Urgent, image-guided drainage that relieves a blocked, swelling kidney — protecting kidney function and treating infection risk without open surgery.
Obstructive uropathy is a blockage anywhere along the urinary tract that prevents urine draining normally from the kidney down to the bladder. When this happens, urine backs up within the kidney, causing it to swell — a condition called hydronephrosis — which raises pressure within the kidney and can progressively damage kidney function the longer it continues. If the obstructed urine also becomes infected, the combination is a genuine emergency: infection trapped behind a blockage, with nowhere to drain, can rapidly progress to severe sepsis and is a leading cause of urgent decompression procedures.
The most common cause of obstructive uropathy is a kidney or ureteric stone, but a blockage can equally result from a tumour pressing on or growing into the ureter, scarring or a stricture from a previous procedure or radiation, or compression from a mass elsewhere in the pelvis or abdomen. Regardless of the cause, the immediate priority when significant obstruction is found — especially with infection or worsening kidney function — is to relieve the blockage promptly, with definitive treatment of the underlying cause (removing a stone, or treating a tumour) generally following once the patient is stabilised.
Fever, loin pain, and a blocked kidney together represent a urological emergency requiring decompression within hours.
Particularly in a patient with a single functioning kidney, or obstruction affecting both kidneys.
From an obstructing stone that hasn't responded to medical management.
Where treatment options are limited and prompt, safe decompression is particularly important.
A needle is guided under ultrasound into the kidney's collecting system under local anaesthesia.
Contrast dye and X-ray confirm correct catheter position in the collecting system.
A catheter, or an internal ureteric stent, relieves the obstruction.
Most patients are observed briefly; the tube is checked regularly.
Both procedures achieve the same essential goal — relieving the pressure of a blocked kidney — but do so via different routes, and the choice between them depends on the clinical situation:
Percutaneous nephrostomy (PCN) places a small drainage tube directly into the kidney's collecting system through a needle puncture in the back, under ultrasound and X-ray guidance. Urine drains externally into a bag attached to the tube. PCN can be placed quickly, doesn't require general anaesthesia, and is often the fastest way to relieve an infected, obstructed kidney — which is why it's frequently the first choice in an urgent or unstable setting.
Ureteric (double-J) stenting places a thin, flexible tube inside the ureter itself, with one coiled end sitting in the kidney and the other in the bladder, allowing urine to drain internally, bypassing the blockage, without any external tube or bag. A ureteric stent can be placed either retrogradely (via cystoscopy, through the bladder — usually performed by a urologist) or, in some situations, anterogradely — through a nephrostomy access, from the kidney down through the blockage into the bladder — which is the approach performed by interventional radiology when retrograde placement isn't possible or hasn't succeeded.
In practice, the choice between the two is guided by the severity and cause of the obstruction, whether infection is present, the patient's overall stability, and practical factors such as which service is available to act quickly. Some patients start with a PCN in the acute setting and are later converted to an internal ureteric stent once the situation has settled, or vice versa.
Infected, obstructed kidney (pyonephrosis or obstructive pyelonephritis) — fever, loin pain, and a blocked kidney together represent a urological emergency, since infection with nowhere to drain can rapidly progress to life-threatening sepsis; decompression alongside antibiotics is needed urgently, generally within hours.
Worsening kidney function due to obstruction, particularly in a patient with a single functioning kidney, or obstruction affecting both kidneys.
Severe, uncontrolled pain from an obstructing stone that hasn't responded to medical management.
Obstruction in pregnancy, where certain treatment options are limited and prompt, safe decompression is particularly important.
Planned, non-urgent drainage is also used in some situations — for instance, ahead of definitive stone treatment, or to protect kidney function in a patient with a tumour compressing the ureter, before or during cancer treatment.
Planning: ultrasound, sometimes combined with prior CT imaging, is used to select the safest access point into the swollen kidney collecting system.
Access: under local anaesthesia with sedation, a needle is guided under ultrasound into the kidney, and a small drainage catheter is advanced over a guidewire into the collecting system, confirmed with a small amount of contrast dye under X-ray.
Fixation: the catheter is secured in place with a locking mechanism at its tip inside the kidney, and connected to an external drainage bag.
Recovery: most patients are observed for a period after the procedure, and the tube is checked regularly to make sure it's draining well and hasn't become blocked or dislodged.
The procedure typically takes 20 to 45 minutes and is often performed urgently, sometimes on the same day symptoms are recognised, given how quickly an infected, obstructed kidney can deteriorate.
When a stent needs to be placed from above — for instance, when a blockage can't be crossed from below via cystoscopy — access is first gained into the kidney in the same way as for a nephrostomy. A guidewire is then carefully advanced down through the ureter, across the site of obstruction, and into the bladder, and the double-J stent is passed over this wire into its final position, with one coiled end anchored in the kidney and the other in the bladder. A temporary external drain may be left in place alongside the stent for a short period to confirm good drainage before it's removed.
A nephrostomy tube or ureteric stent is not usually intended to be permanent — it's a way of relieving the immediate obstruction while the underlying cause is treated, whether that's a stone being removed, a tumour being treated, or a stricture being addressed. Nephrostomy tubes are generally checked and changed at regular intervals if left in for a longer period, since they can become blocked, dislodged, or a source of infection over time. Ureteric stents are also typically exchanged periodically — usually every three to six months if long-term drainage is needed — since they can become encrusted or blocked with prolonged use. Your treating team will explain the specific plan for your tube or stent, including who is responsible for its removal, exchange, or the definitive treatment that follows.
Both procedures are generally safe and are considered standard, well-established treatments for obstructive uropathy. Recognised risks include bleeding, infection (or worsening of an existing infection immediately after decompression, sometimes requiring close monitoring), tube dislodgement or blockage, and, with ureteric stents specifically, some bladder irritation or discomfort while the stent is in place, which usually settles once it's removed or exchanged. These risks are discussed individually, and the choice of technique is made to balance the urgency of the situation against the safest, most appropriate route of drainage for each patient.
Because obstructive uropathy, particularly with infection, can deteriorate quickly, safe management depends on rapid access to image-guided drainage and close coordination between the emergency team, urology, and interventional radiology. Getting a nephrostomy or stent placed quickly and correctly is only the first step — the equally important part is planning what happens next: treating the underlying cause and deciding, together with the urology team, when and how the tube or stent can eventually be removed.
A nephrostomy tube drains urine externally into a bag through a tube in your back. A ureteric stent sits entirely inside the body, draining urine internally from the kidney to the bladder, with no external bag. The choice depends on your specific situation and how urgently drainage is needed.
It often is, particularly when a blocked kidney is also infected, which can become life-threatening quickly. It's also sometimes done in a planned, non-urgent way — for instance, ahead of stone treatment or to protect kidney function during cancer treatment.
It varies by the underlying cause. It's generally a temporary measure while the blockage itself is treated, though nephrostomy tubes and stents left in longer term are exchanged periodically — often every three to six months for stents — to prevent blockage or infection.
It's performed under local anaesthesia with sedation, so the procedure itself isn't painful, though some soreness at the site is common afterward. Ureteric stents can cause some bladder irritation or urinary symptoms while in place, which typically settles once the stent is removed.
Yes — both procedures are done entirely through a needle puncture under imaging guidance, without any surgical incision, which is why they're generally preferred over open surgical options for relieving obstruction.
This can be a medical emergency — call immediately, or book an urgent consultation with Dr. Giragani.