Kidney Blockage vs Kidney Stones:

Why That Pain Isn’t Always What You Think

When Kidney Pain Isn’t a Stone

If you’ve had sudden, sharp pain in your side or back, you might assume it’s a kidney stone. That’s what most people — and even some providers — think first. But what if that pain keeps coming back? Or the scans don’t show a stone at all? In many cases, the issue is something else entirely — a kidney blockage. Understanding the difference between kidney blockage vs kidney stones can help you get the right treatment before lasting damage occurs.

Kidney Blockage vs Kidney Stones: What’s the Difference?

Kidney stones are hard mineral buildups that form inside your kidneys. When they move, they can cause intense pain, blood in the urine, or difficulty urinating. Once the stone passes or is removed, symptoms usually stop.

A kidney blockage, on the other hand, often doesn’t go away on its own. It can be caused by scar tissue, a narrowed ureter, or even a tumor pressing on the urinary tract. Over time, this can cause the kidney to swell — a condition called hydronephrosis — and slowly lose function.

Why the Difference Matters

Pain isn’t the only issue. While kidney stones are painful, they don’t usually cause lasting damage if treated. But a kidney blockage can silently wear down the kidney, especially if it’s misdiagnosed.

Here’s where the confusion happens: Both can cause similar symptoms, such as:

• Flank or back pain
  
• Nausea or vomiting
  
• Changes in urine flow
  
• Blood in the urine
  

The key is how the symptoms behave. If pain keeps returning, or scans don’t show a stone, your doctor should consider a possible obstruction.

How Kidney Blockages Are Diagnosed

If a stone isn’t found, interventional and urologic teams may order:

• A renal ultrasound to check for swelling
  
• A nuclear medicine renal scan to assess kidney function
  
• A CT urogram or MRI to look for structural issues
  

These tests help determine if one of your kidneys is draining properly or if urine is backing up due to a blockage.

A Minimally Invasive Way to Fix Kidney Blockage

If a blockage is confirmed, a common treatment is nephrostomy or ureteral stenting, both done by interventional radiologists. These image-guided procedures allow urine to flow again — relieving pressure and preserving kidney function.

Depending on the cause, additional treatment like balloon dilation or surgery may be recommended — but restoring urine flow is the first and most important step.

Learn more about nephrostomy tubes from the NIH

When to Ask About Kidney Blockage vs Kidney Stones

Ask your doctor to consider a blockage if you:

• Keep having kidney pain but no stone is found
  
• Were told you had a “stone” that never passed
  
• Have ongoing hydronephrosis on imaging
  
• Experience a drop in kidney function
  

The earlier a blockage is found, the more kidney tissue can be saved.

You Deserve Clarity and Relief

Too many patients are told to “just wait for the stone to pass” — even when that stone doesn’t exist. If your symptoms don’t add up or just won’t stop, it’s time to get a clear diagnosis.

Learn how interventional imaging and treatment can help protect your kidneys — and find more patient-first resources here.