How Hydronephrosis Is Treated: Relieving the Blockage and Protecting Kidney Function

The scan was supposed to be about back pain. Instead, the radiologist’s note used a word the patient had never heard: hydronephrosis. Within an hour she was searching it on her phone in the parking lot, finding pictures of swollen kidneys and a dozen possible causes, and one very practical question kept rising to the top. What do they actually do about it?

That question, how is hydronephrosis treated, has a more reassuring answer than the images suggest. Hydronephrosis is not a disease in its own right. It is what a kidney looks like when urine cannot leave it fast enough, the way a garden hose bulges behind a kink. Treatment is therefore less about the swelling and more about finding the kink and undoing it.

Sometimes that takes a single procedure. Sometimes it takes nothing more than watching. The rest of this article walks through how clinicians decide which is which, what each option involves, and what the weeks afterward usually look like.

Why 'how is hydronephrosis treated' starts with a plumbing question

Each kidney filters blood and drips the resulting urine into a funnel-shaped chamber called the renal pelvis. From there a narrow tube, the ureter, carries it down to the bladder. When something slows or stops that flow, urine backs up, the renal pelvis stretches, and the kidney tissue around it is squeezed. That stretching is hydronephrosis. When the ureter itself is dilated too, clinicians call it hydroureter.

The distinction matters because it reframes the whole conversation. Nobody treats the swelling directly. Clinicians treat the reason urine is trapped, and the swelling follows. A kidney stone lodged in the ureter, a prostate pressing on the bladder outlet, a ureter that was narrow from birth, a pregnant uterus leaning on one side: each produces the same picture on ultrasound, and each calls for a different fix.

The other thing worth knowing early is that the kidney has a surprising amount of patience, up to a point. A partial blockage over days or weeks may cause little lasting harm once it is relieved. A complete blockage, or any blockage combined with infection, is a different matter. Trapped urine behind an obstruction is an ideal place for bacteria to multiply, and pressure plus infection can damage kidney tissue quickly. That is why urgency in treatment is driven less by how big the kidney looks and more by two questions: is the flow completely stopped, and is there an infection behind it?

Both kidneys can be affected, but usually only one is. The healthy partner keeps filtering in the meantime, which is why many people with one-sided hydronephrosis feel nothing at all and learn about it, as our patient in the parking lot did, from a scan ordered for another reason.

What is the root cause of hydronephrosis?

There is no single root cause. Hydronephrosis is a sign, and the list of things that produce it runs from the mundane to the serious. Grouping them by location helps make sense of the treatment choices that follow.

Inside the urinary tract, the classic culprit is a kidney stone that has traveled into the ureter and stuck. Blood clots and, less commonly, tumors of the ureter or bladder can lodge in the same way. In the wall of the tube itself, scarring from earlier surgery, infection, or radiation can leave a narrowed segment called a stricture. Some people are born with a tight junction where the renal pelvis meets the ureter, known as pelviureteric junction obstruction, or with a ureter that lets urine wash backward from the bladder toward the kidney, called vesicoureteral reflux.

Outside the tract, anything that presses on the ureter or the bladder outlet can do it. In men past middle age, an enlarged prostate is the most frequent example. In pregnancy, the growing uterus commonly compresses the right ureter in particular, and the hormone-driven relaxation of smooth muscle slows drainage further. Tumors in the pelvis, fibrosis behind the abdominal lining, and enlarged lymph nodes belong on the same list.

A separate group involves the nerves rather than the pipes. If the bladder cannot empty because its nerve supply is damaged, as in some spinal injuries or long-standing diabetes, urine collects, bladder pressure rises, and both kidneys can swell.

The practical point is that treatment is tailored to the location. A stone is removed or allowed to pass. A stricture is widened or repaired. A prostate is treated medically or surgically. A neurogenic bladder is drained with a catheter. Working out which category a person belongs to is the first real step, and it explains why the imaging phase, covered next, is not something to hurry past.

How is hydronephrosis treated? What actually happens, step by step

Think of treatment as four decisions made in order, sometimes within an hour, sometimes over months.

The first is triage. A clinician checks whether the person is feverish, in severe pain, unable to pass urine, or showing signs that the kidneys are struggling on blood tests. Creatinine, a waste product the kidneys normally clear, rises when filtering falls. If both kidneys are involved, or the only working kidney is blocked, that becomes an emergency regardless of how the person feels.

The second is locating the block. Ultrasound is almost always the first test because it shows the swollen renal pelvis without radiation and can be done at the bedside. A CT scan, often without contrast dye, is the workhorse for stones and for seeing structures outside the ureter. Blood and urine tests look for infection and measure kidney function. In children, and in some adults, a nuclear medicine scan measures how well each kidney drains and how much of the total work it does.

The third decision is whether to decompress, meaning to give the trapped urine a way out immediately. This is done with a thin tube placed inside the ureter, a stent, or with a tube through the skin of the back directly into the kidney, a nephrostomy. Decompression buys time and protects the kidney; it does not fix the cause.

The fourth is definitive treatment of the cause itself, which might be a stone procedure, a prostate treatment, a repair of a narrowed segment, or, in mild cases, nothing beyond scheduled follow-up scans.

What people find hardest is that these steps are not always sequential. A person arriving with a fever and a blocked, infected kidney may have step three done that same night, before anyone has finished step two. The reverse is also true: a healthy adult with mild swelling found incidentally may never need steps three or four. The framework is the same; the pace is set by risk.

Draining the kidney first: stents and nephrostomy tubes explained

Decompression is the part of treatment that feels most abrupt to patients, so it deserves a plain description.

A ureteral stent is a soft, hollow plastic tube roughly the diameter of a piece of cooked spaghetti, curled at both ends so it stays in place. A urologist passes it up through the urethra and bladder into the ureter under anesthesia or sedation, using a small camera. Once in position, one curl sits in the renal pelvis and the other in the bladder, and urine flows both through and around it, bypassing the blockage. Nothing is visible from the outside. Stents are temporary; how long one stays in depends on the plan for treating the cause, and it is removed or exchanged in a short follow-up procedure.

A nephrostomy tube takes the opposite route. A radiologist, guided by ultrasound or CT, passes a needle through the skin of the flank into the swollen renal pelvis, then threads a drainage catheter over it. The tube exits the back and connects to a bag. It is chosen when a stent cannot be passed, when the blockage is dense or infected and clinicians want the most direct drainage possible, or when a person is too unwell for the anesthesia a stent placement needs.

Both have trade-offs. Stents commonly cause bladder irritation, urgency, a burning sensation, and pinkish urine, and some people feel a dull ache in the flank when they pass urine because a small amount refluxes up the tube. Nephrostomy tubes avoid those symptoms but require dressing care, can dislodge, and carry a visible bag. Neither option is more correct in general; the choice depends on the anatomy, the infection risk, and the person in front of the team.

The point of both is time. With the pressure relieved and infection treatable, the kidney is protected while everyone works out the more considered next step.

Treating the cause: when a kidney stone is the blockage

Stones are the most common reason a previously healthy adult ends up with hydronephrosis, and stone treatment illustrates how the size, position, and situation shape the plan.

Small stones frequently pass on their own. If the pain is controlled, there is no infection, and the kidney is not severely affected, a clinician may recommend fluids, pain relief, and watchful waiting for a period, sometimes with a class of medicine called an alpha blocker, which relaxes the muscle of the ureter to ease passage. Whether that is appropriate, and for how long, is a judgment the treating team makes based on stone size on the scan and how the person is doing, so figures here are deliberately left to them.

When a stone is unlikely to pass, or when waiting is unsafe, three procedures cover most situations. Shock wave lithotripsy uses focused sound waves from outside the body to fragment the stone into pieces small enough to pass. Ureteroscopy passes a thin scope up the urethra and ureter to the stone, where it is broken with a laser and the fragments removed; a stent is often left afterward for a short period to let the irritated ureter heal. Percutaneous nephrolithotomy, used for large stones inside the kidney, reaches them through a small incision in the back.

Infection changes everything. A stone with an infected kidney behind it is treated as an emergency: the kidney is drained first, antibiotics are given, and the stone itself is dealt with only after the infection has settled. Removing a stone from an infected system can push bacteria into the bloodstream, which is why urologists resist the understandable wish to simply get it out that night.

After any stone episode, prevention becomes part of treatment. Fluid intake, dietary review, and sometimes stone analysis help reduce the chance of repeating the whole sequence.

Treating the cause: prostate, strictures, reflux, pregnancy, and cancer

When the block is not a stone, treatment follows the anatomy just as closely.

An enlarged prostate, medically benign prostatic hyperplasia, obstructs the bladder outlet, so the bladder fills, pressure rises, and eventually both kidneys can swell. The immediate fix is a bladder catheter to drain the retained urine. Longer term, medicines that relax the prostate’s muscle or gradually shrink the gland, or a procedure to open the channel through it, address the cause. Which route suits a particular person depends on symptoms, kidney function, and other health conditions, and belongs with the urologist.

A ureteral stricture, a scarred narrow segment, may be stretched with a balloon, held open with a stent, or surgically removed with the healthy ends rejoined. Pelviureteric junction obstruction, the congenital narrowing at the top of the ureter, is often repaired with an operation called pyeloplasty, in which the tight segment is cut out and the pelvis is reconnected to the ureter with a wider join. Many of these are now done through keyhole or robot-assisted approaches.

Vesicoureteral reflux, the backwash of urine toward the kidney, is treated differently because the problem is a faulty valve rather than a block. Mild reflux in children is often watched, sometimes with low-dose preventive antibiotics to reduce kidney infections, and many children outgrow it. Persistent or severe reflux can be corrected with an injection at the ureter opening or by reimplanting the ureter into the bladder.

Hydronephrosis in pregnancy is usually mild, more common on the right, and resolves after delivery. It is treated only if there is infection, severe pain, or worsening kidney function, in which case a stent or nephrostomy can be placed safely.

When a tumor is the cause, relieving the obstruction with a stent or nephrostomy runs alongside cancer treatment rather than replacing it.

Who is treated right away, and who is usually asked to wait

Patients often assume that a swollen kidney on a scan automatically means a procedure. It does not, and understanding how clinicians sort urgency can spare a lot of worry.

Immediate treatment, typically within hours, is reserved for a specific set of situations. Fever or other signs of infection with an obstructed kidney is the clearest. A blockage affecting both kidneys, or a person’s only functioning kidney, is another, because there is no healthy partner to compensate and waste products build quickly. Pain that cannot be controlled, vomiting that prevents fluids from staying down, and blood tests showing a sharp fall in kidney function all move someone into the same category.

A second group is treated promptly but not urgently: over days to a few weeks. This includes people with a stone too large to pass, a stricture causing moderate swelling with stable kidney function, or a prostate causing retention that a catheter has relieved for now. Here the team has room to complete imaging, discuss options, and schedule the definitive procedure.

The third group, often larger than people expect, is asked to wait and be watched. Mild hydronephrosis found by chance in an adult who feels well, with normal kidney function and no infection, may simply be rechecked with ultrasound after an interval. Babies with mild antenatal hydronephrosis fall here too; a large proportion improve without intervention, as discussed later. Pregnant women with uncomplicated swelling are usually monitored until after delivery.

Waiting is an active decision, not neglect. It comes with a plan: a date for the next scan, a threshold for acting, and clear instructions on what symptoms should bring the person back sooner. If any of those three elements is missing, it is entirely reasonable to ask for them.

Hydronephrosis treatment options compared

The table below is a map, not a menu. It summarizes what each approach does, when it tends to be chosen, and the trade-offs patients most often ask about. The right combination for one person may include none of these or several in sequence.

Approach	What it does	Typically chosen when	Common trade-offs
Watchful waiting with repeat imaging	Monitors swelling and kidney function over time	Mild swelling, no infection, stable function; many infants; uncomplicated pregnancy	Requires reliable follow-up; small risk the picture changes between scans
Bladder catheter	Drains a bladder that cannot empty	Prostate enlargement, neurogenic bladder, urinary retention	Infection risk with long-term use; does not treat the cause
Ureteral stent	Internal tube bypasses a ureteral block	Stones, strictures, external compression; before or after stone surgery	Bladder irritation, urgency, flank ache; must be removed or exchanged
Nephrostomy tube	External drain placed through the back into the kidney	Stent cannot be passed; infected obstructed kidney; person too unwell for anesthesia	External bag and dressing care; tube can dislodge
Stone procedures (lithotripsy, ureteroscopy, percutaneous removal)	Fragment or remove the stone	Stone unlikely to pass or causing complications	Procedure-specific risks; temporary stent often needed
Reconstructive surgery (pyeloplasty, stricture repair, ureteral reimplantation)	Rebuilds the narrowed or refluxing segment	Congenital narrowing, persistent stricture, significant reflux	General anesthesia; recovery period; small risk of re-narrowing
Treating the external cause (prostate therapy, cancer treatment)	Removes the pressure on the urinary tract	Prostate enlargement, pelvic tumors	Timeline depends on the underlying condition

Two patterns in the table are worth noticing. Drainage options appear in the middle rows because they are bridges rather than destinations. And reconstructive surgery appears last because it is the least common path, reserved for anatomy that will not improve on its own.

What the days and weeks after treatment usually look like

Recovery depends on what was done, but a few experiences are common enough to describe.

After a stent is placed, the first few days often bring urgency, a sense of needing to pass urine frequently, mild burning, and urine tinged pink. A dull ache in the flank while urinating is typical and reflects a small amount of urine traveling back up the stent. These symptoms usually ease as the bladder adjusts, though some people find them bothersome for the stent’s entire stay. Stents are removed in a brief clinic or day-case procedure; the date should be written down, because a forgotten stent can become encrusted with mineral deposits and turn into a problem of its own.

After a nephrostomy, the site needs to stay clean and dry, the bag emptied regularly, and the tube secured to prevent pulling. Patients or family members are taught the routine before going home. Clear or pale urine in the bag is expected; the team will say what changes should prompt a call.

When a blockage that has been present for a while is suddenly relieved, the kidney can produce very large volumes of urine for a day or two, a phenomenon called post-obstructive diuresis. In hospital this is managed with fluid and electrolyte monitoring; it is one reason people with severe or two-sided obstruction are kept in rather than sent home the same day.

After stone or reconstructive surgery, the pattern is more like any minor or moderate operation: soreness at incision sites or in the flank, fatigue, and a gradual return to normal activity over one to several weeks depending on the approach. Follow-up imaging, usually ultrasound, checks that the swelling is settling and that the repair or the stone clearance has held.

Blood tests for kidney function are often repeated. Improvement is common but not guaranteed; a kidney that was obstructed for a long time may recover only partially, which is why treating promptly matters more than treating aggressively.

Does hydronephrosis go away? An honest answer

Often, yes. Whether it does depends on why it was there and how long it lasted.

When a stone passes or is removed, the swelling behind it typically settles over days to weeks as the kidney drains normally again. The same is true after a stricture is repaired or a stent relieves external compression. Pregnancy-related hydronephrosis nearly always resolves after delivery once the uterus shrinks and hormone levels fall. In babies, mild antenatal hydronephrosis frequently improves on its own as the urinary tract matures.

Where the answer becomes more nuanced is in three situations. First, a kidney that has been severely and completely obstructed for a long time may remain somewhat dilated even after the block is gone, because stretched tissue does not always spring back fully. On a scan this can look alarming, yet the kidney may be draining perfectly well. Clinicians distinguish between a dilated but draining kidney and a truly obstructed one using drainage studies, and the first needs no further treatment.

Second, some causes are ongoing. A neurogenic bladder or an inoperable pelvic tumor may need long-term drainage, with stents exchanged at intervals or a permanent catheter. The hydronephrosis is controlled rather than eliminated.

Third, function and appearance are separate questions. The swelling can resolve while the kidney has lost some filtering capacity, or the kidney can remain slightly dilated with function intact. A kidney that has lost most of its function and causes recurrent infection or pain is occasionally removed, though this is uncommon and always a last resort after other options.

So when someone asks whether it goes away, the useful reply is: the swelling usually does once the cause is dealt with, and the earlier that happens the more likely the kidney’s function is preserved. Anyone told their hydronephrosis is being monitored should ask which of these three situations applies to them.

What are the three stages of hydronephrosis, and do they change treatment?

People search for three stages because reports often describe hydronephrosis as mild, moderate, or severe. Behind those words is a grading system based on how much the renal pelvis and its branches, the calyces, are stretched, and how thin the kidney tissue has become.

In mild hydronephrosis, the renal pelvis is a little widened but the calyces look normal and the kidney tissue is full thickness. In moderate hydronephrosis, the calyces are visibly dilated and rounded, though the tissue is still preserved. In severe hydronephrosis, the calyces are ballooned, the pelvis is large, and the surrounding tissue is thinned because it has been compressed against the kidney’s outer edge. Pediatric radiologists often use a four-grade scale from the Society for Fetal Urology that separates these further, which is why a parent may hear a number rather than a word.

Does the grade dictate treatment? Less than most people assume. Grade describes the anatomy at one moment; it does not say how fast the problem developed, whether infection is present, or how well the kidney is actually working. A mild grade with a fever can be more urgent than a severe grade in a stable, pain-free adult with a chronic narrowing. Severe swelling that has been present since birth and is stable on repeated scans may still be watched, whereas a moderate grade that is worsening between scans may prompt surgery.

Where grade earns its keep is in follow-up. Comparing the same kidney over time tells clinicians whether the situation is improving, stable, or progressing, and that trajectory is one of the strongest signals for or against intervention. It also helps in babies, where higher grades are more likely to have an underlying obstruction that needs treatment and lower grades more likely to resolve.

If a report says severe, it is fair to feel concerned, but the questions that matter are about function, infection, and trend, not the label alone.

Hydronephrosis in babies: pathway, comfort, and what parents can expect

Antenatal hydronephrosis, swelling seen on a pregnancy ultrasound, is one of the more common findings during routine scans; the NHS notes it is thought to affect around 1 in every 100 pregnancies. For most families, the pathway is watchful and the outcome reassuring.

After birth, the baby usually has a repeat ultrasound within the first days to weeks. Scanning too early can underestimate the swelling because newborns are relatively dehydrated at first, so the timing is deliberate. If the swelling has resolved or is mild, follow-up scans at intervals are typically all that is needed. Some clinicians prescribe a low-dose preventive antibiotic for certain babies while the picture clarifies, to reduce the chance of a kidney infection; that decision, and any details about the medicine, sit with the pediatric team.

If swelling is moderate or severe, or on both sides, further tests follow. A voiding cystourethrogram introduces contrast into the bladder through a small catheter and takes X-rays as the baby urinates, to look for reflux. A nuclear medicine renal scan measures each kidney’s share of the work and how quickly it drains. These tests are uncomfortable rather than painful, and parents are usually able to stay with the baby.

Surgery is reserved for the minority with a proven obstruction and declining function, most often pyeloplasty for pelviureteric junction obstruction or, in boys with posterior urethral valves, a procedure to open the obstructing tissue in the urethra. The NIH’s kidney institute describes most cases of hydronephrosis in newborns as mild and likely to improve without treatment.

Comfort matters throughout. Feeding on schedule, keeping the baby warm, and bringing a familiar object to scans all help. Parents often report that the hardest part is the waiting between ultrasounds; asking the team exactly what each scan will decide can make that waiting feel purposeful.

What people often get wrong about hydronephrosis treatment

Some misunderstandings come up so reliably that they are worth addressing directly.

The first is that a swollen kidney is a damaged kidney. Dilation and damage are different things. A kidney can be visibly stretched and still filter normally, particularly if the obstruction is partial or recent. Function is assessed by blood tests and drainage scans, not by how large the pelvis looks.

The second is that drinking more water will flush out the blockage. For a small stone that is already moving, fluids help. For a stricture, an enlarged prostate, or a stone wedged tight, extra fluid simply adds to the pressure behind the block. Fluid advice should come from the team, not from a general rule.

The third is that a stent is the treatment. It is a bridge. People sometimes feel better once the stent is in and assume the problem is solved, then miss the appointment to deal with the cause or to remove the stent. Forgotten stents can encrust and become a blockage in their own right.

The fourth is that antibiotics alone will clear an infected, obstructed kidney. They cannot reach trapped urine effectively, and the pressure remains. Drainage plus antibiotics is the standard; antibiotics alone in that setting is unsafe.

The fifth is that hydronephrosis in a baby means surgery is inevitable. Most infants with mild swelling are simply monitored, and many improve as they grow.

The sixth, and perhaps the most important, is that no pain means no problem. A slowly developing blockage can be painless precisely because the pressure rises gradually. Painless hydronephrosis found incidentally still deserves a proper assessment of cause and function, because it is the silent, chronic cases that are most likely to have quietly cost kidney tissue by the time they are found.

Questions to ask your care team

Consultations about hydronephrosis often move quickly, especially if a procedure is being arranged. A short list of questions, written down beforehand, tends to produce a clearer plan than trying to remember everything in the room.

• What is causing the blockage in my case, and how confident are you about that?
• Is one kidney affected or both, and how is my overall kidney function right now?
• Is there any sign of infection, and does that change how urgently we need to act?
• Do I need drainage now, or is it safe to treat the cause directly?
• If a stent or nephrostomy is planned, how long is it expected to stay, and when exactly will it be removed or exchanged?
• What are the options for treating the underlying cause, and what are the trade-offs of each for someone in my situation?
• If we are watching rather than treating, what will the next scan decide, when is it, and what symptoms should bring me back sooner?
• What is the chance my kidney has already lost some function, and can that recover?
• Which of my current medicines, if any, need to be reviewed because of my kidney function? Decisions about changing them rest with you and my prescriber.
• Who do I contact, and how, if something changes in the evening or on a weekend?

Two of these deserve special emphasis. The stent removal date is the single most frequently lost piece of information in this whole journey, and writing it down in more than one place is a small act that prevents a real problem. And the question about what the next scan will decide turns a vague period of monitoring into a plan with a purpose. Teams generally welcome both questions; they signal a patient who is a partner in the process.

When to call your doctor: red-flag signs during hydronephrosis treatment

Most people being treated or monitored for hydronephrosis do well, but a few developments should not wait for the next scheduled appointment. If any of the following occur, contact the care team the same day, or seek emergency care if the team cannot be reached.

• Fever, chills, or shaking, particularly with flank or back pain. This can signal infection behind a blockage, which needs urgent drainage and antibiotics.
• Pain in the side or back that becomes severe, is not controlled by the pain relief you were given, or is accompanied by repeated vomiting.
• Passing very little or no urine over several hours, or a sudden drop in the volume draining into a nephrostomy bag.
• Urine that becomes heavily blood-stained, contains clots, or turns cloudy and foul-smelling. A light pink tinge with a stent is common; frank blood is not.
• A nephrostomy tube that has pulled out, is leaking around the site, or has a dressing that is soaked or shows spreading redness.
• New swelling of the legs, breathlessness, confusion, or extreme drowsiness, which can accompany a sharp fall in kidney function.
• Feeling generally and rapidly more unwell than you were, even without a specific symptom you can name.

Anyone with an obstructed kidney who develops a fever should be seen urgently rather than waiting to see whether it settles. Infection under pressure can progress to a bloodstream infection quickly, and the combination is treated as an emergency in every guideline.

Between appointments, less dramatic changes still merit a phone call: gradually worsening ache, a stent removal date that has passed, or new symptoms of urinary retention such as straining and dribbling. None of these are reasons for panic, but each is a reason for the team to reassess. Every decision about what to do next, from adjusting a plan to bringing forward a procedure, rests with the clinicians who know the full picture.

Frequently asked questions

How is hydronephrosis treated in adults?

By relieving the blockage and treating what caused it. If the kidney is infected, severely obstructed, or losing function, doctors drain it first with a ureteral stent or a nephrostomy tube. Then the cause is addressed: stones are passed or removed, an enlarged prostate is treated, a narrowed ureter is widened or repaired. Mild cases with normal function are often monitored with repeat ultrasounds.

Does hydronephrosis go away on its own?

Sometimes. Swelling caused by a small stone that passes, by pregnancy, or by mild congenital dilation in a baby often resolves without treatment. Swelling from a fixed narrowing, an enlarged prostate, or a stone that will not pass usually persists until the cause is treated. Follow-up imaging tells the team which situation applies.

What are the three stages of hydronephrosis?

Reports describe mild, moderate, and severe hydronephrosis based on how stretched the renal pelvis and calyces are and whether the kidney tissue has thinned. Pediatric teams often use a four-grade scale instead. The grade helps track change over time, but urgency of treatment depends more on infection, kidney function, and whether one or both kidneys are involved.

What is the root cause of hydronephrosis?

Anything that stops urine leaving the kidney normally. Common causes include kidney stones lodged in the ureter, an enlarged prostate, scarring or congenital narrowing of the ureter, vesicoureteral reflux, pressure from a pregnant uterus or a tumor, and bladders that cannot empty because of nerve damage. Identifying which one applies is the first step in treatment.

What are the first signs of hydronephrosis?

Often there are none, and the swelling is found on a scan done for another reason. When symptoms occur, they commonly include aching or sharp pain in the side or back, needing to urinate more often or urgently, difficulty passing urine, nausea, and blood in the urine. Fever alongside these signs suggests infection and needs urgent assessment rather than self-diagnosis.

What are the main hydronephrosis treatment options?

Watchful waiting with repeat imaging, a bladder catheter for retention, a ureteral stent or nephrostomy tube to drain the kidney, stone procedures such as lithotripsy or ureteroscopy, reconstructive surgery like pyeloplasty for congenital narrowing, and treatment of external causes such as prostate enlargement. Most people need only one or two of these, chosen by the treating team.

How long does a ureteral stent stay in for hydronephrosis?

It depends on why it was placed. A stent left after stone surgery is typically short-term, while one bridging to a planned operation stays until that surgery. Stents used for ongoing compression are exchanged at intervals set by the urologist. The removal or exchange date should always be confirmed in writing, because a forgotten stent can encrust and cause problems.

Is hydronephrosis in babies serious?

Usually not. Most cases seen on pregnancy scans are mild and improve on their own as the urinary tract matures, according to the NIH’s kidney institute. Babies have a repeat ultrasound after birth and further tests only if swelling is moderate, severe, or on both sides. Surgery is reserved for the minority with a proven obstruction and declining kidney function.

Can hydronephrosis cause permanent kidney damage?

It can if a complete blockage, or a blockage with infection, is left untreated for long enough, because sustained pressure compresses and thins the filtering tissue. Partial or short-lived obstruction relieved promptly usually leaves function intact. This is why teams prioritize timely drainage in high-risk cases and why painless, incidentally found hydronephrosis still deserves a full assessment.

Can I treat hydronephrosis at home by drinking more water?

Not as a substitute for medical treatment. Fluids can help a small, already moving stone to pass, but they add pressure behind a fixed narrowing, an enlarged prostate, or a wedged stone. Fluid advice should come from the treating team based on the cause. Any fever, severe pain, or reduced urine output needs prompt medical care rather than home measures.

References

• NHS: Hydronephrosis
• Cleveland Clinic: Hydronephrosis (Kidney Swelling)
• MedlinePlus: Hydronephrosis of one kidney
• NIH NIDDK: Hydronephrosis in Newborns

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.