Passing a kidney stone means that a kidney stone has moved from the kidney into the ureter. The ureter is a tube that carries urine from the kidney to the bladder.
Patients often present to doctors with pain and blood in the urine. Imaging tests are often ordered to confirm that the patient is passing a kidney stone.
What is a ureteric calculus?
This is a kidney stone which is located in the ureter (tube which runs from the kidney to the bladder).
Symptoms of passing a kidney stone
There is often severe pain in the flank, nausea and vomiting. Patients will often have blood in their urine.
What does a kidney stone look like on imaging?
Ureteric calculi on X-ray
Ureteric calculus on X-ray will be seen as a small white spot next to the kidney, spine or in the pelvis. Passing stones will be located along the expected position of the ureters since we can’t see the ureters on X-ray.
Ureteric calculi on CT scan
Stones that are passing in the ureter will almost always be visible on CT scan. CT done without contrast placed into your vein are more commonly done when stones are suspected. Stones are white against a black and gray background of the fat, bowel and blood vessels.
The radiologist who interprets the scan will follow the course of the ureter looking for a stone. Often, there is a blockage of the kidney which will alert the radiologist to a passing stone.
What’s the difference between kidney stones and ureteral stones?
Kidney stones are located in the kidney itself. A ureteral stone is one located in the ureter or tube that runs from the kidney to the bladder.
What else can look like ureteric calculi in radiology?
In some cases, it can be difficult to distinguish a stone from a calcification in the pelvis called a phlebolith. A phlebolith is a common finding of a calcification in a pelvic vein. This can mimic a stone in the ureter.
Sometimes atherosclerotic calcifications or hardening of arteries can also mimic a stone.
In these cases, a CT with contrast called a urogram can be done to further evaluate.
Why is CT often done for kidney stones?
CT will exclude other dangerous conditions which can mimic the symptoms of passing a kidney stone. We can diagnose appendicitis and diverticulitis, both of which can mimic the symptoms of a passing stone but are treated much differently.
Additionally, the CT will show how big the passing stone is, how bad the blockage of the kidney is (hydronephrosis) and if there are any other complications.
Is passing a kidney stone dangerous?
Usually not, but it can be when complications arise. At times the stone does not pass and continues to block the kidney which can result in loss of kidney function.
There can be a superimposed infection. This can lead to a dangerous blood infection.
You can get rupture of the kidney collecting system from the blockage of the kidney. This can lead to a urinoma or collection of urine outside the kidney.
There can be severe pain.
What type of doctor treats ureteric calculi?
Often passing kidney stones are managed by a urologist.
Ureteric calculi treatment
Most patients with passing kidney stones are treated conservatively with pain medicine and fluids. Admission to the hospital may be indicated when pain control is inadequate, in those with limited kidney function or superimposed infection.
The odds of passage of the stone without treatment are dependent on the size of the stone. Those stones smaller than 4 mm pass most of the time on their own. In cases where the stone doesn’t pass, an urology doctor may perform a procedure to relieve the blockage and break the stone up.
Ureteric calculi : summary
Ureteric calculi or passing a kidney stone means the stone is located in the ureter (tube that passes from the kidney to the bladder). Ureteric calculi are diagnosed with X-rays and CT. CT offers the advantage of providing alternative diagnosis and more information about the passing stone and any complications.
Odds of stone passage depends on the size, with smaller stones more likely to pass spontaneously. A urologist may perform a procedure for those cases which the stone does not pass.