Multiple myeloma

What is it?

Within the leukocytes we find different types, such as lymphocytes or monocytes, each of them with a specific function within the immune system.

The lymphocytes can be of different classes. A subset of these leukocytes are B lymphocytes, which are responsible for antibody-mediated immunity and are generated and mature in the bone marrow. When other lymphocytes activate them against a certain antigen, the B lymphocytes transform into plasma cells or plasma cells, which are responsible for secreting huge amounts of antibodies against said antigen.

When, for different reasons, the control mechanisms of cell proliferation and programmed death of plasma cells are lost a hematologic malignancy occurs one of these cells is called multiple myeloma.

How is it produced?

The multiple myeloma accounts for 10% of hematological tumors and its cause is unknown. There are no factors or diseases that predispose to this cancer. It is more common in middle-aged or older men.

Multiple myeloma is a cancer formed by plasma cells, that is, cells with the ability to secrete antibodies or immunoglobulins, so that a specific type of these immunoglobulins will be elevated in the blood, the one produced by the cells involved in multiple myeloma. This tumor is part of the so-called monoclonal gammopathies, neoplasms formed by cells with the ability to produce immunoglobulins, which are, together with multiple myeloma, Waldenström's macroglobulinemia, primary amyloidosis, and gammopathies of uncertain significance.

Symptoms

Up to nearly 30% of patients with multiple myeloma do not present any symptoms and are diagnosed incidentally when finding laboratory abnormalities, such as mild anemia, an elevated erythrocyte sedimentation rate (ESR), or a monoclonal paraprotein in the blood, that is, a type of antibody produced by diseased plasma cells.

If there are symptoms, bone pain is the most frequent. It is due to the degeneration suffered by the bone due to the production by tumor cells of substances that activate osteoclasts, the cells responsible for reabsorbing bone tissue.

These injuries occur mainly in the skull, ribs, vertebrae, pelvis and the ends of long bones such as the humerus or tibia. Sometimes, instead of osteolytic lesions, of bone resorption, there is diffuse osteoporosis. Bone injuries can lead, in addition to pain due to periosteal involvement, fractures at different points.

Hypercalcemia leading to bone destruction can lead to asthenia, anorexia, nausea, vomiting, polyuria, polydipsia, constipation and confusion.

The involvement of the bone marrow, which is occupied by plasma cells, leads to a progressive anemia and a decline in the other cell lines.

Due to the defect in antibody-mediated immunity, the patient with multiple myeloma can suffer serious infections, especially in the lungs and kidneys. The infections are the leading cause of death of patients with multiple myeloma.

The kidneys are affected in about half of patients with multiple myeloma due to excess calcium in the blood, as well as by the excessive secretion of a part of the immunoglobulins (the so-called light chains), which are excreted in the urine and give rise to a characteristic affectation called myeloma kidney.

In the long term can lead to kidney failure that can determine the poor prognosis of the patient, since this is the second cause of death of patients with myeloma after infections.

Excess immunoglobulins in the blood make the blood more viscous, which can lead to episodes of interruption of blood supply in different territories, especially at the neurological and ophthalmological level, as well as heart or circulatory failure.

Sometimes the diseased plasma cells they are grouped forming tumor masses in lymphatic tissues outside the bone marrow, mainly in otorhinolaryngological lymphoid tissue, which are called plasmacytomas.

It should be mentioned that multiple myeloma can appear associated with other alterations in what is called POEMS syndrome, which includes polyneuropathies, enlarged organs, endocrine alterations, multiple myeloma, and skin alterations. They are usually patients with a better prognosis.

Diagnosis

The diagnosis of multiple myeloma can be accidental in asymptomatic patients and it is an analytical finding. Otherwise, this entity should be suspected in all patients with severe bone pain without a history of trauma, recurrent infections, or kidney involvement.

A blood test will reveal anemia with red cells of normal size and amount of hemoglobin, an elevated ESR, a decrease in the number of leukocytes and platelets, and an alteration in the parameters that assess coagulation. Likewise, an elevation of calcium and uric acid levels in the blood will be appreciated.

In both blood and urine, an elevation of a paraprotein will be seen, that is, a type of immunoglobulin that will be elevated. Among the different types of immunoglobulins, type G is the most common in multiple myeloma.

The elevation of a specific protein, ß-2-microglobulin, directly reflects the tumor mass of multiple myeloma, although it can be said that this protein is not specific for this disease.

In bone marrow an elevation of plasma cells will be observed, above 10% of the total; if plasma cells exceed 30% of the total, it is considered that this data confirms the diagnosis of multiple myeloma.

The fundamental imaging test to assess bone lesions is radiography.

Ultimately, the diagnosis is based on the presence of some major factors (the existence of plasmacytomas, more than 30% of plasma cells in bone marrow and a peak of monoclonal immunoglobulin greater than 3.5 g / dl) and some minor factors (10-30% plasma cells in bone marrow, a monoclonal immunoglobulin peak below 3.5 g / dl, bone lesions and a decrease in normal immunoglobulins).

Treatment

Asymptomatic patients diagnosed with multiple myeloma do not require treatment initially, as it has not been shown to prolong survival.

Treatment of multiple myeloma in symptomatic patients has several options, including chemotherapy, radiation therapy, interferons, immunotherapy, lenalidomide with dexamethasone, or bone marrow transplantation. Bisphosphonate therapy seeks to reduce bone damage in patients with multiple myeloma.

Precautionary measures

Given the unknown origin of multiple myeloma and the absence of risk factors, there are no preventive measures against it.