Ureteropelvic junction obstruction

Brief introduction of ureteropelvic junction obstruction Obstruction of the ureteropelvic junction is a common urinary tract obstruction that causes hydronephrosis. The obstruction of the ureteropelvic junction obstructs the smooth discharge of renal pelvis into the ureter, causing obstruction of the renal pelvis and causing the expansion of the collecting system of the kidney. . At first, the smooth muscle of the renal pelvis gradually proliferates, strengthens the peristalsis, and attempts to discharge the urine through the distal obstruction; when the increasing amount of creeping power cannot overcome the obstruction, it will lead to atrophy of the renal parenchyma and impaired renal function. basic knowledge The proportion of illness: 0.012% Susceptible people: no special people Mode of infection: non-infectious Complications: hydronephrosis

Causes of obstruction of ureteropelvic junction

Intrinsic factors of the lumen (30%):

The internal factors in the lumen are mainly UPJ stenosis (Fig. 1), valve, polyp and high ureteral opening (Fig. 2). Among them, stenosis is a common cause of UPJ obstruction (87.2%), mainly manifested as muscle hypertrophy at UPJ. , fibrous tissue hyperplasia, the stenosis is generally about 2cm long, the section diameter is only 1 ~ 2mm, often accompanied by a high ureteral opening, UPJ valve is a congenital fold, can contain muscle, polyps are mostly sunflower-like.

External factors of the lumen (25%):

The most common cause is the vagus or accessory blood vessels from the renal artery or the abdominal aorta supplying the inferior pole (Figure 3), which is compressed across the UPJ and hangs the ureter or renal pelvis over the blood vessels. In addition, there is fiber. The compression or adhesion of the cable causes the UPJ to twist or stick.

Functional obstruction (20%):

The performance of the UPJ dynamic dysfunction, which is characterized by UPJ no obvious intraluminal stenosis and extracavitary compression factors, retrograde urography when the ureteral catheter can pass smoothly, but there is significant hydronephrosis.

Pathogenesis

The functional unit of the renal pelvis and ureter is muscle cells. From the renal sputum to the renal pelvis and ureter, the fusiform smooth muscle cells arranged in bundles can be seen. The pulverized longitudinally arranged promoter cells can be seen between the muscle cells, which are closely connected with the muscle cells and Each renal pelvis communicates with each other. These cells can spontaneously or receive pressure from the renal pelvis, and send out information to cause muscle contraction. When the muscle cells in this part are damaged or damaged, they will affect their normal systolic function and cause obstruction. Noeley observed by electron microscopy that the ureter was close to the dilated renal pelvis, and there was no elastic collar-like change due to significant collagen tissue hyperplasia, which was considered to be the initial cause of stenosis of the ureteropelvic junction. Later, some scholars observed through electron microscopy. The smooth muscle cells in the lesion are separated from each other, the gap junction is broken, the intracellular matrix is excessive, and the mitochondria are vacuolar degeneration. These pathological changes hinder the information transmission between the cells, and the smooth muscle function of the ureteropelvic junction is impaired. Therefore, the muscular layer is considered to be developed. Defect is caused by the ureteropelvic junction The main reason for resistance, some scholars have suggested that mechanical obstruction and functional damage may be mutually causal. Under normal circumstances, the coordinated movement of the ureteropelvic junction can make the urine pass through the ureteropelvic junction and the local stenosis of the ureteropelvic junction. Or ureteral peristaltic conduction disorder of the ureteropelvic junction can cause obstruction of urine retention, forming hydronephrosis. The outcome of hydronephrosis after obstruction depends on the severity of obstruction, renal pelvis, renal pelvic compliance and urine flow. If a certain relative balance is reached, the hydronephrosis process will slow down and be in a stable state for a certain period of time, otherwise the hydronephrosis will be further aggravated, and the expansion of the renal collecting system may cause the elongation of the renal medullary blood vessels and the renal parenchyma. Under pressure ischemia, the kidney tissue gradually shrinks and hardens, so that it cannot be completely reversed.

Ureteral ureteral junction obstruction 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.

Ureteral ureteral junction obstruction complications Complications hydronephrosis

Often combined with other malformations such as single kidney, horseshoe kidney, contralateral hydronephrosis and multi-atrial renal cystic changes.

Renal ureteropelvic junction obstruction symptoms common symptoms high fever chills hypertension abdominal mass abdominal pain

1. Abdominal masses are often seen in neonates and infants with a painless mass in the abdomen. The palpation mass is mostly sac, with a smooth surface and no tenderness. Some patients have a history of tumor size changes.

2. Pain in addition to infants and young children, most of the sick children can state upper abdominal pain and umbilical pain, abdominal pain is mostly intermittent and accompanied by vomiting, quite like gastrointestinal disorders, low back pain after drinking plenty of water is one of the disease The main feature is the pain caused by the sudden expansion of the diuresis of the renal pelvis. In addition, it can cause colic due to the combined stone activity or clot blockage.

3. The incidence of hematuria and hematuria is about 10% to 30%, which may be caused by the increase of pressure in the renal pelvis and the rupture of the renal medulla, which may also be caused by infection or stones.

4. Infection urinary tract infections are more common in children. Once they appear, the condition is heavy and difficult to control, often accompanied by symptoms of systemic poisoning, such as high fever, chills and sepsis.

5. Hypertension can occur in children or adults, may be due to increased renin secretion caused by intravascular blood vessels.

6. Renal destruction of kidney damage is mostly traumatic, often leading to acute peritonitis.

7. Uremia due to this disease often combined with other urinary malformations, or due to bilateral hydronephrosis, late renal insufficiency, such as no urine, anemia, growth retardation and anorexia and other digestive disorders.

Examination of obstruction of ureteropelvic junction

1. Urine routine can have microscopic hematuria or gross hematuria, pus cells in combination with infection, urine culture can have pathogenic bacteria.

2. Blood urea nitrogen and creatinine can be increased when renal dysfunction.

3. Ultrasound examination B-ultrasound examination method is simple and non-invasive, and the diagnosis is clear. It is the first choice for examination. B-ultrasound can be used to index hydronephrosis, and the diagnosis of the obstruction site and the nature of the lesion are initially identified. Reversibility is of great significance. Doppler ultrasound reflects changes in renal blood flow through the intra-arterial arteriovenous blood flow spectrum, and measures the resistance index (RI) to help identify obstructive and non-obstructive Hydronephrosis, B-ultrasound for fetal urinary tract obstruction is more superior, prenatal B-ultrasound can make an early diagnosis of congenital hydronephrosis.

4. X-ray examination abdominal plain film examination can understand the size of the kidney outline, can be clearly diagnosed with X-ray positive stones, if the hydronephrosis or the proximal urinary tract can be developed during excretory urography, the obstruction site and renal function Judging, especially the judgment of the function of the kidney, is more important. If the IVU is not developed, and the retrograde pyelography cannot be performed, the percutaneous nephrolithoscopic examination can be performed [can be replaced by magnetic resonance urography (MRU)].

5. Dynamic imaging examination of diuretic kidney map is helpful for clear early lesions, whether it is necessary to treat mild hydronephrosis, especially when bilateral hydronephrosis is light on one side, heavy on one side, and lighter on the side of hydronephrosis. Whether surgery is decisive.

In recent years, the application of diuretic IVU monitored by diuretic B-ultrasound and synchronous TV video has a considerable effect on the identification of obstructive and non-obstructive hydronephrosis and diuretic kidney map.

6. Magnetic resonance imaging (MRI) In recent years, MRI has been widely used in the diagnosis of urinary obstructive diseases, especially MR urography (MRU) is helpful for the location and qualitative diagnosis of obstruction. Imaging and urography Similarly, because MRU does not require the use of iodine-containing contrast agents and intubation techniques, it can show urinary tract conditions, patients are safe, non-invasive, and without complications, especially when there is severe damage to renal function and urinary tract obstruction.

7. The renal pelvis pressure test is to place two catheters to the renal pelvis and bladder respectively. The contrast agent is injected through the percutaneous nephrostomy tube at a rate of 10 ml/s. The pressure change in the renal pelvis during the perfusion of the contrast agent is recorded under the fluorescent screen, and the renal pelvis and bladder are measured. The pressure difference as an indicator of renal obstruction, such as renal pelvic pressure >1.37kPa (1410cmH2O), indicates the presence of obstruction, this method is helpful to determine whether there is obstruction in the ureteropelvic junction, but more complicated and traumatic, clinically Less application.

Diagnosis and diagnosis of ureteropelvic junction obstruction

Renal ureteral junction obstruction lacks specific symptoms of the urinary system. Many patients are found during physical examination. Some children are found after hematuria or kidney rupture after a fall collision. Modern imaging studies, pelvis and ureter The diagnosis of connective obstruction is generally not difficult. In addition to the diagnosis, it should be known whether the lesion is on one side or both sides, and whether there are other complications, such as infection, stones, tumors, etc., and the functional status of the kidneys on both sides should be estimated. In order to choose the right treatment plan.

1. The inferior vena cava ureter can also cause upper ureteral obstruction and ureter and hydronephrosis, but the obstruction is caused by vena cava compression of the ureter, not the ureter itself, IVU examination shows renal pelvis and upper ureter dilatation, ureter "S" shape, and shift to the midline, if the IVU results are not satisfactory, retrograde angiography can help to confirm the diagnosis.

2. Ureteral calculi calculi at the junction of the ureter and ureter can also cause hydronephrosis. It needs to be differentiated from the stenosis at the junction of the fistula. There are many cases of paroxysmal cramps and hematuria in the ureteral calculi. The ureteral stroke is opaque on the X-ray film. Shadow, IVU and retrograde angiography showed ureter and hydronephrosis above the stone obstruction. The obstruction site was cup-shaped. The negative stones had filling defects in the obstruction site. CT examination was helpful for the diagnosis of negative stones.

3. Ureteral tuberculosis ureter tuberculosis can cause ureteral stricture due to ureteral tuberculosis, but ureteral tuberculosis is rarely primary, secondary to renal tuberculosis, early systemic symptoms of tuberculosis, such as loss of appetite, weight loss, night sweats, low fever Etc., and urinary frequency, urgency, dysuria and other bladder irritation symptoms, B-ultrasound, IVU or retrograde urography in addition to showing renal ureteral hydrops, but also pelvic and renal pelvis destruction and void, ureter is bead-like stenosis changes The tube wall is stiff and the surface is not smooth.

4. Ureteral tumor ureteral tumor can cause ureteral obstruction, causing ureteral dilatation and stagnant water above the tumor, but clinically, intermittent painless gross hematuria is the main performance, tumor cells in urine are positive, IVU and retrograde urography show ureteral tube The cavity is narrow and there is a filling defect inside, and the expansion below is a cup-shaped change.

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