What are Kidney Stones?

The kidneys are a part of the body’s urinary system. They are bean-shaped organs that filter the blood of metabolic wastes, which are then excreted as urine. The process of kidney stone formation is called nephrolithiasis. The word comes from the Greek nephros, meaning kidney, and the Greek lithos, meaning stone.

Kidney stones are solid pieces of material made of dissolved minerals in urine and occur when urine becomes too concentrated. They vary in size and can be as small as a grain of sand, as large as a golf ball, and any size in between. They are usually yellow or brown and may be smooth or jagged. They originate in the kidney and usually leave the body when urine is passed. The smallest ones may pass through without you taking any notice. Those are called “silent stones”.

Many kidney stones don’t cause symptoms and are not discovered until it begins to make its way from the kidney to the bladder. Passing a kidney stone causes excruciating pain, especially when it becomes a blockage in the urethra (thin tube that takes the urine to its exit point). In many cases medical removal is necessary.

A person’s chance of passing a stone without medical intervention depends on several different factors, including the size of the person, prostate enlargement, prior passing of a stone, and the size of the stone. There is an 80% chance that a stone no larger than 4mm can be passed without assistance, and only a 20% chance of that occurring with a 5mm stone.

Different Types of Kidney Stones

There are different types of kidney stones, classed according to their mineral composition.

· Struvite stones contain the waste product ammonia and the mineral magnesium.

· Cystine stones are the hardest stones, and also the rarest form. Cystine is an amino acid (basic structural building unit of proteins) found only in people diagnosed with a condition known as “cystinuria,” which is handed down through family genetics.

· Uric acid stones are formed when the urine contains an excess of acid.

· Calcium stones are the most common form. Excess calcium usually exits the body through the urine, but if it does not, it combines with other waste products and creates a stone.