What is kidney stone? – A kidney stone refers to an irregular hard substance formed in the kidney. It is often of small size when formed but can grow larger with time, depending on how long it stays before being passed out and the availability of the ‘ingredients’ for the formation of stone.

How does stone get to the kidney?

A kidney stone forms from the reaction of certain chemicals present in the urine (such as calcium, phosphate, urate, oxalate, xanthine and cystine). These chemicals get into urine from the breakdown of the food we eat.

That is they are by-products of food metabolism which are meant for excretion through the kidneys. These chemicals react with each other to form a solid mass present as stone, especially when present in high concentration (i.e. when there is little water content in urine). 

Once formed, the stone may attract more of the chemicals to itself and grow bigger, as long as it remains in the kidney. On the other hand, it may be passed out in urine through the ureters (pipes that carry urine from the kidneys to the bladder) as soon as it is formed, in which case it will be small in size. The size of the stone and the location along the urinary tract determine the extent of the symptoms felt by the person affected.

What are the risk factors for kidney stone?

The risk factors for kidney stones include: family history, drinking too little water, high protein diet (meat, eggs, beans etc), obesity, diabetes, certain medications and food high in salt and sugar.  

What are the types of kidney stones?

Kidney stones could be calcium oxalate, uric acid, struvite or cystine. The most common of these is calcium oxalate stone followed by uric acid stone. Multiple kidney stones could be of different types.

What are the symptoms of kidney stone?

Kidney stones that are small may be passed without any symptom. The larger the size, the more prominent the symptoms felt by the patient. Some of the symptoms of kidney stone are:

1. Severe pain on either side of the lower back (below the ribs) which may move down the groin
2. Pain while passing urine
3. Passing urine more frequently than before
4. Fever with chills
5. Nausea or vomiting 
6. Blood in the urine
7. Cloudy urine
8. Urine with bad smell

How is kidney stone treated?

Treatment of kidney stones depends on the size and the symptoms it causes.

1. Conservative management – Small kidney stones may not need treatment as they can be passed with urine through the ureters to the bladder and out through the urethra. The passage may elicit pain
2. Medical treatment – Drugs could be given to relieve the pain due to kidney stones or to treat other symptoms such as pain, nausea and vomiting. Other treatments may be given to make the ureters relax in order to allow the stones to be passed easily. 
3. Surgical treatment – This may be necessary for kidney stones that cannot be treated with drugs or when drug treatment has failed to resolve the symptoms. The surgical methods employed may involve open surgery to remove the stone and close the site; use of an instrument passed through the ureter to visualise the stone and either break it in pieces with the aid of laser or retrieve it as a whole (ureteroscopy) or the use of high energy ultrasound wave to break the stone into pieces so it can be passed in urine.

What are the preventive measures against kidney stone?

The risks of having kidney stones can be reduced by:

1. Drinking adequate water – The easiest way to know if you are drinking enough water is the colour of your urine. When you drink water in appropriate quantity for the body, the urine will be slight yellow (amber colour) to almost as clear as water. In hot weather when people sweat a lot, it is recommended to drink water as frequently as possible in order to replace the losses through sweat.
2. Reduction in weight – Weight loss can help reduce the risk of developing kidney stones.