Kidney Stones

WHAT IS A KIDNEY STONE?

Kidney stones are formed when a substance that would normally dissolve in the urine precipitates out to form a crystal, which then grows into a stone. Kidney stones can be so small that they easily pass out of the body during urination without being noticed. However, they can also grow so large that they can become lodged in the kidney or ureter. When stones get stuck, they block the normal flow of urine causing pain, infection, and sometimes kidney damage. Larger stones may require open surgery to remove, or shock wave or laser lithotripsy to break them into smaller pieces so that they can move on their own.

WHAT CAUSES A KIDNEY STONE TO FORM?

Kidney stones can form based on a number of reasons:

  • Recurrent urinary tract infections
  • Dehydration - Drinking too little fluid, especially during hot weather conditions
  • Blockage of the urinary tract
  • Sedentary lifestyle - Limited activity for several weeks or more
  • Excessive calcium oxalate or uric acid in your diet
  • Excessive vitamin C or D
  • Intake of certain medications
  • Presence of certain metabolic diseases
  • Family history of stone formation

The most common reason for stones to form is drinking too little fluid causing dehydration. This results in too much of the stone forming substance and not enough water to keep it dissolved in the urine. Once a crystal forms, more layers of crystal continue to pile up making a stone. 

WHAT DO KIDNEY STONES LOOK LIKE?

Kidney stones are as unique as snowflakes. Their color depends on what substance makes up the stone. Most are yellow, brown, tan, gold, or black. Stones can be round, jagged, or even have branches. They vary in size from specks to stones as big as golf balls.

FOUR MAJOR TYPES OF KIDNEY STONES

There are different types of kidney stones. Some are made of only one substance and some are made up of a mixture of substances.

  • Calcium stones: The most common type of kidney stone contains calcium. Most stones (70 to 80%) contain mainly Calcium Oxalate crystals.
  • Struvite stones: A struvite stone forms from an infection in the urinary system. These stones contain the mineral magnesium and the waste product ammonia.
  • Urid acid stones: A uric acid stone may form when there is too much acid in the urine. If the acid level in the urine is high, the uric acid normally found in the urine may not dissolve and uric acid stones may form. 
  • Cystine stones: Cystine stones are rare. Cystine is one of the building blocks that make up muscles, nerves, and other parts of the body. It is an amino acid and protein that does not dissolve well. Some people inherit a rare condition that results in large amounts of cystine in the urine. This condition, called Cystinuria, causes cystine stones that are difficult to treat and requires long-life therapy.

WHAT ARE THE SYMPTOMS OF KIDNEY STONES?

  • Pain - Intense pain; typically a constant pain that intensifies in waves. This pain is usually located below the ribs in the vicinity of the kidney. The pain can often shoot from that location to the groin. The patient usually cannot find a position that is comfortable, so usually stands, sits, paces, or reclines, in search of a position that will bring relief.
  • Blood in the urine - It is common to find blood in the urine either microscopically or, less frequently, visible to the naked eye.

If fever and chills accompany these symptoms, an infection may be present and medical attention is required as soon as possible. 

HOW ARE KIDNEY STONES DIAGNOSED?

  • Physical examination - A Urologist will ask questions about your medical and family history and perform a physical examination. A physical examination may be difficult if the patient is experiencing severe pain. 
  • Urinalysis - To detect the presence of blood and/or bacteria.
  • Blood tests - To detect Creatinine (to evaluate kidney function); BUN and electrolytes to detect dehydration; calcium to detect hyperparathyroidism, and a complete blood count to detect infection.
  • Imaging - Ultrasound, X-rays or CT Scan. A CT Scan is the most common and precise imaging test used today to evaluate a possible kidney stone attack.
  • IVP (Intravenous Pyelogram) - For an IVP, a special dye is injected into the patient's veins. The dye collects in the urinary system and produces white shadow when an x-ray is taken. The dye allows the doctor to precisely locate the stone and to determine the condition of the kidneys and ureters. Most kidney stones can be precisely located using this procedure.

TREATMENT OPTIONS FOR KIDNEY STONES

Treatment for kidney stones depends on the size of the stone(s), its location, the presence of a urinary infection, your medical profile, and the severity of the condition. Urologists use several procedures to break up, remove, or bypass kidney stones.

  • Ureteroscopy - This procedure can be used to remove or fragment stones located anywhere from the kidney down to the bladder. A ureteroscope, which is a fiber optic instrument resembling a long, thin telescope, is inserted through the urethra and passed through the bladder to the stone. The ureteroscope has a camera that allows the Urologist to see the stone, and a working channel that tiny instruments pass through. Once the stone is located, the Urologist can break the stone up into dust sized pieces, using a laser or other fragmenting device. A Ureteroscopy is performed under general or spinal anesthesia on an outpatient basis.
  • Percutaneous Nephrostolithotomy (PCNL or tunnel surgery) - Percutaneous (through the skin) removal of kidney stones is accomplished by making a small cut through the skin on the patient's back and creating a narrow tunnel through the kidney to the stone. With a special instrument that goes through the tunnel, the doctor finds the stone and removes it. This treatment can achieve the best stone-free outcome in the treatment of very large stones within the kidney. This procedure requires general anesthesia. 
  • Shockwaves - Extra-corporeal shockwave lithotripsy (ESWL) has been used in the United States since 1984. It is performed using a machine called a lithotriptor.
  • Open or Laparoscipic Surgery - This procedure requires general anesthesia. An incision is made in the patient's back or abdomen and the stone is removed by making an opening in the ureter or kidney, removing the stone and repairing the opening.