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Results for “Urethral Obstruction”

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PubMed1983

Correction of congenital hydronephrosis in utero. I. The model: fetal urethral obstruction produces hydronephrosis and pulmonary hypoplasia in fetal lambs.

In an attempt to simulate congenital hydronephrosis secondary to urethral obstruction, we evaluated the consequences of obstructing the urethra in fetal lambs by several techniques. When the urethra was ligated before 108 days gestation, the bladder decompressed through the urachus and the upper-urinary tract developed normally. Ligation of both the urethra and urachus produced gross bilateral hydronephrosis, hydroureter, and megacystis, as well as severe pulmonary hypoplasia, and was associated with a high perinatal mortality. Intermittent urethral obstruction produced with a balloon constrictor or by diverting urine externally and pressure-limited obstruction produced with a Pudenz valve both proved unsatisfactory for producing congenital hydronephrosis. Finally, ligation of the urachus and progressive gradual obstruction of the urethra with an ameroid constrictor produced hydronephrosis and pulmonary hypoplasia. This model simulates urethral obstruction in the human fetus and produces a clinical and pathologic picture similar to that seen in infants born with congenital hydronephrosis.

Animals↗

PubMed1993

Urethral obstruction of 6 hours or less causes bacteriuria, bacteremia, and pyelonephritis in mice challenged with "nonuropathogenic" Escherichia coli.

Urethral obstruction may be caused by prostatic hypertrophy, urethral stricture, or encrustation of a urethral-catheter lumen. Bacteriuria often complicates these obstructions. The sequelae include fever, acute pyelonephritis, chronic renal inflammation, and death. We hypothesized that even brief obstruction of the urinary tract containing a nonvirulent bacterium would result in these complications. Mice challenged transurethrally with Escherichia coli FN414, which is rapidly eliminated from normal mice without causing bacteriuria, bacteremia, or renal pathology, were subjected to reversible urethral obstruction by coating the urethral meatus with collodion for 1, 3, or 6 h. The majority of mice obstructed for 1 h demonstrated parenchymal renal inflammation 48 h later. At the end of 3 h of obstruction, 9 of 10 mice were bacteremic; some bacteremias were present at 48 h after removal of the obstruction. At that time, more severe renal inflammation was seen in these mice. As little as 6 h of obstruction resulted not only in the acute changes described above but also in chronic renal inflammation and fibrosis in the majority of animals sacrificed 3 and 6 weeks later. Additional studies demonstrated that urethral obstruction enhanced the uropathogenicity of another nonpathogenic E. coli strain (K-12 strain HB101) and caused more severe renal lesions in mice challenged with E. coli CFT073, isolated from a patient with symptoms of pyelonephritis. These findings demonstrate that brief urethral obstruction may (i) induce organisms which are cleared rapidly from the normal urinary tract to cause bacteriuria, bacteremia, and pyelonephritis and (ii) intensify the renal lesions caused by a uropathogen.

Animals↗

PubMed2000

[Rational approach to the patient with urination disorders caused by cervico-urethral obstruction].

Benign prostatic hypertrophy is the most frequent cause of cervico-urethral obstruction in adults. The symptomatology is complex and varied, and includes both irritative and obstructive symptoms. A number of methods are used to evaluate-quantify obstruction caused by benign prostatic hypertrophy. A series of tests are traditionally used to identify disorders caused by altered vesical filling (LUTS) and the degree of obstruction (BOO). An analysis of the various methods generally allows the most suitable treatment to be commenced. This critical review aimed to identify the real value and specificity of each method in relation to the possibility of quantifying the degree of cervico-urethral obstruction.

Humans↗

PubMed1991

The guinea pig as a model of gradual urethral obstruction.

We developed a new model of partial urethral obstruction using the guinea pig. We placed jeweler's jump rings loosely around the proximal urethra of immature guinea pigs and allowed the obstruction to develop gradually as the animal grew. After four or eight weeks of obstruction, we studied the filling and emptying characteristics of the bladder during continuous repetitive cycling under urethane anesthesia. Following this examination, bladders were removed and weighed. Wet weight was compared to urodynamic findings. We identified four abnormal urodynamic patterns: high pressure voiding, instability, poor compliance and decompensation. All obstructed bladders showed weight gain associated with muscle hypertrophy, but the degree of weight gain was different for each of the various urodynamic categories. High pressure voiding was associated with the least weight gain, whereas instability and decompensation showed the most weight gain. The results are consistent with a thesis that partial urethral outlet obstruction in the guinea pig gives rise to several distinct forms of abnormal voiding characterized by high pressure in the early stages, and progressing to more advanced forms of dysfunction characterized by instability and decompensation in the later stages.

Animals↗

PubMed1996

The Glidewire technique for overcoming urethral obstruction.

PURPOSE: Using the hydrophilic Terumo Glidewire we developed a less traumatic, yet effective alternative method to filiforms and followers for cases of urethral obstruction. MATERIALS AND METHODS: The initial step and cornerstone of our method is the passage of the Glidewire per urethra in a manner similar to a filiform. After the appropriate intravesical location of the Glidewire is confirmed using a ureteral catheter, it is exchanged for a standard polytetrafluoroethylene (Teflon) coated guide wire. Urethral dilation and/or catheter placement is then performed. RESULTS: This technique was successful in 19 of 20 attempts, several of which followed unsuccessful passage of filliform catheters. Urethral obstruction due to strictures, bladder neck contractures and benign prostatic hyperplasia in our group was treated effectively. Furthermore, no complications occurred due to the technique. CONCLUSIONS: The Glidewire method is safe and effective for treating most cases of urethral obstruction. Therefore, we recommend this technique over standard filiforms and followers when flexible or rigid cystourethroscopy is not immediately available.

Drainage↗

PubMed1997

Prepubic urethrostomy for relief of urethral obstruction in a sheep and a goat.

Urethral obstruction is common in castrated male small ruminants. Perineal urethrostomy is the recommended treatment in animals not intended for breeding; however, stricture formation is a common complication, and few surgical options are available once a stricture has formed. Prepubic urethrostomy has been used successfully in dogs and cats to treat urethral trauma or stricture formation, and in this report, use of prepubic urethrostomy in 2 small ruminants to treat urethral strictures that developed alter perineal urethrostomy is described. Both animals maintained urinary continence and were able to void urine normally. Complications after prepubic urethrostomy included recurrent cystitis in sheep and urethral stricture in goats. Prepubic urethrostomy may be considered in as an alternative for treatment of urethral disorders in small ruminants.

Animals↗

PubMed1984

Emergency treatment of urethral obstruction in male cats.

Cats with mild urethral obstruction are anesthetized, the obstruction removed and the bladder lavaged. Moderately affected cats are sedated and given IV fluids, and usually return to normal soon after the obstruction is removed. Severely affected cats are given IV fluids, NaHCO3 and Ca gluconate, sedated or anesthetized and unblocked. Fluid administration is continued to avoid renal failure. The bladder can be expressed 3-4 times daily or bethanechol given to aid recovery of detrusor muscle function. Halothane, 1% thiopental or thiamylal, or ketamine-acepromazine can be used to anesthetize blocked cats. An 18- or 20-ga, 2 1/2-inch over-the-needle catheter or a lacrimal needle is used to relieve the obstruction, after which a 3 1/2-Fr Silastic or vinyl catheter is used for catheterization and bladder lavage with sterile saline. Cystotomy allows recuperation before definitive corrective surgery.

Anesthesia, Intravenous↗

PubMed2003

Effects of chronic blockade of N-methyl-D-aspartate receptors by MK-801 on neuroplasticity of the micturition reflex pathway after partial urethral obstruction in the rat.

PURPOSE: To determine the role of N-methyl-D-aspartate (NMDA) glutamatergic receptors in the development of functional bladder changes after partial urethral obstruction we investigated the effects of repeat injection of MK-801, a noncompetitive NMDA receptor antagonist, on the micturition reflex in conscious obstructed rats. MATERIALS AND METHODS: In 9 female Wistar rats 1.0 mg/kg MK-801 was injected intramuscularly once weekly just prior to the creation of partial urethral obstruction until 5 weeks after obstruction. Five to 7 days after the last injection of MK-801 conscious filling cystometry was performed and compared with that in 9 obstructed rats treated with vehicle (saline). Conscious filling cystometry was also compared in 9 and 7 sham operated rats treated with repeat injection of MK-801 and vehicle, respectively. RESULTS: Partial urethral obstruction caused a significant increase in bladder weight. However, chronic MK-801 treatment did not affect bladder weight in obstructed or sham operated rats. In the obstructed/MK-801 vs the obstructed/vehicle group chronic treatment with MK-801 significantly increased bladder capacity (2.29 +/- 0.12 vs 1.73 +/- 0.16 ml, p <0.01) and voided volume (2.00 +/- 0.10 vs 1.56 +/- 0.17 ml, p <0.05) without changes in voiding efficiency (87.5% +/- 1.6% vs 87.8% +/- 1.7%) or micturition pressure (55.8 +/- 2.3 vs 56.4 +/- 3.0 cm water). Interestingly neither the frequency nor amplitude of premicturition contractions during filling was different in the groups. In sham operated rats chronic MK-801 treatment did not change bladder capacity, voided volume, voiding efficiency or micturition pressure significantly. CONCLUSIONS: The results in the current study suggest that bladder outlet obstruction causes NMDA receptor mediated alterations in bladder afferent pathways in the rat.

Animals↗

PubMed1996

The origin of vesico-ureteric reflux in male newborns: further evidence in favour of a transient fetal urethral obstruction.

OBJECTIVE: To present further arguments supporting a transient urethral obstruction occurring during early fetal development as an explanation of the origin of vesico-ureteric reflux (VUR) in baby boys. PATIENTS AND METHODS: The findings of ultrasonography and voiding cysto-urethrography (VCUG) in 25 baby boys with VUR were reviewed, studying mainly bladder and urethral anomalies on VCUG and bladder-wall thickness on ultrasonography. RESULTS: A bladder or urethral anomaly was found in 15 patients, comprising isolated posterior urethral dilatation in five, posterior urethral dilatation with a bladder anomaly in four, tubular appearance of the urethra in two and bladder neck hypercontractility with diverticulae in four. Bladder-wall thickness ranged from 1 to 8 mm (mean 3.7) and in eight patients, the thickness exceeded 5 mm. CONCLUSION: The bladder and urethral anomalies found in this series of patients with neonatal VUR could be explained by a transient bladder outlet obstruction that possibly occurred in utero. These findings support the theory that a significant number of cases of VUR seen in baby boys result from a transient fetal urethral obstruction.

Dilatation, Pathologic↗

PubMed1999

Degenerative changes of afferent neurons in the lumbosacral dorsal root ganglia following complete urethral obstruction in guinea pigs.

OBJECTIVE: The ultrastructural changes in the bladder afferent neurons were examined in the guinea pig following acute complete urethral obstruction. MATERIAL AND METHODS: Complete urethral ligation was carried out in nine guinea pigs under anaesthesia and the animals were sacrificed at 12, 24 and 48 h postoperatively. Three sham-operated animals were sacrificed at 48 h postoperatively as controls. The dorsal root ganglia (DRG) at L6, S1 and S2 spinal segments of the animals in each group were removed and processed for electron microscopic study. RESULTS: In the control groups, all the DRG neurons at L6-S2 segments appeared normal. At 12 h after urethral ligation, a few neurons in the DRG at various segments showed signs of structural changes, notably the mitochondria. Mitochondrial swelling was more pronounced at 24 h, and by 48 h most of them became vacuolated and lysed. It was estimated by semiquantitative study that 18.6% and 22% of DRG neuronal profiles at 24 and 48 h, respectively, displayed severe mitochondrial swelling and vacuolation. CONCLUSIONS: The observed degenerative changes in DRG neurons following complete urethral obstruction may be a cellular reaction in response to the axonal injury elicited by bladder overdistension. This may account for alterations in visceral sensation in patients with acute urinary retention.

Acute Disease↗

PubMed1983

[A plainly apparent cause of urethral obstruction].

Some mariginal notes regarding possible forms of treatment are made with reference to acute urethral obstruction appearing in a male dog. Although this obstruction was due to a rare cause, the procedure adopted may serve as guidance in planning a scheme of treatment in common cases of urethral obstruction caused by urinary calculi in male dogs.

Animals↗

PubMed1997

Upregulation of nicotinamide adenine dinucleotide phosphate-diaphorase reactivity in the ventral horn motoneurons of lumbosacral spinal cord after urethral obstruction in the guinea pig.

The role of nitric oxide (NO) in pathophysiology of urethral obstruction in male guinea pig was investigated by using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry. In normal and sham-operated control animals, NADPH-d reactivity in the ventral horn motoneurons at L5-L6 and S1-S2 segments of spinal cord was barely detectable or virtually absent. In animals receiving urethral ligation and killed at 6 h after operation, NADPH-d reactivity in the ventral horn motoneurons was comparable to that of control animals. At 12 h, NADPH-d reactivity in the same cells began evident and was markedly enhanced in animals killed at 24 and 48 h. In order to verify whether the increased NADPH-d reactivity was linked to neuronal death, some sections of the lumbosacral spinal cord from urethral obstructed animals were stained in Nissl staining. There was no sign of cell death or atrophy of the ventral horn neurons. Present results suggest the plasticity of NADPH-d in ventral horn neurons which is readily upregulated by urethral ligation. The enhanced NADPH-d reactivity would imply increased nitric oxide synthase (NOS) activity and consequently generation of higher levels of NO in ventral horn neurons. Such alteration maybe involved in distension-induced urethral relaxation in the external urethral sphincter following urethral ligation.

Animals↗

PubMed2000

Urethral obstruction in patients with nighttime wetting: urodynamic evaluation and outcome of surgical incision.

The aim of this study was to investigate urodynamic findings and the outcome of surgical incision in patients with nighttime wetting due to urethral obstruction. A total of 239 patients with nighttime wetting (157 males and 82 females; mean age, 8.7; range, 4-18 years) was studied. One hundred and ten patients had monosymptomatic enuresis alone and 129 both nighttime wetting and daytime symptoms, that is, the majority was not simple bedwetters, but had signs of bladder overactivity. All patients were first treated with bladder training and fluid intake after dinner was restricted. The non-responders were then treated with tricyclic antidepressants, anticholinergics, or intra-nasal desmopressin and conditioning therapy. Ninety-seven patients who did not respond to these conventional treatments were investigated by voiding cystourethrography, bougie à boule, and urodynamic study. Urethral obstruction was noted in 34 patients (14.2%); posterior urethral valves in three males, ring stricture of the bulbar urethra in 26 males and distal urethral stenosis in five females. Detrusor instability was noted in 30 (94%) of 32 patients. Three patients had <15 mL/s of maximum flow rate and none had post-void residual urine. Pressure at maximum flow (PQ(max)) was 106.5 +/- 26.3 cm H(2)O in pressure/flow study. After surgery, nighttime wetting was cured in 25 patients (73.5%), improved in four (11.8%). Detrusor instability disappeared in six of 16 patients studied (37.5%) and improved in 8 (50%), and PQ(max) decreased significantly after operation (P = 0. 0034). In conclusion, most of the patients with urethral obstruction have detrusor instability and high pressure voiding, and these conditions improved after operation.

Adolescent↗

PubMed1982