In our body, in the process of metabolism, numerous and varied processes continuously occur, resulting in the formation of toxic substances to be removed. The role of scavengers can perform four systems, overlapping each other: the respiratory system; leather; digestive system; urinary system.
Accordingly, toxins and metabolic products are removed: through the skin - with sweat, while breathing - with air, through the intestines - with feces and with urine.
A nephrologist is a specialist in the urinary system. The nephrologist will tell you about its structure, functions, diseases, methods of treatment and prevention.
Anatomy of the urinary system
The urinary, or excretory, human system consists of two kidneys, two ureters, the bladder and the urethra. Its main task is to remove the waste substances from the body and maintain the blood-salt balance of blood at a certain level. All parts of this system are divided into urinary and urinary. The first are the kidneys, and the second are the ureters, the bladder and the urinary canal.
What you see under the microscope
The kidneys are incredibly complex. They consist of structural filtering units - nephrons. There are about a million nephrons in each kidney, their number decreases with age, and they are replaced by connective tissue. Like the cells of the nervous tissue, the kidney cells do not regenerate. The nephron consists of a glomerulus (capsules of Shumlyansky - Bowman, containing a collection of blood vessels) and very long tubules that continue into the collecting tubules, which, in turn, open into the renal pelvis.
How the kidneys work
Through the arteries in the kidneys under great pressure continuously flows blood, which contains everything: trace elements, cells, amino acids, but also toxins, toxic compounds. This is a very subtle, regulating filtration function of the kidneys - to determine what to withdraw, what to leave, in what quantity. First, the primary urine is formed in the glomerulus, which is very similar in composition to the blood plasma in terms of glucose, sodium, phosphate, creatinine, urea, and uric acid. Passing through the tubules, the necessary substances are reabsorbed and as a result only 1.5-2 liters of final urine are formed.
Normally, large protein molecules and blood cells do not pass through the renal filter. And with “leaky” kidneys in the urine, red blood cells and protein appear!
Formed in the kidneys urine enters the ureters in the bladder. The ureters and bladder are equipped with muscle sphincters, which play the role of valves. They open and close automatically - out of our control. As urine enters the bladder, its size gradually increases, with a certain level of stretching, there is an urge to urinate. The bladder continues into the urethra, between them there is the sphincter, which normally a person can consciously control and control the excretion of urine.
The most important function of the kidneys: the elimination and disposal of toxins. In addition, by constantly changing the composition of the urine of the kidney, they ensure the constancy of the blood composition — they remove excess sodium (if you have had salted cucumbers), retain potassium and so on.
The kidneys are also considered one of the main organs regulating blood pressure, produce the hormone necessary for the formation of red blood cells, activate vitamin D and are involved in many other processes.
To the urologist or nephrologist
Urologist is a surgical specialty, nephrologist is a therapeutic one. The difference is about the same as between a cardiologist and a heart surgeon. The urologist should be contacted when it comes to:
- infections (especially neglected pyelonephritis);
- tumors - malignant, benign and incomprehensible;
- abnormalities of the urinary system.
Also, urologists deal with the male urogenital system, namely, such diseases as prostatitis, prostatic hyperplasia, prostate tumors. Women urologists can help with the omission of the vagina and the incontinence of urine, although it is more often the operating gynecologists.
Nephrology deals with such states as:
- infectious inflammation of the renal tissue - pyelonephritis;
- immune or autoimmune inflammation of the kidneys - glomerulonephritis;
- urolithiasis disease;
- acute renal failure;
- chronic renal failure;
- polycystic kidney disease;
- kidney tuberculosis;
- kidney tumors;
- congenital and hereditary tubulopathies - lesions of the renal tubules;
- kidney damage within systemic autoimmune diseases, for example, systemic lupus erythematosus, hemorrhagic vasculitis;
- abnormal development of the urinary system;
- kidney damage due to hypertension and diabetes;
- atherosclerotic lesion of the renal vessels.
Now all kidney diseases are combined under a single term: chronic kidney disease - CKD. Therefore, the diagnosis looks like this:
- CKD: Diabetic nephropathy. CKD 1. (CKD - chronic renal failure).
- CKD: Chronic glomerulonephritis. CRF 2.
How kidney disease manifests
The kidneys are a very silent and patient organ. A bright exception - an attack of renal colic - one of the strongest pain syndromes, comparable in intensity with childbirth. But sometimes the opposite happens - a person lives and does not know what is wrong with his kidneys, and he turns to a doctor with renal insufficiency, when there is little that can be done. Severe pain when a stone passes through a narrow ureter is explained by disproportionate stretching of the wall and irritation of pain receptors, in functional (parenchymal) kidney tissue (as in the lungs and liver, for example) there are no pain receptors - this is the hidden course of most kidney diseases.
And yet there are signals that give sick kidneys:
- Increased blood pressure - sometimes the only sign!
- Edemas - despite the well-established popular opinion not only of the eyes and face, but also of the feet and legs.
- Change in color and clarity of urine (red, brown, turbid, frothy, containing "flakes" and sediment).
- Increased urge to urinate, imperative urges (it is difficult to endure the urge, you must immediately run to the toilet).
- Pain and chilliness in the lower back.
- Pain, cramps, discomfort during urination.
- A sharp decrease or absence of urine on the background of edema and hypertension: a decrease in the daily amount of urine (less than 500 ml).
- A lot of pale clear urine, a violation of the process of urine concentration by the kidneys at night (regular urge to urinate at night).
- Constant feeling of thirst, poor appetite, aversion to meat food.
- General weakness, malaise, shortness of breath, reduced exercise tolerance, pruritus.
- Pallor or sallow skin color, bad breath and from the body - in the later stages of renal failure.
All these symptoms are non-specific. The particular danger of chronic kidney disease, as well as other, more well-known, "silent killers" - diabetes and hypertension - is that it can not cause any complaints for a long time, which would prompt the patient to see a doctor and start treatment.
Laboratory examination: what tests and analyzes will help to make a diagnosis
Laboratory tests are an indispensable tool in the practice of any doctor, but this is especially true of the nephrologist. It is laboratory tests that sometimes have decisive knowledge in making a diagnosis and determining the effectiveness of therapy — do not throw away analyzes even a hundred years old — they may be useful to you in consultations:
- Urinalysis - a favorite, simple, cheap and most informative nephrologist analysis. Very rarely, kidney disease is encountered with normal urine tests. Any changes in the urine can talk about kidney problems.
- Nechiporenko's test is an analysis that allows to detect elevated levels of leukocytes (inflammation) and red blood cells in the urine (stones, glomerulonephritis, tumors).
- Biochemical analysis of blood - the concentration of creatinine and urea - the main indicators of renal function.
- Complete blood count - anemia (not necessarily because of the kidneys, but often against the background of renal failure).
- Zimnitsky's test - an assessment of concentration function of kidneys
- Daily proteinuria - assessment of protein loss per day.
- Urine for microalbuminuria.
- Tests for various antibodies in case of suspicion of the autoimmune nature of the disease.
Instrumental research methods
The classic principle of diagnosis: from simple to complex works here.
Considering instrumental diagnostics, one can distinguish a group of radiation methods, among them ultrasound (ultrasound of the kidney and bladder; renal vessels) and X-ray. Each method has its own advantages and disadvantages, the choice is determined by sensitivity, specificity, accuracy of the method, safety and accessibility for the patient.
Ultrasound of the kidneys
Ultrasound examination is a non-invasive (not violating the integrity of the body) study using ultrasound waves, which allows to evaluate the structure of the kidneys and the renal blood flow.
What the nephrologist usually pays special attention to (and, alas, the ultrasound doctor does not always describe):
- The size of the kidneys (it is better to evaluate in the dynamics, that is, compared with previous studies). In chronic kidney diseases - over time they “shrink” - decrease in size, functionally active tissue is replaced by connective (scar). The exceptions are enlarged kidneys for diabetes mellitus and polycystic kidney disease. In acute inflammation of the kidneys or edema on the background of acute failure of the kidneys will be large, edematous.
- The thickness of the parenchyma is the same functional layer where the bodies of the nephrons are located. With its thinning, renal failure develops.
Absolutely all studies should be considered together with clinical manifestations - complaints, external signs, and best of all in dynamics! One ultrasound each - no diagnosis is made.
Ultrasound is prescribed during routine routine examination of patients with an established diagnosis, for example, urolithiasis, kidney cyst, pyelonephritis, etc., during professional examination. Also, ultrasound of the kidneys is prescribed for hypertension, since the kidneys act as a target organ at the same time as pressure increases and regulate the level of blood pressure.
This method is widely used to detect abnormalities in the development of the urinary system, trauma, impaired urination and pain syndrome. Another indication for ultrasound of the kidneys and bladder will be persistent changes in urinalysis, increased blood creatinine. USDG of the renal arteries is prescribed for persistent arterial hypertension and / or reduction of renal function, reduction of the size of the kidneys during ultrasound examination of the kidneys to detect narrowing of the renal arteries with atherosclerotic plaques or underdevelopment (hypoplasia).
X-ray methods in nephrology
The main disadvantage of these methods is radiation exposure. The following methods are used for examining the urinary system.
Survey radiography is a cheap method with relatively low radiation exposure, available in almost every medical institution. It does not require the introduction of contrast agents. Of the minuses, low informativeness can be called - it allows to detect only large stones and only X-ray positive ones. For example, cystine stones consisting of amino acids and calcium salt are not detected. In the image obtained after radiography, it is possible to establish the presence of changes in the lumbar spine, in the bones of the pelvis, in the ribs. Sometimes found changes in the spine, which cause pain, which until then was considered a sign of kidney damage.
Excretory urography - assesses not only the structure, but also the excretory function of the kidneys. All images are taken at the time of the kidneys excretion of a contrast agent. This allows you to determine the rate of filling of the bladder and pelvis fluid, as well as to identify the localization of tumors and stones. Methods: a radiopaque substance is injected intravenously, which begins to be excreted by the kidneys. At this time, a series of shots are taken (at intervals of about 7 minutes).
The introduction of a contrast agent can cause a serious allergic or toxic reaction. Therefore, this method is used with extreme caution and is not allowed in the following cases:
- to persons who have experienced allergic reactions to injected contrast agents or iodine;
- women during pregnancy and lactation;
- people with bleeding disorders;
- in patients with renal failure.
Before conducting this study, it is important to take a sufficient amount of fluid - this reduces the risk of complications.
Renal angiography - kidney vessels are examined. The contrast is injected directly into the aorta, then a series of X-rays is performed. Analysis of the images makes it possible to assess the state of the vessels, the degree of their narrowing, the presence of thrombosis and atherosclerosis, as well as aneurysm. This complicated study can be called a small operation.
The advantages of magnetic resonance imaging include the absence of radiation exposure, in contrast to x-ray methods; It is also possible to build a three-dimensional image.
The study is contraindicated in the case of:
- allergic reactions to drugs that are administered to patients as a contrast;
- the presence of pacemakers;
- metal implants, staples, fragments;
- mental illness;
- overweight over 120 kg;
- nursing mothers in the case of the procedure with contrasting is not recommended to feed the child for 1-2 days.
This is the only reliable method for the diagnosis of kidney disease, allowing the physician to objectively assess the severity of the disease, select the most appropriate treatment method and avoid side effects and complications.
Indications for a biopsy of the kidney:
- acute or chronic kidney disease of unclear cause;
- rapidly progressive glomerulonephritis;
- complex urinary tract infections;
- there is a suspicion of a cancer in the kidney;
- impaired transplanted kidney;
- determining the severity of the disease and how irreversible damage occurred in the kidneys;
- monitoring the effectiveness of the treatment.
The main risk factors for chronic kidney diseases include diabetes and other metabolic disorders, cardiovascular diseases, a number of autoimmune and infectious diseases, neoplasms, smoking and other bad habits, old age and male sex, and the presence of renal diseases in direct relatives. Of particular importance are the factors leading to the development of oligonephronia, i.e. the inconsistency of the number of active nephrons with the needs of the body: kidney surgery, aplasia and renal hypoplasia on the one hand, and obesity on the other.
Take care of the kidneys
A very important risk factor for kidney damage, in the fight against which not enough attention is paid in Russia, can safely be called the abuse of analgesics and nonsteroidal anti-inflammatory drugs, “passion” for dietary supplements (means for reducing weight in women, protein shakes for building muscle mass in men) . A case in point is Australia and many European countries, where a number of years after the ban on over-the-counter selling of analgesics and NSAIDs, the percentage of patients with analgesic nephropathy among those entering dialysis or kidney transplantation has decreased several times.
Specialty: Therapist, nephrologist, exercise therapy doctor.
Total experience: 10 years.
Place of work: fitness blog "LifeStyle Medicine".
Education: 2006, Medical Academy. Therapy, sports medicine and physical therapy, nephrology.