Renal tuberculosis - Symptoms and diagnosis

Symptoms of kidney tuberculosis

Symptoms of renal tuberculosis are, unfortunately, few and non-specific. In the parenchymatous stage, when foci of inflammation are present only in the organ tissue, clinical manifestations may be minimal, scanty: mild malaise, occasionally subfebrile temperature. In 30-40% of patients, clinical manifestations may be absent. As the process progresses, pain in the lumbar region, macrohematuria and dysuria may occur.

Pain on the affected side is observed in 7% of patients at the initial stage and in 95% - with an advanced destructive process; it can be dull aching against the background of progression of infiltrative inflammation and gradually developing processes that disrupt the outflow of urine from the kidney. When destruction occurs, rejection of necrotic caseous masses, especially with changes in the ureteropelvic segment and ureter, the pain can resemble renal colic with all its clinical features, accompanied by chills, fever, signs of intoxication. However, bright symptoms of an acute inflammatory process in the kidney may be absent.

Painless macrohematuria is observed in 17% of patients. Arterial hypertension as a sign of specific kidney damage occurs in 1% of observations in the initial stages and in 20% in advanced tuberculosis. Macroscopic hematuria, according to summary statistics, occurs in only 8-10% of cases, is not massive and is rarely accompanied by the passage of blood clots in the urine.

The most common symptoms of renal tuberculosis are: dysuria, frequent painful urination (2% in the initial stages and 59% in subtotal and total destruction). Dysuria occurs due to early damage to the bladder. Anamnesis provides significant information: a history of tuberculosis of the lungs, lymph nodes, exudative pleurisy, tuberculosis of the bones and joints, etc. should make one suspect possible renal tuberculosis. Long-term contact with tuberculosis patients in the family and at home, in industrial teams, in places of imprisonment, etc. is of great anamnestic importance.

Diagnosis of kidney tuberculosis

History of pulmonary or other organ tuberculosis; extrarenal tuberculosis coexisting with renal tuberculosis; tuberculosis in close relatives; contact with tuberculosis patients; changes characteristic of previous tuberculosis revealed by X-ray examination of the lungs - all this allows us to suspect the specific nature of the kidney disease. In most patients with kidney tuberculosis, a comprehensive examination can reveal damage to other organs and systems by a specific process. Diagnosis and therapy of urogenital tuberculosis is especially relevant today, when in our country there is a pronounced tendency for the incidence of pulmonary tuberculosis to increase.

Unfortunately, the diagnosis is not always made in a timely manner, which deprives the patient of the opportunity for full conservative treatment and often makes the outcome of the disease favorable. Many patients with newly diagnosed renal tuberculosis suffer from severe, advanced forms of the disease and require nephrectomy. Late diagnosis of renal tuberculosis is due not so much to the atypical or latent course of the disease process, but to insufficient information from practicing physicians about this serious and frequent disease.

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Laboratory diagnostics of renal tuberculosis

Laboratory diagnostics of renal tuberculosis plays an important role. Clinical blood tests are largely non-specific. Enzyme immunoassay allows for the detection of antibodies to human and bovine mycobacteria, it is highly specific for detecting the tuberculosis process, but is useless in specifying its localization.

Important and reliable information that allows one to suspect tuberculosis is provided by a general urine analysis. It reveals a persistent, sharply acidic reaction, proteinuria (92% of patients), which is false, does not exceed 0.001 g and is not accompanied by the formation of cylinders; significant leukocyturia (70-96% of patients), less pronounced microhematuria (30-95%) in the absence of banal microflora. In this case, a routine urine culture, despite reliable signs of inflammation of the kidneys and urinary tract, is usually sterile (aseptic pyuria). It should be emphasized that the combination of the described laboratory signs should certainly alert any doctor in terms of specific tuberculous kidney damage.

A quantitative urine test (Nechiporenko test) can provide more reliable data if the urine is obtained directly from the affected kidney by catheterization. In doubtful cases, a comparative analysis of leukocyturia before and during provocation by subcutaneous administration of tuberculin (the prototype of the Koch test), which increases its intensity in the presence of a specific process, is possible. No less valuable are the results of sowing and bacteriological examination of urine obtained directly from the affected kidney.

Renal tuberculosis may be combined with non-specific pyelonephritis, especially in patients who have undergone instrumental diagnostic examinations and massive antimicrobial therapy. Such a combination greatly complicates the recognition of the tuberculosis process, since secondary non-specific flora joins (up to 70% of observations), the urine reaction changes towards neutral or alkaline. The lack of the desired effect against the background of banal antibacterial and anti-inflammatory therapy in patients with pyelonephritis, even in the presence of non-specific flora, should be an indication for polymerase chain reaction, urine cultures and bacteriological studies to diagnose tuberculosis.

One of the leading methods of diagnosing this disease can rightfully be considered bacteriological. For this purpose, in aseptic conditions under the supervision of medical personnel, a morning portion of urine is collected in a sterile container for sowing on special elective media. This allows, after 2-3 weeks, to identify the initial growth of mycobacteria using fluorescence microscopy and give an approximate answer, and within 2-3 months to obtain their growth with determination of sensitivity to drugs. Biological tests by intraperitoneal introduction of the patient's urine to a guinea pig and observation for 2-4 weeks, despite the sensitivity (they can be positive even with an extremely low titer of the pathogen down to single mycobacteria), are not widely used today due to significant financial costs.

In terms of sensitivity (more than 1 mycobacterium in 1 ml), only the polymerase chain reaction of urine can compare with the bioassay. After 5 hours, renal tuberculosis can be confirmed with a sensitivity of 94% and a specificity of 100%. Thus, in modern conditions, a reliable diagnosis of tuberculosis can only be made using diagnostic methods: polymerase chain reaction of urine, bacteriological (growth of mycobacterium tuberculosis in urine culture) and morphological, when histological examination of kidney tissue, urinary tract, and bladder wall biopsy reveals characteristic signs of tuberculous inflammation with the presence of Pirogov-Langhans giant cells.

Tuberculin diagnostics

Among other diagnostic methods, especially in doubtful cases, so-called provocative tests using tuberculin are used. Its dose for these purposes is usually 20 TE, if necessary, it can be increased to 100 TE. After its subcutaneous administration, the focal reaction is assessed by examining the urine. In this case, the specific nature of the inflammation is confirmed by an increase in the titer of formed elements in the sediment, especially when examining renal urine. Sometimes it is possible to achieve the growth of mycobacteria tuberculosis. Since the tuberculous process in the kidney is often one-sided, and in the bladder the urine is diluted due to the unaffected kidney, the titer of cells, especially mycobacteria, drops sharply and the results of the provocation when examining only bladder urine can be negative. Therefore, if necessary, it is advisable to combine provocative tuberculin tests with catheterization of the corresponding ureter to obtain urine directly from the kidney, and retrograde ureteropyelography, thereby increasing the informativeness of the studies.

Ultrasound diagnostics of renal tuberculosis

Unfortunately, this method does not allow diagnosing early manifestations of renal tuberculosis, and is effective only in destructive, cavernous forms of the process. In cavernous kidney lesions, it is possible to identify rounded echo-negative formations that are surrounded by a dense echo-positive membrane, since the boundary of the cavern, unlike the cyst, is dense. Sometimes, in the center of the cavern, individual echo-positive inclusions are visible in the liquid contents due to the heterogeneous contents. Ultrasound diagnostics does not allow for a reliable diagnosis of a specific process in the kidney, but it significantly helps in establishing the severity and precise localization of destructive changes. The results of an ultrasound examination allow for clarification of indications for other radiation studies, and also make it possible to judge the regression or progression of a specific process during therapy.

X-ray diagnostics of renal tuberculosis

On the overview image and native nephrotomograms, one can notice an increase in the contours of the kidney, areas of calcification, more often with calcification of a section or the entire kidney. Excretory urography and retrograde ureteropyelography are traditionally of great importance in obtaining information about the nature, localization and prevalence of tuberculous lesions.

Computed tomography and magnetic resonance imaging of renal tuberculosis

The use of multispiral CT and MRI, especially with contrast, in patients with renal tuberculosis allows for clear identification of foci of destruction located in the parenchyma. These methods make it possible to visually assess the relationship of destructive foci with the calyceal-pelvic system, elements of the renal sinus and main vessels, as well as to clarify the involvement of regional lymph nodes in the inflammatory process.

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Radionuclide diagnostics of renal tuberculosis

Radionuclide studies (dynamic nephroscintigraphy) provide an idea of the functional capacity of the kidney as a whole and segment by segment, assessing the dynamics of the intake, accumulation of the radiopharmaceutical in the parenchyma and its excretion through the urinary tract. In this case, it is possible to use isotopic preparations that are tropic to a greater extent to the vascular, glomerular and tubular system of the kidney. Combinations of such studies with tuberculin provocation are successfully used. Deterioration of renal function indicators after the introduction of tuberculin when compared with the initial ones indirectly indicates the possibility of a specific lesion.

Morphological diagnostics of renal tuberculosis

Due to the focal nature of the pathological process, kidney biopsy with subsequent histological examination in case of tuberculous lesions is ineffective and dangerous due to dissemination of infection into surrounding tissues. In case of dysuria, endoscopic examinations with biopsy of altered areas of the mucous membrane allow diagnosing tuberculous lesions. However, in more than 50% of patients with kidney tuberculosis, even in the absence of visible changes in the mucous membrane of the bladder, with a thorough histological examination of its biopsy specimens obtained endoscopically, giant Pirogov-Langhans cells can be detected in the submucosal layer, indicating a specific lesion.

Differential diagnosis of renal tuberculosis

Differential diagnostics of renal tuberculosis should be carried out with hydronephrosis, ureterohydronephrosis, pyelonephritis, especially with the outcome in pyonephrosis and the presence of purulent fistulas in the lumbar region. Radiographic signs of the process must be distinguished from medullary necrosis, complicating the course of purulent pyelonephritis, anomalies of the medullary substance (spongy kidney, calyceal diverticulum, megacalyx, megacaliosis). Excluded destructive foci in tuberculosis may be similar to cystic and dense tumor-like formations in the parenchyma, deforming the contours of the kidney and the calyceal-pelvic system. The leading criterion should be a combination of clinical, laboratory, ultrasound, radiological and other data. Persistent dysuria and pyuria should be an indication for excluding banal chronic inflammation using laboratory tests of urine in two (in men, three, with a study of prostate secretion) portions and bacteriological studies, as well as urethrocystoscopy and endovesical biopsy.

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