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Ureter: obstruction
Synonym(s): urinary
Introduction
- Causes:
- Intraluminal: urolithiasis (most common), solidified blood clots/pus, ureteritis.
- Intramural: tumors (rare), strictures (fibrosis).
- Extramural: abdominal tumors, ligation, uterine stump infections, trauma, ectopic ureterocele.
- Signs: dysuria, hematuria, depression, vomiting, dehydration if renal failure present. Obstruction of a single ureter can also be clinically silent.
- Treatment: identify and correct acid base/electrolyte abnormalities, establish diuresis. Remove obstruction (often surgical) or divert urinary flow (SUB device).
- Stenting has been described which is minimally invasive, potentially avoids some surgical risks and can be successful.
- Subcutaneous Ureteral Bypass surgery allows to divert the urine from the renal pelvis into the bladder, bypassing the blocked ureter and restoring kidney function.
- Prognosis: prolonged obstruction (>7 days) → permanent kidney damage. Renal damage increases with duration of obstruction.
Presenting signs
- Hematuria Hematuria.
- Polyuria, polydipsia Polyuria/polydipsia (PU/PD).
- Flank pain.
- Anuria (if bilateral and complete).
- None.
Acute presentation
- Anuria (if bilateral).
- Flank pain, abdominal pain.
- Depression, weakness, vomiting.
Cost considerations
- Bilateral ureteral obstruction → emergency surgery, treatment of obstructive uropathy.
Pathogenesis
Etiology
- Intraluminal: urolithiasis Urolithiasis, solidified blood clots, inflammation and inflammatory debris (bacterial ureteritis, pyelonephritis Pyelonephritis).
- Intramural: tumors of the ureter (not reported), strictures (secondary to ureteritis or ureterolithiasis), neoplasia or polyps at ureteral opening in the trigone.
- Extramural:
- Abdominal tumors Large intestine: neoplasia.
- Trauma Ureter: trauma - ligation during ovariohysterectomy Ovariohysterectomy.
- Uterine stump infections.
- Ectopic ureteroceles.
Pathophysiology
- Prolonged partial ureteral obstruction → dilation of proximal segment and hydronephrosis Hydronephrosis / hydroureter and fibrosis → reduction in renal blood flow and GFR Glomerular filtration rate → ultimately tubular dilation and interstitial fibrosis.
- If complete ureteral obstruction is relieved within 7 days in experimental studiesin experimental studies → little permanent damage. Correction of complete obstruction at 4 weeks → renal function recovers to 30% of normal GFR.
- Bilateral obstruction → azotemia Azotemia, uremia Uremia → eventual acute intrinsic renal failure Kidney: acute renal failure.
Timecourse
- Correction within 7 days in experimental studies → little permanent damage.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Kulendra N J, Borgeat K, Syme H, Dirrig H, Halfacree Z (2021) Survival and complications in cats treated with subcutaneous ureteral bypass. JSAP 62(1), 4-11 PubMed.
- Vrijsen E, Devriendt N, Mortier F, Stock E, Van Goethem B, de Rooster H (2020) Complications and survival after subcutaneous ureteral bypass device placement in 24 cats: a retrospective study (2016-2019). J Feline Med Surg ePub PubMed.
- Chik C, Berent A C, Weisse C W, Ryder M (2019) Therapeutic use of tetrasodium ethylenediaminetetraacetic acid solution for treatment of subcutaneous ureteral bypass device mineralization in cats. J Vet Intern Med 33(5), 2124-2132 PubMed.
- Fages J, Dunn M, Specchi S, Pey P (2018) Ultrasound evaluation of the renal pelvis in cats with ureteral obstruction treated with a subcutaneous ureteral bypass: a retrospective study of 27 cases (2010-2015). J Feline Med Surg 20(10), 875-883 PubMed.
- Berent A C (2011) Ureteral obstructions in dogs and cats: a review of traditional and new interventional diagnostic and therapeutic options. J Vet Emer Crit Care 21 (2), 86-103 PubMed.
- Zaid M S, Berent A C, Weisse C et al (2011) Feline ureteral strictures: 10 cases (2007–2009). J Vet Intern Med 25, 222-229 PubMed.
- Kyles A E, Hardie E M, Wooden B G et al (2005) Management and outcome of cats with ureteral calculi: 153 cases (1984-2002). JAVMA 226 (6), 937-944 PubMed.
- Kyles A E, Hardie E M, Wooden B G et al (2005) Clinical, clinicopathologic, radiographic, and ultrasonographic abnormalities in cats with ureteral calculi: 163 cases (1984-2002). JAVMA 226 (6), 932-936 PubMed.
- Nwadike B S, Wilson L P & Stone E A (2000) Use of bilateral temporary nephrostomy catheters for emergency treatment of bilateral ureter transection in a cat. JAVMA 217 (12), 1862-1865 PubMed.
- Kyles A E, Stone E A, Gookin J et al (1998) Diagnosis and surgical management of obstructive ureteral calculi in cats - 11 cases (1993-1996). JAVMA 213 (8), 1150-1156 PubMed.
- Lamb C R (1998) Ultrasonography of the ureters. Vet Clin North Am Small Anim Pract 28 (4), 823-848 PubMed.