Crossed ectopic kidney

Cross-specific ectopic kidney When the kidney is located in the contralateral kidney socket, it is called kidney cross ectopic. More than 90% of the crossed ectopic kidneys are fused with the contralateral normal kidney, and the most common is the horseshoe kidney deformity. The concept of fusion of kidney abnormalities was first proposed by Wilmer in 1938. In 1957, Mcdonald extended his concept, including renal cross ectopic fusion or cross ectopic without fusion. There are several types of fusion kidneys: 1 fusion kidney and lower ectopic; 2C or S-shaped fusion kidney; 3 block or cake-like fusion kidney; 4L fusion kidney; 5 round fusion kidney; The cephalic side is ectopic. basic knowledge The proportion of illness: this disease is rare, the incidence rate is about 0.0001% - 0.0002% Susceptible population: often in middle-aged disease Mode of infection: non-infectious Complications: hypospadias pyelonephritis hydronephrosis renal empyema

Cross ectopic nephropathy

(1) Causes of the disease

The exact cause of the occurrence of kidney cross ectopic is still unclear. Wilmer believes that it may be that the abnormality of the umbilical artery causes a pressure that hinders the kidney from migrating to the cephalad, and thus turns to the contralateral side with less resistance. Poter et al believe that it is a ureteral bud tour. Going to the opposite side, Cook and Stephens speculated that the embryo had an abnormal translocation in the caudal side during development, which caused abnormalities in the location of the cloaca and the Wolffian tube structure. It may be that one side of the ureteral bud crossed the midline and entered the contralateral side. Middle kidney embryo base, or the kidney and its ureter are transposed to the contralateral side during renal ascending, and fusion of the posterior renal tissue occurs before or at the same time as it is still in the true pelvis and displaced to the cephalad, or in its The later stages of the rise occur, and the degree of fusion depends on how close the developing kidney primordia are to each other.

(two) pathogenesis

The occurrence of cross-ectopic renal fusion is related to the time of contact between the two kidneys. The ectopic kidney is often located on the lower side of the normal kidney. Generally, the two kidneys rise synchronously, but the ectopic kidney is behind the normal kidney, probably because it is A time lag occurs in the process of crossing to the contralateral side, so usually the upper pole of the ectopic kidney fuses with the lower pole of the normal kidney, and when the normal kidney rises to its own position or is obstructed by the retroperitoneal structure The fusion kidney stops rising, and the final shape of the fusion kidney depends on the degree of fusion and self-rotation. Once the two kidneys are fused, the rotation does not occur any more. Therefore, the position of the two kidneys indicates the time of occurrence of congenital defects, and the renal pelvis is more advanced. The fusion occurs earlier. If the position of the renal pelvis is normal, it indicates that the fusion occurs after the rotation is complete. 90% of the ectopic kidneys are often fused with the normal kidney. If the two kidneys do not fuse, the ectopic kidneys are often in their normal position. The ectopic kidney is located below it, the renal pelvis is facing forward, and the two kidneys are separated by their capsules. When the two kidneys are not fused, the normal ureter enters the ipsilateral bladder. The ureter of the ectopic kidney crosses the midline and enters the contralateral bladder. When the kidney is crossed, the kidney is often located in the contralateral renal fossa, and the position is low. At the level of the first to third lumbar vertebrae, the rotation is often poor. When the pelvic cavity only rises to the low waist, there is almost no rotating renal pelvis facing forward. The ureter crosses the contralateral side into the bladder at the level of 2, while the contralateral ureter is absent, or only a degenerate residue remains. The shape of the two kidneys, the renal pelvis is normal, the ureter crosses the midline at the lower lumbar level and crosses into the contralateral bladder. There are various types of fusion, and the blood supply of each kidney also changes greatly. Or multiple integrations.

Among all kinds of fusion abnormalities, the ureter is mostly normal, and the bladder triangle is normal. Only when the orphan kidney is ectopic, the contralateral ureteral orifice is degenerated or absent. Occasionally, the normal side kidney also has ectopic ureteral orifice. Bladder ureteral reflux often occurs in ectopic kidneys, and other comorbidities of orphanal ectopic in children are the most common, including the following: about 50% of patients have skeletal abnormalities, and about 40% of patients have reproductive system abnormalities. Such as occult penis in men and vaginal atresia in women, in addition to cardiovascular system defects (Figure 1).

Cross ectopic kidney prevention

There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.

Cross ectopic renal complications Complications hypospadias pyelonephritis hydronephrosis kidney empyema

Congenital complications include visceral transposition, residual umbilical urethra, spondylolysis and hypospadias. Acquired complications include pyelonephritis, hydronephrosis, renal empyema, stones, tuberculosis and tumors. In 30% of cases, but a group of 34 non-fused cross-ectopic kidneys, 19 (57%) had various complications, including concurrent infections, a total of 11 (33%), tumor 3 Example (9.1%).

Cross ectopic kidney symptoms Common symptoms Abdominal pain Pus urinary urinary urinary tract infection Abdominal mass Isolated kidney

Most patients with crossed ectopic kidneys are asymptomatic. If symptoms are often present in middle age, including blurred lower abdominal pain, pyuria, hematuria and urinary tract infections, abnormal renal position and ectopic blood vessels can cause obstruction and cause hydronephrosis. And the formation of stones, some patients may have asymptomatic abdominal mass, clinically encountered when the lower abdominal active mass, should think of ectopic kidney.

Cross ectopic kidney examination

Intravenous urography can make a diagnosis, the ureteral reflux rate of this disease is very high, so urinary bladder urethrography is necessary, and renal radionuclide scanning can understand renal function and obstruction, for other reasons to do B-ultrasound and Radionuclide scanning has found more asymptomatic cases in recent years. In order to determine the renal contour, renal tomography can be applied. Because renal blood vessels are usually deformed, renal angiography is needed before surgery.

Cross ectopic kidney diagnosis

diagnosis

Most of the disease is asymptomatic, and the diagnosis depends on imaging examination.

Differential diagnosis

The pelvic kidney can be misdiagnosed as appendicitis, ileocecal tumor or tuberculosis, ovarian tumor and other diseases. Therefore, when the lower abdominal active mass is encountered clinically, the possibility of ectopic kidney should be considered.

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