Diagnosis of megoureteritis

Megaureter is diagnosed immediately after birth. It is performed using ultrasound (revealing the renal pelvis by more than 1.0 cm with thinning of the organ parenchyma to 0.5 cm, and ureter dilation by more than 0.7 cm). Ultrasound with color Doppler mapping allows assessing the degree of reduction in renal blood flow.

UFM allows to determine the type of urination (obstructive/non-obstructive), exclude IBO, and suspect neurogenic dysfunction of the bladder.

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X-ray diagnostics of megaureter

These research methods allow us to establish the underlying cause of the disease and determine the stage of megaureter.

• Survey urography. During the examination, spinal anomalies (incomplete fusion of the vertebral arches, sacralization of the sacrum and coccyx, diastematomyelia) are often detected, which are considered manifestations of myelodysplasia. They are often combined with defects of the genitourinary system.
• Excretory urography is a routine examination performed using non-ionic iodine-containing contrast agents (iohexol, iopomid, etc.). Images are taken in direct, lateral (1/4) projections, in wedge- and orthostatic positions. Excretory urography allows determining:
  • excretory capacity of the kidneys (symmetry, lagging excretory function of one of them);
  • anatomy of the organ [location and shape of the kidneys, doubling of the renal pelvis, structure of the renal pelvis system, condition of the renal parenchyma (early nephrograms allow us to judge the presence of areas of parenchymal sclerosis)];
  • dilation of the renal pelvis and calyces;
  • passage of contrast agent through the ureter;
  • the flow of contrast medium into the bladder;
  • features of the release of contrast agent from the renal pelvis and ureter (including the patency of the renal pelvis), the presence of achalasia, which is not visible with a full bladder.

When an obstruction is detected at the level of the vesicoureteral junction with the development of achalasia/megaureter/hydroureteronephrosis, delayed urograms (after 120 and 180 minutes) are performed in order to obtain data on the time of contrast agent release.

Cystography

It is performed to determine the anatomical condition of the lower urinary tract and to exclude VUR. Warm solutions with a radiopaque agent and Nelaton or Foley urethral catheters No. 6-14 CH must be used for the study. The volume of fluid slowly introduced into the bladder by its preliminary retrograde catheterization must correspond to the physiological norm.

Formulas for calculating the volume of liquid:

30+30 x child's age in years (for preschool-age children); 146+6.1 x child's age in years (for school-age children) - Tisher's formula.

Two images are taken: in a direct projection with a full bladder and in 1/4 (lateral projection) during urination (after removal of the urethral catheter).

According to the International Classification of VUR, five degrees of reflux are distinguished. Megaureter is characterized by reflux of degree IV (reflux into the dilated ureter and the calyceal-pelvic system with dilation of the necks of the calyces and smoothing of the fornices) and degree V (reflux into a sharply dilated tortuous ureter and a sharply dilated calyceal-pelvic system according to the type of terminal hydronephrosis).

Radioisotope diagnostics of megaureter is performed to assess the structural and functional state of the kidneys. The method has a number of significant advantages over excretory urography and ultrasound. This is due to the lower radiation load (compared to urography), a clearer image and the possibility of earlier diagnostics of structural changes in the parenchyma.

The radiopharmaceuticals mainly used are glomerulotropic Tc-pentatekh • (calcium trisodium pentetate) (determination of SCF) and tubulotropic sodium iodine hippurate (assessment of renal plasma flow). Scanning is performed on gamma cameras. This diagnostics of megaureter is performed after bolus intravenous administration of the isotope in doses corresponding to 1 mСІ per 1 kg of body weight (age from 1 year to 7 years) and 2-3 mСl per 1 kg (age from 7 years and older). The radiation load on critical organs, taking into account the characteristics of the isotope, is from 0.2 to 2.0 mSv. Subsequent computer processing of the data allows us to judge the location, size and contours of the kidneys, the characteristics and time of accumulation of the radiopharmaceutical in the renal parenchyma (assessment of the structure), the time and symmetry of the drug's excretion, its movement through the upper urinary tract with an assessment of their anatomical features, which, in turn, allows us to quantitatively identify and calculate the insufficiency of the functional capacity of the kidneys.

Diagnosis of megaureter is relatively simple if the patient is suspected of having a disease of the urinary system. In cases where renal function is preserved, the excretory urogram in case of bilateral disease shows sharply dilated tortuous ureters with a relatively small renal pelvis. If renal function decreases, delayed images or infusion urography should be performed.

Uro-cinematographic diagnostics of megaureter allows to specify the stage of this disease of the genitourinary system and to evaluate the functional capabilities of the affected ureter. L.N. Lopatkina (1974) with the help of uro-cinematography established that with achalasia the contraction wave reaches the lower cystoid and does not spread further. With megaloureterohydronephrosis contraction waves are very rare or absent altogether. Uretero-nephrotic transformation inevitably leads to the development of chronic renal failure.