What kind of disease is multiple myeloma? Why does this disease cause bone pain? What are the characteristics of this disease? How can we in the general population raise awareness of this disease?
Multiple myeloma is a malignant hematologic disease that originates from plasma cells and has three basic characteristics in terms of its onset. Thirdly, the disease has a high age of onset, the average age of onset is about 55 years old, more than 90% are older than 40 years old, and only about 1-3% are younger than 40 years old.
The immune function of normal human includes cellular immunity and humoral immunity. Simply put, cellular immunity is accomplished by secreting various cytokines or auxiliary B lymphocytes through T lymphocytes, while humoral immunity is accomplished by producing immunoglobulins through B lymphocytes. When a clonal malignant lesion occurs in plasma cells, the body will produce a large number of malignant plasma cells, and the normal bone marrow will be replaced by malignant plasma cells, which will then produce a large number of abnormal monoclonal immunoglobulins and destruction of bone, causing the corresponding clinical symptoms and signs, and multiple myeloma will occur.
What is M protein? How is it produced? What is its significance in multiple myeloma?
When malignant lesions occur in plasma cells, one strain of plasma cell precursor cells often becomes malignant, and this strain of malignant cells proliferates uncontrollably to form a huge number of monoclonal cell populations, while the normal proliferation of thousands of other plasma cells is inhibited. M protein shows a narrow-bottom peak on serum protein acetate film electrophoresis, and the detection of M protein is one of the main clinical indicators for the diagnosis and follow-up of multiple myeloma. It is also one of the main indicators for the diagnosis and follow-up of multiple myeloma in our clinical practice.
What causes multiple myeloma in our normal population? At present, the causes of multiple myeloma are not yet cleared, and its possible risk factors are probably the following.
1, age factor, age is probably the most meaningful risk factor for the development of multiple myeloma. The disease is rare in people under 40 years of age, but the reason why the incidence of multiple myeloma increases significantly with age is still unclear.
Radiation exposure, radiation-related occupational workers, diagnostic and therapeutic X-ray exposure, and nuclear industry workers are also at risk, but a study of 27,000 Chinese diagnostic X-ray workers showed that the risk of multiple myeloma did not increase among X-ray workers with 30 years of service compared to other medical workers with non-X-ray exposure.
3. Occupational and environmental factors, some data show that agricultural workers (especially farmers) have a significantly increased risk of developing multiple myeloma, which may be related to exposure to dust, aflatoxin, certain zoonotic viruses, agricultural chemicals, pesticides, etc.; however, there are those who hold the opposite view. Others, such as heavy metals, benzene and other chemicals, oil and fuel combustion, and hair dye, also have an increased risk of developing multiple myeloma.
Non-occupational exposure, drugs such as certain sedatives, stimulants, antibiotics, etc. may be associated with the risk of multiple myeloma, and some people even believe that smoking and drinking are also associated with the risk of multiple myeloma, but there are also those who deny it.
5. Family and genetic factors, the incidence of multiple myeloma varies among different nationalities and ethnicities. The incidence of multiple myeloma in black Americans is twice that of whites; Japanese and Chinese have the lowest incidence of multiple myeloma, and even Japanese and Chinese who immigrated to Europe and America still maintain a low level of incidence for a long time. Among first-degree relatives of patients with a history of multiple myeloma, the risk of multiple myeloma increases 3- to 6-fold. Although the occurrence of multiple myeloma is familial and there are some studies of hereditary markers, there is no conclusive evidence that multiple myeloma is a hereditary disease.
6. Chronic antigenic stimulation and immune dysfunction, repeated or chronic antigenic stimulation of the immune system may induce multiple myeloma. The incidence of multiple myeloma increases twofold in patients with certain underlying diseases such as rheumatoid arthritis, and the risk of multiple myeloma increases in patients with some viral infections such as herpes virus and HIV infection.
It was once thought that the incidence of multiple myeloma was higher in areas with a higher standard of living, but this has now been denied. The incidence of multiple myeloma in black families in the United States cannot be explained by family environment and economic income status; recently, it is widely believed that people with lower living standards are susceptible due to their harsher living environment and greater exposure to risk factors or relative ease.
Since multiple myeloma is a malignant clonal proliferation of plasma cells that produce abnormal monoclonal immunoglobulins, its main manifestations are proliferation of myeloma cells, infiltration and destruction of bone tissue and other tissues outside the bone marrow, bone pain, fractures, anemia, hemorrhage, and infections and renal lesions caused by large amounts of monoclonal immunoglobulins.
Bone pain, often the first symptom of multiple myeloma, is also one of the most prominent symptoms of the disease. About 2/3 of patients have this symptom at the time of consultation. In the early stage of the disease, many patients are misdiagnosed as rheumatism, rheumatoid arthritis, costochondritis, osteophytes, herniated disc, osteoporosis, lumbar sprain, bone tuberculosis, etc. Many patients initially do not go to the hematology department, but to other departments such as orthopedics, etc. As the disease progresses, bone pain may become persistent and severe, and even pathological fractures may occur. Bone pain is due to osteolytic lesions caused by multiple myeloma, and is one of the important features of multiple myeloma.
Why does multiple myeloma cause such severe osteolytic lesions and why are they present at the beginning of the disease?
The mechanisms are not well understood. Direct erosion of bone by tumor cells is not the main cause. Most current opinions suggest that it is due to the activation of osteoclasts by a number of cytokines secreted by tumor cells. One of the more important cytokines is osteoclast activating factor, while the activity of OAF is mediated by some other cytokines, such as interleukin 1β, lymphocyte toxin, tumor necrosis factor beta, interleukin 6, etc. These cytokines are able to activate osteoclasts, leading to osteoporosis and bone destruction. These complex biological mechanisms have yet to be further investigated by our scientists to gradually reveal their mysteries.
Can the bone pain caused by multiple myeloma be alerted by the general population at a relatively early stage or not?
Since myeloma cells initially invade bone marrow hematopoietic tissues, there are more myeloma cells in hematopoietic bone marrow tissues, and bone tissue destruction is serious, so bone pain is easy to occur. These bone tissues mainly include vertebrae, pelvis, ribs, skull, scapula and other flat bone tissues, so bone pain of multiple myeloma mostly occurs here.
2. Since myeloma cells invade diffusely with the bone marrow, the resulting bone damage is extensive, so bone pain may not occur in a single place but in multiple places, or the bone pain may start in one place and gradually become multiple bone pains. Some data show that the bone disease in multiple myeloma patients occurs in a single location (18.06%) and in multiple locations (more than 2 locations) (81.94%).
3.Bone pain is most common in the lumbosacral region, followed by the thoracic rib region, and less often in the long bones of the limbs, due to the thin bone cortex of flat bones and weight-bearing or force on the bones.
4.Bone pain is often aggravated by movement, weight bearing, changing position or even coughing, etc., and can be relieved after a short rest or position change.
5.Conventional symptomatic treatment has no obvious effect, and some physical treatments such as massage often aggravate bone pain.
6.Bone pain is often accompanied by fractures without obvious reasons or fractures even after slight exertion, and such fractures are often multiple.
7. Since multiple myeloma will produce a large amount of abnormal monoclonal immunoglobulins and other clinical manifestations, such as anemia, proteinuria, infection, etc., we should be very alert to the occurrence of multiple myeloma if bone pain is accompanied by other clinical manifestations, such as anemia, infection, renal insufficiency, etc.
In conclusion, if we have unexplained bone pain or bone pain accompanied by other adverse reactions, we should see a doctor as soon as possible so that an experienced doctor can make a correct diagnosis of our disease.
The final diagnosis of multiple myeloma requires a bone marrow aspiration as well as a monoclonal immunoglobulin test or even a tissue biopsy. With the improvement of medical technology, it is not very difficult to diagnose this disease, but it is crucial that the general population, and even some non-hematologists, be aware of the disease and detect it in time so that the correct diagnosis of multiple myeloma can be made in a timely and early manner.