Kidney damage is regarded as the most common clinical, morphological and laboratory (biochemical) manifestation of myeloma and at the same time one of the most severe and unfavorable prognostic complications of this disease. The incidence of kidney damage in myeloma ranges from 60 to 90 and even up to 100%. In many cases (according to A.P. Peleshchuk, 28%), pathological changes in the kidneys serve as the first, earliest clinical and laboratory manifestations of myeloma, which served as the basis for identifying the renal form of this disease. Kidney damage caused by multiple myeloma is referred to as “myeloma nephropathy” or “myeloma kidney”, less often as “paraproteinemic nephrosis” (N. E. Andreeva, 1979). Pathological changes in the kidneys can be of a different nature and differ in significant polymorphism. In some cases, they are strictly specific to myeloma and are caused by para- and disproteinosis. The term “myeloma kidney” corresponds to this nature of kidney damage. In other cases of myeloma nephropathy, changes in the kidneys are nonspecific (or not strictly specific) for this disease and manifest themselves in the form of pyelonephritis, renal amyloidosis, nephrocalcinosis, arteriolosclerosis.
Relatively frequent pyelonephritis and arteriolosclerosis of the kidneys are explained by the predominance of elderly people among patients with multiple myeloma and a decrease in the body's resistance to infection in this disease.
For a better understanding of the mechanism of development of myeloma nephropathy, its morphological and clinical manifestations, it is advisable, without dwelling in detail on the pathogenetic essence of myeloma itself, to remind the reader of the main symptoms of this disease and the criteria for its diagnosis.
Multiple myeloma (myeloma, plasmacytoma). This is a systemic disease of the tumor-hyperplastic type with predominant damage to the skeletal bones, characterized by malignant proliferation of cells of a reticuloplasmic nature (G. A. Alekseev, 197O).
What provokes / Causes of kidney damage in multiple myeloma:
The etiology of multiple myeloma is still unclear. Its characteristic feature is the ability of myeloma cells to produce pathological proteins - paraproteins. Therefore, multiple myeloma is also referred to as “paraproteinosis.”
The disease occurs mainly at the age of 45-65 years and tends to noticeably increase. This is due not only to improved diagnosis, but also to an increase in the proportion of elderly people. Although there are cases of multiple myeloma at a younger age. Men and women get sick with approximately the same frequency.
Symptoms of kidney damage in multiple myeloma:
The clinical picture of multiple myeloma is caused by damage to the bone and hematopoietic systems, metabolic disorders (mainly protein and mineral) and visceral pathology.
The first clinical symptoms of myeloma, which are found in more than 50% of patients, are general symptoms such as weakness, decreased performance and appetite, asthenia, weight loss and bone pain. Often the disease begins with sudden pain in the bones or even a spontaneous fracture of one of the bones. In some cases, patients seek medical help if protein is accidentally detected in the urine or an increase in ESR.
Pathological changes in the skeletal system are among the most common and characteristic clinical manifestations of myeloma. They are expressed by the classic triad of symptoms: pain, swelling and fractures. In 75-90% of cases, patients seek medical help specifically for bone pain (ossalgia). Their occurrence is associated with destructive changes in the bones due to tumor growth of myeloma tissue. Mostly flat bones are affected - the skull, sternum, ribs, vertebrae, iliac bones, as well as the proximal parts of the tubular bones (shoulder, femur). In a later stage of the disease, visible deformation appears, and then spontaneous fractures, which are observed in 50-60% of patients; Fractures of the ribs, vertebrae and hips are especially common. In this case, the vertebral bodies become flattened and deformed (compression fracture), taking on the shape of “fish vertebrae” and accompanied by a shortening of the patient’s height. Tumors (myelomas) arising from flat bones are usually multiple, sometimes reaching large sizes; occur in approximately 15-20% of cases.
X-rays reveal round-shaped bone tissue defects with a diameter ranging from a few millimeters to 2-3 cm or more, which in the bones of the skull appear to be “moth-eaten” or “knocked out with a punch,” creating a characteristic X-ray picture of the so-called “leaky skull.” In the proximal sections of the tubular bones (humerus, femur), bone defects are radiologically detected in the form of “soap bubbles” or “honeycombs”, and pathologically altered vertebrae resemble “fish vertebrae”.
The picture of peripheral blood in the initial stage of the disease usually does not have significant deviations from the norm. However, as the disease progresses, all patients develop normochromic anemia, the pathogenesis of which is not entirely clear. The occurrence and progression of anemia is associated with the replacement of bone marrow with elements of myeloma tissue. The severity and rate of increase of anemia may vary. As the disease progresses, more or less pronounced leukopenia (neutropenia) is observed. Absolute monocytosis is often observed, and in 2-3% of patients, eosinophilia is observed. Some patients have a tendency to hyperthrombotic
cytosis (mainly in the initial stage of the disease); Thrombocytopenia is not typical for multiple myeloma. The number of reticulocytes, as a rule, does not increase. It is possible to develop hemorrhagic syndrome, the genesis of which is complex and not entirely clear. A classic sign of myeloma is a pronounced (up to 50-70 mm/h) and stable increase in ESR, which is often detected long before the appearance of bone and other symptoms of this disease.
Analysis of the myelogram obtained by sternal puncture reveals in the vast majority of patients (90-95%) a clear myeloma cell proliferation with the presence of tumor (myeloma) cells of more than 15%. Examination of bone marrow puncture is of crucial diagnostic importance.
The syndrome of protein pathology in myeloma is most clearly manifested in the form of hyper- and paraproteinemia (or pathoproteinemia). These disorders of protein metabolism are associated with excessive production by pathologically altered plasma (myeloma) cells of abnormal proteins - patho(or para) proteins from the group of immunoglobulins, which, however, although related (similar), are not identical to the corresponding normal fraction of IgM, IgG and IgA . This is the fundamental difference between myeloma paraproteinemia and dysproteinemia of other origins (for example, in rheumatoid arthritis, liver cirrhosis, etc.), characterized by hypergammaglobulinemia. Consequently, it is not the quantitative ratios of the globulin fractions of the electropherogram that have diagnostic significance in myeloma, but their qualitative features. As for the content of ordinary γ-globulins in the blood serum during myeloma, it is not only not increased, but, on the contrary, is always significantly reduced, i.e., there is constant hypogammaglobulinemia. Using protein electrophoresis, paraproteinemia is detected in 90-92% of cases. In this case, the most important and specific criterion for myeloma paraproteinemia is the presence on the proteinogram of a narrow intense M band either between the y-, b-fractions, or in the area of the y-, b- and less often the a-2-globulin fraction.
For myeloma paraproteinemia, a very characteristic and pathognomonic sign is also the presence of low molecular weight Bence-Jones protein (with a molecular weight of 40,000) in the urine. This protein is synthesized only by myeloma cells. Entering the bloodstream due to its small size, it is quickly excreted by the kidneys and appears in the urine. Like creatine, almost complete purification of this protein from the blood occurs in the kidneys. Therefore, it can be detected in the blood only in minimal quantities and only with the help of immunoelectrophoresis. Freely penetrating through the glomerular filter, Bence-Jones protein gives a picture of isolated proteinuria typical of multiple myeloma. Detection of this protein using electrophoresis is of extremely important diagnostic value; it allows making a diagnosis at an early stage, even before pronounced clinical signs, which is especially important in elderly people with proteinuria of unknown origin. Only at the late stage of myeloma is a significant amount of other (serum) proteins detected in the urine, which neutralize the electrophoretic picture characteristic of Bence-Jones proteinuria.
Hyperproteinemia (over 80-90 g/l) in multiple myeloma occurs in 50-85% of cases and sometimes reaches 150-180 g/l. It is caused by hyperglobulinemia, which in combination with hypoalbuminemia leads to a significant decrease in the A/G coefficient (to 0.6-0.2).
Visceral pathology in myeloma most often manifests itself as damage to the kidneys and much less often - to the liver, spleen and other organs. In 5-17% of patients, hepato- and (or) splenomegaly is detected. Tumor plasma cell infiltrates can be found in all internal organs, but they rarely appear clinically: they are usually found at autopsy.
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Other diseases from the group Diseases of the genitourinary system:
| "Acute abdomen" in gynecology |
| Algodismenorrhea (dysmenorrhea) |
| Algodismenorrhea secondary |
| Amenorrhea |
| Amenorrhea of pituitary origin |
| Kidney amyloidosis |
| Ovarian apoplexy |
| Bacterial vaginosis |
| Infertility |
| Vaginal candidiasis |
| Ectopic pregnancy |
| Intrauterine septum |
| Intrauterine synechiae (fusions) |
| Inflammatory diseases of the genital organs in women |
| Secondary renal amyloidosis |
| Secondary acute pyelonephritis |
| Genital fistulas |
| Genital herpes |
| Genital tuberculosis |
| Hepatorenal syndrome |
| Germ cell tumors |
| Hyperplastic processes of the endometrium |
| Gonorrhea |
| Diabetic glomerulosclerosis |
| Dysfunctional uterine bleeding |
| Dysfunctional uterine bleeding of the perimenopausal period |
| Cervical diseases |
| Delayed puberty in girls |
| Foreign bodies in the uterus |
| Interstitial nephritis |
| Vaginal candidiasis |
| Corpus luteum cyst |
| Intestinal-genital fistulas of inflammatory origin |
| Colpitis |
| Myeloma nephropathy |
| Uterine fibroids |
| Genitourinary fistulas |
| Disorders of sexual development in girls |
| Hereditary nephropathies |
| Urinary incontinence in women |
| Necrosis of myomatous node |
| Incorrect positions of the genitals |
| Nephrocalcinosis |
| Nephropathy in pregnancy |
| Nephrotic syndrome |
| Nephrotic syndrome primary and secondary |
| Acute urological diseases |
| Oliguria and anuria |
| Tumor-like formations of the uterine appendages |
| Tumors and tumor-like formations of the ovaries |
| Sex cord stromal tumors (hormonally active) |
| Prolapse and prolapse of the uterus and vagina |
| Acute renal failure |
| Acute glomerulonephritis |
| Acute glomerulonephritis (AGN) |
| Acute diffuse glomerulonephritis |
| Acute nephritic syndrome |
| Acute pyelonephritis |
| Acute pyelonephritis |
| Lack of sexual development in girls |
| Focal nephritis |
| Paraovarian cysts |
| Torsion of the pedicle of adnexal tumors |
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Kidney damage in myeloma is clinically characterized primarily urinary syndrome, a feature of which is the relative isolation of proteinuria, although it is possible to detect a large number of casts and sometimes leukocytes in the urine; hematuria is rare. There have been reports of plasma cells being detected in the urine of patients with myeloma.
Proteinuria- the most constant symptom of kidney damage in myeloma. As already noted, proteinuria in some patients may precede other clinical signs of myeloma or remain its only symptom.
Qualitative characterization of urine protein in all cases of proteinuria for the diagnosis of myeloma acquires exceptional value. Essentially, paper or starch gel electrophoresis of 24-hour urine proteins, as well as immunoelectrophoresis, which reveals a monoclonal peak (M-gradient) similar to the serum peak, can serve as one of the most reliable methods for correct diagnosis. This method also allows us to predict the nature of nephropathy in myeloma, without resorting to a puncture biopsy of the kidney, which is dangerous for this pathology.
The following observation demonstrates the possibility of long-term existence of isolated proteinuria as the only symptom of later confirmed myeloma, the paucity of data obtained from renal biopsy, the complications of this procedure, and the importance of simple urine protein electrophoresis for the diagnosis of myeloma.
Patient Sh., 50 years old, was admitted to the clinic with complaints of severe general weakness, increased fatigue, severe weight loss (he lost 12 kg in 1½ years), and a feeling of stiffness in the small and large joints of the extremities in the morning. During a preventive examination approximately 1½ years before admission to the clinic, massive proteinuria (up to 20‰) was detected, which remained as severe during subsequent outpatient follow-up.
During the examinations, attention was constantly drawn to normal general and biochemical blood parameters. He was admitted to the clinic with suspected amyloidosis. No pathology was detected from the internal organs. Blood Hb 120 g/l, ESR 4 mm/h. Biochemical blood test without deviations from the norm. Protein in urine is 5.5-10‰ (17 g/day). Myeloma is suspected, although Bence Jones protein was not found in the urine. Repeated studies of serum proteins by paper electrophoresis and thyseliogram did not reveal dysproteinemia.
ESR remained normal (4-18 mm/h). For the purpose of differential diagnosis, a “closed” puncture biopsy of the kidney was performed, which revealed severe degeneration of the tubular epithelium and splitting of the glomerular BM. Electrophoresis of urine proteins revealed an M-gradient paraprotein peak in the region of the γ-fraction, and then a thorough radiographic examination of the skull bones revealed bone symptoms of myeloma.
Urinary excretion of albumin in multiple myeloma is practically very small, which is usually what explains the extreme rarity of NS in this pathology (except for cases of amyloidosis). The bulk of urine proteins in typical observations is Bence-Jones protein, the excretion of which can reach 20 g/day or more. It is possible that light chain dimers and polymers, which are also found in urine, are formed in the tubular fluid. It is known that Bence Jones proteinuria is not always accompanied by the development of a “myeloma kidney,” and a “myeloma kidney” can be detected in the absence of Bence Jones protein in the urine.
In some cases of myeloma due to severe damage tubular apparatus tubular dysfunction can reach a large degree, manifesting itself clinically as partial disorders, combined into corresponding syndromes. Renal glycosuria and aminoaciduria, unusually high clearance of phosphates and uric acid, proximal acidosis, sometimes combined with generalized osteomalacia, i.e. essentially Fanconi syndrome in adults, are described in various combinations.
It is of interest that when Fanconi syndrome and myeloma are combined, the former almost always precedes the diagnosis of myeloma. This peculiar stage of the disease can last for many years. In contrast, distal tubular dysfunction in myeloma is rare and is never detected in the absence of globulin light chains in the urine. Finally, a combination of functional disorders of the proximal and distal tubules, in particular in the form of vasopressin-resistant nephrogenic diabetes, has been described in patients with the presence of protein light chains in the urine, but without diagnostic signs of myeloma (“light chain nephropathy”).
All these data are of some practical value, since they force long-term observation and re-examination of this category of patients in order to identify myeloma.
As already indicated, the prognosis for myeloma is often determined by the onset and progression renal failure; In this case, the rate of increase in azotemia plays a decisive role. Although the development of renal failure is usually associated with the occurrence of tubular obstruction characteristic of myeloma or, less commonly, the addition of amyloidosis, complex mechanisms of interaction of excreted Bence-Jones protein or protein light chains with the tubular epithelium also play an important role in the pathogenesis of functional disorders, i.e., a certain nephrotoxic effect of these substances.
Thus, in vitro in tissue culture, inhibition of certain functions of the renal tubules under the influence of certain protein fractions of the urine of patients with myeloma (with Bence-Jones protein in the urine) has been shown; and patients with “light chain nephropathy”. Of interest in this regard is what was discovered by D. Clyne et al. (1974) damage to the proximal tubules during intraperitoneal administration of χ-type light chains of the Bence-Jones protein. A number of other factors, of course, can play a certain role in the development of renal failure - hypercalcemia, hyperuricemia, increased plasma viscosity, increased intravascular coagulation.
Identifying the mechanism of renal failure is important in connection with the choice of therapeutic measures, especially those applied in the early stages. Thus, a large intake of fluids and alkalizing agents promotes better excretion of uric acid and calcium, hyperuricemia can be controlled by the administration of allopurinol, the fight against urinary tract infections, etc. plays a positive role. Sometimes with the help of these measures, it is possible to improve kidney function.
A special place in functional renal failure in myeloma is occupied by acute renal failure, which sometimes complicates the course of the disease. Undoubtedly, the occurrence of acute renal failure is primarily facilitated by dehydration and the associated increase in urine concentration and decrease in the flow rate of tubular fluid. Under these conditions, the nephrotoxic effect of Bence Jones protein manifests itself more quickly. The role of radiocontrast research methods (urography) in such patients in the occurrence of acute renal failure in myeloma is less certain.
However, administration of contrast agents to patients with myeloma should still be avoided, and if intravenous urography is absolutely necessary, dehydration should be excluded. Finally, it is necessary to remember the great danger of hypercalcemia for these patients, especially with uncontrollable vomiting, when the concentration of calcium in the blood can reach 3.5 mmol/l or more.
Thus, the clinical picture of kidney damage in multiple myeloma, despite the apparent uniformity (urinary syndrome with increasing renal failure, the rarity of edematous urinary tract and nephrogenic hypertension), can in some cases acquire features associated with impaired tubular functions (Fanconi syndrome in adults), episodes of EPN .
In any case, with difficult to explain proteinuria, especially massive, but without other signs of NS, as well as with symptoms of partial renal tubular failure, especially in elderly patients, examination for myeloma is necessary. It must be remembered that for a long time nephropathy may be the only, at first glance isolated, manifestation of a general disease. A complex of studies, and above all simple electrophoresis of 24-hour urine proteins, and, if possible, also their immunoelectrophoresis, makes it possible to confirm the diagnosis of “myeloma kidney” with almost complete certainty.
In differential diagnostic terms, it should be remembered that there are rare myeloma-like kidney lesions that occur with certain tumors of internal organs. Thus, with medullary carcinoma of the thyroid gland, adenocarcinoma of the pancreas, excess abnormal protein can be excreted, which is freely filtered by the glomeruli of the kidneys and precipitated in the tubules, resembling myeloma of the kidneys.
Features of the clinical picture of kidney damage in other dysproteinoses are associated with the degree of involvement of the glomeruli of the kidneys in the process, which is characteristic of each of them. As with multiple myeloma, NS is rare in other dysproteinoses. With Waldenström's disease and mixed cryoglobulinemia, proteinuria is usually minimal, so the clinical picture of the disease is usually determined not by kidney damage, but by the involvement of other organs in the process. This is especially pronounced in cryoglobulinemia with its characteristic skin symptoms (purpura, necrosis), neuritis, arthralgia, and hepatosplenomegaly.
However, even with these dysproteinoses, sometimes the prognosis depends on kidney damage; including possible death due to the development of oliguric acute renal failure, for example, with mixed cryoglobulinemia. As already indicated, kidney damage in cryofibrinogenemia and heavy chain disease is minimal, which determines the virtual absence of clinical signs of nephropathy in these conditions.
Treatment of persons suffering from multiple myeloma with kidney damage, of course, primarily includes modern methods of treating this neoplastic condition. Timely and rational use of chemotherapy (melphalan, diclophosphamide, prednisolone) and radiation therapy in some cases stops the progression of renal failure. If you have nephropathy, you should remember the dangers of dehydration. Therefore, it is mandatory to ensure a large diuresis (at least 3 l/day), which, in combination with alkalinization of urine, which reduces the precipitation of Bence-Jones protein, can maintain satisfactory renal function for a long time. It is also necessary, if possible, to correct hypercalcemia (hyperhydration, CS, diuretics, calcitonin), hyperuricemia (allopurinol), and combat increased blood viscosity. In some cases, plasmapheresis can have a good effect.
In end-stage renal failure, as well as in connection with episodes of acute renal failure, the possibilities of using peritoneal dialysis and hemodialysis are discussed. Although the selection criteria for hemodialysis of patients with myeloma cannot yet be considered generally accepted, some publications on this subject indicate that hemodialysis for myeloma should be carried out in cases of irreversible renal failure, when there are no complications, there is a high probability of good remission of the disease , significant rehabilitation is possible. Recently, there have been reports of kidney transplantation for multiple myeloma.
Clinical Nephrology
edited by EAT. Tareeva
Myeloma nephropathy is a disease that consists primarily of damage to the renal nephrons by abnormal proteins - paraproteins. A characteristic feature of a true myeloma kidney is the deposition of precipitates of abnormal myeloma proteins in the distal parts of the tubules with damage and blockage of the latter. Kidneys with myeloma nephropathy are enlarged in size, have a dense consistency, and an intense red color. The edematous medulla swells on the incision. In some cases, the kidneys are wrinkled and reduced in size. Most typical for a myeloma kidney is an abundance of cylinders in the dilated lumens of the tubules, in some areas with calcium deposits (calcareous cylinders). In some cases, most of the tubules are flooded with homogeneous protein masses. Sometimes cylinders of a specific scaly shape are cordoned off along the periphery by giant cells, like foreign body resorption cells. The epithelium of the tubules is subject to significant transformations in the form of vacuole, hyaline-vacuole and granular dystrophy, and is freely desquamated. In the interstitial tissue, areas of cellular infiltrates and fibrosis are found (in no less than 50% of cases). With true myeloma, the renal vessels, like the glomeruli, remain almost intact. With severe and prolonged hypercalcemia, nephrocalcinosis and stone formation begin (in almost 10% of cases). Since multiple myeloma develops mainly in elderly people, the phenomena of atherosclerosis of the renal vessels are often detected and the possibility of developing renal ischemia is combined with this.
treatment
To date, there are no reliable methods and remedies for the treatment of multiple myeloma. Nevertheless, the use of complex therapy using cytostatics (cyclophosphamide, sarcolysine, etc.) in combination with glucocorticoids and anabolic hormones allows in many cases to achieve long-term (up to 2-4 years) clinical remission and, thus, increase the patient’s life expectancy.
symptoms
The earliest and most persistent sign of myeloma is proteinuria, which is found in 65-100% of patients. The symptoms of myeloma nephropathy lack the usual HC variant: hypoproteinemia, edema, hypercholesterolemia; do not note symptoms of vascular lesions of the kidney - retinopathy, hypertension. Hyper- and dysproteinemia with a predominant content of beta-globulins and abnormal paraprotein are characteristic. Various types of cylinders are found in urine sediment, mostly giant cylinders with a layered structure. Leukocyturia and erythrocyturia are often absent. Some patients (23%) experience symptoms of acute nephronecrosis, which leads to acute renal failure with oligo- or anuria and a constant increase in azotemia.
What is Kidney Damage in Myeloma?
Kidney damage is regarded as the most common clinical, morphological and laboratory (biochemical) manifestation of myeloma and at the same time one of the most severe and unfavorable prognostic complications of this disease. The incidence of kidney damage in myeloma ranges from 60 to 90 and even up to 100%. In many cases (according to A.P. Peleshchuk, 28%), pathological changes in the kidneys serve as the first, earliest clinical and laboratory manifestations of myeloma, which served as the basis for identifying the renal form of this disease. Kidney damage caused by multiple myeloma is referred to as “myeloma nephropathy” or “myeloma kidney”, less often as “paraproteinemic nephrosis” (N. E. Andreeva, 1979). Pathological changes in the kidneys can be of a different nature and differ in significant polymorphism. In some cases, they are strictly specific to myeloma and are caused by para- and disproteinosis. The term “myeloma kidney” corresponds to this nature of kidney damage. In other cases of myeloma nephropathy, changes in the kidneys are nonspecific (or not strictly specific) for this disease and manifest themselves in the form of pyelonephritis, renal amyloidosis, nephrocalcinosis, arteriolosclerosis.
Relatively frequent pyelonephritis and arteriolosclerosis of the kidneys are explained by the predominance of elderly people among patients with multiple myeloma and a decrease in the body's resistance to infection in this disease.
For a better understanding of the mechanism of development of myeloma nephropathy, its morphological and clinical manifestations, it is advisable, without dwelling in detail on the pathogenetic essence of myeloma itself, to remind the reader of the main symptoms of this disease and the criteria for its diagnosis.
Multiple myeloma (myeloma, plasmacytoma). This is a systemic disease of the tumor-hyperplastic type with predominant damage to the skeletal bones, characterized by malignant proliferation of cells of a reticuloplasmic nature (G. A. Alekseev, 197O).
What causes kidney damage in multiple myeloma?
The etiology of multiple myeloma is still unclear. Its characteristic feature is the ability of myeloma cells to produce pathological proteins - paraproteins. Therefore, multiple myeloma is also referred to as “paraproteinosis.”
The disease occurs mainly at the age of 45-65 years and tends to noticeably increase. This is due not only to improved diagnosis, but also to an increase in the proportion of elderly people. Although there are cases of multiple myeloma at a younger age. Men and women get sick with approximately the same frequency.
Symptoms of kidney damage in multiple myeloma
The clinical picture of multiple myeloma is caused by damage to the bone and hematopoietic systems, metabolic disorders (mainly protein and mineral) and visceral pathology.
The first clinical symptoms of myeloma, which are found in more than 50% of patients, are general symptoms such as weakness, decreased performance and appetite, asthenia, weight loss and bone pain. Often the disease begins with sudden pain in the bones or even a spontaneous fracture of one of the bones. In some cases, patients seek medical help if protein is accidentally detected in the urine or an increase in ESR.
Pathological changes in the skeletal system are among the most common and characteristic clinical manifestations of myeloma. They are expressed by the classic triad of symptoms: pain, swelling and fractures. In 75-90% of cases, patients seek medical help specifically for bone pain (ossalgia). Their occurrence is associated with destructive changes in the bones due to tumor growth of myeloma tissue. Mostly flat bones are affected - the skull, sternum, ribs, vertebrae, iliac bones, as well as the proximal parts of the tubular bones (shoulder, femur). In a later stage of the disease, visible deformation appears, and then spontaneous fractures, which are observed in 50-60% of patients; Fractures of the ribs, vertebrae and hips are especially common. In this case, the vertebral bodies become flattened and deformed (compression fracture), taking on the shape of “fish vertebrae” and accompanied by a shortening of the patient’s height. Tumors (myelomas) arising from flat bones are usually multiple, sometimes reaching large sizes; occur in approximately 15-20% of cases.
X-rays reveal round-shaped bone tissue defects with a diameter ranging from a few millimeters to 2-3 cm or more, which in the bones of the skull appear to be “moth-eaten” or “knocked out with a punch,” creating a characteristic X-ray picture of the so-called “leaky skull.” In the proximal sections of the tubular bones (humerus, femur), bone defects are radiologically detected in the form of “soap bubbles” or “honeycombs”, and pathologically altered vertebrae resemble “fish vertebrae”.
The picture of peripheral blood in the initial stage of the disease usually does not have significant deviations from the norm. However, as the disease progresses, all patients develop normochromic anemia, the pathogenesis of which is not entirely clear. The occurrence and progression of anemia is associated with the replacement of bone marrow with elements of myeloma tissue. The severity and rate of increase of anemia may vary. As the disease progresses, more or less pronounced leukopenia (neutropenia) is observed. Absolute monocytosis is often observed, and in 2-3% of patients, eosinophilia is observed. Some patients have a tendency to hyperthrombotic
cytosis (mainly in the initial stage of the disease); Thrombocytopenia is not typical for multiple myeloma. The number of reticulocytes, as a rule, does not increase. It is possible to develop hemorrhagic syndrome, the genesis of which is complex and not entirely clear. A classic sign of myeloma is a pronounced (up to 50-70 mm/h) and stable increase in ESR, which is often detected long before the appearance of bone and other symptoms of this disease.
Analysis of the myelogram obtained by sternal puncture reveals in the vast majority of patients (90-95%) a clear myeloma cell proliferation with the presence of tumor (myeloma) cells of more than 15%. Examination of bone marrow puncture is of crucial diagnostic importance.
The syndrome of protein pathology in myeloma is most clearly manifested in the form of hyper- and paraproteinemia (or pathoproteinemia). These disorders of protein metabolism are associated with excessive production by pathologically altered plasma (myeloma) cells of abnormal proteins - patho(or para) proteins from the group of immunoglobulins, which, however, although related (similar), are not identical to the corresponding normal fraction of IgM, IgG and IgA . This is the fundamental difference between myeloma paraproteinemia and dysproteinemia of other origins (for example, in rheumatoid arthritis, liver cirrhosis, etc.), characterized by hypergammaglobulinemia. Consequently, it is not the quantitative ratios of the globulin fractions of the electropherogram that have diagnostic significance in myeloma, but their qualitative features. As for the content of ordinary γ-globulins in the blood serum during myeloma, it is not only not increased, but, on the contrary, is always significantly reduced, i.e., there is constant hypogammaglobulinemia. Using protein electrophoresis, paraproteinemia is detected in 90-92% of cases. In this case, the most important and specific criterion for myeloma paraproteinemia is the presence on the proteinogram of a narrow intense M band either between the y-, b-fractions, or in the area of the y-, b- and less often the a-2-globulin fraction.
For myeloma paraproteinemia, a very characteristic and pathognomonic sign is also the presence of low molecular weight Bence-Jones protein (with a molecular weight of 40,000) in the urine. This protein is synthesized only by myeloma cells. Entering the bloodstream due to its small size, it is quickly excreted by the kidneys and appears in the urine. Like creatine, almost complete purification of this protein from the blood occurs in the kidneys. Therefore, it can be detected in the blood only in minimal quantities and only with the help of immunoelectrophoresis. Freely penetrating through the glomerular filter, Bence-Jones protein gives a picture of isolated proteinuria typical of multiple myeloma. Detection of this protein using electrophoresis is of extremely important diagnostic value; it allows making a diagnosis at an early stage, even before pronounced clinical signs, which is especially important in elderly people with proteinuria of unknown origin. Only at the late stage of myeloma is a significant amount of other (serum) proteins detected in the urine, which neutralize the electrophoretic picture characteristic of Bence-Jones proteinuria.
Hyperproteinemia (over 80-90 g/l) in multiple myeloma occurs in 50-85% of cases and sometimes reaches 150-180 g/l. It is caused by hyperglobulinemia, which in combination with hypoalbuminemia leads to a significant decrease in the A/G coefficient (to 0.6-0.2).
Visceral pathology in myeloma most often manifests itself as damage to the kidneys and much less often - to the liver, spleen and other organs. In 5-17% of patients, hepato- and (or) splenomegaly is detected. Tumor plasma cell infiltrates can be found in all internal organs, but they rarely appear clinically: they are usually found at autopsy.
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Myeloma nephropathy is a fatal disease characterized by kidney damage. The tissues of the organ become denser, acquire a bright red tint, and the kidneys increase in size. The consequence of the disease is progressive renal failure, which is impossible to get rid of. In addition, the disease is accompanied by vascular atherosclerosis. With timely treatment, it is possible to prolong the period of remission and the patient’s quality of life.
Elderly people are at risk. Nephropathy in this case is a manifestation of myeloma, a malignant oncological disease, which is characterized by the appearance of multiple tumor growths throughout the body.
Etiology
The disease is characterized by damage to the renal tubules and glomeruli caused by myeloma. The latter is a cancerous disease, the essence of which is the production of a large number of plasma cells by the bone marrow.
Thus, the main cause of nephropathy is multiple myeloma. Cancer cells release pathological Bence Jones protein into the blood, which is deposited on the surface of the kidneys and provokes scarring of the organ tissue.
In the early stages of the disease, provided that the patient’s kidneys are healthy, protein molecules penetrate the openings of the kidney membranes. Here they oxidize and coagulate. The toxins that appear during this block the function of the kidney glomeruli.
As a result, the pressure in the latter increases, and its performance deteriorates. Over time, due to high intrarenal pressure, the tissues of the organ are replaced by connective tissue, resulting in kidney dysfunction.
In addition, under the influence of oxidized protein, nephrosis (that is, damage to the kidney) occurs because its filtration is impossible due to blocked renal tubules.
Clinical picture
The disease is characterized by the complexity of diagnosis, which is associated with the absence of specific and obvious signs of myeloma nephropathy. With the disease, functional renal failure progresses (it causes death in 30%), which, however, has almost no symptoms.
An indicative symptom is proteinuria, that is, the presence of protein in the urine. This may be one of its forms: mini- or macroproteinuria. The latter is more common - the level of protein in the urine can reach 50-60 g/l.
Sometimes proteinuria is detected even without a clinical urine test - by the foam cap in the urine. However, this sign does not always mean proteinuria. In addition, there are small traces of blood in the urine. We are talking about microhematuria.
The clinical picture is complemented by symptoms characteristic of multiple myeloma:
- Bone pain.
- Osteoporosis.
- Increased bone fragility, frequent fractures.
- Hypercalcemia (that is, an increase in the amount of calcium in the blood)
- Deformation of the bones, leading to changes in the skeleton and a decrease in the patient’s height.
- Frequent infectious diseases of bacterial etiology;
- Anemia.
In rare cases, the patient suffers from swelling. His blood pressure tends to drop as the cancer progresses.
Diagnostic methods
The first method of diagnosis is to test urine for protein content. If the result is positive, the task of further research is to differentiate the disease in question and glomerulonephritis. Indicative should be the patient’s absence in the past of staphylococcal and streptococcal infections and exacerbations of glomerulonephritis. In this case, the doctor may suspect nephropathy, etiologically related to myeloma.
“Unreasonable” proteinuria, an increase in the number of leukocytes in the blood and unexplained anemia, especially in people over 35-40 years of age, should be a reason to think about the presence of myeloma nephropathy in the patient.
To establish a diagnosis, 3 types of diagnostics must be carried out:
- Urine electrophoresis (detects Bence Jones protein in urine)
- Determination of paraproteins in blood and urine.
- Sternal puncture, through which the level of plasma cells is determined.
Renal puncture biopsy is used extremely rarely. Primarily due to the lack of information content. Despite the fact that a biopsy can exclude glomerulonephritis and amyloidosis, morphological changes in the organ can be diverse. This, in turn, does not give reason to talk exclusively about the development of nephropathy against the background of myeloma. Secondly, this diagnostic method is difficult to perform and there is a risk of patient death.
Treatment
Today, myeloma nephropathy is considered an incurable disease. The purpose of treatment measures is improve the quality and increase the patient's life expectancy. With timely treatment, it is possible to increase the patient’s life expectancy by 5, less often 7-10 years.
In order to achieve a period of remission, they are prescribed cytostatics(cyclophosphamide, sarcolysin) and glucocorticosteroids. In combination with anabolic hormones they give stable and long-term (up to 2-4 years) remission.
However, they are contraindicated in renal failure. Then they resort to symptomatic therapy. Peritoneal dialysis (blood purification, in which the peritoneum takes over the function of the filtering organ), hemodialysis (another method of extrarenal blood purification), and kidney transplantation are not recommended.
Forecast
The disease has poor prognosis. Treatment depends on the severity of the lesion, the effectiveness of cytostatic therapy, and the rate of progression of renal failure. During treatment, it is possible to increase the patient’s life expectancy to 5-10 years and achieve stable remission.
Moreover, in 60% of cases after cytostatic therapy, acute leukemia. The main causes of death are death from infection and acute renal failure.
Prevention
The only preventive measure can be called regular preventive medical examinations and contacting specialists at the first signs of the disease.
Achieving long-term remission will be achieved by following the doctor’s instructions.