History
Most acute obstructive uropathies are associated with significant pain or the abrupt diminution of urine flow that alerts the clinician to the need for further evaluation and treatment. However, the insidious nature of chronic urinary obstruction requires a careful history and a high index of suspicion, which prompt an appropriate evaluation that may confirm or rule out the presence of obstruction. A large (933 patients) prospective study by de la Rosette et al failed to correlate a wide range of symptoms of lower urinary tract obstruction with bladder outflow studies. [6]
Pain secondary to stretching of the urinary collecting system is the most common symptom in acute obstruction. Prevalence of pain is related more to acuity of obstruction than degree of distention. Acute obstruction of the ureter by a calculus commonly results in an excruciating pain, commonly referred to as renal colic. This pain is described as unrelenting, radiating from the flank to lower abdomen and testicles or labia on the affected side.
Patients often present to the emergency department with acute urinary tract disorders manifesting as flank pain. Because laboratory and clinical findings (eg, hematuria) are neither sensitive nor specific for identifying the cause of the flank pain, imaging is important for both diagnosis and management. [7]
By contrast, pathologic processes that slowly obstruct, such as retroperitoneal tumors, are relatively pain free. Prostatic hypertrophy also may be associated with an obstructive uropathy that is relatively painless. It usually is identified when a superimposed acute obstruction occurs with the inability to void effectively; the resultant painful, distended bladder prompts a visit to an emergency physician.
Alterations in patterns of micturition often associated with more distal obstructions are early but frequently missed symptoms. Although anuria is dramatic and specific for obstruction, nocturia and polyuria are much more common presenting symptoms associated with renal concentrating defects due to partial obstruction. Bladder outlet obstruction leads to the symptoms of prostatism (eg, frequency, urgency, hesitancy, dribbling, decrease in voiding stream, the need to double void).
Acute and chronic renal failures are common complications of urinary obstruction. Obstructive nephropathy should be considered, especially in uremic patients without a previous history of renal disease, hypertension, or diabetes. Gross or microscopic hematuria often is associated with renal calculi, papillary necrosis, and tumors, all of which can cause obstruction.
Recurrent UTIs should always lead to an investigation for urinary obstruction. New-onset or poorly controlled hypertension secondary to obstruction and increased renin-angiotensin has been reported. Polycythemia secondary to increased erythropoietin production in the hydronephrotic kidney also has been reported.
History of recent gynecologic or abdominal surgery can give important clues to the etiology of urinary obstruction.
Pediatric patients may present with recurrent infections. Symptoms of voiding dysfunction such as enuresis, incontinence, or urgency should be sought.
A thorough medication history should be elicited. A variety of drugs and toxins affect renal function. Bladder dysfunction is seen with a variety of xenobiotic drugs with antimuscarinic anticholinergic activity such as antihistamines, antipsychotics, and antidepressants. A variety of xenobiotics such as ethylene glycol, indinavir, methotrexate, phenylbutazone, or sulfonamides will induce crystal deposition throughout the tubulointerstium obstructing urine output. Additionally, drug-induced retroperitoneal fibrosis may obstruct ureteral function such as methysergide or other natural-occurring ergotamines.
In cases of both acute and chronic obstructive uropathy, occupational exposure history may be beneficial. For example, in textile manufactures, shipyard workers, roofers, or asbestos miners, retroperitoneal fibrosis due to asbestos-induced mesothelioma should be considered. Bladder cancer–induced outlet obstruction may occur in textile workers, rubber manufacturing workers, leather workers, painters, hairdressers, or drill press workers exposed to alpha- or beta-naphthylamine, 4-aminobiphenyl, benzidine, chlornaphazine, 4-chlor-o-toluidine, 2-chloroaniline, phenacetin compounds, benzidine azo dyes, or methylenedianiline.
Causes
Infants and children
Urethral and bladder outlet obstruction may be associated with the following:
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Urethral atresia
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Phimosis
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Meatal stenosis
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Anterior and posterior urethral valves (males)
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Calculus (Southeast Asia)
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Blood clot
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Neurogenic bladder (meningomyelocele)
Ureteral obstruction may be associated with the following:
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Vesicoureteral reflux (female preponderance)
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Ureterovesical junction narrowing or obstruction
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Ureterocele
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Retrocaval ureter
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Retroperitoneal tumor
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Megaureter - Prune belly syndrome
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Blood clot
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Ureteropelvic junction narrowing or obstruction
In a study of 56 patients (42 boys, 14 girls) younger than 18 years who presented to the emergency department with acute urinary retention, causes of urinary retention were mechanical obstruction in 14 patients (25%), infection or inflammation in 10 (18%), fecal impaction in 7 (13%), neurologic disorders in 6 (11%), gynecologic disorders in 4 (7%), and behavioral processes in 3 (5%); 12 patients (21%) were idiopathic. All patients with mechanical obstruction were boys, 5 of whom had a pelvic tumor. Fifteen children underwent surgery, and 3 children required continuous catheterization during follow-up. [8]
Lower urinary tract obstruction caused by polyps of the urethra has been reported. [9]
Adults
Urethral and bladder outlet obstruction may be associated with the following:
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Stricture (male preponderance)
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Sexually transmitted diseases (STDs), particularly in women with severe genital herpes involving the urethral orifice, occasionally in males with significant prostatitis or purulent urethritis
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Trauma
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Blood clot
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Calculi
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Benign prostate hypertrophy (BPH)
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Carcinoma of cervix or colon
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Neurogenic bladder (diabetes mellitus, spinal cord disease, multiple sclerosis, Parkinson disease, anticholinergic drugs, alpha-adrenergic antagonists, calcium channel blockers, opioids, sedative-hypnotics) [10]
Ureteral obstruction may be associated with the following:
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Vesicoureteral reflux (female preponderance)
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Uric acid crystals
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Blood clot
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Trauma
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Papillary necrosis (sickle cell disease, diabetes mellitus, pyelonephritis)
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Pregnant uterus
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Aortic aneurysm
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Carcinoma of ureter, uterus, prostate, bladder, colon, or rectum
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Retroperitoneal fibrosis
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Idiopathic tumors (cervix, uterus, prostate, colon)
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Chronic UTI (methysergide, propranolol)
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Retroperitoneal lymphoma
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Uterine leiomyomata
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Stricture (tuberculosis, radiation, schistosomiasis, nonsteroidal anti-inflammatory drugs [NSAIDs])
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Accidental surgical ligation
Intrarenal obstruction may be associated with the following:
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Crystals (uric acid, sulfonamide, acyclovir)
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Protein casts (multiple myeloma, amyloidosis)
