be caused by viruses, bacteria or fungi and can affect the production of cells
- Cancer may spread from other parts of the body (metastasize) into the bone marrow, affecting cell production