Kidney Stones

A kidney stone develops from crystals that separate from the urine and build up on the inner surfaces of the kidney. Normally, urine contains chemicals that prevent or inhibit the crystals from forming. These inhibitors do not seem to work for everyone, however, so some people form stones. If the crystals remain tiny enough, they will travel through the urinary tract and pass out of the body in the urine without being noticed.??Doctors do not always know what causes a stone to form. While certain foods may promote stone formation in people who are susceptible, scientists do not believe that eating any specific food causes stones to form in people who are not susceptible.??A person with a family history of kidney stones may be more likely to develop stones. Urinary tract infections, kidney disorders such as cystic kidney diseases, and certain metabolic disorders such as hyperparathyroidism are also linked to stone formation.??In addition, more than 70 percent of people with a rare hereditary disease called renal tubular acidosis develop kidney stones.

About 5-10% of people will have a kidney stone at some time, although not everyone suffers from the symptoms. Men tend to be affected more frequently than women but recent evidence suggests that the incidence of stones in women is rapidly increasing.The prevalence of kidney stones rises dramatically as men enter their 40s and continues to rise into their 70s. For women, the prevalence of kidney stones peaks in their 50s, although this age is rapidly decreasing. Once a person gets more than one stone, others are likely to develop.

There are 4 common types of kidney stones:

1. Calcium

Of the four main types of urinary stones, calcium stones are the most common. Almost 80% of all kidney stones are calcium stones. They occur when there is too much calcium in the urine. Defective kidney function may allow too much calcium in the urine, or excessive calcium may be absorbed from the stomach and intestines.

Some calcium stones are caused by an excess of a chemical called oxalate, present in many foods, which binds easily with calcium to form a stone. The risk of calcium stone formation is increased if you have certain medical diseases; for example, hyperparathyroidism and inflammatory bowel disease.

2. Uric Acid

A second type of kidney stone is made of uric acid. These stones are much less common than calcium stones. Uric acid stones occur because you have too much uric acid in your urine. They might occur if you have become dehydrated; for example, during strenuous exercise on a hot day or perhaps during an illness. Uric acid stones are common in people who have gout, a disease that causes high uric acid levels in the blood.

3. Infection Stones (Struvite)

A third type, struvite stones, are not quite so well understood. It is thought that these stones form as a result of an interaction between protein-breakdown products and infection-causing bacteria in the urine.

4. Cystine

Finally, a rare type of kidney stone is a cystine stone. It occurs if you have the genetic disease called cystinuria. This disease results from a birth defect that causes the kidney to allow too much cystine into the urine. This type of stone formation is almost always diagnosed during childhood.

1. Asymptomatic 

The stones are found by accident by routine examination with x-rays, or urine tests. Depending on whether they are causing problems, they may or may not require treatment.

2. Signs / Symptoms:

• Pain – Usually, the first symptom of a kidney stone is extreme pain, which occurs when a stone acutely blocks the flow of urine. The pain often begins suddenly when a stone moves in the urinary tract, causing irritation or blockage. Typically, a person feels a sharp, cramping pain in the back and side in the area of the kidney or in the lower abdomen. Sometimes nausea and vomiting occur. Later, pain may spread to the groin.
• Blood in the urine

That is dissolving with medication – only applies to uric acid stones.

Shock Wave Lithotripsy (SWL) is the most frequently used procedure for the treatment of kidney stones. In SWL, shock waves that are created outside the body travel through the skin and body tissues until they hit the denser stones. The stones break down into sand-like particles and are easily passed through the urinary tract in the urine.

In most cases, SWL may be done on an outpatient basis. Recovery time is short, and most people can resume normal activities in a few days.

Complications may occur with SWL. Most patients have blood in their urine for a few days after treatment. Bruising and minor discomfort in the back or abdomen from the shock waves are also common. To reduce the risk of complications, doctors usually tell patients to avoid taking aspirin and other drugs that affect blood clotting for several weeks before treatment. Another complication may occur if the shattered stone particles cause discomfort as they pass through the urinary tract.

In some cases, the doctor will insert a small tube called a stent through the bladder into the ureter to help the fragments pass. Sometimes the stone is not completely shattered with one treatment, and additional treatments may be needed. SWL is not ideal for very large stones.

Sometimes a procedure called percutaneous nephrolithotomy is recommended to remove a stone. In this procedure, the surgeon makes a tiny incision in the back and creates a tunnel directly into the kidney. Using an instrument called a nephroscope, the surgeon locates and removes the stone. For large stones, some type of energy probe (kinetic or laser) may be needed to break the stone into small pieces. Generally, patients stay in the hospital for several days and may have a small tube called a nephrostomy tube left in the kidney during the healing process.

One advantage of percutaneous nephrolithotomy over SWL is that the surgeon removes the stone fragments instead of relying on their natural passage from the kidney.

Treatment option for Kidney Stones. Pyeloscopy, the endoscope is designed to reach all the way to the renal pelvis (also called pyelum), thereby allowing visualisation of the entire drainage system of the kidney.The endoscope can contain an instrument port which allows for introduction of laser fibres to fragment stones, and micro-baskets to retrieve stone fragments.Kidney stones up to 2 cm in size can be treated by pyeloscopy.