Kidney Stones

Overview

Substances in the urine (calcium, oxalate, phosphate, and uric acid, in particular) can crystallize within the kidney and form rock-like particles (calculi) called stones. The medical term for this condition is nephrolithiasis or renal stone disease. Kidney stones may be as small as a grain of sand or larger than a golf ball. They may be smooth, round, jagged, spiky, or asymmetrical depending on their composition. Most stones are yellowish to brownish-black in color, but variations in chemical composition can produce stones that are tan, gold, or black.

The four most common types of stones are made of various combinations of calcium, phosphorus, oxalate, magnesium, ammonia, uric acid, and cystine.

There are four common types of Kidney Stones.

 

Calcium Stones make up about 70% to 80% of all kidney stones and are composed of hard crystals of calcium oxalate, insoluble phosphate salt, or both. They occur in patients with hypercalciuria (excessive calcium in the urine) or hyperoxaluria (excessive oxalate in the urine). In about 40% of patients who develop calcium stones, this build up is caused by an inherited metabolic disorder. In rare cases, a non-cancerous tumor of the parathyroid gland may trigger an overproduction of parathyroid hormone, the chemical that regulates calcium metabolism. Intestinal disease, excessive amounts of vitamin A or D, and a diet too high in purine (associated with meat, fish, and poultry consumption) also can cause hypercalciuria. Calcium oxalate stones are commonly associated with vitamin B deficiency or an excess of vitamin C in the diet.

 

Struvite stones (also called infection stones) account for up to 20% of all kidney stones and are made of magnesium, ammonia, and phosphate. This often occurs in patients who develop urinary tract infections. Struvite stones are more common in women because they generally suffer more urinary tract infections than men. This type of kidney stone typically develops as a jagged or branched structure called a “staghorn” calculus.

 

Cystine Stones are composed of Cystine, an amino acid found in nerves, muscles, and other body tissues. Cystinuria, a rare genetic defect in which excessive cystine build-up in the urine can lead to the development of cystine stones. This type of stone occurs in about 1% to 2% of patients with kidney stone disease. The condition often is hereditary.

 

Uric Acid Stones are composed of Uric acid, a by-product produced by the body as it breaks down protein that is normally flushed out by the kidneys in urine. Some people, particularly men, build up excessive uric acid concentration in their kidneys or joints. In the joints, this can cause pain, and is known as “gout,” an inherited disorder with painful arthritic symptoms. If uric acid builds up in the kidneys, especially if the urine tends to run acidic a lot of the time, uric acid stones may form. An estimated 5% to 13% of patients with kidney stone disease develop uric acid stones. Genetics may be a factor in uric acid stone propensity. Patients prone to developing uric acid stones are advised to reduce their consumption of high-protein foods, especially meat and often may be placed on urinary alkalinizers.

Signs & Symptoms

Kidney stone symptoms can vary from person to person. Most people complain of a sharp and severe pain in their back localized to one side or the other. It may slowly evolve over a few days or it may come on quickly. The pain may radiate down into the abdomen and groin or even cause nausea and vomiting. Some patients will note blood in their urine or very dark urine

"the pain from a stone is typically sudden in onset and quite severe"

As most people are aware, the pain from a stone is typically sudden in onset and quite severe. Although the pain is usually located in the flank region, some patients will experience pain in the abdominal region, which may be mistaken for other conditions. Associated symptoms may include nausea and vomiting as well as fever and chills if any infection is present. At times the patient may notice urinary frequency and a sense of bladder irritation as the stone nears the bladder. Although gross urinary tract bleeding is sometimes seen, microscopic bleeding is more common.

  • Extreme pain in your side and back, below your ribs
  • Pain that spreads to your lower abdomen and groin area
  • Pain that comes and goes and changes in intensity
  • Nausea, vomiting, fever or chills Pink, red or brown urine
  • Cloudy or bad smelling urine
  • Persistent urge to urinate or urinating more than usual

Diagnosis & Treatment

If a stone is found, there are many kidney stone treatment options available. Small stones will usually pass on their own, however it is impossible to predict when this will occur. If the stone is blocking the kidney, creating infection or causing severe symptoms, there may be a need to intervene before the stone passes.

An x-ray in our office may show an obvious stone, however, if no stone is seen and the symptoms are consistent with a kidney stone, a CT scan or IVP may be needed. These special x-rays help find a stone that is too small to be seen or is invisible to plain x-rays. A urine check at our Columbia, Missouri office is necessary to make sure there is no infection. Blood is not always present in the urine.

"Blood is not always present in the urine."

Small Stones

If your stone is small, your doctor may recommend you try to pass it out in your urine. To do this, you need to drink a lot of water so that your urine is almost clear. Normally, your doctor will prescribe a pain medication to help with the discomfort and a medication help your ureters (the tubes that carry urine) relax to allow the stone to pass.

 

Ureteroscopy

A small stone in the ureter (thin tube connecting the kidney to the bladder) can be treated with a procedure called ureteroscopy if it does not pass on its own. In this procedure, your urologist passes a flexible tube with a camera through your urethra. A wisk-like basket on the end of the scope snares the stone and removes it. If the stone is too large, the urologist can use a laser inserted through the scope to break the stone apart. After a ureteroscopy, the urologist places a stent in the ureter to hold it open until the swelling subsides. The stent is removed a day later.

Shockwave Lithotripsy

Larger stones in the kidneys can usually be treated with a procedure called lithotripsy. This is a way to break up the stone in the kidney without making any incisions or utilizing any scopes. In an outpatient surgery center, your urologist uses a machine called a lithotriper to direct ultrasonic shock waves to hit the stone repeatedly until it crumbles into small particles that you an pass in your urine. This is the most frequently used procedure for eliminating kidney stones.

 

Large or Complicated Stones

If your stone is too large to pass, blocking the flow of urine or causing other complications, your doctor may recommend one of these treatments.

Percutaneous Nephrolithotomy/Stone Extraction

For large stones that can’t be effectively treated with lithotripsy or ureteroscopy, your urologist can perform a minimally-invasive surgery through a 1 centimeter incision in your back. Using a scope and special tools, the urologist can break apart the stone and suction it out. Typically requires hospitalization at least overnight.