Approach
Patients who present with signs and symptoms of obstructive uropathy often need prompt treatment. The approach depends on the clinical presentation and suspected aetiology. Treatment options can generally be grouped according to whether there is unilateral obstructive uropathy or bilateral obstructive uropathy, and whether ureteric calculi are the cause.
Urinary tract obstruction with evidence of infection
Urinary tract infection (UTI) in a patient with obstruction at any site in the urinary tract is a complicated UTI. Clinical presentation can vary and can include imminent urosepsis.[29] It is advisable to seek the advice of a urologist if infection exists in the setting of urinary tract obstruction, and to consult local guidelines on the use of antimicrobial therapy.
In patients with urinary tract obstruction and suspected infection, the first priority is to decompress the obstruction. This can be done with a ureteric stent or nephrostomy tube.[40][41] A nephrostomy tube may be preferred as it can provide better drainage of the kidney.[42][43][44]
Obstruction in the urinary tract is the most frequent urological source of urosepsis.[29] Sepsis should be clinically suspected in those with fever or hypothermia, leukocytosis or leukopenia, tachypnoea, and tachycardia. A validated scoring system such as the quick Sequential [sepsis-related] Organ Failure Assessment (SOFA) score can identify those at risk of deterioration due to sepsis. Patients with at least two of the following three criteria: respiratory rate of 22 breaths per min or greater, altered mental state (Glasgow Coma Scale score <15), or systolic blood pressure of 100 mmHg or less, are likely to have poor outcomes and require initiation or escalation of therapy as appropriate.[29][30]
Parenteral broad-spectrum antimicrobials should be given within 1 hour of the suspicion of sepsis. Examples of suitable first-line empiric antibiotics include a third-generation cephalosporin (e.g., cefotaxime, ceftriaxone), piperacillin/tazobactam, or a carbapenem (e.g., meropenem).[29]
Definitive treatment, such as lithotripsy to remove obstructing stones, can be carried out with the nephrostomy or stent in situ once infection has resolved. This may be days, weeks, or months later.
Unilateral or bilateral obstruction due to ureteric calculi
Patients who present with acute renal colic will require analgesia as soon as possible in order to facilitate further examination. Once the diagnosis is confirmed, further treatment depends on the size and location of the calculus and clinical condition. Patients who have evidence of infections, a solitary kidney, or renal insufficiency, all require immediate intervention.
The options for treatment are a trial of conservative management to allow the stone to pass or active stone removal.
Conservative management. Most stones <5 mm will pass without intervention and patients are managed conservatively with rehydration (either oral or intravenous) and analgesia.[19][40] If the stone is collected, it should be sent for composition analysis. Urine can be strained in order to catch the stone as it passes. The American Urological Association guidelines on the management of ureteral calculi recommend that patients with uncomplicated ureteral stones smaller than or equal to 10 mm be offered medical expulsive therapy with alpha-blockers.[40][45] [
]
[Evidence C] The European Urological Association guidelines recommend consideration of alpha-blockers as medical expulsive therapy for (distal) ureteral stones >5 mm.[41] If the stone does not pass within 4 to 6 weeks, definitive intervention is recommended. During observation, regular imaging to delineate stone position and degree of hydronephrosis is recommended. If the stone is visible on plain film, an abdomen and pelvis x-ray (kidneys, ureter, bladder) can be used for monitoring. If not, an intravenous pyelogram or computed tomography scan may be used. The frequency of monitoring can be weekly or biweekly, depending on the patient's symptoms and the size of the stone. Routine prophylactic antibiotics are not recommended if there is no evidence of infection.Active stone removal. Options for removal of stones that are not able to pass spontaneously include extracorporeal shock wave lithotripsy, ureteroscopy with laser lithotripsy, and percutaneous nephrolithotomy.[40][46] Active stone removal is usually required for stones >10 mm. This may be done with lithotripsy or initial placement of a nephrostomy tube or stent (to decompress the kidney) followed by lithotripsy at a later date. Stones between 5 mm and 10 mm frequently require treatment but may warrant a trial of conservative management. Stones <5 mm usually pass spontaneously but lithotripsy may be required if they fail to do so. The decision on which treatment to use depends on stone location, stone size, and patient preferences. Stone removal is not recommended in the acute setting if the patient has evidence of a urinary tract infection or sepsis.
Unilateral obstruction not due to ureteric calculi
When a patient is found to have unilateral obstruction but no evidence of a ureteric calculus, definitive management will depend on the underlying cause. The urgency of intervention will be greater if the patient is in acute distress or has evidence of infection, a solitary kidney, or renal insufficiency.
In most cases, the first-line intervention is placement of a ureteric stent. In some cases, a stent cannot be technically placed, and a nephrostomy is necessary.
Once the cause of obstruction is identified, treatment plans are tailored to the individual. If a patient has underlying malignancy, a multidisciplinary approach is usually required to determine the optimal treatment strategy. Advanced malignancy causing ureteral obstruction carries a poor prognosis. However, many options are available for palliative relief of symptoms such as pain, uraemia, and urinary tract infections. The benefits of these treatments often far outweigh the risks.[47] For example, in obstruction caused by advanced prostate cancer, a nephrostomy tube may be considered to relieve the obstruction; however, the decision on whether to proceed must be made on an individual basis, considering the patient's overall clinical status and wishes.[48] Options also include ureteric stents or no intervention.[49] If obstruction is thought to be due to a ureteral stricture, evaluation by a urologist is required, as surgical intervention is likely to be needed. In the event of severe loss of renal function, a nephrectomy may be indicated. This is a complex decision requiring the input of consultants.
Bilateral obstruction not due to ureteric calculi
Immediate treatment will usually involve placement of a catheter to relieve acute or chronic obstruction or a posterior urethral valve. Alpha-blocker therapy is recommended to improve urinary flow if benign prostatic hyperplasia (BPH) is thought to be the cause.[50] If difficulty catheterising occurs, the catheter should never be forced. If the catheter cannot be passed due to meatal stenosis, it may be necessary to dilate the meatus or place a suprapubic tube. If the blockage is within the penile urethra, it is most likely due to urethral stricture disease. A smaller silicone catheter may pass more easily, or a suprapubic tube may be required. Resistance near the level of the prostate is a sign of BPH. A Coude tip (curved) catheter can often be inserted successfully in these patients.
In the absence of sepsis, a trial without catheter can be attempted after at least 3 days of alpha-blocker therapy; if unsuccessful, the catheter may need to be reinserted and left in situ pending definitive intervention. BPH may treated with medication or surgical intervention.[50][51] Combination therapy of doxazosin and finasteride has been shown to significantly decrease the progression in symptoms and the development of acute urinary retention in patients with BPH, more than either drug alone.[13] Based on this evidence, 5-alpha-reductase inhibitors such as finasteride may be considered as adjunctive therapy for men whose prostate is thought to be >40 grams on digital rectal examination or transrectal ultrasound.
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