Guide to Ureteral Obstruction
Discover everything you need to know about ureteral obstruction, including its causes, common symptoms, diagnosis methods, and effective treatment options.
Written by Dr. Siri Nallapu
Reviewed by Dr. Rohinipriyanka Pondugula MBBS
Last updated on 12th Sep, 2025
Introduction
Imagine a vital pipeline in your body getting clogged. That’s essentially what a ureteral obstruction is—a blockage in one or both of the tubes (ureters) that carry urine from your kidneys to your bladder. This blockage can be partial or complete, and it’s more than just a minor inconvenience; it’s a serious medical condition that can lead to severe pain, infections, and permanent kidney damage if left untreated. Whether the cause is a common kidney stone or a more complex issue, understanding the signs is crucial for your health. This comprehensive guide will walk you through everything you need to know about ureteral obstructions: from recognising the early symptoms to exploring the latest treatment options, empowering you to take informed action for your well-being.
What is a Ureteral Obstruction?
A ureteral obstruction is any hindrance that disrupts the normal flow of urine through the ureter. Your ureters are muscular tubes, each about 8-10 inches long, that use gentle waves of contraction (peristalsis) to move urine along. When a blockage occurs, urine backs up into the kidney, a condition known as hydronephrosis. This causes the kidney to swell and, over time, can impair its function. The severity of the problem depends on whether the blockage is unilateral (affecting one kidney) or bilateral (affecting both), as well as whether it developed suddenly or gradually over a long period.
The Role of Your Ureters and Kidneys
Think of your kidneys as sophisticated filtration plants. They constantly clean your blood, removing waste and excess water to produce urine. The ureters are the dedicated outflow pipes for these plants. If these pipes get blocked, the "plant" (your kidney) can flood and its delicate internal structures can be damaged under the pressure. This underscores why a ureteral blockage is a urologic emergency that requires prompt attention.
Common Symptoms of a Ureteral Blockage
Symptoms can vary widely based on the location, cause, and speed of onset of the obstruction.
- Flank Pain: The most classic symptom is a sharp, severe, and cramping pain in your side and back (below the ribs), which may radiate to your lower abdomen and groin. This pain, known as renal colic, comes in waves.
- Changes in Urination: You might experience pain during urination, a persistent urge to urinate, decreased urine output, or even blood in the urine (hematuria), which can appear pink, red, or brown.
- Signs of Infection: A blockage can trap bacteria, leading to a urinary tract infection (UTI) with symptoms like fever, chills, cloudy or foul-smelling urine, and burning with urination.
- General Malaise: Nausea and vomiting often accompany the intense pain of a sudden obstruction.
When to Seek Immediate Medical Attention
If you experience a sudden onset of severe flank pain, especially when combined with fever, chills, and vomiting, you must seek emergency care. These could be signs of an infected obstructed kidney, which is a life-threatening condition that requires immediate drainage and antibiotics.
Consult a Urologist for the best advice
What Causes Ureteral Obstruction?
The causes are broadly categorised into problems originating from within the ureter itself and those caused by external compression.
Intrinsic Causes (Inside the Ureter)
These are blockages that form inside the lumen of the ureter.
- Kidney Stones (Ureteral Calculi): This is the most common cause. Stones formed in the kidney can travel down and get lodged in the narrow sections of the ureter, causing a sudden and painful blockage.
- Ureteral Strictures: A stricture is a narrowing of the ureter due to scar tissue, which can result from previous surgery, radiation therapy, or long-term stone disease.
Extrinsic Causes (Outside the Ureter)
These occur when structures outside the ureter press on it, pinching it closed.
- Cancers and Tumors: Tumors in nearby organs—such as bladder cancer, cervical cancer, prostate cancer, or colon cancer—can press on and invade the ureters. Additionally, retroperitoneal fibrosis, a rare condition involving tissue growth behind the abdomen, can encase and constrict the ureters.
- Conditions like Endometriosis and PID: In women, endometrial tissue can grow and affect the ureters. Severe pelvic inflammatory disease (PID) can also lead to scarring that impacts the urinary tract.
Other Contributing Factors
Other causes include enlarged lymph nodes, pregnancy (where the enlarging uterus can compress the ureters), and congenital abnormalities present at birth, such as a ureterocele or an obstructed ureter at the kidney junction (UPJ obstruction).
How is Ureteral Obstruction Diagnosed?
If a ureteral obstruction is suspected based on your symptoms, a urologist will recommend tests to confirm the diagnosis, locate the blockage, and determine its cause.
Imaging Tests: Ultrasound, CT, and IVP
- Ultrasound: This is often the first test. It's non-invasive and excellent at detecting hydronephrosis (kidney swelling).
- CT Scan: A CT urogram is the gold standard. It provides detailed, 3D images that can pinpoint the exact location and cause of the blockage, such as a small kidney stone or a tumor.
- MRI Urogram: Used for patients who cannot have CT scans (e.g., due to pregnancy or allergy to contrast dye), an MRU offers excellent soft-tissue detail.
Functional Tests: Assessing Kidney Performance
- Nuclear Renal Scan: This test uses a small amount of radioactive tracer to evaluate blood flow, function, and drainage of each kidney individually, showing how well the obstructed kidney is working.
Ureteral Obstruction Treatment Pathways
The goal of treatment is twofold: to relieve the obstruction immediately and to address the underlying cause.
Immediate Relief: Ureteral Stents and Nephrostomy Tubes
To quickly decompress the kidney and protect its function, a urologist may place:
- A Ureteral Stent: A thin, flexible tube inserted via cystoscopy (through the bladder) that spans from the kidney to the bladder, allowing urine to bypass the blockage.
- A Nephrostomy Tube: A tube inserted directly through the skin on the back into the kidney to drain urine externally into a bag. This is often used if placing a stent is not possible.
Treating the Underlying Cause
- Breaking Up and Removing Kidney Stones: Lithotripsy (using shock waves to break stones into passable fragments) or ureteroscopy (using a scope to retrieve or laser stones) are common procedures for ureteral calculi.
- Surgical Options for Strictures and Tumors: For a ureteral stricture, surgery may involve cutting out the narrowed segment and reconnecting the healthy ends (ureteral reimplantation). For blockages caused by cancer, treatment is directed at the cancer itself, which may involve surgery, chemotherapy, or radiation.
Potential Complications of an Untreated Blockage
Ignoring the symptoms of a blockage can lead to severe, sometimes irreversible, consequences.
- Kidney Damage (Hydronephrosis): The persistent back-pressure of urine causes the kidney to swell and its delicate filtering units (nephrons) to be destroyed.
- Kidney Failure and Loss of Function: If both kidneys are obstructed or if a single kidney is blocked, it can lead to a rapid rise in waste products in the blood, resulting in acute kidney injury. Chronic, long-term obstructions can lead to permanent end-stage renal disease, requiring dialysis or a transplant.
Can Ureteral Obstruction Be Prevented?
While not all causes are preventable, you can reduce your risk for the most common cause (kidney stones):
- Stay Hydrated: Drinking plenty of water throughout the day is the single most effective way to prevent stone formation.
- Dietary Modifications: Depending on the type of stones you form, your doctor might recommend reducing sodium, animal protein, or oxalate-rich foods (like spinach and nuts).
- Manage Underlying Conditions: Regular check-ups for conditions like recurrent UTIs, endometriosis, or a history of abdominal cancers can help catch potential problems early.
Conclusion: Taking Action for Your Kidney Health
A ureteral obstruction is a clear signal from your body that something is wrong. Understanding the causes—from a passing kidney stone to more serious health issues—empowers you to recognise the symptoms early. While the pain can be debilitating, modern medicine offers highly effective treatments to relieve the blockage, address the root cause, and preserve your precious kidney function. The key is not to ignore the signs. Listening to your body and seeking timely medical advice can make all the difference. If you are experiencing persistent flank pain or other urinary symptoms, consult a urologist online with Apollo24|7 for a preliminary evaluation and to discuss the need for further diagnostic tests.
Consult a Urologist for the best advice
Consult a Urologist for the best advice
Dr Karthik Maripeddi
Urologist
13 Years • MBBS MS FMAS MCh URO(OSM)
Hyderguda
Apollo Hospitals Hyderguda, Hyderguda
Dr. Mohammed Rehan Khan
Urologist
8 Years • MBBS, MS (General Surgery), Mch (Urology)
Barasat
Diab-Eat-Ease, Barasat
Dr. Ravishankar L S
Urologist
25 Years • MS, DNB (Gen. Surg.) DNB (Genitourinary Surg.)
Chennai
Apollo Hospitals Cancer Centre Nandanam, Chennai
Dr. P. Roy John
Urologist
15 Years • MBBS ,MS MCH (UROLOGY) FELLOWSHIP RENAL TRANSPLANT SURGERY
Angamaly
Apollo Hospitals Karukutty, Angamaly
(25+ Patients)
Dr. Karunakar Reddy Ch
Urologist
4 Years • MBBS., MS., DNB
Kakinada
Apollo Hospitals Surya Rao Peta, Kakinada
Consult a Urologist for the best advice
Dr Karthik Maripeddi
Urologist
13 Years • MBBS MS FMAS MCh URO(OSM)
Hyderguda
Apollo Hospitals Hyderguda, Hyderguda
Dr. Mohammed Rehan Khan
Urologist
8 Years • MBBS, MS (General Surgery), Mch (Urology)
Barasat
Diab-Eat-Ease, Barasat
Dr. Ravishankar L S
Urologist
25 Years • MS, DNB (Gen. Surg.) DNB (Genitourinary Surg.)
Chennai
Apollo Hospitals Cancer Centre Nandanam, Chennai
Dr. P. Roy John
Urologist
15 Years • MBBS ,MS MCH (UROLOGY) FELLOWSHIP RENAL TRANSPLANT SURGERY
Angamaly
Apollo Hospitals Karukutty, Angamaly
(25+ Patients)
Dr. Karunakar Reddy Ch
Urologist
4 Years • MBBS., MS., DNB
Kakinada
Apollo Hospitals Surya Rao Peta, Kakinada
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Frequently Asked Questions
1. Can a ureteral obstruction resolve on its own?
Yes, if the cause is a small kidney stone, it may pass spontaneously with hydration and pain management. However, medical supervision is essential, as larger stones or other causes will not resolve without intervention and can cause damage.
2. How long can a ureteral stent stay in?
Typically, a ureteral stent is meant to be a temporary solution and is usually kept in place for a few weeks to a few months. Long-term stenting is possible but requires periodic changing every 3-6 months to prevent complications like infection or encrustation.
3. What does hydronephrosis feel like?
Hydronephrosis itself (the kidney swelling) may not always cause pain, especially if it develops slowly. When it does cause symptoms, it's often a dull ache in the flank or back. The severe, colicky pain is usually from the acute obstruction itself (e.g., a stone trying to move).
4. Is ureteral obstruction a sign of cancer?
It can be, but it is not the most common sign. While cancers in the abdomen or pelvis can cause an extrinsic ureteral obstruction, far more blockages are caused by benign conditions like kidney stones or benign strictures. Diagnosis is needed to determine the cause.
5. What are the first signs of kidney damage from an obstruction?
Early signs can be subtle but may include fatigue, swelling in the legs or ankles (edema), changes in urination patterns, and nausea. A blood test to measure creatinine (a marker of kidney function) is the most reliable way to assess for damage.