Congenital pelvic-ureteral junction obstruction resulting in hydronephrosis and dilatation of the renal pelvis and calyces and causing atrophy of the renal parenchyma is known as congenital hydronephrosis. Pathological types of obstruction: ① intrinsic stenosis (the majority of cases) ②Vagal or paranephric vascular compression. ③Mucosal flap stenosis. ④Ureteral upper end adhesions twisted and folded. ⑤ High ureteral insertion into the renal mons. ⑥Congenital power obstruction, etc. Intrarenal hydronephrosis causes more severe kidney tissue damage than extrarenal hydronephrosis. The volume of hydronephrosis exceeds the 24-h urine volume of the child, which is considered a giant hydronephrosis. The lesions eventually lead to severe impairment of renal function. In some cases, an early diagnosis is made during the perinatal ultrasound examination. Severe hydronephrosis should be treated with early surgery.
The normal renal pelvis volume in children increases with age. In the fetus, the renal pelvis volume is less than 1 ml. In infants around one year of age, the renal pelvis volume is 1 to 2 ml, and in those under 5 years of age, the volume is estimated to be about 1 ml/year. Once hydronephrosis occurs, urinary drainage is blocked. In order to overcome the obstruction, the peristalsis of the renal pelvis strengthens and compensatory hypertrophy of the renal pelvic muscles occurs. If the obstruction continues or worsens, there is a loss of compensation and the pressure in the renal pelvis rises, as does the tubular pressure. If tubular pressure exceeds glomerular filtration pressure, glomerular filtration is suspended. The thickness of the affected kidney reflects the degree of pathological changes: if the thickness of the renal parenchyma is below 2 mm, the glomerulus and tubules can no longer be seen, and the cell structure can not be seen under electron microscopy, which is often the standard for nephrectomy; if the thickness of the renal parenchyma is 3 mm, there are still some glomeruli and tubules, but from electron microscopy, the cells have pathological changes, if the obstruction can be lifted, the cells may have partial recovery; if the thickness of the renal parenchyma is above 4 mm The glomerulus, tubules and cell structure were basically normal.
Diagnostic points
1.Clinical manifestations
(1) Abdominal mass or bulging mass in the posterior lumbar region, located on the lateral side of the upper abdomen, and there is also a full bulge in the posterior lumbar region. The surface of the cystic mass is smooth and flat, with a medium texture and no pressure pain, and occasionally the abdominal mass shrinks significantly after a large amount of urination. The abdominal mass may not be palpable in cases of lighter fluid accumulation.
(2) Abdominal discomfort and gastrointestinal symptoms, with varying degrees of abdominal and lumbar discomfort in older children, sometimes manifesting as irregular abdominal pain, and non-specific gastrointestinal symptoms such as dyspepsia and loss of appetite in infants and young children.
(3) Hematuria of the naked eye or microscopic hematuria.
(4) Urinary tract infection. Secondary infection with symptoms of urinary tract infection and toxic sepsis-like manifestations such as high fever and chills. There may be obvious tenderness and percussion pain in the kidney area.
(5) Renal rupture. Mild external force may cause renal rupture with internal bleeding, urinary extravasation and peritonitis symptoms. Spontaneous rupture may also occur.
(6) Renal insufficiency. It is an advanced symptom of double hydronephrosis or sole kidney combined with hydronephrosis. Symptoms include loss of appetite, nausea and vomiting, pallor, anemia and swelling, and weakness.
(7) Renal hypertension, a late complication of hydronephrosis. Hypertension that can only be controlled with angiotensin-converting enzyme inhibitors.
2.Laboratory tests
(1) Ultrasound can detect hydronephrosis in the perinatal period. It can affirm that the mass is a renal fluid mass. It shows separation of the renal pelvis, dilatation of the renal pelvis, varying degrees of thinning of the renal cortex and enlargement of the renal shape. If the thickness of the renal cortex is more than 3mm, the prognosis is better if the obstruction is lifted by treatment. If the hydronephrosis is small and the diagnosis cannot be confirmed, the patient can be examined regularly and repeatedly.
(2) X-ray examination
(1) Plain film: the normal kidney shadow disappears, the upper abdominal mass shadow, the colonic frame is pushed inward, and the complication of stones can be observed.
(2) IVP: Double dose delayed radiographs, Onepac sedation, immediately after sedation to show the renal parenchymal image, to understand the size of the kidney, renal cortical morphology and its function. The films were then taken at 5, 15, 30 and 60 min to show the morphology and function of the kidney. If necessary, delayed films up to 120, 240 and 360 min are used to observe the presence of contrast concentration, which often shows the site of stenosis and partially replaces retrograde pyelogram. It is not necessary to abstain from water and abdominal pressure during the imaging procedure. Full attention must be paid to the visualization of the kidneys bilaterally. IVP can be used to differentiate from duplicated kidneys, ureteral cysts and dysplastic kidneys.
(3) Cystoureteral imaging: It can be differentiated from vesicoureteral reflux, ureteral cysts, urethral valves and urethral s-chambers.
(4) Blood renal function measurement and routine urine examination to understand the renal function of infection, bleeding and bilateral hydronephrosis.
(5) Nuclear nephrogram shows a parabolic image with a lowered secretory segment and a low and delayed excretory segment, indicating renal impairment and obstruction of the excretory system.
Treatment points
To remove the obstruction and control the infection to protect the renal function. At present, the use of disconnected pyeloureteroplasty is mostly advocated. Complicated infection should be actively treated with antibiotics, and the infection that cannot be controlled should be actively treated with surgery.
(1) Mild and moderate hydronephrosis can be treated conservatively with ultrasound follow-up. Severe and very severe hydronephrosis should be treated surgically.
(2) Isolated hydronephrosis should be operated when the diagnosis of hydronephrosis is clear. If it is complicated by stone or infection, it is urgent to release the obstruction.
(3) Bilateral hydronephrosis of similar degree can be operated in one stage or in a short period of time.
(4) Bilateral hydronephrosis, if one side is complicated by infection and stone, surgery should be performed first to release the obstruction, and the other side should be operated as soon as possible after the condition improves.
(5) One side of the hydronephrosis, kidney function is very poor, the opposite side also has hydronephrosis, then the first contralateral surgery, kidney function is very poor, then arrange nephrostomy.
(6) One side has hydronephrosis with poor function and the other side is light. The heavy side will be operated first, and then the light side.
Nowadays, minimally invasive laparoscopic surgery is used to perform disconnected pyeloureteroplasty (Anderson-Hynes procedure), which has satisfactory results and can be the preferred procedure.
Pyeloplasty: It is suitable for severe infection complicated by hydronephrosis, which is difficult to control by strong antibiotic treatment. Bilateral severe hydronephrosis with poor renal function and inability to undergo surgery. It can be incised fistula or percutaneous perforator fistula, and after the situation improves, it can be shaped.
(4) nephrectomy: strict control of the indications, for ① the kidney cortex is as thin as paper and gray, the blood supply is very poor. (2) Abscess kidney with multiple ulcers and no function. (3) Non-functional and still have infection that cannot be easily controlled after pyelostomy, while the other kidney is functioning well.
【Follow up
Follow-up: 6 months to 1 year, ultrasound once a month, IVP once every 6 months. The effectiveness of the procedure is indicated by the fact that the hydronephrosis is no longer increasing or the hydronephrosis is decreasing and the renal function has improved significantly.