The Tribune

By DR GREGGORY PINTO

Kidney stones are formed when hard crystals supersaturate and accumulate in the kidneys. Kidney stones can vary greatly in size, ranging from a small grain of sand to the size of a marble or larger. There are five main types of kidney stones: calcium oxalate and calcium phosphate stones, infective stones called struvite, uric acid stones and cystine stones.

One in ten adults will develop a kidney stone in their lifetime and approximately 50 percent of kidney stone formers will have a recurrence. More than 500 thousand Americans are forced to visit a hospital emergency room due to the severe pain of a kidney stone. Many persons with kidney stones are able to spontaneously pass the stone but the process can potentially be a severely painful long ordeal. The pain associated with passing a kidney stone can be off the pain scale charts. The majority of the sometimes severe pain associated with passing a kidney stone stems from the inflammation and colicky cramping in the ureter as the stone passes through the narrow tube ureter (the tube that connects the kidneys to the bladder).

The current medical conservative expulsion therapy for promoting kidney stones, involves prescribing pain killers and the medication Tamsulosin/Flomax, which is a drug often prescribed for men with benign prostate hyperplasia (BPH). Flomax is believed to relax the ureter and aid in the passage of a stone. According to the American Urological Association (AUA), a kidney stone patient should not wait more than six weeks to pass a small kidney stone and urological consult should be sought sooner if there are complications of infection or persistent or worsening pain. There are two main factors that determine how fast a kidney/ureter stone is passed and that is the size of the kidney stone and the location thereof. Generally speaking, smaller stones pass faster and with less pain.

Scientific researchers at the Massachusetts Institute of Technology (MIT) and Massachusetts General Hospital have developed a new promising potential treatment to assist people in passing kidney stones faster and with much less pain. Two drugs given in combination have shown to cause effective relaxation of the ureter and thus promote the passage of stones down the ureter more easily and into the bladder. The two drugs are Nifedipine, a calcium channel blocker that is often used to treat high blood pressure, and the drug ROCK (Rho-associated protein kinase), an inhibitor that is used in eye glaucoma treatment.

The two drugs are delivered directly into the affected ureter with the obstructive kidney/ureter stone in an endoscopic minimally invasive procedure using a cystoscope, an instrument with optic fibres and a camera, that is placed through the urethra and into the bladder. The experiments determined that these two drugs remained in the ureter and were not detected in the blood stream, thus reducing potential side effects to the body. The Nifedipine and ROCK inhibitor combination therapy could also potentially make the placement of kidney/ureter stents easier and less painful. Kidney/ureter stents are often placed to relieve the obstruction and pain in the case of obstructive kidney stones.

A kidney stone larger than 6mm has, on average, a 20 percent chance of being spontaneously passed without any intervention. Kidney stones smaller than 4mm have about an 80 percent chance of passing spontaneously within 30 days. Large stones will need some urological intervention that is often minimally invasive, such as a laser procedure.

People suffering from kidney stones should seek hospital emergency room consult or an urologist consult with symptoms of severe or persistent flank, back or lower abdominal pain, foul smelling urine or increased urinary urgency and frequency, blood in the urine, fever and chills and/or gastrointestinal symptoms such as nausea or vomiting.

A large and obstructive kidney stone could lead to back pressure on the affected kidney and acute or potentially chronic kidney failure.

Never ignore the worsening symptoms of a suspected kidney stone. Seek confidential, compassionate and comprehensive urological care for kidney stones.

•Dr Greggory Pinto is a Bahamian urologist who has trained in South Africa, Germany, France and India. He is a member of the European Association of Urologists. Dr Pinto can be reached at Urology Care Bahamas at the Surgical Suite, Centreville Medical Centre, Collins Avenue and Sixth Terrace. Call 326 1929, e-mail welcome@urologycarebahamas.com, or visit www.urologycarebahamas.com.