Introduction

Stones in the kidney are also called Nephrolithiasis or renal calculi. Stones can also be formed in the bladder and the ureters(connecting tubes between the kidneys and bladder). It is important to evaluate and treat kidney stones because they can lead to infection due to stasis and obstruction and if untreated can progress to damage to kidneys and kidney failure.

The common type of stones are made of calcium, calcium phosphate, calcium oxalate and magnesium ammonium phosphate. The other less common types are made of diammonium calcium phosphate, magnesium phosphate, cystine, urate and xanthine.

Incidence

Renal stones are more common in men (80%) than women(20%).
It affects two out of every thousand people.
It is more common in persons between 30-50 yrs.
Children and teenagers can also be affected.

Cause and Pathogenesis

Generally stones form due to supersaturation of the substances in the urine that leads to crystal formation. The crystals act as a nidus for further accumulation of the substances leading to increase in the size of the stones. There are certain factors that predispose to stone formation.
They are:

• Genetic predisposition.
• Excess of calcium or other minerals in the diet.
• Excess of Uric acid, Vitamin C, Vitamin D in the diet.
• Dehydration leading to concentrated urine.
• High environmental temperature causing sweating and fluid loss.
• Sedentary lifestyle.
• Bowel diseases like ulcerative colitis and Crohns disease, illeal bypass for obesity.
• Renal tubular acidosis.
• Diets rich in fruits and vegetables that contain oxalate.
• Lack of factors that inhibit stone formation like citrate and magnesium.
• Resorptive hypercalciuria-resorption of calcium from the bone into the blood.
• Renal hypercalciuria- the kidneys filter out the calcium but do not reabsorb.

Symptoms

Kidney stones are often painless and without any symptoms. Many of them pass off in the urine. However some stones will not pass out of the system:

• Extreme pain in your back or side that will not go away.
• Blood in your urine.
• Fever and chills.
• Vomiting.
• Urine that smells bad or looks cloudy.
• A burning feeling when you urinate.
• Increased frequency, urgency or hesitancy when passing urine.

Investigations

Some or all of the following tests may be necessary:

• Urine Exams.
• A plain X-ray of the abdomen.
• An ultrasound as a small number are radiolucent (cannot be seen by an X-ray) stones may not be visible in a simple X-ray and can be picked up by an ultrasound examination of the abdomen.
• Abdominal CT Scan.
• Stone Analysis.

Treatment

The type of stone, in size and content, determines the nature of treatment.

Usually, if the stone is less than 5mm in size, there is a good chance of it passing without any surgical intervention. If it is very painful, painkillers may be prescribed. Depending on the type of stone, medication may also be prescribed.

If the kidney stone is larger than 1/2 inch (or 10mm) in diameter it will likely need to be either removed by surgery (open or endoscopic) or by lithrotripsy.

Percutaneous Nephrolithotomy

The advantages are a small incision in the flank through which an endoscope is passed into the kidney and the stone is removed. Stones larger than 3 cm can be removed by this method.

Extra Corporeal Shock Wave Lithotripsy

In this method high energy shock waves are used to break the stones. The stones are crushed into sand like fragments which subsequently pass out in the urine over a period of even months.

Surgery

Open surgery may be necessary in less than 5% of cases. The surgery consists in opening the kidney to remove the stones. This leaves a long scar. The recovery takes about four to six weeks. In most cases simpler procedures are opted for.

Ureteroscopy

If the stone is found in the lower part of the ureter, laser can be used along the path of the ureter to vaporise the stone while in situ.

Lithoclast

This uses air pressure to break the stone. The fragments are removed using a forceps or flushed with water and sucked out.

Prevention

Drink more water. Try to drink 12 full glasses of water a day. This may help the flushing away of stones.

You can take juices but water is preferable. Limit tea and coffee intake as this may make you lose fluid content.

You may be asked to make changes in your diet depending on the type of stone.