Can non-obstructing kidney stones cause back pain in a patient with a history of gross hematuria (visible blood in urine) and bacterial growth, who also has a renal cyst, liver cyst, and left groin hernia?

Can Non-Obstructing Kidney Stones Cause Back Pain?

Yes, non-obstructing kidney stones can cause back pain in your patient, and this is a well-recognized clinical entity sometimes called "small stone syndrome." 1, 2

Evidence for Pain from Non-Obstructing Stones

While traditional teaching suggests that renal colic results primarily from urinary tract obstruction, recent high-quality evidence demonstrates that small, non-obstructing calyceal stones can indeed cause significant pain:

• A 2024 prospective multicenter trial found that 86% of patients with non-obstructing kidney stones (up to 10 mm) and moderate to severe pain experienced at least a 20% reduction in pain after stone removal, with mean pain scores dropping from 5.5 to 1.8 at 12 weeks post-treatment. 2

• A 2013 retrospective study showed that 85% of patients with small non-obstructing calyceal stones (≤4 mm) achieved complete pain resolution after ureteroscopic treatment, with 67% reporting improved quality of life. 1

• The absence of hematuria should not deter evaluation when kidney stones are clinically suspected, as a significant number of patients with urolithiasis do not have hematuria. 3

Alternative Pain Sources to Consider

Your patient has several other potential causes of back pain that must be evaluated:

• Renal cyst complications: The small renal cyst could cause pain if it becomes hemorrhagic, infected, or enlarges. Hemorrhagic cysts can present with hematuria and pain. 4

• Residual infection: Even though symptoms resolved with treatment, ensure complete resolution of the urinary tract infection, as persistent or recurrent UTIs can cause ongoing discomfort. 5

• Musculoskeletal causes: The left groin hernia could potentially cause referred back pain, though this is less likely to be the primary source. [@general medical knowledge@]

Clinical Approach

Determine if the back pain is truly renal in origin by assessing these specific features:

• Location: Flank pain radiating to the groin suggests renal/ureteral origin 5
• Character: Colicky vs. constant pain (stones typically cause intermittent colicky pain) 5
• Timing: Relationship to the previous hematuria episode 3
• Associated symptoms: Dysuria, urinary frequency, fever, or recurrent hematuria 6

If renal stone pain is suspected despite non-obstructing status:

• The American College of Radiology recommends that CT has superior diagnostic accuracy (sensitivity and specificity >90%) for detecting stones and can identify complications. 3
• Consider repeat imaging if pain persists, as stone position can change and cause intermittent obstruction not evident on initial CT. 5
• Discuss with urology regarding potential ureteroscopic treatment, as surgical removal has demonstrated significant pain reduction and quality of life improvement in this specific population. 2

Important Caveats

• Do not assume pain is unrelated to stones simply because they are non-obstructing—this is a common pitfall that can lead to prolonged patient suffering. 1, 2

• Evaluate the renal cyst with follow-up imaging if pain persists, as hemorrhagic or infected cysts can mimic stone pain and may require different management. 4

• Consider metabolic evaluation for stone prevention if not already done, particularly given the patient's age and stone burden. 6