Kidney stones: 5 things your kidneys wish you knew

15% of people will have a kidney stone in their lifetimes. They are more common among men than women. Kidney stones also have a troubling tendency to recur. Stones can be particularly problematic when they occur during vulnerable times like infancy, very old age, pregnancy, etc. Hot, humid climates favour stone formation. Within India, the western part has the highest burden of this disease but other parts are also significantly affected.

Only in a small percentage of patients one specific cause can be found. Generally, these are genetic diseases like primary hyperoxaluria, cystinuria, etc. The genetic diseases are quite rare. The usual components of stones are calcium, uric acid, and oxalate. Common causes that contribute to stone formation are :
Very low fluid intake, dietary indiscretion (high salt, high animal protein, high sugar) and indiscriminate use of calcium supplements. For people already having a kidney stones, a fluid intake of three liters per day is suggested. Uric acid stones are derived from molecules called “purines” in the diet. Red meat, sea food and alcohol are very high in purines. A high blood uric acid may be associated with other diseases like gout, high blood pressure and kidney disease.

Kidney stones are formed in the kidneys but cause pain when they get stuck in narrow tubes called ureters, which convey urine to the bladder. The pain is generally severe and usually starts in the flank and radiates downwards to the private parts. It comes in waves ("colic") and may go on for days. Most patients describe it as the "worst " pain they have experienced so far. Frequently, it is accompanied by nausea and vomiting. Sometimes, the nausea and vomiting can be bad enough to require admission in the hospital and intravenous medications. Fever, if present, points to superadded infection and calls for urgent treatment. Decreased or no urine output is also a warning sign and should not be neglected. Other symptoms include passage of blood in the urine and pain while urinating. In some patients, even large stones may not cause any symptoms. Stones blocking the outflow of urine from one kidney can cause silent damage to the kidney without any over symptoms for months or even years. If one is getting a health check, it is prudent to include ultrasound examination of the kidneys to detect silent stones.

Every patient with kidney stone needs to be treated keeping her specific requirements in mind. Diagnosis can be made on the basis of ultrasound scan though a CT scan may be needed to visualise the actual stones. Repeated CT scans cause radiation exposure and need to be used judiciously. A small stone stuck in the ureter can be expected to pass if the pain is tolerable. Pain relief medications can buy time till the stone passes. Larger stones stuck in the ureter are unlikely to pass and will need minimally invasive surgery ("ureteroscopy") for relief of symptoms. If pain is not severe, then extracorporeal shockwave lithotripsy ("ESWL") which breaks the stones into fragments that can then be passed in the urine can be considered. For very big stones, percutaneous nephrolithotomy("PCNL"), in which kidneys are entered through a small incision in the back and stones evacuated is needed. Retrograde intrarenal surgery ("RIRS") in which stones are removed by entering the kidney through the urinary route is also an option. Bleeding and infection are the complications that can happen with these procedures but can usually be managed conservatively.

Since stones are chronic conditions, it gives ample scope for unqualified "quacks" to ply their wares. Fruit seeds are commonly implicated as "THE" cause for kidney stones but there is no truth behind this. Calcium containing foods are painted as the villain but the fact remains that calcium is an important nutrient that has to be consumed. It is the imbalance between calcium, oxalate and water that leads to stone formation and not just calcium alone. Medications that can "melt" stones are a common stock of trade though there is no evidence that stones can decrease in size. Be very suspicious of any preparation that claims to cure all kidney diseases like stones, infections and kidney failure. Many times these medications/mixtures contain chemicals that can actually harm the kidneys. So, one needs to be careful and avoid unscientific treatments.