Anomalies of the structure of the kidney parenchyma

Anomalies of the structure of the renal parenchyma are divided into megacalyx, spongy kidney, medullary cystic disease (Fanconi disease).

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Forms

Megacalyx (megacalycosis)

Megacalyx (megacalicosis) is an anomaly of the renal parenchyma structure, a congenital local non-retentive expansion of the calyx. If all groups of calyces are expanded, this defect is called polymegacalyx (megapolycalyx). The renal pelvis and ureter have a normal structure. Bilateral damage is typical for men, most often found in residents of southeastern Europe. The causes of megacalyx are hypoplasia of the Malpighian pyramids, as well as dysplasia of the fornix and calyx muscles. Megacalyx can be attributed to true calyceal-medullary anomalies, because both causes (medullary and calyceal) are equal. With megacalyx, there is no stagnation of urine in the calyces, which distinguishes it from retention hydrocalycosis. Megacalyx is diagnosed by ultrasound in the form of fluid formations in the renal medulla. However, differential diagnostics of megacalicosis with cysts and hydrocalicosis can be performed using excretory urography. Megacalicosis is characterized by complete emptying of the calyces from the contrast agent on delayed images (30-60 min). The same symptoms are also detected with MSCT. Uncomplicated megacalicosis does not require treatment. The most common complications of megacalicosis are pyelonephritis and nephrolithiasis.

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Spongy kidney

Spongy kidney - anomalies of the structure of the renal parenchyma, characterized by uneven (in the form of pseudocysts and diverticula) expansion of most collecting tubules of the renal pyramids. Renal glomeruli and the calyceal-pelvic system are developed normally. It is quite rare - 0.32% of all renal anomalies, almost always in men, since this defect is hereditary, partially linked to sex. Unilateral damage is not typical, occurs in isolated cases. The most common complications of spongy kidney are the following diseases: stone formation, pyelonephritis, hematuria, arterial hypertension.

A spongy kidney can be detected after a general image of the urinary system, which shows clusters of concrement shadows resembling pyramids in shape. Excretory urograms show sac-like expansions of the collecting ducts. These symptoms are more clearly defined by MSCT. Patients with stones located in the renal pelvis or migrated from it to the ureter are subject to treatment. Endoscopic methods of stone removal, as well as DLT, are used for this purpose.

Medullary cystic disease or Fanconi nephronophthisis has a similar embryofetal morphogenesis to the sponge kidney. Despite similar structural changes, these are different types of developmental defects. Unlike the sponge kidney, medullary cystic disease is inherited in an autosomal recessive (juvenile, nephronophthisis) and autosomal dominant (adult nephronophthisis, or medullary cystic disease) manner. Damage to the glomerular (hyalinosis) and tubular (epithelial atrophy) apparatus is expressed by the early onset of chronic renal failure due to gradual wrinkling of the kidneys. According to some data, it occurs in one out of 100,000 observations.