Kidney stones are the mineral deposits formed in the inner surface in the urinary tract. Generally small stones can pass out of the body. There are various kinds of kidney stones calcium stones, uric acid stones, struvite stones, cystine stones and xanthine stones.
The urine contains various salts like calcium, cysteine, xanthine and many others. If there is no enough urine or the concentration of salts is very high then the salt concentration reaches such a level that they can not dissolve in urine and form crystals. This process is called as super saturation.
Magnesium, citrate, pyrophosphate and certain enzymes present in urine prevent crystal formation or coat the crystals and prevent them to stick to the walls of the kidney tubes. When the concentrations of these substances decrease the risk of kidney stone formation increases. Changes in the acidity of the urine also affect stone formation.
Being male, family history of kidney stones, obesity, weight gain, inherited metabolic disorders, kidney diseases intravenous feeding in low birth weight children, diet rich in sodium and animal protein, diet low in calcium, stress, being bed ridden, gout, inflammatory bowel disease, high blood pressure, hyperthyroidism, urinary tract infections and certain medications are the risk factors for kidney stones. Certain medications also cause kidney stones.
Symptoms depend on the location of the stone. There may not be any symptoms in most of the cases. Kidney stone attacks are more common in late night or early morning due to constriction of ureters and they are least common in late afternoon.
There may be pain on one side that may become intense and constant. It may be at the side of the back near the vest and radiates down to the groin area as the stone passes down. The patient is uncomfortable and keeps changing the positions for relief. The pain may last for 20 to 60 minutes. There may be nausea, vomiting, loss of appetite, unintentional weight loss, blood in urine, pus in urine, reduced volume of urine (due to obstruction) or urine with foul smell. When the stone reaches near to the bladder there is an increased need to urinate and there may be burning sensation or pain at the time of urination. There may be fever and chills with any of the described symptoms if there is an infection.
Kidney stones are diagnosed based upon the medical history, physical examination and imaging techniques. The imaging techniques include X-ray, CT scan (Computerized Tomography), MRI (Magnetic Resonance Imaging), ultrasound, intravenous pyelogram or spiral (helical) CT scan.
Laboratory analysis of urine is also done to check for the presence of red blood cells, crystals, infection and presence of chemicals that hinder or support the stone formation. Blood is also tested for stone factors.
Treatment for kidney stones includes watchful waiting for the kidney stone to pass in urine. Medications for expulsion of kidney stone include alpha blockers, diuretics, citrate salts, phosphates or antibiotics. Pain killers and non- steroidal anti-inflammatory drugs are also given. Extracorporeal shock wave lithotripsy, percutaneous nephrolithotomy, ureteroscopic stone removal and standard open surgery (nephrolithotomy) are the procedures to remove kidney stones.
More intake of fluid, control over intake of sodium salt, high potassium and low protein diet help in preventing kidney stones. However to prevent different kidney stones different diet changes are required. One should follow the individualized diet plan. Lots of fluid and frequent urination are also important.
