Myelophthisic Anemia

Myelophthisic anemia is a type of anemia, a condition caused by a decreased number of red blood cells or dysfunctional red blood cells. Myelophthisic anemia is a kind of normocytic anemia, which means that an individual with this condition will produce red blood cells that are a normal size. However, it is also a hypoproliferative anemia, meaning that the individual will not produce enough of these red blood cells. When blood from an individual with myelophthisic anemia is used for a peripheral blood smear, a microscopic examination of the appearance of blood cells, immature red and white blood cells will be apparent. This accumulation of cells, which are not typically present in the bone marrow, prevents the appropriate production of blood components. 

Myelophthisic anemia usually results from the accumulation in the bone marrow of non-hematopoietic cells, cells that do not help produce blood cells. Most frequently, the bone marrow is infiltrated by tumor cells, such as breast cancer cells, prostate cancer cells, or cells from other hematological malignancies (e.g., acute myeloid leukemia, primary myelofibrosis). 

Inflammatory cells can also accumulate in the bone marrow. This generally occurs in response to chronic inflammation due to conditions such as tuberculosis, sarcoidosis, and rheumatoid arthritis. The inflammatory cells ultimately form granulomatous lesions, collections of immune cells, which cluster together when they can't kill invading pathogens. These lesions interfere with hemopoiesis. 

Additionally, connective tissue can infiltrate the bone marrow in a disorder called “myelofibrosis.” Myelofibrosis may be a result of infections (e.g., tuberculosis), autoimmune diseases (e.g., systemic lupus erythematosus), hypothyroidism (i.e., low levels of thyroid hormones), or hyperthyroidism (high levels of thyroid hormones). 

Lastly, some lipid storage diseases, which are inherited metabolic disorders, can cause lipids to  accumulate in the bone marrow, thereby causing myelophthisic anemia.

Individuals with myelophthisic anemia may present with common symptoms of anemia, which include weakness, dizziness, and headaches. They may also have increased heart rate (i.e., tachycardia), low blood pressure (i.e., hypotension), as well as cold and pale-colored skin. 

A more detailed examination can reveal pallor, or paleness, of the conjunctiva, which is the tissue that lines the inside of the eyelids; delayed capillary refill, which is the time needed for a finger to regain color after pressure is applied; and enlargement of the spleen, known as splenomegaly. Hepatosplenomegaly, or enlargement of both the liver and spleen, can be found in individuals with myelophthisic anemia, as both organs have a role in extramedullary hematopoiesis. 

Additionally, those with myelophthisic anemia may also present with bleeding diathesis, or a tendency to bleed, due to thrombocytopenia, which is a deficiency of platelets, as well as an increased risk for repeated infections due to leukopenia, which is a deficiency of white blood cells.

In order to diagnose myelophthisic anemia, a detailed review of the individual’s medical history and a physical examination are necessary. Assessment of the individual’s blood tests, peripheral blood smear, and bone marrow biopsy are typically necessary for diagnosis. 

Treatment for myelophthisic anemia varies depending on the underlying cause. For individuals with malignancies, chemotherapy or radiation therapy may be used to decrease the accumulated cancer cells. In cases of myelofibrosis, ruxolitinib, a medication for proper production of blood cells, may be prescribed. Moreover, there are new treatment options for myelophthisic anemia that focus on the interaction between the immune and skeletal systems. For example, pembrolizumab is a drug that has been shown to increase cancer cells’ vulnerability to the body’s immune system, so it may be effective in cases of myelophthisic anemia caused by cancer.