泌尿外科学

泌尿外科学 　　梗阻性尿路疾病 　　Obstruction is one of the most important abnormalities of the urinary tract， since it eventually leads to decompensation of the muscular conduits and reservoirs， back pressure， and atrophy of renal parenchyma. It also invites infection and stone formation， which cause additional damage and can ultimately end in complete unilateral or bilateral destruction of the kidneys. 　　梗阻是泌尿道最重要的异常之一，因其最终使肌性管道及其容器失去代偿能力，发生反压及肾实质萎缩。它亦可导致感染及结石形成，加重肾脏损害，最终使一侧或双侧肾脏完全破坏。 　　Both the level and degree of obstruction are important to an understanding of the pathologic consequences. Any obstruction at or distal to the bladder neck may lead to back pressure affecting both kidneys. Obstruction at or proximal to the ureteral orifice leads to unilateral damage unless the lesion involves both ureters simultaneously. Complete obstruction leads to rapid decompensation of the system proximal to the site of obstruction ，with immediate muscular failure. For example， acute retention occurs if the obstruction is distal to the bladder， and anuria occurs if obstruction involves both ureters. Partial obstruction leads to gradual progressive muscular hypertrophy followed by gradual dilation. decompensation ，and hydronephrotic changs. Vesicoureteral reflux may develop in some cases. 　　梗阻的平面及程度对了解其病后果是重要的。膀胱颈或膀膛颈以下部位梗阻，其反压可影响双侧肾脏，而输尿管口或其近端梗阻则引起单侧损害，除非双侧输尿管同时有病变。完全梗阻可能可使梗阻以上泌尿系统迅速增值失代偿能力，伴有立刻肌力丧失。例如梗阻在膀胱以下部位可以引起急性尿潴留，而双侧输尿管发生梗阻则可出现无尿。部分梗阻则逐渐引起进行性肌肉肥厚，随后出现逐渐扩张，代偿功能丧失及肾积水变化。膀胱输尿管反流可在某些病例出现。 　　Etiology 　　病因 　　Acquired urinary tract obstruction may be due to inflammatory or traumatic urethral strictures， bladder outlet obstruction （benign prostatic hypertrophy or cancer of the prostate）， vesical tumors， neuropathic bladder， extrinsic ureteral compression （tumor， retroperitoneal fibrosis， or enlarged lymph nodes）， ureteral or pelvic stones， ureteral strictures， or ureteral or pelivic tumors. 　　获得性尿路梗阻可能由于炎性或损伤性尿道狭窄，膀胱出口梗阻（良性前列腺肥大或前列腺癌）、膀胱肿瘤、神经性膀胱疾病、外源性输尿管压迫（肿瘤、腹膜后纤维化或巨大的淋巴结）、输尿管结石或肾盂结石、输尿管狭窄、及输尿管或肾盂肿瘤引起。 　　Pathogenesis 　　病原学 　　Regardless of its cause， acquired obstruction leads to similar changes in the urinary tract， which vary depending on the severity and duration of obstruction. 　　不论何种原因，获得性梗阻引起尿路内相类似的改变，而改变的具体情况则因梗阻的严重程度和时间长短有所不同。 　　a. Urethral Changes： Proximal to the obstruction， the urethra dilates and balloons. Aurethral diverticulum may develop， and dilatation and gaping of the prostatic and ejaculatory ducts may occur. 　　a.尿道改变：梗阻近端尿道扩张及膨胀可发展为尿道憩室、前列腺管及射精管扩张及裂口。 　　b. Vesical Changes： Early， the detrusor and trigonal thickening and hypertrophy compensate for the outlet obstruction， allowing complete bladder emptying . This change leads to progressive development of bladder trabeculation， cellules， saccules， and then， diverticula. Subsequently， bladder decompensation occurs and is characterized by the above changes plus incomplete bladder emptying， resulting in residual urine. Trigonal hypertrophy leads to secondary urteral obstruction owing to increased resistance to flow through the intravesical ureter. With detrusor decompensation and residual urine accumulation， there is strectching of the hypertrophied trigone， which appreciable increases ureteral obstruction. This is the mechanism of back pressure on the kidney in the presence of vesical outlet obstruction （while the urterovesical junction maintains its competence）。 Catheter drainage of the bladder relieves trigonal stretch and improves drainage from the upper tract. 　　b.膀胱改变：早期为使膀胱完全排空，逼尿肌及膀胱三角增厚及肥厚，以代偿膀胱出口梗阻。这种改变逐渐发展成膀胱小梁、小腺泡、囊泡，终成为膀胱憩室，最后膀胱失去代偿功能，表现长期持征为上述改变加重，和膀胱排空不完全，最终出现残余尿。膀胱三角区肥厚可引起继发性输尿管口梗阻，这是由于尿液通过膀胱壁部分输尿管时阻力增加而造成的。由于逼尿肌失代偿及残余尿增加，肥厚的三角区过度伸展，加重输尿管梗阻，这就是由于膀胱出口梗阻对肾脏发生反压的机制（此时膀胱输尿管连接处功能健全）。膀胱置管引流减少三角区牵张，并改善上尿路引流。 　　A very late change with persistent obstruction （more frequently encountered with neuropathic dysfunction） is decompensation of the ureterovesical junction， leading to reflux. Reflux aggravates the back pressure effect on the upper tract by exposing it to abnormally high intravesical pressures——in addition to favoring the onset or persistence of urinary tract infection. 　　持续性梗阻（常由于神经原疾病膀胱功能失常）非常晚期限改变为输尿管膀胱连接处失偿导致尿液反应。面对膀胱非常高的压力，尿液反流除促使尿路发生感染或使感染持续性，还加重上尿路的反压。 　　c. Ureteral Changes： The first noted change is a gradually progressive increase in uretereal distention. This increases ureteral wall stretch， which in turn increase contractile power and produces ureteral hyperactivity and hypertrophy. Because the ureteral musculature runs in an irregular helical pattern， stretching of its muscular elements leads to lengthening as well as widening. This is the start of ureteral decompensation， where tortuosity and dilatation become apparent. These changes progress until the ureter becomes atonic， with infrequent and ineffective or completely absent peristalsis. 　　c.输尿管改变：最先可见的改变为输尿扩张逐渐增加，这就增加输尿管壁的牵张，从而增加收缩力，产生输尿管过度活动及肥厚。因为输尿管是不规则螺旋形走向，肌内成份的牵张使输尿管延长及增宽。输尿管的弯曲及扩张标志着它功能失偿的开始，这种改变继续进行直至输尿管失去张力，蠕动减少或完消失。 　　d. Pelvicaliceal Changes： The renal pelvis and calices， being subjected to progressively increasing volumes of retained urine， progressively distend. The pelvis first shows evidence of hyperactivity and hypertrophy and then progressive dilatation and atony. The calices show the same changes to a variable degree， depending on whether the renal pelvis is intrarenal or extrarenal. In the latter， caliceal dilatation may be minimal in spite of marked pelvic dilatation. In the intrarenal pelvis， caliceal dilatation and renal parenchymal damage are maximal. The successive phases seen with obstruction are rounding of the fornices， followed by flattening of the papillae and finally clubbing of the minor calices. 　　d.肾盂肾盏改变：肾盂肾盏由于承受的残余尿容量逐渐增加而扩张。肾盂早期表现是蠕动增强及肥厚，以后逐渐扩大及无张力。肾盂根据其是肾内肾盂抑或外肾盂，而呈不同程度的同样改变。如为后者，虽然肾盂已明显扩大，肾盏扩张可能不明显；而若为肾内肾盂，肾盏扩张和肾实质损害均严重。其梗阻连续相（Successive phase）所见为穹窿呈圆形，接着肾乳头呈扁平，最后肾小盏呈杵状。 　　e. Renal Parenchymal Changes： With progressive pelvicaliceal distention， there is parenchymal compression against the renal capsule. This， plus the more important factor of compression of the arcuate vessels as a result of the expanding distended calices， results in a marked drop in renal blood flow. This leads to progressive parenchymal compression and ischemic atrophy. Lateral groups of nephrons are affected more than central ones， leading to patchy atrophy with variable degrees of severity. The glomeruli and proximal convoluted tubules suffer most from this ischemia. Associated with the increased intrapelvic pressure， there is progressive dilation of the collecting and distal tubules， with compression and atrophy of tubular cells. 　　e.肾实质改变：随着肾盂肾盏进行性扩大，肾实质向包膜侧受压，加上由于肾盏扩大，向弓形动脉压迫这一重要因素终于使血流明显下降，而导致进行性肾实质受压和缺血性萎缩。侧组肾单位受累较中央组为重，而导致严重程度不等的斑状萎缩。肾小球及近曲小管受缺血损害最重。伴随肾盂内压增加，集合管及远曲小管呈进行性扩大，肾小管细胞受压和萎缩。 　　Clinical Findings 　　临床表现 　　a. Symptoms and Signs： The findings vary according to the site of obstruction： 　　症状与体征：其表现因梗阻位置而异。 　　Infravesical obstruction——Infravesical obstruction leads to difficulty in initiation of voiding， a weak stream， and a diminished flow rate with terminal dribbling. Burning and frequency are common associated symptoms. A distended or thickened bladder wall may be palpable. Urethral induration of a stricture， benign prostatic hypertrophy， or cancer of the prostate may be noted on rectal examination. Meatal stenosis and impacted urethral stones are readily diagnosed by physical examination. 　　膀胱下梗阻：膀胱下梗阻导致起始排尿困难，排尿无力及尿流率减少，伴随尿后滴沥。烧灼感及尿频为常见伴随症状。可触及膨胀或增厚的膀胱壁，肛门检查可发现狭窄部尿道变硬，良性前列腺增加或前列腺癌。尿道口狭窄和尿道嵌塞结石常可由物理学检查而获诊断。 　　Supravesical obstruction——Renal pain or renal colic and gastrointestinal symptoms are commonly associated. Supravesical obstruction may be completely asymptomatic when it develops gradually over a period of several weeks or months. An enlarged kidney may be palpable. Costovertebral angle tenderness may be present. 　　膀胱上梗阻：肾区疼痛或肾绞痛常与胃肠道症状同时出现。当膀胱上梗阻发展缓慢时。经数周或数月可完全无症状。可触及增大的肾脏。肋脊角可有压痛。 　　b. Laboratory Findings： Evidence of urinary infection， hematuria， or crystalluria may be seen. Impaired kidney function is noted by elevated blood urea nitrogen and serum creatinine， with the ratio well above the normal 10：1 because of urea reabsorption. 　　b.化验结果：可观察到感染尿，血尿或晶体尿，血尿素氮及血清酐升高，由于尿素氮再吸收以致其比值高于10：1.这表明肾功能受损害。 　　c. X-Ray Findings： Radiologic examination is usually diagnostic in cases of stasis， tumors， and strictures. Dilatation and anatomic changes occur above the level of obstruction， whereas distal to the obstruction， the configuration is usually normal. This helps in localizing the site of obstruction .Combined antegrade imaging by intravenous urograms and retrograde imaging by ureterograms or urethrograms， depending on the site of obstruction， is sometimes needed to demonstrate the extent of the obstructed segment. In supravesical obstruction， demonstration of stasis and delayed drainage is essential to establish and measure the severity of obstruction. 　　c.X线表示：尿液胡滞，肿瘤或狭窄的病例，放射学检查可获诊断。梗阻平面以上有扩张和解剖学改变，而在梗阻远端形态为正常，这有助于诊断梗阻位置。根据梗阻位置有时需同时作顺利性静脉尿路造影及逆行性输尿管造影或尿道造影，以确定梗阻段的伸延。在膀胱以上梗阻，显示郁滞及延迟，引流，对于确定及估计梗阻的严重性是重要的。 　　d. Special Examinations： 　　d.特殊检查： 　　Antegrade urography via percutaneous needle or tube nephrostomy is of particular value when the obstructed kidney fails to excrete the radiopaque material on excretory urography. This procedure allows application of the Whitaker test， during which fluid is introduced into the renal pelvis at varying rates. The fluid transport can be measured and the degree of obstruction estimated by the use of a pressure monitor. 　　顺行时尿路造影：当阻塞的肾脏在排泄性尿路中造影剂不能排泄时，使用经皮针或者说导管行肾造瘘特别有价值，这种操作可施行Whitaker试验， 在试验期间液体可以不同程度注入肾盂。可测量液体转移，以压力监测器来估计梗阻程度。 　　Ultrasonography——This will reveal the degree of dilatation of the renal pelvis and calices and allows for diagnosis of hydronephrosis in the prenatal period. 　　超声显像：它可展示肾盂及肾盏的扩大程度，及可在胎儿期诊断肾积水。 　　Isotope studies——A technetium Tc 99m DMSA scan portrays the degree of hydronephrosis， as well as renal function. Use of diruretics during the scan can provide information similar to that obtained with the Whitaker test. 　　同位素检查：用锝99M DMSA扫描可了解肾盏积水程度及肾功能。在扫描时使用利尿剂可得到与Whitaker试验相似的效果。 　　CT scan——This may be of value in revealing the degree and site of obstruction as well as the as the cause in many cases. The use of contrast agents will allow estimation of residual renal function. 　　CT扫描：在某些病例，对显示梗阻部位，程度以及原因有一定价值，使用对比剂可估计残留有肾功能。 　　Complications 　　并发症 　　The most important complication of urinary tract obstruction is renal parenchymal atrophy as a result of back pressure. Obstruction also predisposes to infection and stone formation， and infection occurring with obstruction leads to rapid kidney destruction. 　　尿路梗阻最重要的并发症为反压所致的肾实质萎缩。梗阻也可以使肾脏易于感染和形成结石，而发生于梗阻的感染则可加速对肾脏的破坏。 　　Treatment 　　治疗 　　The aim of therapy is relief of the obstruction（eg， catheterization for relief of acute urinary retention）。 Surgery is often necessary. Simple urethral stricture may be managed conservatively by dilation or urethrotomy. However， urethroplasty may be required. Benign prostatic hypertrophy and obstructing bladder tumors require surgical removal. 　　治疗的目的在于解除梗阻（例如：上导尿管以解除急性尿潴留）。常常需要外科治疗。单纯尿道狭窄可用尿道扩张及尿道切开等保守法治疗，但有时需行尿道成形术。良性前列腺增生及阻塞性膀胱肿瘤需外科切除。 　　Impacted stones must either be removed or bypassed by a catheter if it is thought that they may pass spontaneously. If they do not pass spontaneously， the stones must be removed surgically later. 　　嵌顿性结石必须取石；如认为结石可能自行排出，亦可经旁道置管。如不能自行排出，以后必须手术取石。 　　Ureteral or ureteropelvic junction obstruction requires surgical revision and plastic repair， either by ureterovesicoplasty， ureteroureteral anastomosis， bladder flaps to bridge a gap in the lower ureter， transureteroureteral anastomosis or ureteropyeloplasty. Penal stones may be removed instrumentally via percutaneous nephrostomy or by irrigation through a tube placed directly into the kidney. 　　输尿道或肾盂输尿管交界梗阻需行手术矫正或行整形修补；输尿管膀胱成形术，输尿管输尿管吻合术，或输尿管肾盂成形术。在下段输尿管则可用膀胱瓣作搭桥填补缺损。肾结石可通过皮穿器械摘除，或者经皮穿刺肾造瘘或经肾直接置管进行冲洗。 　　Preliminary drainage above the obstruction is sometimes needed to improve kidney function. Occasionally， permanent drainage and diversion by cutaneous ureterostomy， ileal or colonic loop diversion， or permanent nephrostomy is required. If damage is advanced， nephrectomy may be indieated. 　　有时为改善肾功能可先在梗阻上方置管引流，有时需作永久性引流，输尿管皮肤造口尿流改道术，回肠或结肠改道或永久性肾造口等。如损害加重，可通适用肾切除。 　　Prognosis 　　预后 　　The prognosis depends on the cause， site， duration， and degree of kidney damage and renal decompensation. In general， relief of obstruction leads to improvement in kidney function except in seriously damaged kidneys， especially those destroyed by inflammatory scarring. 　　预后取决于原因，位置，病程及肾脏损害和肾脏失偿程度。一般来说，解除梗阻可使肾功能改善，除非肾脏严重受损，尤其是炎性疤痕所破坏的。