The kidneys, the ureters (small tubes that connect the kidneys to the urinary bladder), and the urinary bladder form the urinary tract. Kidney stones also referred to as renal calculi, are formed in the kidney due to the deposits of minerals and salts. The person is then said to be suffering from kidney stone disease, nephrolithiasis, or urolithiasis.
The stones formed in the kidneys can travel from the kidneys into the ureters from where they land in the urinary bladder. The passage from the kidneys into the ureters and to the bladder does not happen in one go but happens a little at a time over a period. Every time the stone moves, the person suffers from severe pain.
While the lungs filter unwanted gases from the lungs, our kidneys filter impurities and excess water from the blood.
They remove from the blood unwanted products of metabolism such as ammonia, urea, uric acid, creatinine, hormone metabolites, and toxins. They also excrete excess water, nutrients, or food constituents such as salt, vitamin C, B vitamins, and more.
Kidney stones start small and can be as small as a sugar crystal. They grow in size and may even be as large as a ping-pong ball, or even larger. However, most kidney stones are about the size of a chickpea. Small stones can pass out through the urine but you might need surgery to remove the larger ones.
Early signs and symptoms of kidney stones
A kidney stone does not cause any symptoms until it moves. It may move within the kidney or from the kidney to the ureters or may inch downward in the ureter.
If the stone gets lodged in the ureters, it may block the urine flow downward into the bladder. This causes the kidneys to swell and the ureters may go into spasm. This may cause intense pain.
However, some kidney stones do not cause any symptoms. They are known as “silent” kidney stones. But, most people who have kidney stones often complain of a sudden onset of excruciating pain in their low back and/or side, groin, or abdomen. The pain can radiate from the abdominal side down toward the groin.
The pain of a kidney stone is one of the most intense pains you can experience even worse than that of childbirth or a compound bone fracture. It is referred to as renal colic. It may wax and wane in severity and is often accompanied by nausea and vomiting.
The location and the severity of pain may vary as the stone may move down the urinary tract. As the stone moves towards the neck of the bladder, you may experience a little difficulty in passing urine, an urgent need to urinate, and pain in the penis or testicles ( in males).
Other symptoms could be:
Blood-stained urine is a characteristic feature.
There may be fever with chills if infection has set in.
There could be pain or burning while passing urine.
The person may feel a persistent need to urinate along with an increase in the frequency of passing urine.
Location of kidney stone and corresponding symptoms
Stone in the kidney: Vague flank pain and hematuria
Stone in proximal ureter: Renal colic, flank pain, and upper abdominal pain
The middle part of the ureter: Renal colic, anterior abdominal pain, flank pain
The distal part of the ureter: Renal colic, dysuria, increased urinary frequency, anterior abdominal pain, flank pain, pain radiating to the tip of the penis, or the labia
Can kidney stones cause gastrointestinal symptoms?
A person who has a kidney stone may have problems with their stomach and gastrointestinal (GI) tract. Some GI symptoms that kidney stones may cause you to experience include:
nausea
vomiting
persistent stomach discomfort
The appearance of such GI symptoms should make you suspect kidney stones.
What causes kidney stones?
There is no single specific cause for the formation of kidney stones, though there are several factors that increase your risk. Anyone can develop kidney stones but some people harbor risk factors that make them more prone.
Men suffer from kidney stones more often than women do. Kidney stones are also more predominant in non-Hispanic white people than in people of other ethnicities.
Kidney stones develop when crystals of minerals, like calcium, oxalate, and uric acid, in your urine clump together to form one or more stones. This happens when there is not enough water in the urine to dissolve these crystals.
Additionally, there may be a lack of stone inhibitors in your urine and more stone promoters. This creates an ideal environment for the formation of kidney stones. Stone-promoting substances promote the formation of stones while stone inhibitors inhibit them.
For example, apart from low urine volume and low urine pH, high calcium, sodium, oxalate, and urate are known to promote or encourage calcium oxalate stone formation. Many inorganic (citrate, magnesium) and organic substances (nephrocalcin, urinary prothrombin fragment-1, osteopontin) are known to inhibit or prevent stone formation.
An imbalance between urinary stone inhibitors and stone promoters has been suggested to be an important cause of stone formation.
Risk factors
Risk factors are those factors that significantly increase your chances of developing stones. If you are associated with any of them, you should take preventive measures, which can help you avoid this problem
1. Personal and family history
If you have suffered from kidney stones in the past, it is very likely, a 50-50 chance, that you will develop this problem again. If any member of your family had suffered from kidney stones it makes you very prone to develop them.
2. Dehydration
A person who does not habitually drink enough water is a likely candidate to develop renal stones. This is more likely in those who live in places with warm dry climates, and in those who either sweat a lot through habit or occupation of hard physical labor. This can deplete water in the body and cause dehydration.
3. Certain foods can give you kidney stones
What you habitually eat plays a big role in your risk. Regularly eating a diet high in animal proteins, sugar, and particularly sodium (salt) and low in carbohydrates reduces the body’s ability to absorb calcium and significantly increases your risk of certain types of kidney stones.
A diet that has too much salt increases the calcium amount in the blood for your kidneys to filter and enhances your risk of developing calcium stones.
Consuming too much vitamin C makes your body produce more oxalate, which increases your chances of developing oxalate stones. A diet high in purines can predispose to uric acid stones or stones
4. Obesity
It is established that a high body mass index (BMI), a large waist circumference, and an obese weight are definitely associated with an increased risk of developing different types of kidney stones but more calcium oxalate stones than uric acid stones. The degree of the increased risk may be more in women than in men.
5. Gastrointestinal diseases and surgery
Inflammatory bowel disease and gastric bypass surgery can interfere with the digestion and absorption of calcium and water. This can make your urine more concentrated and increase the proportion of stone-forming substances in your urine, which can predispose you to stone formation.
6. Certain medications
Excessive use of certain medicines and supplements can increase your risk of developing kidney stones. These include:
It was believed that kidney stones were a problem in middle-aged men, but now they have increasingly become common in middle-aged women and also affect women during pregnancy.
Besides the risk factors that increase stone formation described above, some are exclusive to women. They include obesity, a high-salt diet, and high sugar diet, and diabetes. All these factors have increased stone formation in women over the past 30 years.
Note: Of all the causes and risk factors mentioned above, a constant habit of low intake of water leading to dehydration is the most important single factor for causing kidney stones of all types.
If you are prone due to the risk factors mentioned above, you should pay attention to your daily water intake and make sure you stay well hydrated.
A daily intake of 2 liters of water will reduce your risk by half. The American Urological Association recommends that patients with stones should drink 2.5 liters of water every day.
According to Mayo Clinic, for the average, healthy adult living in a temperate climate, The U.S. National Academies of Sciences, Engineering, and Medicine recommends an adequate daily fluid intake as follows:
About 15.5 cups (3.7 liters) of fluids a day for men
About 11.5 cups (2.7 liters) of fluids a day for women
