Kidney stones are also called renal calculi. They may be formed in any portion of urinary tract, from kidney tubules to external opening.

Types: 

Depending on their composition, kidney stones are classified into the following types.

1. Calcium stones : These are usually calcium oxalate or calcium phosphate stones. 

2. Struvite stones : These are formed in response to bacterial infection caused by urea – splitting bacteria. They grow in size quickly and become quite large. 

3. Uric acid stones : These stones usually affect people drinking less water or consuming high protein diet. 

4. Cystine stones : It is a genetic disorder that causes the kidney to excrete too much of certain amino acid. 

Symptoms: Intermittent pain below rib cage in back and side ways. Hazy, brownish/reddish/ pinkish urine. Frequent urge to pass urine. Pain during micturition. 

Diagnosis: Uric acid content of blood, colour of urine, kidney X-ray, sonography of kidney are different diagnostic tests prescribed depending on symptoms.