Kidney stones

Kidney stones are solids formed in the kidneys when substances like calcium, oxalate and phosphorus that are excreted through the urine become concentrated. A kidney stone may either settle down in the kidneys or travel through the urinary tract. Kidney stones usually vary in size. So a smaller crystal may comfortably travel down the urinary tract and get expelled on its own without causing any pain or discomfort.

However, when the crystals increase in size they may from larger hard stones which tend to get stuck as they pass along the urinary tract. This can cause several problems. Mainly it may block the usual flow of urine, causing extreme pain and bleeding. Other symptoms of kidney stones include pain in the lowerback region, vomiting and nausea.

Various factors put an individual to risk for kidney stones. Most common factors include a family history of kidney stones, repeated urinary tract infections, blocked urinary tract, or any health condition that increases the level of substances usually excreted through the urine. Lack of sufficient intake of water and certain medications can also cause kidney stones. Prevention of kidney stones include medications and dietary modification.

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There are four types of kidney stones which include:

Uric acid stones: The factors that can contribute to the formation of uric acid stones is a high protein diet, malabsorption, diabetes, chronic diarrhoea or metabolic syndrome.

Calcium stones: Calcium stones are the most prevalent type of kidney stones. These are in the form of calcium oxalate stones.

Metabolic disorders, high consumption of vitamin D can increase oxalate levels in urine. Another form in which calcium stones are found is calcium phosphate stones. Medical treatment of migraines with topiramate may also be associated with the formation of calcium stones.

Cystine stones: The aetiology of cystine stones is related to cystinuria, a hereditary condition that promotes kidneys to excrete a higher amount of amino acid.

Struvite stones- these stones are caused due to a urinary tract infection. Struvite stones are large and fast-growing.


Unfortunately, kidney stones do not cause any symptoms until they move around in your kidney or pass through your ureter, the tube connecting the kidneys and urinary bladder. Small stones may pass out even without causing any symptoms. But, with larger stones, the following symptoms may be seen:

  • Back and groin pain

  • Pain on urination

  • Abnormal urine colour

  • Nausea and vomiting

  • Persistent urge to urinate

Causes And Risk Factors


Accumulation of uric acid, calcium or oxalate in the urine in the levels higher than your urine can dilute, can cause Kidney stones. These accumulations are in the form of crystals. 

Risk Factors

As men have more muscle mass than women, they are at an increased risk of kidney stones. This is because the daily breakdown of muscle mass leads to a tendency to form stones in the kidneys. 

Other common risk factors of kidney stones include -

Family history: You are more susceptible to develop kidney stones if someone in your family has had stones.

Personal history: The risk of having a kidney stone is much greater if you already have a stone.

Age: Though kidney stones can occur at any age, they are most commonly diagnosed in adults aged 40 and above.

Obesity: High body mass index (BMI), large waist size and weight gain have been linked to an increased risk of kidney stones.

Dehydration: Less fluid intake will increase your risk of getting kidney stones. People that live in hot regions or those who work in environments where they tend to sweat a lot will have a higher risk of developing stones. 

Existing medical conditions: Gastric bypass surgery, inflammatory bowel disease or chronic diarrhoea may cause changes in the digestive process that affect your absorption of calcium and water, increasing the levels of stone-forming substances in your urine. Renal tubular acidosis, cystinuria, thyroid problem (hyperparathyroidism) and urinary tract infections can increase stone formation.

Certain diets: Eating a diet that's high in animal protein, sodium and has low fibre content can increase your risk for kidney stones. This is especially true for a high-sodium diet. Too much sodium increases the calcium load on your kidneys, significantly increases your risk of kidney stones. 


Here are 10 simple ways to prevent kidney stones -

  • Drink lots of water

  • Drink healthy beverages

  • Eat smartly

  • Eat more dairy foods every day(no scientific data)

  • Limit the intake of seafood

  • Reduce the intake of salt

  • Maintain a healthy weight

  • Know your risk

  • Don’t hold your pee for too long

  • Avoid alcohol and cigarettes


Ultrasound of the kidney, ureter and bladder (KUB) is the most convenient and frequently used investigation to diagnose kidney stones. An X-ray KUB can further assist in diagnosis. However, if the stones are small, the patient is obese, or there is an unusual formation of gas in the abdomen, a CT scan is a better method of diagnosis.

Urine testing is significant in the detection of stone-forming minerals. A blood test can help in marking high levels of calcium or uric acid, which help in the diagnosis of kidney stones.


Treatment is based on the size of the stones. Smaller stones can be treated with plenty of fluids, pain medications and certain antispasmodic drugs (pain and spasm relieving), which help in passing the stone out. But even when the symptoms disappear, it is essential to confirm whether the stone has been eliminated through an ultrasound or a CT scan.

Larger stones which do not pass out easily require medical therapy and more advanced treatments such as -

Sound waves: Depending on the size and location of the stones, extracorporeal shock wave lithotripsy (ESWL) may be done. ESWL uses sound waves to create strong vibrations (shock waves) that break the stones into tiny pieces, making them easier to be passed through urine. The procedure lasts for about 45 to 60 minutes. It can cause moderate pain, so it is preferably performed under sedation or light anaesthesia. ESWL can also cause blood in the urine and discomfort as the stone fragments pass through the urinary tract. Depending on the size of the stones, one or more sessions may be needed.

Here's a new method to treat kidney stones.

Percutaneous Nephrolithotomy (PCNL): This treatment is used for very large stones or where ESWL is unsuccessful. The procedure involves surgically removing the stone using small telescopes and instruments inserted through a small incision in the back.


Ureteroscopic Removal: Smaller stones in the ureter or kidneys may be removed by passing a thin, lighted tube (ureteroscope) equipped with a camera through the urethra and urinary bladder to the ureter. Once the stone is located, special tools can snare the stone or break it into pieces, making them easier to pass through the urine. A small tube (stent) may be placed in the ureter to relieve symptoms like swelling and promote healing.


Laser Lithotripsy: Some stones cannot be treated with ESWL because of their size, location, type. In such cases, ureteroscopic laser lithotripsy may be used. In this procedure, a tiny fiberoptic camera is passed into the urinary tract through the urethra to locate the stones in the bladder, kidney or ureter. Then using laser technique, larger stones are fragmented into thousands of small pieces, which are flushed out through urine.


Stay hydrated – a daily requirement of drinking enough fluids should be fulfilled to pass about 2 litres of urine all day.

Salt restriction – restrict the amount of salt in your diet.

Avoid oxalate-rich food, such as spinach, beets, okra, tea, black pepper, Soy products and chocolate should be restricted as they are found to have higher levels of oxalate.

Choose calcium-rich foods instead of calcium supplements – calcium-rich food does not affect kidney stones; however, calcium supplements increase the risk of kidney stones. Therefore, use calcium supplements with caution.

Prognosis And Complications


The chances of recurrence of kidney stones are quite high. More than half of the people, who have had a stone in the past, will develop a new stone in their lifetime.


Untreated kidney stones can significantly damage the kidneys and even lead to end-stage renal disease (ESRD), requiring dialysis. But early detection and treatment may completely reverse the damage, even in those on dialysis.

Unfortunately, many a time, kidney stones remain undetected for years because minor symptoms are ignored/neglected. By the time the patient consults a doctor, the damage becomes irreversible or only partially reversible.


  1. American kidney fund. Kidney stone causes, treatment, symptoms and fund [Internet] Available at

  2. Beth Israel Lahey Health Winchester Hospital. Lifestyle changes to manage kidney stones [Internet] Available at,


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