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Stone with Hydronephrosis: What It Means

Stone with Hydronephrosis: What It Means

📖 9 min read Written/reviewed by Dr. Alhad Naragude, MBBS, MS, DrNB Urology Last updated: June 17, 2026

A stone with hydronephrosis means a kidney stone is blocking urine flow and causing swelling of the kidney’s urine drainage system. It does not always mean permanent kidney damage, but it should not be ignored. The urgency depends on the stone size, stone location, degree of swelling, fever, urine infection, pain, vomiting and kidney function. Mild hydronephrosis may sometimes be observed with medicines and follow-up. Fever, chills, high creatinine, severe pain, vomiting, single kidney or severe hydronephrosis needs urgent urology care.

What is hydronephrosis?

Hydronephrosis means swelling of the kidney because urine is not draining freely.

Normally, urine flows from the kidney into a narrow tube called the ureter, then into the bladder and out through the urine passage.

Kidney → ureter → bladder → urine passage

When a stone gets stuck in the ureter, urine builds up behind the blockage. This creates pressure inside the kidney’s collecting system. That swelling is called hydronephrosis.

Hydronephrosis is not a separate disease. It is a sign of urine back-pressure. Kidney stones are one common cause of this blockage. The National Kidney Foundation notes that hydronephrosis can affect one or both kidneys and, over time, kidney function can decrease if the cause is not treated.

Stone with hydronephrosis: what your USG or CT report means

Your ultrasound or CT report may use words such as calculus, ureteric calculus, hydroureteronephrosis, PUJ stone, VUJ stone or back pressure changes. These terms can sound frightening, but they can be understood step by step.

Report term Simple meaning
Calculus Stone
Ureteric calculus Stone stuck in the ureter
Hydronephrosis Swelling of the kidney drainage system
Hydroureteronephrosis Swelling of both ureter and kidney due to blockage
PUJ stone Stone near the kidney-ureter junction
Upper ureteric stone Stone in the upper part of the ureter
Lower ureteric / VUJ stone Stone near the bladder end of the ureter
Back pressure changes Kidney swelling due to obstruction

The key question is not only, “Is there hydronephrosis?” The better question is, “Is this stone causing a dangerous blockage?”

Is stone with hydronephrosis serious?

It can be serious, especially if infection or kidney function damage is present.

A small stone with mild hydronephrosis, normal creatinine, no fever and controlled pain may sometimes be treated with medicines and close follow-up. But a blocked kidney with fever, chills, pus in urine, high creatinine or low urine output is urgent.

The European Association of Urology states that an obstructed kidney with signs of urinary tract infection and/or anuria is a urological emergency, and urgent decompression is often needed in infected hydronephrosis due to stone obstruction.

Mild, moderate and severe hydronephrosis

Mild hydronephrosis

Mild hydronephrosis means early or low-grade swelling. It may happen when the stone is small, the blockage is partial, the stone is close to passing or the obstruction has started recently.

Mild hydronephrosis is not automatically dangerous, but it still needs correlation with symptoms, urine test and creatinine. Pain may reduce even if the stone is still stuck.

Moderate hydronephrosis

Moderate hydronephrosis means more significant swelling. It needs closer evaluation, especially if the stone is in the ureter, pain is recurring, urine test shows infection or creatinine is raised.

A CT KUB is often useful if ultrasound has not clearly shown stone size and location.

Severe hydronephrosis

Severe hydronephrosis means marked back-pressure on the kidney. This needs prompt urology evaluation. It becomes urgent if there is fever, vomiting, rising creatinine, low urine output, single kidney, stones on both sides or uncontrolled pain.

Severe hydronephrosis does not always mean permanent kidney damage, but delaying treatment increases risk.

Symptoms of stone with hydronephrosis

Symptoms depend on stone size, stone location and whether urine flow is blocked. A small ureteric stone can cause severe pain, while a larger stone inside the kidney may sometimes remain silent.

  • Severe side, back or flank pain.
  • Pain moving to the lower abdomen, groin or testicle.
  • Pain that comes in waves.
  • Nausea or vomiting.
  • Burning urination.
  • Frequent urge to pass urine.
  • Blood in urine.
  • Cloudy or foul-smelling urine.
  • Fever or chills.
  • Reduced urine output in serious obstruction.

NIDDK lists sharp pain in the back, side, lower abdomen or groin, blood in urine, frequent urination, painful urination, inability to urinate, cloudy urine and bad-smelling urine among symptoms of kidney stones.

Emergency signs: do not wait at home

Go to hospital urgently if a stone with hydronephrosis is associated with:

  • Fever.
  • Chills or shivering.
  • Severe pain not settling with medicines.
  • Persistent vomiting.
  • Very low urine output.
  • Inability to pass urine.
  • High creatinine.
  • Diabetes with fever or infection.
  • Pregnancy with stone pain.
  • Single functioning kidney.
  • Stones blocking both kidneys.
  • Severe hydronephrosis on scan.

Infection plus obstruction is dangerous because infected urine may be trapped inside a blocked kidney. In such cases, the first step is usually urgent drainage, not immediate stone breaking.

Tests needed for stone with hydronephrosis

Ultrasound KUB

Ultrasound is commonly used first. It can show kidney swelling, many kidney stones and bladder urine retention. It is useful for follow-up and is preferred first in pregnancy and children. However, ultrasound may miss some ureteric stones.

CT KUB / NCCT KUB

NCCT KUB means non-contrast CT scan of kidneys, ureters and bladder. It is usually the most accurate test in adults for exact stone size, stone location, number of stones, degree of obstruction and treatment planning.

NICE recommends urgent low-dose non-contrast CT within 24 hours for adults with suspected renal colic. It recommends ultrasound first for pregnant women, children and young people.

Urine tests

Urine routine and microscopy may show blood cells, pus cells, crystals or signs of infection. A urine culture is important if infection is suspected or if surgery is being planned.

Blood tests

Common blood tests include serum creatinine, CBC, CRP in selected infection cases and electrolytes if kidney function is affected.

Stone with hydronephrosis treatment

Treatment depends on the whole clinical picture, not just one word in the report. A urologist considers stone size, location, degree of hydronephrosis, fever, urine infection, pain severity, vomiting, creatinine level, single kidney or both kidneys affected, previous stone history and patient fitness.

Situation Common treatment direction
Small stone, mild hydronephrosis, no fever, normal creatinine Medicines, observation and follow-up may be considered
Moderate hydronephrosis or recurring pain Closer evaluation, usually CT KUB if not already done
Ureteric stone stuck with severe pain or failure to pass URSL may be advised
Fever or urine infection with blockage Urgent drainage first, stone treatment later
High creatinine, single kidney or both kidneys blocked Urgent urology care and drainage may be needed
Large or complex kidney stone RIRS, PCNL or another planned procedure depending on CT findings

When medicines and observation may be enough

Medicines and close follow-up may be considered when the stone is small, pain is controlled, there is no fever, urine test does not suggest infection, creatinine is normal, hydronephrosis is mild and the patient can return for follow-up.

Medicines may help with pain, vomiting and selected ureteric stone passage. Avoid repeated painkiller injections without reassessment. Pain relief does not always mean the stone has passed.

When urgent drainage is needed

Urgent drainage may be needed when there is fever with obstruction, pus cells or urine infection with obstruction, sepsis, rising creatinine, single kidney with obstruction, both kidneys blocked, persistent vomiting, uncontrolled pain or severe hydronephrosis with clinical concern.

DJ stent

A DJ stent is a soft tube placed inside the ureter. It allows urine to drain from the kidney to the bladder by bypassing the stone.

A stent relieves obstruction. It may not remove the stone immediately. Stone removal may be planned later after infection and swelling improve.

Nephrostomy tube

A nephrostomy tube is placed through the back directly into the kidney to drain urine into a bag. It may be used when stenting is not possible, the patient is very sick or urgent external drainage is safer.

Stone removal options

URSL

URSL, or ureteroscopic stone removal, is commonly used for ureteric stones. A small scope is passed through the urine passage into the ureter. The stone is broken with laser and removed or allowed to pass as tiny fragments.

RIRS

RIRS, or retrograde intrarenal surgery, uses a flexible scope to treat selected kidney stones through the natural urinary passage.

ESWL

ESWL, or shock wave lithotripsy, breaks selected stones from outside the body using shock waves. Suitability depends on stone size, location, hardness and kidney anatomy.

PCNL

PCNL, or percutaneous nephrolithotomy, is used for larger or complex kidney stones. A small tract is made through the back into the kidney to remove the stone.

NICE includes shock wave lithotripsy, ureteroscopy and PCNL as treatment options depending on stone size, site and clinical situation. It also recommends early surgical treatment for adults with ureteric stones and renal colic if pain is ongoing or the stone is unlikely to pass.

Can hydronephrosis damage the kidney?

Yes, if obstruction is severe, prolonged or infected. But many kidneys recover well when treated in time. NIDDK notes that kidney stones rarely cause permanent damage if treated by a health care professional.

Risk is higher when the stone remains stuck for a long time, fever or infection is present, both kidneys are blocked, the patient has a single functioning kidney, creatinine is rising, severe hydronephrosis is ignored or follow-up is missed after temporary pain relief.

What not to do

  • Do not ignore fever with a stone.
  • Do not keep taking painkiller injections without follow-up.
  • Do not assume the stone has passed because pain stopped.
  • Do not force excessive water during severe pain or vomiting.
  • Do not self-start antibiotics repeatedly.
  • Do not delay care if urine output is falling.
  • Do not forget DJ stent removal.
  • Do not skip repeat imaging when advised.

A DJ stent is temporary. It must be removed or changed as advised.

What to bring for consultation

Bring these if available:

  • USG KUB report and images.
  • CT KUB film, CD or link.
  • Urine routine report.
  • Urine culture report.
  • Serum creatinine.
  • CBC.
  • Previous stone surgery records.
  • Previous discharge summaries.
  • Current medicines.
  • Allergy history.
  • DJ stent details if already placed.
  • Stone analysis report if available.

FAQs

Is stone with hydronephrosis an emergency?

It is an emergency if there is fever, chills, severe pain, vomiting, high creatinine, low urine output, single kidney, stones on both sides or severe hydronephrosis. Mild hydronephrosis without infection may sometimes be managed with medicines and follow-up.

Can a stone with hydronephrosis pass naturally?

Yes, some small ureteric stones can pass naturally. The chance depends on stone size, location, symptoms, infection status and kidney function.

Does hydronephrosis mean kidney failure?

No. Hydronephrosis means kidney swelling due to urine back-pressure. It does not always mean kidney failure, but prolonged or infected obstruction can damage kidney function.

Which test is best: ultrasound or CT KUB?

Ultrasound is useful for detecting kidney swelling. CT KUB is usually better in adults for confirming exact stone size and location. Ultrasound is preferred first in pregnancy and children.

Why did my pain stop but hydronephrosis is still present?

Pain can reduce even if the stone is still stuck. Follow-up imaging confirms whether the obstruction has cleared.

When is a DJ stent needed?

A DJ stent may be needed when the kidney is blocked and there is infection, high creatinine, severe pain, vomiting, single kidney, bilateral obstruction or need to delay definitive stone surgery safely.

Is DJ stent the final treatment?

Not always. A DJ stent drains the kidney. The stone may still need treatment later by URSL, RIRS, ESWL or PCNL.

Can I travel with stone and hydronephrosis?

Avoid travel if you have fever, vomiting, uncontrolled pain, high creatinine, severe hydronephrosis, single kidney or low urine output. Travel may be considered only after urology assessment in low-risk cases.

Related reading

References

Note: This information is for educational purposes only and is not a substitute for medical advice. Please consult your doctor for any symptoms.