Does Every Case of Hydronephrosis Need a Procedure? When Monitoring Is the Plan

The ultrasound report arrives in the patient portal before the appointment does. One word is underlined: hydronephrosis. By the time the phone call comes, most people have already read that the kidney is “swollen” and have quietly started planning for surgery. Then the urologist says something unexpected: let’s look again in a few weeks.

That gap between what the word sounds like and what it often means is the reason this article exists. Does hydronephrosis need treatment? Sometimes urgently, sometimes never. The swelling is a sign, not a diagnosis, and the right response depends on what is causing it, how long it has been there, and whether the kidney is actually struggling.

Monitoring is not the same as doing nothing. It is a deliberate plan with scheduled scans, specific thresholds and a clear list of reasons to move faster. Understanding that plan makes the wait considerably easier to live with.

Does hydronephrosis need treatment every time? Start with what the word means

Hydronephrosis describes a kidney whose internal drainage system has stretched because urine is not flowing out as freely as it flows in. The kidney makes urine continuously, roughly a liter and a half a day in a healthy adult, and that fluid collects in a funnel called the renal pelvis before traveling down the ureter, the narrow tube that connects each kidney to the bladder. Slow the outflow anywhere along that route and pressure backs up, widening the funnel like a balloon being filled through a pinched straw.

The important point, and the one that most consumer websites rush past, is that the ultrasound only shows the stretch. It does not show why the stretch happened. A kidney stone lodged in the ureter, a narrow segment a baby was born with, an enlarged prostate pressing on the bladder outlet, a pregnancy pushing on the ureter, or scarring from an old infection can all produce the same picture on a screen.

Whether hydronephrosis needs treatment therefore hinges on three questions the care team works through in order. Is there a true obstruction, or simply a wide drainage system that empties normally? Is the kidney losing function, measured by blood tests and sometimes a nuclear medicine scan? And is there an immediate threat such as infection trapped behind the blockage? The NHS describes exactly this logic: treatment depends on the cause and severity, and some people need no specific treatment beyond monitoring.

Think of it the way you would think of a swollen ankle. Swelling after a long flight and swelling after a fall look similar from across the room, but one is watched and the other is imaged, splinted or operated on. Hydronephrosis works the same way.

What actually happens inside a swollen kidney

Picture the kidney as a filtration plant with a drain. Blood enters, waste and excess water leave as urine, and the urine funnels into the renal pelvis. In a healthy system the pressure in that funnel stays low because urine leaves as quickly as it arrives. When outflow slows, pressure rises, and the soft tissue of the pelvis and the cup-shaped calyces around it begin to expand.

For a short time, the kidney copes. It can tolerate modest pressure for days to weeks without permanent harm, which is why a stone that passes within a couple of weeks usually leaves no lasting mark. The problem comes with sustained, high-pressure obstruction. Rising pressure squeezes the tiny blood vessels and filtering units within the kidney’s working tissue, known as the parenchyma. Blood flow falls, filtration slows, and if the squeeze continues, the parenchyma thins. Johns Hopkins notes that untreated obstruction can lead to permanent loss of kidney function on the affected side.

Two features make the picture more or less worrying. The first is whether the obstruction is complete or partial. A partial narrowing often lets enough urine through to keep the kidney healthy indefinitely, which is why many congenital cases never need an operation. The second is time. A kidney blocked for a few days behaves very differently from one blocked for months.

There is also the question of infection. Stagnant urine behind a blockage is an ideal environment for bacteria, and an infected obstructed kidney is one of the few genuine emergencies in this story. Mayo Clinic and the NHS both describe fever with flank pain in someone with known hydronephrosis as a reason for same-day assessment. Everything else in this article sits below that line.

How is mild hydronephrosis treated? Often by watching it carefully

Mild hydronephrosis treatment frequently consists of a follow-up appointment and another ultrasound. That can feel anticlimactic, but it reflects what the evidence shows. The NHS states plainly that mild cases, particularly in babies and during pregnancy, often get better without treatment, and that the main aim in adults is to find and address whatever is causing the problem rather than to treat the swelling itself.

“Mild” on a radiology report usually means the renal pelvis is slightly widened but the calyces and the kidney tissue look normal. The kidney is doing its job; it simply has a roomier funnel. A single ultrasound cannot tell the team whether that roominess is new, old, stable or progressing, so the first step is a second ultrasound to establish direction of travel. Cleveland Clinic describes this repeat-imaging approach as standard for low-grade findings.

When monitoring is the plan, the visit still has substance. A clinician will typically:

• Check kidney function with a blood test, often creatinine, a waste product that rises when filtration falls.
• Test the urine for blood, protein or signs of infection.
• Ask about pain, fever, urinary symptoms and any history of stones or surgery.
• Decide on an interval for the next scan, commonly weeks to a few months depending on the cause.

If the cause is already obvious and self-limiting, such as a small stone that has moved on or a pregnancy that is progressing normally, the plan may simply be to confirm resolution once. If the cause is unclear, additional imaging such as a CT scan or a nuclear medicine drainage study may be added before any procedure is discussed. Treatment of mild hydronephrosis, in other words, is mostly treatment of the question behind it.

What does grade 4 hydronephrosis mean, and does the grade decide the plan?

Radiologists grade hydronephrosis so that scans taken months apart can be compared consistently. The most widely used scale in children runs from grade 1 to grade 4, and the same descriptive language, mild, moderate and severe, is used in adults.

Grade 1 means the renal pelvis is slightly widened with everything else normal. Grade 2 adds mild widening of the calyces. Grade 3 means the pelvis and calyces are clearly dilated but the kidney tissue still looks full thickness. Grade 4 hydronephrosis means the drainage system is markedly dilated and the parenchyma, the working tissue, has visibly thinned. Cleveland Clinic summarizes grade 4 as severe swelling with thinning of the kidney, which is why it attracts more attention and a shorter follow-up interval.

Here is the nuance worth holding onto: grade describes appearance, not destiny. A grade 4 kidney in a newborn may have thinned because of months of pressure before birth, yet still drain adequately and keep its function once measured properly. Conversely, a grade 2 kidney with a complete fresh blockage from a stone can be in more immediate trouble than a long-standing grade 3 that has reached a stable equilibrium.

So the grade raises or lowers the threshold for action rather than deciding it. Higher grades generally prompt the team to measure function directly, usually with a nuclear medicine renogram, a scan that tracks a tracer through each kidney to show how much work each side is doing and how quickly it empties. If function is preserved and drainage is adequate, even severe-looking hydronephrosis can be monitored. If function is falling on repeat scans, that trend, not the grade alone, is what tips the decision toward a procedure.

What are the most common causes of congenital hydronephrosis in newborns?

Hydronephrosis in newborns causes understandable worry because it is usually spotted on a routine pregnancy ultrasound, long before the baby can be examined. It is also common. The NHS reports that antenatal hydronephrosis is found in around 1 in every 100 pregnancies, and that in most of those cases the swelling settles before birth or in the first months of life without any treatment.

The most frequent explanation is transient or physiological dilation, meaning the drainage system is simply a little wide while the baby’s urinary tract matures. Among true structural causes, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) lists several that account for most of the remainder:

• Ureteropelvic junction obstruction: a narrowing where the renal pelvis joins the ureter, the single most common surgical cause.
• Vesicoureteral reflux: urine flowing backward from the bladder up the ureter, which stretches the system from below rather than blocking it from above; many children outgrow it.
• Ureterovesical junction obstruction: narrowing where the ureter enters the bladder.
• Posterior urethral valves: extra tissue flaps in the urethra of boys that obstruct bladder emptying and affect both kidneys.
• Ureterocele: a balloon-like swelling at the lower end of the ureter.

Reflux and ureteropelvic junction narrowing behave very differently from posterior urethral valves. The first two are often mild, one-sided and watched for months or years. Valves affect both kidneys and the bladder and are usually treated soon after birth. That difference explains why two families given the same word, hydronephrosis, can be given completely different plans in the same clinic on the same afternoon.

Hydronephrosis in babies: what the monitoring pathway looks like after birth

A newborn with antenatal hydronephrosis usually goes home on an ordinary schedule. What changes is the calendar of scans. NIDDK explains that the first ultrasound after birth is often delayed by several days because newborns produce little urine in the first 48 hours, which can make a genuinely dilated kidney look deceptively normal. Scanning too early risks a false reassurance.

From there, the pathway branches on severity and side. A mild one-sided finding typically gets a repeat ultrasound within weeks to a few months, then at lengthening intervals if stable. A moderate or severe finding, or any finding in both kidneys, usually prompts further tests. These commonly include a voiding cystourethrogram, an X-ray study with contrast placed in the bladder to look for reflux, and a renogram to measure how each kidney drains and how much it contributes. The NHS notes that some babies are also prescribed a low-dose preventive antibiotic while the picture is clarified; that decision, and its duration, rests with the pediatric team.

Parents often ask what they should watch for at home. The honest answer is that most monitored babies feed, grow and wet diapers normally, and the kidney does its work quietly. The signs that matter are the ones that suggest infection: fever without an obvious cause, unusual irritability, poor feeding, or foul-smelling urine. Any of these warrant a same-day call.

Surgery, when it is needed, is most often a pyeloplasty, an operation that removes a narrowed junction and reconnects the ureter to the renal pelvis. It is usually planned rather than urgent, scheduled once scans show that drainage is worsening or function is falling, and the timing is individualized by the surgical team rather than fixed by age.

What are the treatment options for a blocked kidney in adults?

Blocked kidney treatment options in adults fall into two groups: relieving pressure now, and fixing the underlying cause later. They are not always both needed, and they are rarely needed at the same moment.

Relieving pressure is reserved for kidneys that are infected, in severe pain that cannot be controlled, failing on blood tests, or obstructed on both sides. The NHS describes three tools. A urinary catheter drains the bladder when the blockage is at the bladder outlet, for example from an enlarged prostate. A ureteric stent, a thin flexible tube passed through the bladder and up the ureter, holds the channel open from the inside. A nephrostomy, a small tube placed through the skin of the back directly into the kidney, drains urine externally when a stent cannot be placed or infection makes the kidney too fragile to instrument from below.

Fixing the cause depends entirely on what the cause is. Kidney stones may pass on their own, be broken up with shock waves from outside the body, or be removed through a thin telescope passed up the ureter. NIDDK notes that whether a stone passes depends on its size and position, which is why small stones are often watched with pain control and fluids while larger or stuck stones are treated. An enlarged prostate may be managed with medicines that relax or shrink the gland, or with surgery. A scarred or narrowed ureter may be repaired. Tumors pressing on the ureter are managed within cancer care.

The framing that helps most people is this: a stent or nephrostomy is a bridge, not a destination. It buys the kidney time and safety while the team decides on, or recovers from, definitive treatment. Many adults with mild hydronephrosis and a clear, resolving cause cross no bridge at all.

Who is usually asked to wait, and who is usually treated promptly

Clinicians do not have a single cutoff for action, but their decisions cluster around recognizable profiles. Monitoring is the usual first plan when:

• The hydronephrosis is mild to moderate and on one side only.
• The other kidney is healthy and overall kidney function is normal.
• The likely cause is self-limiting: pregnancy, a small stone that is moving, or antenatal dilation in a baby.
• There is no infection, no uncontrolled pain, and no bleeding.
• A drainage study shows the kidney empties adequately despite looking wide.

Prompt treatment, meaning drainage within hours to days, is usually advised when the opposite is true. The NHS and Mayo Clinic both describe infection behind an obstruction, obstruction of a solitary or both kidneys, and rising creatinine as situations that should not wait. Severe pain that does not respond to medicines, or a stone that has not moved after a reasonable interval, also tips the balance.

Between those poles sits a large group of people for whom the plan is scheduled rather than urgent: a known ureteropelvic junction narrowing with slowly worsening drainage, an enlarged prostate causing recurring retention, or a stricture after previous surgery. For them the question is not whether to intervene but when, and that timing is a conversation about symptoms, test trends and personal circumstances.

Age matters less than people assume. A fit 80-year-old with a solitary obstructed kidney will be drained quickly; a healthy infant with grade 2 one-sided hydronephrosis will be watched for a year or more. The deciding factors are function, bilaterality, infection and trajectory, and the treating team weighs all four at each visit.

Monitoring versus a procedure: a side-by-side summary

The table below pulls the threads together. It is a general orientation drawn from NHS, Cleveland Clinic and NIDDK descriptions, not a decision tool; the team caring for you or your child will weigh factors that no table can hold.

Feature	Monitoring is commonly the plan	A procedure is commonly discussed
Grade on ultrasound	Mild to moderate, stable on repeat scans	Severe, or worsening between scans
Which kidneys	One side, other kidney normal	Both sides, or a solitary kidney
Kidney function tests	Normal and stable	Rising creatinine or falling function on renogram
Infection	None	Fever or urine infection with obstruction: urgent
Pain	Absent or controlled	Severe and not responding to medicines
Likely cause	Pregnancy, small passing stone, antenatal dilation, reflux that may resolve	Fixed narrowing, large or stuck stone, bladder outlet obstruction, tumor
Typical next step	Repeat ultrasound in weeks to months	Stent, nephrostomy, catheter, or definitive surgery

Two things are worth saying about this layout. First, a single row rarely decides anything on its own; a severe grade with normal function and no symptoms may still be monitored, while a mild grade with infection is treated the same day. Second, the columns are not permanent. People move from left to right when scans change, and occasionally from right to left when a stent has done its job and the underlying cause has resolved. The plan is revisited at every appointment, which is why keeping those appointments matters more than memorizing the categories.

What the following weeks usually look like when monitoring is the plan

The first stretch of monitoring is mostly about establishing a baseline. For an adult with newly found mild hydronephrosis and no clear cause, that often means a repeat ultrasound and blood test within a few weeks, sometimes with a CT scan in between to look for stones or other structural explanations. If the second scan matches the first and function is normal, the interval stretches, commonly to several months, and then longer still if nothing changes. Cleveland Clinic describes this lengthening cadence as typical for stable, low-grade findings.

For a stone, the timeline is shorter and more active. Many small stones pass within days to a few weeks, and the team will usually ask you to drink enough to keep urine pale, take the pain relief they have prescribed, and sometimes strain urine to catch the stone for analysis. NIDDK notes that a stone which has not passed after a reasonable period, or that causes uncontrolled pain, fever or worsening hydronephrosis, is generally treated rather than watched further.

Babies follow their own rhythm, described earlier: an early ultrasound after the first few days, further tests if the finding is moderate or bilateral, and otherwise a scan every few months through the first year or two.

Day to day, most monitored people feel ordinary, and that is precisely the point. There is no special diet for hydronephrosis itself, although people with stones may be given specific advice based on stone type. Normal activity is usually fine. What the team asks is that symptoms be reported promptly rather than saved for the next scheduled visit, because the plan is built on the assumption that silence means stability. A new fever, new flank pain or a sudden drop in how much urine you pass changes the plan immediately.

Does hydronephrosis need treatment during pregnancy?

Hydronephrosis during pregnancy is so common that many obstetric and radiology services consider mild cases a normal finding rather than a diagnosis. Two mechanisms are at work. Pregnancy hormones relax the smooth muscle of the ureter, so it carries urine less briskly, and the growing uterus presses on the ureters where they cross the pelvic brim. The right side is affected more often than the left because of how the uterus tends to rotate. The NHS describes pregnancy-related hydronephrosis as a condition that typically resolves after the baby is born and usually requires no treatment.

Monitoring is therefore the default. Clinicians look for the same exceptions they look for elsewhere: pain that cannot be controlled, a urinary infection that does not settle, worsening kidney function on blood tests, or a stone that is clearly obstructing rather than hormones alone. In those uncommon situations a ureteric stent or nephrostomy can be placed during pregnancy to protect the kidney until delivery, with definitive treatment of any stone deferred until afterward where possible.

Two questions come up repeatedly in clinic. Will it affect the baby? Simple pregnancy-related hydronephrosis without infection or kidney failure is not known to harm the baby, and the pregnancy is managed normally. Will it come back next time? It frequently does, for the same anatomical reasons, and that is expected rather than worrying.

Imaging choices are also adjusted. Ultrasound is the first-line test because it involves no radiation, and the team will weigh the need for any further imaging against the stage of pregnancy. If you are pregnant and told you have hydronephrosis, the most useful question to ask is simply: is this the usual pregnancy kind, or something you think needs a closer look?

Bilateral versus unilateral hydronephrosis: why both sides change the calculus

One healthy kidney can do the work of two. That biological spare capacity is the quiet reason monitoring is so often reasonable for one-sided hydronephrosis: even if the affected kidney underperforms for a while, overall filtration and blood chemistry stay normal, and the team has time to investigate calmly.

Bilateral hydronephrosis removes that cushion. When both kidneys are backed up, the cause usually sits below them, at the bladder or urethra, rather than in one ureter. MedlinePlus lists the typical culprits: an enlarged prostate blocking the bladder outlet, a bladder that does not empty because of nerve damage, posterior urethral valves in baby boys, scarring or tumors in the pelvis, and, in pregnancy, the uterus itself. Because the whole urinary output is affected, kidney function can fall quickly, and MedlinePlus notes that bilateral obstruction can lead to acute kidney injury if not relieved.

The practical consequence is a lower threshold for action. A bladder outlet obstruction is often relieved promptly with a catheter, which alone can let both kidneys recover. The urologist then addresses the prostate or bladder problem on a planned basis. In babies with suspected posterior urethral valves, drainage and early assessment are standard rather than the months of watchful waiting used for one-sided findings.

None of this means bilateral always equals surgery. Mild bilateral dilation in pregnancy is still watched, and some adults with mild bilateral hydronephrosis from a long-standing bladder problem are managed with catheterization and medicines rather than an operation. The difference is tempo. One-sided hydronephrosis lets the team ask “why” at leisure; two-sided hydronephrosis makes them ask “is function safe today” first and “why” second.

What people often get wrong about hydronephrosis

The first misunderstanding is that a swollen kidney is a damaged kidney. Swelling means pressure, and pressure over time can cause damage, but a kidney with a wide drainage system and normal function on a renogram is not injured; it is simply shaped differently. Many people, and many children, live their whole lives with a dilated renal pelvis that never causes harm.

The second is that hydronephrosis is a disease that medicines can treat directly. There is no tablet that shrinks a stretched renal pelvis. Medicines play supporting roles: pain relief and sometimes agents that relax the ureter during stone passage, antibiotics when infection is present, prostate medicines when the bladder outlet is the problem, and preventive antibiotics in selected infants. Each targets a cause or a complication, and each is a decision for the prescribing clinician.

The third is that a higher grade means surgery is inevitable. As discussed, grade describes appearance. Function and trajectory decide the plan, and a severe-looking kidney that drains well can be monitored for years.

The fourth is the opposite error: that monitoring means the problem is trivial and appointments are optional. Monitoring works only if scans happen on schedule and symptoms are reported. A kidney that is quietly losing function does not announce itself with pain, which is why the blood tests and renograms exist.

The fifth is that drinking large amounts of water will “flush” the blockage. Adequate hydration matters for stones, but flooding an obstructed kidney raises pressure rather than clearing the obstruction. Follow the fluid advice you were actually given.

Finally, antenatal hydronephrosis is not a verdict on the pregnancy. The NHS figure of around 1 in 100 pregnancies, with most resolving without treatment, is the statistic to keep in mind when the scan report arrives.

Questions to ask your care team

A monitoring plan is easier to trust when you understand its logic. These questions tend to produce the most useful answers, whether the patient is you, a parent, or a newborn.

• What do you think is causing the hydronephrosis, and how confident are you?
• Is it one kidney or both, and how is the other kidney functioning?
• What grade or severity is it, and has it changed since the last scan?
• Have you measured kidney function directly, or do you plan to, and with which test?
• What exactly are we watching for on the next ultrasound, and what result would change the plan?
• How long between scans, and what is the plan if I miss one?
• Which symptoms should make me call before the next appointment, and which should send me to emergency care?
• If a procedure becomes necessary, what would it most likely be, and would it be a temporary drain or a definitive repair?
• Are there activities, fluids or medicines I should adjust in the meantime?
• For a baby: do you recommend preventive antibiotics, and what are the pros and cons in this case?
• For pregnancy: is this the usual pregnancy-related type, and will it need any follow-up after delivery?

Write the answers down. Hydronephrosis is a condition of trends, and the most reassuring sentence a clinician can say at a follow-up visit is “no change.” That sentence only carries weight if you know what the previous measurement was. Ask for the numbers, ask what they mean, and ask what would make the team move faster. A good monitoring plan has a clear exit on both sides: discharge when the swelling resolves or proves harmless, and escalation when it does not.

When to call your doctor

Monitoring rests on a simple bargain: the team watches the scans, and you watch for the handful of signs that cannot wait. Mayo Clinic, the NHS and MedlinePlus agree on the list.

Seek same-day or emergency care if you or your child has hydronephrosis and develops:

• Fever or chills, particularly with pain in the side, back or lower abdomen. Infection behind a blocked kidney can progress to sepsis, a body-wide response to infection, within hours.
• Severe pain that does not ease with the pain relief you were prescribed, or pain accompanied by vomiting so that you cannot keep fluids down.
• Passing much less urine than usual, or none at all, especially if both kidneys are affected or you have only one kidney.
• Visible blood in the urine together with pain or fever.
• Confusion, drowsiness, rapid breathing or a racing pulse, which can signal infection or kidney failure.

For a baby: fever without an obvious cause, refusal to feed, unusual sleepiness or irritability, or urine that smells strongly or looks cloudy. Infants cannot report flank pain, so these general signs stand in for it.

Call during office hours, rather than waiting for the next scheduled scan, if there is new milder pain, burning when passing urine, swelling of the ankles, or any symptom that simply feels different from your baseline.

None of these signs means a procedure is certain. They mean the plan needs to be reassessed by someone who can examine you, check your blood and urine, and look at the kidney again. Every decision about drainage, surgery or continued watching remains with the treating team, informed by what they find on that day.

Frequently asked questions

Does hydronephrosis need treatment if there are no symptoms?

Not necessarily. Symptom-free hydronephrosis with normal kidney function and a stable appearance on repeat ultrasound is often monitored rather than treated. The team will usually confirm the kidney drains adequately, sometimes with a nuclear medicine renogram, before deciding that watching is safe. Absence of pain does not rule out slow loss of function, so scheduled scans and blood tests remain part of the plan.

How is mild hydronephrosis treated?

Mild hydronephrosis treatment usually means finding the cause and repeating the ultrasound rather than any procedure. If the cause is self-limiting, such as pregnancy, a small passing stone or antenatal dilation in a baby, the swelling typically settles on its own. Treatment is directed at the underlying problem only if it persists, worsens, or begins to affect kidney function.

What does grade 4 hydronephrosis mean for my child?

Grade 4 hydronephrosis meaning, in plain terms, is severe widening of the kidney’s drainage system with visible thinning of the kidney tissue. It prompts closer follow-up and usually a renogram to measure how well that kidney works and drains. Some grade 4 kidneys keep good function and are monitored; others show falling function and are repaired surgically, most often with a pyeloplasty.

What are the treatment options for a blocked kidney?

Blocked kidney treatment options fall into relieving pressure and fixing the cause. Pressure is relieved with a catheter, a ureteric stent or a nephrostomy tube when infection, pain, poor function or bilateral blockage make waiting unsafe. The cause is then addressed: stones may pass, be fragmented or removed; an enlarged prostate may be managed with medicines or surgery; narrowed segments can be repaired.

What are the most common hydronephrosis in newborns causes?

Most newborn hydronephrosis is transient dilation of an immature urinary tract that resolves on its own. Among structural causes, NIDDK lists ureteropelvic junction obstruction, vesicoureteral reflux, ureterovesical junction obstruction, ureterocele and, in boys, posterior urethral valves. The last of these affects both kidneys and the bladder and is usually treated soon after birth, while the others are often monitored.

Can hydronephrosis go away on its own?

Yes, in many cases. Pregnancy-related hydronephrosis usually resolves after delivery, stone-related swelling settles once the stone passes, and the NHS notes that most antenatal cases improve before birth or in the first months of life. Hydronephrosis from a fixed narrowing, a large stuck stone or a bladder outlet problem generally does not resolve without addressing that cause.

Is hydronephrosis during pregnancy dangerous?

Usually not. Mild hydronephrosis during pregnancy is extremely common, caused by hormonal relaxation of the ureter and pressure from the uterus, and it typically resolves after birth without treatment. It becomes a concern only with infection that does not settle, uncontrolled pain, worsening kidney function or a true obstructing stone, in which case a temporary stent or nephrostomy can protect the kidney until delivery.

How often will I need scans if we are monitoring?

Intervals vary with the cause and severity. A new mild finding is often rechecked within weeks, then every few months if stable, with intervals lengthening further over time. Babies are commonly scanned after the first few days of life and then every few months through the first year or two. Your team sets the schedule and shortens it if anything changes.

Does a stent mean I will need surgery later?

Not always. A stent is a temporary measure that keeps the ureter open and relieves pressure. Sometimes the underlying problem, such as a stone, is treated or passes while the stent is in place, and the stent is simply removed. In other cases the stent bridges to a planned operation on a narrowing or the bladder outlet. The plan depends on the cause.

Can hydronephrosis cause permanent kidney damage?

It can if a significant obstruction continues long enough, because sustained pressure reduces blood flow and thins the working tissue of the kidney. Johns Hopkins notes that untreated obstruction may lead to permanent loss of function on that side. This is exactly why monitoring includes function tests and why infection, bilateral blockage or falling function prompt earlier intervention.

References

• NHS: Hydronephrosis
• MedlinePlus Medical Encyclopedia: Bilateral hydronephrosis
• Cleveland Clinic: Hydronephrosis
• NIH NIDDK: Kidney Stones

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.