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Kidney study
Last reviewed: 04.07.2025

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The examination (diagnosis) of the kidneys is a rather difficult task, since most of the so-called nephrological diseases have a latent course for a long time, do not manifest themselves with subjective signs (unpleasant sensations, and most importantly - pain), forcing a visit to the doctor, and therefore are discovered as if by chance during a medical examination for another reason: for example, during pregnancy or with the initial detection of high blood pressure, a simple urine test is very important for identifying a latent kidney disease. Many famous clinicians paid attention to the examination of a patient with kidney disease. First of all, it is necessary to name R. Bright (1789-1858), with whose name the development of nephrology is especially closely associated.
The clinical descriptions of various manifestations of kidney disease made by R. Bright more than 150 years ago are very vivid: “As time goes by, the healthy complexion fades, weakness or back pain increases, headaches are added to the general discomfort, often accompanied by vomiting: fatigue, lethargy and depression gradually take hold of his spirit and body... If the nature of the disease is suspected, a careful analysis of the urine is carried out, and albumin is found in almost every examination.”
Questioning the patient about kidney disease
Knowledge of the basics of clinical examination of the kidneys is important not only for a future nephrologist, but also for a doctor of any other specialty, not to mention a general practitioner. It begins with questioning the patient, primarily studying his complaints.
Complaints
The state of health of a kidney patient, despite the existing disease, often remains satisfactory for a long time. Often, active targeted questioning with clarification of complaints and anamnesis of the disease is necessary.
Considering that kidney damage is often the leading cause of a number of general and systemic diseases ( gout, diabetes mellitus, systemic lupus erythematosus, etc.), the signs of the latter may be the main ones in the picture of the disease.
Very often the patient is bothered by general weakness, rapid fatigue, decreased ability to work, which are noted by patients of any age, most often during the period of exacerbation of kidney disease: usually during the period of increasing renal edema or arterial hypertension, i.e. during the intensification of the activity of the pathological process. Such complaints as nausea, vomiting, diarrhea, as well as skin itching, can be signs of already advanced renal failure (uremia), the terminal stage of renal disease (long-term and latent), which the patient did not know about.
A number of complaints may be associated with disturbances of homeostasis, the maintenance of which, as is well known, largely depends on the activity of the kidneys, this most important "arbiter" of homeostasis. Thus, some symptoms are associated with a large loss of albumin with urine, and with it other substances - trace elements, enzymes, etc. For example, the excretion of iron leads to the development of anemia and related complaints, the loss of zinc causes a decrease in taste sensations, etc. A symptom common to many diseases - fever - in kidney diseases in some cases develops as a result of a urinary tract infection (fever with chills and profuse sweat in pyelonephritis ), but often also as a result of a general infection, sepsis (for example, in subacute infective endocarditis ), in which there is often kidney damage. Sometimes the fever is non-infectious (immune), which occurs in a number of systemic diseases (systemic lupus erythematosus, rheumatoid arthritis, etc.), occurring with nephropathy. These systemic diseases are characterized by the involvement of joints, skin, muscles, which makes the symptoms of the renal process caused by them more diverse. In such common general diseases as gout, diabetes mellitus, the clinical symptoms of the renal process can be obscured by signs of the general disease: joint syndrome in gout, severe thirst in diabetes mellitus, etc.
In some cases, the patient may experience symptoms directly related to kidney disease, but manifesting atypically: for example, sudden blindness due to severe renal hypertension forces the patient to seek help from an ophthalmologist, or bone fractures due to the nephrogenic nature of osteopathy lead him to a surgical hospital. Headache, dizziness, palpitations with pain in the heart, shortness of breath often occur with nephrogenic hypertensive syndrome, mistakenly interpreted as a sign of hypertension, and not kidney disease.
There are a number of complaints that are traditionally associated directly with kidney damage. First of all, these are edemas, which are often a sign of diseases of other organs and systems: cardiovascular (decompensated heart defects, but more often congestive heart failure in patients with ischemic and hypertensive diseases, cardiomyopathy), as well as endocrine ( myxedema ), etc.
R. Bright was the first to link the main manifestation of kidney disease - edema (dropsy) - with the obligatory pronounced albuminuria and with anatomical changes in the kidneys revealed during autopsy. He wrote: "I have never yet autopsied a large corpse with edema and coagulating urine, in which obvious pathology of the kidneys was not found."
In kidney diseases, edema varies in severity, location, and persistence. Most often, it is detected on the face, usually in the morning. Severe edema causes a number of unpleasant subjective sensations and inconveniences to the kidney patient - a cosmetic defect, the inability to wear shoes, difficulty walking due to swelling of the scrotum, etc., and with anasarca (total edema), when widespread swelling of the subcutaneous fat tissue, dropsy of the cavities (hydrothorax, ascites, hydropericardium ) are noted, additional more serious complaints appear, such as shortness of breath. Most often, edema develops gradually, but sometimes it can occur acutely, within a few hours (acute nephritis). Edema is usually combined with a decrease in the formation and excretion of urine (a decrease in diuresis) - oliguria (diuresis less than 500 ml / day), anuria (diuresis less than 200 ml / day). Of particular clinical significance is true anuria - cessation of urine flow into the bladder, usually due to cessation of its formation, which results from acute kidney damage by nephrotoxic factors (various poisonings, severe intoxication) or disruption of their blood supply (shock of various etiologies, including cardiogenic shock in acute myocardial infarction), as well as acute inflammation of the renal parenchyma (acute nephritis). Most often, true anuria is a sign of acute renal failure. It should be borne in mind that a sharp decrease in diuresis can be a consequence of not only true anuria, but also be associated with acute retention in the bladder of urine normally formed by the kidneys (acute urinary retention ), which most often occurs with adenoma or prostate cancer, paraproctitis, diseases of the central nervous system, the use of narcotics, atropine, ganglionic blockers and other medications.
Increased diuresis - polyuria (diuresis over 2000 ml/day) may be associated with certain features of nutrition, drinking regimen, and the use of diuretics. However, a combination of polyuria with nocturia (predominance of nocturnal diuresis over daytime) is often detected in a patient with chronic kidney disease as a sign of chronic renal failure and may remain its only manifestation for a long time.
The pain that often occurs with a large number of diseases of internal organs is usually absent in the most common kidney diseases (primarily chronic nephritis).
Bilateral pain in the lumbar region, usually dull in nature, but sometimes more severe, bother patients with acute nephritis. Sharp lumbar pain, often unilateral, is caused by renal infarction and acute pyelonephritis. Special attention is required by the so-called renal colic - paroxysmal, severe pain localized in one of the halves of the lumbar region, radiating to the groin area, along the ureter, into the urethra, perineum, thigh. The pain is often accompanied by nausea and vomiting, the appearance of blood in the urine (macrohematuria, more often microhematuria), anxiety of the patient, who cannot find a place for himself due to the pain.
These pains are apparently caused by spastic contractions of the renal pelvis, caused by its stretching due to blockage of the ureter by a stone, purulent or blood clots, less often by tissue detritus (tumor decay). Tapping the lumbar region (as well as sudden movements), riding a car, or a bicycle cause increased pain. Pain in the lumbar region can be caused by a mobile, shifting, especially with sudden movements, so-called wandering kidney. Severe pain in the lumbar region of a constant nature occurs with acute inflammation of the perirenal tissue - acute paranephritis, these pains intensify with an extended leg.
There are other localizations of pain sensations - in the lower abdomen (with acute inflammation of the bladder - acute cystitis), in the area of the urethra with its inflammation (acute urethritis); in these cases, pain is often combined with unpleasant sensations during urination.
In general, urination disorders - dysuria - are usually a sign of urological diseases. Frequent urination - pollakiuria - is the result of increased sensitivity of nerve endings in the mucous membrane of the bladder, irritation of which leads to frequent urges to urinate, which occur even with a small amount of urine in the bladder.
Frequent urination is often accompanied by pain, a feeling of stinging and burning. Usually, the above-mentioned dysuric phenomena are caused by cystitis, urethritis, pyelonephritis, and urolithiasis.
Patients may complain of a change in the appearance of urine, which is primarily due to macrohematuria - an admixture of a large number of red blood cells. Red urine usually occurs after renal colic (stones). They specifically talk about urine that looks like "meat slops", when, in addition to red blood cells, it contains a lot of leukocytes, mucus, epithelium, which is usually characteristic of acute nephritis.
Medical history
A carefully collected anamnesis is no less important for understanding the essence of nephropathy than in diagnosing diseases of the heart, lungs, etc.
Kidney damage often develops after exposure to colds, colds, streptococcal infections (tonsillitis, scarlet fever), allergic reactions (drug, post-vaccination, (less often food allergies), toxicosis of pregnancy, treatment with gold preparations, penicillamine, antiepileptic drugs; abuse of analgesics, alcohol, drugs (heroin) should be specifically mentioned.
Of course, when studying the anamnesis, one should take into account the fact that kidney damage can develop with systemic diseases (systemic lupus erythematosus, rheumatoid arthritis), cirrhosis of the liver, and can complicate diabetes mellitus, gout, hypertension and atherosclerosis, chronic purulent (osteomyelitis, bronchiectasis) and oncological diseases.
When studying the professional anamnesis, attention should be paid to contact with ionizing radiation, hydrocarbons and organic solvents, heavy and rare metals (mercury, lead, chromium, cadmium, copper, uranium), aminoazo compounds (benzene, hemolytic poisons (arsenic hydrogen, phenylhydrazine, nitrobenzene).
Indications of the development of anuria (oliguria) after shock or collapse, blood transfusion, septic abortion, and the use of nephrotoxic medications (aminoglycoside antibiotics) are significant.
It is necessary to clarify whether the patient has a history of tuberculosis, viral hepatitis, syphilis, or whether he has been in endemic areas of leptospirosis, hemorrhagic fever, schistosomiasis, malaria, which may cause kidney damage.
Knowledge of the patient's family history is necessary to exclude hereditary nephritis, genetic (primarily in periodic disease) amyloidosis, tubulopathies and enzymopathies. All these data should be reflected in the chart of the disease history, for example, of a young sailor who fell ill with acute nephritis with a rapidly progressing course and died of acute heart failure, observed by R. Bright.