Kidney stones are solid masses or crystals that form from substances found in urine. These deposits primarily develop within the kidneys when minerals and salts become highly concentrated. This article traces a kidney stone’s path through the urinary tract, addressing whether pain persists once it reaches the bladder.
The Stone’s Path Through the Urinary Tract
Kidney stones typically begin to form in the kidneys when urine contains more crystal-forming substances than the available fluid can dilute. These stones range in size from a grain of sand to, rarely, larger than a golf ball. While forming in the kidney, they often do not cause symptoms. Symptoms typically begin when a stone dislodges and starts its descent into the ureter.
The ureters are narrow tubes connecting the kidneys and the bladder. If a kidney stone lodges in a ureter, it can obstruct urine flow. This blockage causes pressure to build up behind the stone, leading to significant pain. This pain, known as renal colic, is often severe, sharp, and cramping.
It frequently radiates from the back or side, below the ribs, to the lower abdomen and groin. This pain typically occurs in waves as ureter muscles contract to push the stone through. Smaller stones, generally 1-5 millimeters, can take 8 to 12 days to pass through this section.
When a Stone Reaches the Bladder
Once a kidney stone enters the bladder, the intense, colicky pain often subsides. However, the stone’s presence can still cause discomfort or pain, depending on its size and shape. The bladder is more spacious than the ureter, allowing the stone to move more freely, but it can also irritate the bladder lining.
Individuals may experience an increased urge to urinate frequently, sometimes every few minutes, due to the stone’s irritation. Other symptoms include a persistent feeling of bladder pressure or lower abdominal discomfort. A burning sensation during urination, medically termed dysuria, is also common.
Urine might show changes, appearing cloudy, having an unusual smell, or containing visible blood (hematuria). These bladder-related symptoms are distinct from the sharp, radiating pain associated with the stone’s journey through the ureters.
Exiting the Bladder and Complications
After a kidney stone reaches the bladder, the final stage involves its passage out of the body through the urethra. This step can still be accompanied by a burning or stinging sensation as the stone exits. While the urethra is generally wider than the ureters, a larger stone may still cause notable discomfort during expulsion.
In some instances, a stone might get lodged within the bladder or urethra, leading to potential complications. This can result in urinary retention, making it difficult or impossible to urinate. The presence of a stone, especially if it causes a blockage, increases the risk of urinary tract infections (UTIs) because bacteria can become trapped and multiply.
Untreated UTIs can escalate to kidney infections or cause persistent bladder irritation. Individuals should promptly seek medical attention if they experience severe pain, an inability to urinate, fever, chills, or persistent symptoms, as these could indicate a more serious complication. Nausea and vomiting accompanying any of these symptoms also warrant immediate medical assessment.