What are Obstructing and Non-Obstructing Stones? Does it Matter?
Dr. Alex Shteynshlyuger is a board certified urologist in NYC who specializes in treating men and women with kidney stones and ureteral stones.
Obstructing vs. Non-Obstructing Stones in Ureter and Kidney
Kidney stones that block the flow of urine from the kidney or down the ureter are called obstructive kidney stones. Depending on stone size and location the blockage can be complete or partial. Non-obstructing stones do not block urine flow but can also cause symptoms that are commonly associated with kidney stones. A non-obstructive kidney stone may at some point start moving and become obstructive.
Obstructive Kidney Stones: What You Need to Know
Obstructing stones cause blockage in the urinary system and can be potentially dangerous. Obstructing stones usually, but not always, cause symptoms. Obstruction can be complete or partial. Symptoms are typically more severe with complete obstruction but occasionally even patients with large stones and complete obstruction do not have much pain but only some discomfort.
Most commonly obstructing stones are located in the ureter. Obstructing ureteral stones can also occur at UPJ (uretero-pelvic junction) and in the kidneys.
Stones can also be partially obstructing or intermittently obstructing. This is likely the explanation for intermittent pain – the severity of obstruction increases as stone moves and leads to pain. If it moves and becomes less obstructing, pain subsides.
Obstructing stones can lead to severe infection and renal failure. Stones associated with infection or renal failure require prompt treatment.
The presence of obstructing stones in both ureters concurrently, although rare, is a urological emergency as it can lead to acute renal failure because of the inability to pass urine. ESWL cannot be performed in patients with an obstructing stone and signs of infection (fever).
Non-Obstructing Stones: Today a Friend Tomorrow a Foe
Non-obstructing stones are typically not symptomatic, but may occasionally cause infection, pain, renal insufficiency, or blood in urine. These can be treated electively with ESWL, ureteroscopy or PCNL.
If non-obstructing stones are symptomatic or sufficiently large, they should be treated electively as long-term they are likely to cause symptoms, grow and make it more challenging to break them.
It is important to remember that non-obstructive kidney stones can move at any time and become ‘obstructive’ at the UPJ or in the ureter. If they grow to a large size, they can become obstructive even in the kidney causing partial renal caliceal obstruction.
Most of non-obstructive stones occur in the kidney but some smaller stones in the ureter can also cause minimal partial obstruction or no significant obstruction at all. This is the most likely explanation for why patients sometimes pass kidney stones without knowing it or without experiencing any pain.
Dr. Alex Shteynshlyuger is a board certified urologist in NYC who specializes in treating men and women with kidney stones and ureteral stones. He has treated hundreds of men and women with large kidney stones.
We offer affordable, highest-quality urology care. We offer weekday, weekend, and evening office hours.
We see patients from all parts of New York City (Manhattan, Brooklyn, Queens, Bronx, Staten Island), Long Island, Westchester and New Jersey as well as other parts of the USA. We also see international patients from Canada, Japan, South America, Russia, Asia, Europe, Middle East, Africa, the Caribbean and other parts of the world.