Diagnosis of polycystic kidney disease

The need for further in-depth search for criteria for reliable diagnostics is dictated by the similarity of many known clinical and diagnostic signs of this disease with other kidney diseases. Despite the emergence of new high-quality medical equipment, the diagnosis of polycystic kidney disease is difficult and often belated, and due to diagnostic errors in polycystic kidney disease, although rare, unjustified surgical interventions are performed.

Diagnosis of polycystic kidney disease is based on anamnesis, which necessarily includes a study of the family line, which often allows us to establish the hereditary nature of the disease.

When examining patients, attention should be paid to dryness and some yellowness of the skin, scratching due to skin itching. When palpating the abdominal cavity, the kidneys are felt as large, dense, lumpy formations. Sometimes polycystic kidneys bulge out from the hypochondrium so much that they can not be determined visually. When examining urine, the following is found:

• hypoisosthenuria (relative urine density from 1.005 to 1.010), which indicates damage to the renal tubular apparatus;
• proteinuria (not higher than 1 g/l):
• leukocyturia, indicating the presence of a urinary infection.

Blood tests often reveal hypochromic anemia, and in pyelonephritis, moderate neutrophilic leukocytosis with a left shift in the leukocyte formula. To assess the functional state of polycystic kidneys, the concentration of urea and creatinine in the blood serum is determined, and a urine analysis according to Zimnitsky and the Reberg test are performed.

Roentgenological examination methods play a decisive role in the diagnosis of polycystic kidney disease. On survey radiographs, it is possible to detect the vertical localization of both kidneys, a more medial and low location of their shadows, and insignificant mobility of the kidneys. These signs are much more clearly revealed against the background of presacral retropneumoperitoneum, but at present it has practically lost its diagnostic value, since ultrasound, CT and MRI allow us to clearly determine this anomaly.

Excretory urography allows obtaining valuable data in the initial stages of the disease. Since polycystic disease is accompanied by a decrease in kidney function, it is advisable to carry out its infusion modification. N.A. Lopatkin and A.V. Lyulko (1987) identified three radiological signs:

• changes in the shape of the kidneys (low position, increase in length and width, uneven contour);
• changes in the renal pelvis and calyces (deformation of the axes of the large and small calyces, their crescent, spherical and flask-shaped changes, narrowing and lengthening of the necks, lengthening and displacement of the renal pelvis);
• changes in the vascular system of the kidneys (narrowing of large arterial trunks and a decrease in the number of small arteries, the presence of different-sized avascular fields).

It should be added that with polycystic disease the number of cups is always increased - hyperramification, compression, elongation, displacement and prolapse of the pelvis. The LMS is usually displaced to the medial side, and the pelvis is located intrarenally.

In addition, radionuclide methods of examination, ultrasound scanning, and CT are used to clarify the diagnosis of polycystic kidney disease. On renograms performed in patients with polycystic disease, N.A. Lopatkin, Yu.Ya. and E.B. Mazo (1977) identified three variants:

• bilateral slowing of secretion and evacuation;
• predominant damage to one kidney with its function preserved;
• damage to the tubular apparatus of one and the absence of function of the second polycystic kidney, which is observed in severe forms of polycystic disease, when atrophy of the parenchyma of one of the kidneys occurs due to its compression by cysts.

As a rule, these patients have varying degrees of renal failure. Renography serves as an orientation test, since it does not even indirectly answer the question of the amount of functioning parenchyma. Dynamic scintigraphy compensates for the listed shortcomings of renography.

Ultrasound allows diagnosing polycystic kidney disease by a large number of echo-negative zones. In the early stages of polycystic kidney disease, ultrasonography reveals their enlargement. If this developmental defect progresses, cysts of various sizes and shapes are usually found in the renal parenchyma. CT is an absolutely reliable method for diagnosing polycystic kidney disease. Sometimes, renal angiography is necessary to clarify the diagnosis. In polycystic kidney disease, angiograms (the parenchymatous phase is especially important) reveal saturation defects, renal vessels are narrowed, and the number of small arteries is reduced. Fields without vessels corresponding to cysts are determined.

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