Kidney stone is a hard, crystalline material made of minerals and salts which forms in your kidney. A stone that is small enough to pass through your urinary tract will be removed from the body without causing any symptoms. However, when the size is too big, it might be trapped in the kidney, urinary bladder or ureter (urinary duct) causing pain, bleeding, obstruction and infection. It is a common condition which is experienced by one in ten people. Book appointment with the clinic if you experience symptoms suggestive of kidney stones. In this article, we will look into detail on the causes of kidney stones.

What causes kidney stones?

The most common cause of stone formation is the supersaturation of urine. When the concentration of minerals in urine exceeds its solubility, it might precipitate to form stones. It might flow out with urine or be retained in the kidney and increase in size to the extent that it blocks the outflow of urine. Various minerals in the urine might contribute to concentrated urine.

Calcium stone

Calcium stone is the most common type of kidney stone, making up 75% cases of kidney stones. It occurs when one has excessive calcium in the urine, either due to increased calcium absorption by the body, increased calcium released from the bone or impaired kidney function in calcium excretion.

Hyperparathyroidism is a condition in which the parathyroid gland located in your neck releases excessive hormone, leading to the release of calcium from bones. Besides, the condition also leads to increased calcium absorption from your gut and decreased excretion of it in the urine.

A majority of calcium stones exist in the form of calcium oxalate. A diet rich in oxalate such as nuts, seeds, grains, spinach and beets is a contributing factor to high levels of oxalate. In addition, certain bowel conditions such as inflammatory bowel diseases or short bowel syndrome might lead to higher oxalate absorption.

Uric acid stone

Uric acid is a byproduct when your body breaks down purine, a chemical which is produced naturally by your body and also found in certain foods. Organ meats, seafood and wild game are foods that contain high levels of purines. There is also an increased risk of uric acid stone in patients receiving chemotherapy and patients with kidney failure.

A high level of uric acid in the blood might lead to uric acid crystal formation, which accumulates in various parts of the body. Deposition of uric acid crystals in joints precipitates gout, a condition of painful joints. Meanwhile, a high level in the urine might lead to the formation of kidney stones.

Cystine stone

Cystine stones are rare. They are caused by a genetic condition known as cystinuria, leaking of cystine into urine. Cystine has a reduced solubility in the urine. Thus, too much cystine in the urine leads to formation of kidney stones in the urinary tract.

Struvite stones

Struvite stones consist of magnesium, ammonium and phosphate. It is a mineral produced by the bacteria Proteus, Pseudomonas and Klebsiella during an urinary tract infection. Besides, the urine becomes alkaline during the infection, creating an environment which is favourable for the formation of stone.


Kidney stones are hard mass made of crystalline minerals and salts. Diet, certain diseases, medications and infection might precipitate the formation of stones along your urinary tract such as the kidney, urinary duct (ureter) or urinary bladder. Stones which are too big might obstruct the urinary tract, leading to symptoms such as pain during urination, difficulty in passing urine, passing blood in urine and fever. Do consult your doctor immediately if you experience symptoms suggestive of kidney stones.