Urinary tract obstruction can be induced by a myriad of conditions and is defined as a renal disease that causes hydronephrosis and leads to significant changes in normal kidney function [1] [2] [3] [4]. Narrowing or complete obstruction of the ureteropelvic or ureterovesical junctions, ureterocele, phimosis, and the presence of posterior urethral valves are common causes of congenital urinary tract obstruction, whereas nephrolithiasis, urinary tract infections (UTIs), benign prostatic hyperplasia (BPH), malignant tumors (both primary and metastatic), diabetic neuropathy, trauma, and use of several drugs (anticholinergics and alpha-adrenergic antagonists) are important acquired etiologies [1] [2] [4] [5] [6]. Depending on the degree of obstruction (unilateral vs. bilateral) and the rate at which hydronephrosis develops, symptoms are either abrupt or slowly progressive. In the acute setting, a sudden onset of sharp and often severe abdominal pain (known as renal colic) is the hallmark of urinary tract obstruction and is often accompanied by diminished urine output (ranging from oliguria to anuria) in complete obstruction [5] [6]. Pain might project into the genitalia if the lower urinary tract is the site of obstruction [6]. In slowly progressive forms, pain may be mild or even absent, while dysuria, nocturia, increased frequency and urgency, as well as a sensation of incomplete bladder emptying, are often reported [2] [6].

• Inflammation

  Alternatively, the ureters may be compressed or encased by metastatic retroperitoneal lymphadenopathy from a distant primary. 20 Retroperitoneal fibrosis may lead to obstruction of one or both ureters via inflammation. [clinicalgate.com]

  Structural and or traumatic change can lead to hemorrhage, functional blockage or inflammation. Colonisation by bacteria, protozoa or fungi can cause infection. Uncontrolled cell growth can cause neoplasia. [en.wikipedia.org]

  Infections can set in, which may cause further thickening and inflammation in the ureter, bladder, and pelvic walls. [britannica.com]

  It is caused by infection, inflammation, prior surgeries (hypospadias is the most common), instrumentation or trauma. A common cause of urethral stricture in boys is trauma from straddle injury. [urology.ucsf.edu]

• Asymptomatic

  Patients range from having oliguria / anuria to only having asymptomatic hydronephrosis that is incidentally identified through imaging or elevated creatinine levels. [amboss.com]

  CONCLUSIONS: β2-Microglobulin concentration may be a useful marker to screen for asymptomatic UTO in patients with idiopathic scoliosis. © 2016 Japan Pediatric Society. [ncbi.nlm.nih.gov]

  Urinary tract obstruction can result in a wide range of symptoms from asymptomatic to severe renal colic and renal failure. The symptoms depend upon: Duration over which the obstruction occurs. Unilateral or bilateral obstruction. [clevelandurology.net]

  However, no therapy is necessary in an asymptomatic patient with a negative diuretic renogram or with a positive diuretic renogram but normal renal function. [merckmanuals.com]

• Recurrent Urinary Tract Infection

  A doctor may recommend surgery in the following circumstances: Severe problems with urination, such as straining to urinate, weak stream, and urinary retention (inability to urinate) Stones in the bladder Recurrent urinary tract infections Increasing [medicinenet.com]

  urinary retention, recurrent UTIs, renal insufficiency, bladder calculi, recurrent gross hematuria). [1] See Treatment and Medication for more detail. [emedicine.medscape.com]

• Anemia

   Anemia  secondary to chronic infection or in advanced bilateral hydronephrosis (stage of uremia). Leukocytosisis  acute stage of infection. Microscopic hematuria may indicate renal or vesical infection, tumor, or stone. Bilateral hydronephrosis [slideshare.net]

• Respiratory Insufficiency

  Three had respiratory insufficiency, and one required a tracheostomy. CONCLUSION: Despite significant perinatal and long-term morbidity, VAS offers patients faced with a poor prognosis an improved chance of survival. [ncbi.nlm.nih.gov]

• Abdominal Pain

  PATIENT CONCERNS: A 58-year-old man complained of right lower abdominal pain with hematuria for 3 hours after flexible ureteroscopy, combined with holmium laser lithotripsy of right renal calculi was performed 1 month ago. [ncbi.nlm.nih.gov]

  In the acute setting, a sudden onset of sharp and often severe abdominal pain (known as renal colic) is the hallmark of urinary tract obstruction and is often accompanied by diminished urine output (ranging from oliguria to anuria) in complete obstruction [symptoma.com]

  Signs and symptoms include: Inability to pass urine (urinary retention) Weak stream of urine Interrupted stream Blood in the urine Pain in either flank (side) or in the back Abdominal pain and/or swelling Prostate enlargement (in men), which may be benign [gmcdhcc.com]

  Symptoms of a stricture include pain with urination, slow urination, decreased bladder emptying, spraying of the urinary stream, blood in the urine, abdominal pain from a full bladder, urethral discharge, and bladder infections. [urology.ucsf.edu]

  Failure to thrive Recurrent pyelonephritis Children and adults Flank pain or upper abdominal pain that may be triggered or worsened during states of increased diuresis (e.g., after caffeine or alcohol consumption). [amboss.com]

• Abdominal Mass

  Intra-abdominal mass Abdominal aortic aneurysm : surgical excision and repair Lower UTO See benign prostatic hyperplasia, prostate cancer, posterior urethral valves, urethral carcinoma, retroperitoneal fibrosis, ureterocele, and ectopic ureter for further [amboss.com]

  Most patients present with nonspecific symptoms, including dull abdominal pain, of less than 12 months' duration but patients can present with the complications of the fibrosis. [patient.info]

• Failure to Thrive

  Patients were divided into two groups: (1) 'stable renal function' - probable stable long-term renal function and reasonable growth - and (2) 'loss of renal function' - early loss of renal function and failure to thrive. [ncbi.nlm.nih.gov]

• Loss of Appetite

  Other symptoms for VUR may include: Trouble urinating (wetting pants or bed, leakages, urgency to urinate) Mass in the abdominal area (possible sign of swollen bladder) Poor weight gain (loss of appetite) High blood pressure Constipation (and loss of [webmd.com]

• Hypertension

  Evidence exists of an association with metabolic syndrome, obesity, diabetes and hypertension, and of enhanced risk of chronic kidney disease and metabolic bone disease. [ncbi.nlm.nih.gov]

  The remaining twelve sections cover various types of diseases, including hypertension, urological problems, and urinary tract concerns. [books.google.de]

  For instance, it has been shown that protein released by the kidneys in diabetes mellitus sensitises the kidney to the damaging effects of hypertension. [1] Diabetes also can have a direct effect on urination due to peripheral neuropathies, which occur [en.wikipedia.org]

  Intrarenal varices in portal hypertension: demonstration by color Doppler imaging. Abdom Imaging 1996;21:549–50. CrossRef PubMed Google Scholar 9. Kember PG, Peck RJ. Renal arteriovenous malformation mimicking hydronephrosis. [link.springer.com]

• Hypotension

  I also prefer this class of medications for patients who have a history of postural hypotension, dizziness, or fainting. [consultant360.com]

• Urinary Retention

  Acute urinary retention is treated by placement of a urinary catheter (small thin flexible tube) into the bladder. [en.wikipedia.org]

  Is Surgery Needed for Urinary Retention? Depending on the cause of the urinary retention, surgery may be indicated to help resolve the urinary retention. [emedicinehealth.com]

  A 41-year-old man presented in urinary retention 36 hours after self-injecting his urethra with the foam sealant, which could be palpated throughout his entire urethra. [ncbi.nlm.nih.gov]

• Kidney Failure

  If both kidneys are obstructed, kidney failure may result. [merckmanuals.com]

  The condition may be diagnosed through ultrasound scan of the kidneys and bladder, abdominal CT scan, and blood tests to check the kidney function Kidney failure, a significant complication of Chronic Obstructive Uropathy can be potentially avoided by [dovemed.com]

  There are long-term risks for chronic renal disease, kidney failure, dialysis, transplantation, and problems with lung development. [prenatalpediatrics.org]

  failure 3 – 5 and is a factor in 2.6% of acute kidney failure cases in the intensive care setting. 6 Many disorders may lead to urinary tract obstruction. [clinicalgate.com]

• Dysuria

  In slowly progressive forms, pain may be mild or even absent, while dysuria, nocturia, increased frequency and urgency, as well as a sensation of incomplete bladder emptying, are often reported. [symptoma.com]

  Endometriosis: recurrent flank pain, dysuria, hematuria Extra-uterine pregnancy Tuboovarial abscess Pelvic floor insufficiency with organ prolapse Tumors: cervical cancer, ovarian cysts, ovarian cancer, uterine leiomyoma ... [urology-textbook.com]

  When infection is present, the patient may experience fever, chills, and dysuria. Hematuria may also be present. [emedicine.medscape.com]

  […] the bladder falls into the vagina) Foreign objects Urethral or pelvic muscle spasms Inguinal (groin) hernia The symptoms of BOO may vary, but can include: Abdominal pain Continuous feeling of a full bladder Frequent urination Pain during urination ( dysuria [nlm.nih.gov]

• Flank Pain

  Pain: Severe flank pain may result if obstruction develops relatively acutely. [pathwaymedicine.org]

  Endometriosis: recurrent flank pain, dysuria, hematuria Extra-uterine pregnancy Tuboovarial abscess Pelvic floor insufficiency with organ prolapse Tumors: cervical cancer, ovarian cysts, ovarian cancer, uterine leiomyoma ... [urology-textbook.com]

  The presentation of UTO depends on the site, degree, and duration of obstruction and may be acute (flank pain, urinary retention, etc.) or chronic. [amboss.com]

  Upper ureteral or renal pelvic lesions cause flank pain or tenderness, whereas lower ureteral obstruction causes pain that may radiate to the ipsilateral testis or labium. The distribution of kidney and ureteral pain is usually along T11 to T12. [merckmanuals.com]

• Renal Insufficiency

  Survival of neonates with intrauterine renal insufficiency and oligo- or anhydramnios correlates with the severity of secondary pulmonary hypoplasia. [ncbi.nlm.nih.gov]

  Obstructive nephropathy is renal dysfunction (renal insufficiency, renal failure, or tubulointerstitial damage) resulting from urinary tract obstruction. [merckmanuals.com]

  […] substance, other quinazolines (e. g. prazosin, terazosin), or to any of the excipients Benign hyperplasia and concomitant congestion of the upper urinary tract, chronic urinary tract infections or bladder stones Overflow bladder, anuria or progressive renal [glosbe.com]

  Fig. 1 Patient 1 with a history of IgG kappa multiple myeloma presented with acute renal insufficiency. [ckj.oxfordjournals.org]

Urinary tract obstruction is a known risk factor for the development of both acute and chronic kidney disease, especially in children [4], which may have devastating long-term consequences in the absence of an early diagnosis. For this reason, physicians must conduct a thorough clinical workup, starting with a detailed patient history that will assess the presenting signs and symptoms and reveal preexisting disorders or events that might have caused obstruction [2]. In addition, a meticulous physical examination, with an emphasis on abdominal and genital inspection, palpation and percussion, is necessary to raise valid suspicion [2]. Urinalysis is one of the first laboratory studies that can be performed, and often shows hematuria and bacteriuria [5]. In addition, a full laboratory workup comprised of serum electrolytes, a complete blood count (CBC) and renal function tests must be carried out. Serum creatinine and blood urea nitrogen (BUN) are both high in acute obstruction, in which case imaging studies should be employed to identify the cause. If obstruction at the level of the urethra is suspected, either cystourethroscopy or voiding cystourethrography is recommended, whereas abdominal ultrasonography and computed tomography (CT) are used if hydronephrosis or ureteral obstruction might be present [5] [6]. If ultrasound and CT are not conclusive, urography or pyelography (anterograde or retrograde) is indicated [5] [6]. Several biochemical markers have been proposed as potentially useful indicators of obstructive uropathy and its severity (kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin, or KIM-1 and NGAL, but also several other), although further studies are required to solidify their place in general practice [4].

Early prenatal diagnosis together with repetitive amnioinfusions and modern intensive care treatment have improved the prognosis of these neonates. [ncbi.nlm.nih.gov]

Treatment As mentioned earlier, elective termination of the pregnancy should be discussed with couples facing a child with LUTO. [mhnpjournal.biomedcentral.com]

Once the diagnosis of LUTO is established, the prognosis for survival is then assessed. The baby’s outcomes have been correlated to the kidney function as assessed prior to treatment. There are two methods to determine the prognosis before surgery. [losangelesfetaltherapy.org]

Sensitivity and specificity in defining a poor renal prognosis were 80.6% and 89% for β-2-microglobulin, 61.3% and 100% for sodium and 64.5% and 100% for calcium, respectively. [ncbi.nlm.nih.gov]

Postnatal/Prognosis? Among survivors, LUTO is associated with multiple hospitalizations and potentially multiple surgeries. [prenatalpediatrics.org]

Evaluation Lab tests: PSA in men, electrolytes, and kidney function Urine tests: urinalysis, urine culture and sensitivity, possible urine cytology if concern for a malignant etiology Imaging: Depending on concern for different etiologies (plain film [nuomed.com]

CONCLUSIONS: Fetal cystoscopy is accurate in the diagnosis of the etiology of LUTO and serves as a guide to the specific prenatal treatment. [ncbi.nlm.nih.gov]

References: [7] [16] [17] [18] [19] [20] [21] [22] [23] [24] [3] [25] Complications Hydronephrosis Definition : dilation of the renal pelvis and calyces Etiology Urinary tract obstruction (see “Etiology” above) Vesicoureteral reflux Clinical features [amboss.com]

Urinary tract obstruction can occur due to both congenital and acquired disorders of different etiologies, which may ultimately lead to hydronephrosis, significant obstruction of urine passage, and even acute or chronic kidney disease. [symptoma.com]

Recruitment was hampered by logistical and regulatory difficulties, a lower incidence of LUTO and lower antenatal diagnosis rate [estimated to be 3.34 (95% CI 2.95 to 3.72) per 10,000 total births and 47%, respectively, in an associated epidemiological [ncbi.nlm.nih.gov]

Epidemiology Frequency In an autopsy series of 59,064 patients aged 0-80 years, the frequency of hydronephrosis was 3.1%. [emedicine.medscape.com]

Epidemiology Age Urinary tract obstruction occurs most commonly in the young and the old: In older men, this is a relatively common condition due to prostatic enlargement: Incidence of lower urinary tract symptoms (LUTs)/BPH averages 15 per 1,000 man-years [patient.info]

Each disease-oriented section begins with an up-to-date review of pathophysiology and then focuses on specific diseases. [books.google.de]

Pathophysiology of urinary tract obstruction. In: Wein J, ed. Campbell-Walsh Urology. Vol 2. 9th ed. Saunders; 2007:1195-226 7. Renal colic - acute, Clinical Knowledge Summaries (April 2009) 8. Chen MY, Zagoria RJ, Dyer RB. [degruyter.com]

Pathophysiology of urinary tract obstruction. In: Wein AJ, Kavoussi LR, Partin AW, Peters CA, eds. Campbell-Walsh Urology. 11th ed. Philadelphia, PA: Elsevier; 2016:chap 48. Zeidel ML. Obstructive uropathy. In: Goldman L, Schafer AI, eds. [nlm.nih.gov]

Pathophysiology Normal urine production in an adult is about 1.5-2 L/day. [emedicine.medscape.com]

Fetal urinary tract obstruction may prevent normal development of the lungs, be associated with other anomalies which cannot be diagnosed before delivery and retard infant development in survivors. [ncbi.nlm.nih.gov]

Can it be prevented? Preventing a urinary tract obstruction relies on identifying and treating the condition that is causing it. [clicks.co.za]

This will relieve pain and prevent damage to the kidneys and urinary tract. Thorough assessment will reveal the cause of the obstruction and accordingly, your trusted Urologist will decide on the best course of action. [gmcdhcc.com]

1. Chevalier RL. Congenital Urinary Tract Obstruction: The Long View. Advances in chronic kidney disease. 2015;22(4):312-319.
2. Dmochowski RR. Bladder Outlet Obstruction: Etiology and Evaluation. Reviews in Urology. 2005;7(Suppl 6):S3-S13.
3. Bascands J-L, Schanstra JP. Obstructive nephropathy: insights from genetically engineered animals. Kidney International. 2005;68(3):925-937.
4. Wasilewska A, Taranta-Janusz K, Dębek W, Zoch-Zwierz W, Kuroczycka-Saniutycz E. KIM-1 and NGAL: new markers of obstructive nephropathy. Pediatr Nephrol. 2011;26(4):579-586.
5. Kasper DL, Fauci AS, Hauser SL, Longo DL, Jameson J, Loscalzo J. eds. Harrison's Principles of Internal Medicine, 19e. New York, NY: McGraw-Hill; 2016.
6. Porter RS, Kaplan JL. Merck Manual of Diagnosis and Therapy. 19th Edition. Merck Sharp & Dohme Corp. Whitehouse Station, N.J; 2011.