Patients Without Evidence of Ureteral Stone Passage Should Seek Follow-up Imaging
Key findings
- 14 of 52 patients (26%) still had a ureteral stone despite reporting complete cessation of pain for at least three days
- The likelihood of stone passage was not associated with stone size or location
- To prevent renal damage from silent obstruction, follow-up imaging is recommended for all patients who do not have physical evidence of stone passage
For unknown reasons, a ureteral stone that causes hydronephrosis and obstruction may not cause pain, or the pain may cease even though the stone has not been passed. There is no consensus on whether follow-up imaging is needed for any patient with a ureteral stone, much less for the subgroup with silent obstruction.
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Urologists at Massachusetts General Hospital have determined that resolution of symptoms is insufficient to determine that a ureteral stone has been expelled, and they recommend follow-up imaging for all patients who cannot present the stone. Brian H. Eisner, MD, co-director of the Kidney Stone Program at Massachusetts General Hospital, and colleagues report their findings in The Journal of Urology.
Standard Practice
At Mass General, patients diagnosed in the emergency department with an obstructing ureteral stone are typically seen in the urology clinic for follow-up imaging three to six weeks later. Patients with persistent stones are offered observation, shock wave lithotripsy or ureteroscopy.
A Retrospective Study
The researchers analyzed 52 patients who: presented to Mass General with acute renal colic between 2010 and 2014, had a single ureteral stone detected by imaging and had been pain-free for at least 72 hours by the time of the follow-up appointment. The average time to the follow-up appointment was 36 days.
At those appointments, imaging showed that 14 patients (26%) still had a stone in the ureter. None of these stones was in a significantly different location than at the time of the emergency department visit.
On multivariate regression analysis, the likelihood of stone passage was not associated with stone size or location. Pain scores reported in the emergency department did not differ between patients who did versus did not subsequently pass the stone.
Prevent Renal Damage
Ureteral obstruction can cause irreversible renal damage and the presence of symptoms is not a prerequisite for such damage. Dr. Eisner's group recommends follow-up imaging for all patients who do not have physical evidence of stone passage, namely those who do not bring in a stone for analysis and those who say they visualized passage but could not collect the stone.
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Learn more about the Kidney Stone Program
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