Kidney stones are hard mineral deposits that form in the kidneys and can cause pain, urinary changes, and sometimes infection. The first signs of kidney stones often include back or side pain, changes in urine color, and increased urgency to urinate.
Kidney stones are common in adults over 65, but symptoms can appear differently in different people, sometimes making them harder to recognize early. Understanding how kidney stones develop, what they feel like, and how long kidney stones last can help prevent complications.
What Are Kidney Stones?
Kidney stones, also called renal stones or nephrolithiasis, are solid clusters of minerals and salts that form inside the kidneys when urine becomes concentrated.
The kidneys normally filter waste and excess fluid from the blood to produce urine. When there isn’t enough fluid, or when minerals like calcium, oxalate, or uric acid build up, tiny crystals form. Over time, these crystals stick together and grow into stones.
A stone may remain in the kidney without causing symptoms. Problems usually begin when the stone moves into the ureter, which is the narrow tube carrying urine to the bladder. This can cause blockage or irritation.
Why Kidney Stones Are More Common in Older Adults
Kidney stones are more common in older adults because of several reasons.
- Lower daily fluid intake. As people age, their sensation of thirst diminishes, causing them to drink less water.
- Reduced kidney filtering capacity.
- Use of medications like diuretics, also known as ‘water pills’. These help the kidneys remove excess salt and water from the body through urine.
- Conditions such as diabetes, gout, or high blood pressure.
- Limited mobility or dietary changes.
What Are the First Signs of Kidney Stones?
Since early symptoms may often be subtle, how to know you have kidney stones can be somewhat tricky. Confusion, weakness, or even unexplained falls sometimes appear before severe pain. Symptoms also vary depending on stone size and location. Common warning signs include:
- Frequent or urgent need to pee
- Pain or burning while urinating
- Cloudy or foul-smelling urine
- Pink, red, or brown colored urine. This indicates blood.
- Nausea, mild stomach upset, or vomiting
- Fatigue or weakness without clear cause
- Fever or chills. These indicate possible infection
Because many of these symptoms overlap with urinary infections or prostate issues, imaging tests like ultrasound or CT scans are often needed for confirmation.
Pain Specific to Kidney Stones
Kidney stones are often accompanied by pain. This can be different for different people.
- Dull pain or discomfort in the lower back, side, abdomen, or groin
- Pain that feels like it’s coming in ‘waves’
- Sudden sharp pain episodes
- Pressure or heaviness rather than stabbing pain
- Pain spreading toward the groin
- Restlessness or inability to get comfortable
Older adults may feel constant discomfort rather than severe attacks, making stones easier to mistake for arthritis or back problems.
The Development of Kidney Stones
Kidney stones usually take months or even years to develop, as minerals slowly accumulate layer by layer into larger deposits.
However, in people at high risk, stones can form within weeks, especially when dehydration, high salt intake, or dietary imbalances are involved.
This is how kidney stones are formed:
- Crystals: Tiny crystals of minerals and salts, most commonly calcium combined with oxalate or phosphate, form in urine. There are usually no symptoms at this stage.
- Stone growth: The crystals collect in the kidneys and begin to grow larger. You may experience mild urinary changes such as cloudy urine, mild discomfort while urinating, increased urge to urinate, or slight changes in urine color or smell.
- Movement: The stone travels from the kidney through the renal pelvis (a funnel shaped collection chamber that channels urine from kidneys to the ureter) and enters the ureter. This causes pain, burning during urination, blood in urine, nausea, vomiting, and frequent or urgent urination.
- Blockage: Urine flow becomes blocked, potentially leading to infection or kidney damage such as kidney swelling (hydronephrosis), reduced kidney function, or, in severe untreated cases, permanent kidney damage or kidney failure.
How Long Do Kidney Stones Last?
Kidney stones can remain silent for months or years while sitting in the kidney. Once symptoms begin, the duration of symptoms and stone passage depends on stone size:
- Small stones (under 4mm): Often pass within days to weeks.
- Medium stones (4-6mm): May take weeks or need medical help.
- Large stones: Often require medical procedures such as shock wave therapy (ESWL), ureteroscopy with laser stone removal, or, for very large stones, percutaneous nephrolithotomy (PCNL), a minimally invasive surgical procedure.
What Foods Cause Kidney Stones?
Diet plays a significant role in stone formation, though not all stones are caused by food alone. Common dietary contributors include:
High-Sodium Foods: Excess salt increases calcium in urine, raising stone risk.
Examples:
- Processed foods
- Packaged snacks
- Canned soups
- Fast food
Oxalate-Rich Foods: Oxalate can bind with calcium to form stones.
Examples:
- Spinach
- Beets
- Nuts
- Chocolate
- Tea
Excess Animal Protein: Too much red meat, poultry, or seafood increases uric acid levels.
Sugary Drinks and Soda: High sugar intake can increase stone risk and reduce hydration.
Low Fluid Intake: Not drinking enough water concentrates urine, making it easier for minerals like calcium and oxalate to stick together and form crystals
Kidney Reserve: Why it Matters with Age
Kidney reserve refers to unused filtering capacity that the body can draw upon when needed, such as during illness or stress. As people age, this reserve shrinks. Therefore:
- Even small blockages affect kidney function more quickly.
- Infections become more serious.
- Recovery takes longer.
What is Kidney Reserve?
Your kidneys don’t run at full power all the time. Under normal conditions, only part of their filtering ability is being used. The unused capacity remains as backup, to be called into use when needed. This backup capacity is the kidney reserve.
When your body needs to filter out more waste material from the blood, like after a high-protein meal, during illness, or if one kidney is damaged, the kidneys call in the backup reserve and temporarily increase filtration to compensate.
When to Seek Medical Care
Immediate medical attention is needed if an older adult experiences:
- Fever or chills
- Severe pain
- Vomiting, especially when it prevents you from drinking water
- Blood in urine
- Confusion or sudden weakness
- Difficulty urinating
These may signal infection or dangerous blockage.
Frequently Asked Questions
- Can kidney stones appear without pain?
Yes. Some stones remain in the kidney without causing pain and are discovered accidentally during imaging tests.
- Do kidney stones always need surgery?
No. Many small stones pass naturally with fluids and medication. Only larger or obstructive stones need procedures.
- Can dehydration alone cause kidney stones?
No, but it greatly increases the risk. When you don’t drink enough water, your urine becomes concentrated, making it easier for minerals like calcium, oxalate, and uric acid to clump together and form stones. In other words, dehydration sets the perfect stage, but other factors, like diet, genetics, and medical conditions, usually play a role too.
- Are kidney stones preventable after one episode?
Drinking plenty of water, making dietary changes (like reducing salt, limiting high-oxalate foods, or moderating animal protein), and, in some cases, taking prescribed medications can significantly lower the risk of kidney stones coming back.
- Can kidney stones cause urinary infections?
Yes. Stones can block urine flow, allowing bacteria to grow and leading to infections.
Acting Early Protects Kidney Health
Kidney stones in adults over 65 often present differently than in younger people, with milder or unusual symptoms. Knowing how to recognize the first signs of kidney stones, how long they may last, and what dietary factors contribute can help older adults and caregivers seek care early and prevent serious complications.
If symptoms seem unusual or persistent, it is always safer to check sooner rather than later. Early action can prevent pain, infection, and long-term kidney problems.