From the Guidelines
The typical timeframe for passing kidney stones can range from a few days to several weeks, with most small stones passing on their own within 1-2 weeks. The size of the stone plays a significant role in determining how long it takes to pass, with smaller stones (less than 4mm) having a higher chance of passing quickly, typically within 1-2 weeks 1. Medium-sized stones (4-6mm) generally take 2-4 weeks to pass, while larger stones (greater than 6mm) may take longer or require medical intervention as they have less than a 50% chance of passing naturally. During this time, pain management typically includes NSAIDs like ibuprofen or prescription medications such as tamsulosin (0.4mg daily), which may help stones pass more quickly by relaxing ureter muscles, as evidenced by a meta-analysis showing that alpha blockers facilitate ureteral stone passage 1. Staying hydrated by drinking 2-3 liters of water daily increases urine flow and helps move stones along. Some key points to consider when managing kidney stones include:
- The use of alpha blockers, such as tamsulosin, to facilitate stone passage, with a statistically significant 29% more patients passing their stones with alpha blocker therapy than did control patients 1
- The importance of staying hydrated to increase urine flow and help move stones along
- The need for medical intervention if a stone hasn't passed within 4-6 weeks, causes severe pain uncontrolled by medication, leads to infection, or if you have only one kidney.
From the Research
Timeframe for Passing Kidney Stones
The timeframe for passing kidney stones can vary depending on several factors, including the size and location of the stone.
- Studies have shown that the spontaneous passage rate of ureteral stones is highly dependent on the size of the stone 2.
- For stones that are 0-2 mm in size, the spontaneous passage rate is approximately 98% within 20 weeks 2.
- For stones that are 3 mm in size, the spontaneous passage rate is also approximately 98% within 20 weeks 2.
- However, for stones that are 4 mm in size, the spontaneous passage rate decreases to around 81% within 20 weeks 2.
- For stones that are 5 mm in size, the spontaneous passage rate decreases further to around 65% within 20 weeks 2.
- Stones that are 6 mm or larger have a significantly lower spontaneous passage rate, with only around 33% passing within 20 weeks for 6 mm stones and 9% for stones larger than 6.5 mm 2.
Factors Affecting Stone Passage
Several factors can affect the passage of kidney stones, including:
- Stone size: Larger stones are less likely to pass spontaneously 2, 3.
- Stone location: Stones that are located in the distal ureter are more likely to pass spontaneously than those located in the proximal ureter 2, 3.
- Patient factors: While patient factors such as age, gender, and degree of pain do not appear to affect the time to stone passage, other factors such as obesity, older age, metabolic syndrome, diabetes, and hypertension may increase the risk of stone development 4.
Treatment Options
For stones that do not pass spontaneously, several treatment options are available, including:
- Medical expulsive therapy (MET): This involves the use of medications such as alpha-blockers to help facilitate the passage of the stone 5.
- Extracorporeal shock wave lithotripsy (ESWL): This is a non-invasive treatment that uses shock waves to break up the stone into smaller pieces that can then pass out of the body 5, 6.
- Ureteroscopy: This is a minimally invasive procedure that involves the use of a small scope to visualize the stone and remove it or break it up into smaller pieces 6.
- Percutaneous nephrolithotomy: This is a more invasive procedure that involves making a small incision in the back to access the kidney and remove the stone 6.