Nephrology is a specialty of medicine that deals with the study of kidney diseases. The term comes from the ancient Greek word “nephros” which means “kidney”. Hence, nephrologists are doctors who specialize in the treatment of diseases of these organs. Their activities include early recognition, determining a diagnosis, assessment of functional disorders and non-surgical therapy.
Common nephrological diseases:
- Non-infectious, inflammatory diseases of the kidneys
- Infectious diseases of the kidneys and urinary tract
- Malignant kidney disease (kidney cancer)
- Genetically determined kidney function abnormalities
The typical symptoms and diagnostic results that require professional treatment by nephrologists are:
- Reduced renal function (kidney failure)
- Edema (fluid retention)
- Protein or other impurities in urine or a colour change of urine
- High blood pressure
- Pain in the kidney and bladder
- Renal colic
Kidney diseases are divided into primary renal diseases, the cause of which lies directly in the kidneys, and secondary forms. The spectrum of primary renal diseases begins with immune-inflammatory diseases (glomerulonephritis), continues with infections (pyelonephritis) and ends with congenital genetic disorders (for example, polycystic kidney disease). Functional disorders and destruction of tissues can also occur because of toxins and drugs. In addition, some systemic diseases (diabetes mellitus, high blood pressure, autoimmune diseases) again lead to kidney damage. In such cases the treatment of the underlying disease, which is the primary cause, is put in the forefront. The main goal of any therapy is to stabilize the kidney function to prevent the onset of the disease or slow down its progression.
Since the kidneys in the human body perform a large number of different functions (excretion of toxic substances, regulation of water and salt balance, regulation of blood pressure, production of hormones), deterioration of their functioning or complete loss of their function is a complex problem which in most cases may concern other organ systems or the whole organism, and therefore requires careful therapeutic intervention. The typical problems are hypertension, anemia, metabolic diseases in the cartilage and bone tissues, metabolic disorders, as well as cardiovascular diseases. Therefore, at the stage of the disease progression urgent control examinations and comprehensive medical treatment are needed. In case of kidney failure it is possible to perform replacement therapy in the form of hemodialysis (blood purification), peritoneal dialysis (purification of blood through the peritoneum), and kidney transplantation. It is possible to restore completely normal functioning of the organ only with the help of transplantation. All types of dialysis are performed by nephrologists, as well as preparation for transplantation and subsequent treatment after a successful operation.
Renal replacement therapy is understood as the treatment methods used to deal with complete or partial loss of detoxification and secretory functions of the kidney. They include peritoneal dialysis, hemodialysis, hemofiltration, hemodiafiltration and kidney transplantation.
Hemodialysis is a form of blood purification, which is carried out in most cases three times a week for an average of 4-5 hours. In this case, the patient’s blood is extracted through the hose system into the extracorporeal circle of blood circulation, in which the artificial kidney (dialyzer) participates.
In the dialyzer the blood passes through numerous capillaries, whose walls (filter partitions) correspond to a semipermeable membrane. On the outer side of the membrane dialysis fluid (a sterile solution obtained by reverse osmosis, which, depending on the needs, has a certain concentration of electrolytes) flows in the opposite direction. The process is based on the principle of equalization of low-molecular substance concentrations in two liquids (diffusion). The substances released with the urine are transferred from the blood to the dialysis fluid. While high-molecular substances, such as blood cells and serum proteins, are retained by the filter in the blood.
Either osmosis or ultrafiltration (reduced pressure on the side of the dialysis fluid) is used to remove the amount of water that is usually released by urine. Thus, depending on the needs, you can control the reduction of the volume.
After the blood in the dialyzer has cleared, it is again sent to the large circle of blood circulation.
Hemofiltration and Hemodiafiltration
Hemofiltration means an extracorporeal method, in which the liquid constituent of the blood is squeezed out and replaced with an electrolyte solution. Thus, a rapid change in the volume of circulating blood can be achieved. Hemodiafiltration is also a method of treating chronic kidney failure. It is a combination of hemodialysis and hemofiltration.
With various forms of peritoneal dialysis, the peritoneal membrane (peritoneum) of the body is used as a filter membrane to remove the substances released with the urine. In order to perform the peritoneal dialysis, a catheter must be inserted through which the dialysis fluid is pumped into the abdominal cavity. It remains there for some time (depending on the method). After low-molecular substances, following the decrease in concentration, have been transferred to the dialysis solution, it is removed from the abdominal cavity and a new portion of the liquid is pumped.
Common types of peritoneal dialysis are CAPD (continuous ambulatory peritoneal dialysis), IPD (intermittent peritoneal dialysis) and NIPD (nocturnal intermittent peritoneal dialysis).
Only with the help of successful kidney transplantation can normal or relatively normal kidney function be achieved. Besides, in this case, not only the functions of excretion and regulation are restored, but also the endocrine functions of the kidneys. Organs for transplantation are borrowed from donors who have died of brain damage, or from living relatives or altruists. To prevent the rejection of foreign tissues, the patient needs to take immunosuppressive medications after the organ transplantation till the grafted organ functions. Since the intake of these vital drugs for many years is associated with various risks and side effects, possible recipients need to undergo an examination before kidney transplantation to determine the feasibility of transplantation.
Change in the Form of Renal Replacement Therapy
If a particular form of treatment is poorly tolerated, one method of replacement renal therapy can be replaced by another (for example, peritoneal dialysis by hemodialysis or vice versa). Most patients who are eligible for transplantation should wait for a suitable donor organ as a dialysis patient. In case the donor kidney is already available (for example, from a living donor), the transplantation can be performed immediately, without prior treatment as a chronic dialysis patient.
Urology is a surgical discipline with a specialization in the urinary tract. Urologists perform surgery in this area, and also on the kidneys. Urinary tract includes bladder, prostate, as well as urethra and ureters. The focus in treatment is put on local inflammation, stone and sand formation in the kidneys. A nephrologist is also a therapist and is engaged in study and treatment of functional abnormalities of the kidneys, as well as their effect on the entire body. The activities of these special areas sometimes intersect and imply close professional cooperation.