A kidney stone is a hard, crystalline mass, formed when dissolved minerals separate from the urine and get deposited on the inner lining of the kidneys. Kidney stones can be as small as a grain of sand, or grow to the size of a golf ball. Most kidney stones are very tiny and pass out of the urinary tract on their own. Larger stones can be treated by various techniques which do not involve major surgery.
What are kidney stones made of?
Kidney stones are a by-product of various combinations of chemicals that are part of a normal diet.
1. The most common type of kidney stone contains calcium in combination with either oxalate or phosphate. Calcium oxalate stones may also form in people who have chronic inflammation of the bowel or who have had intestinal surgery.
2. A less common type of stone is triggered by recurrent urinary tract infections (UTIs). This type of stone is called a “struvite” or “Stag horn stone,” due to its characteristic antler-like appearance.
What causes kidney stones?
When one’s water intake is low, uric acid (formed when our body metabolizes protein) in urine makes the kidney environment acidic and more conducive to stone formation. Moreover, kidney stones could develop when natural chemicals present in the urine cannot prevent the crystals from forming. Consuming certain foods may promote stone formation in the case of already susceptible individuals, however, that may not be a factor for people who are not susceptible to kidney stones.
Kidney stones may form in case of gout, UTIs, excess intake of vitamin D, diuretics (water pills), or calcium-based antacids. Cystic kidney diseases and certain rare metabolic disorders have also been linked to stone formation.
Occurrence of Kidney Stones
Statistically, kidney stones are likely to occur in males more than females. Having even one kidney stone increases the likelihood of having another. Recurrence can be prevented if one sticks to the treating doctor’s prescribed medicinal and dietary regimen.
Symptoms of Kidney Stones
Usually, the first symptom of a kidney stone is the sudden, extreme pain caused when a stone moves in the urinary tract and blocks the flow of urine. It may increase or decrease, cause constant and intense discomfort. Typically, the sufferer feels a sharp, cramping pain in the back and side in the area of the kidney, or in the lower abdomen or groin. It could be followed by nausea and vomiting.
Evidentially, drinking 2 to 3 litres of water daily can help most kidney stones move along and exit the urinary tract.
When the stone is too large, muscles in the wall of the ureter (a narrow tube that connects the kidney to the urinary bladder) try to push the stone into the bladder. There may be an urge to urinate more often, or an accompanying burning sensation. The urine itself may appear pink-tinged due to the presence of blood. These symptoms, plus fever or chills could signal an infection that calls for urgent medical attention.
Even “silent” stones whose symptoms do not manifest can be spotted on X-rays; alternatively, the doctor may opt for a CT scan. Diagnostic imaging reveals the stone’s size and location, crucial to decide the course of treatment. Blood and urine tests help detect any abnormal substance that might promote stone formation.
Surgical intervention (in consultation with the treating doctor) may be required if the stone:
- causes constant pain and does not pass
- is at a difficult location or too big to dislodge by other means
- blocks the flow of urine
- causes or worsens UTI
- causes constant bleeding
- damages kidney tissue
- is growing in size (detectable through follow-up x-rays)
Modern ways to treat kidney stones do not often require open surgery, and can be performed in an outpatient setting.
Extracorporeal Shock Wave Lithotripsy (ESWL) is the most frequently used procedure, wherein shock waves generated outside of the body are sent through the skin and body tissues until they hit the kidney stones. The denser stones splinter into smaller pieces that can easily pass through the urinary tract.
Ureteroscopy may be needed for stones situated near the middle or lower regions of the ureter. No cut is made; instead, the surgeon passes a small fibre-optic instrument called an “Ureteroscope” through the urinary system to locate the stone, then either removes it with a special device or shatters it using shock waves.
Kidney stones can be prevented by consciously drinking more water during phases of heavy sweating, such as exercise, and regularly consuming sugar-free lemonade or orange juice. Recent studies have shown that foods high in calcium, including dairy products, may help prevent calcium stones.
Highly acidic urine could be prevented by eating less meat, fish, and poultry and avoiding alcohol. A diet rich in vegetables and fruits, whole grains, and low-fat dairy products is recommended overall. Doctor-prescribed preventative medications also act by controlling the amount of acid or alkali in the urine— key factors in crystal formation.