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 can 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.
• 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.

A common reason for stones to form is not being properly hydrated. Dehydration can result in having an overabundance of the stone forming substance in the urine. Once a crystal forms, more layers of crystal continue to pile up making a stone.

Kidney stones and diet

Dietary choices can also lead to stone formation. There are several foods that contain a high concentration of calcium oxalate. To help avoid stone formation, and for those individuals with a history of kidney stones, the following foods should be consumed in moderation:

• Spinach.
• Rhubarb.
• Beets.
• Wheat bran and bran flakes.
• Peanuts – A legume.
• Nuts – Nuts are high in fat.
• Nut butters and spreads.
• Potato chips.
• French fries.

In addition there are a long list of food items that contain uric acid and may help promote stone formation. These foods include:

• Spinach.
• Asparagus.
• Cauliflower.
• Mushrooms.
• Dried beans / legumes.
• Dairy products with full fat content.
• Baked goods that are high in fat.
• Fried foods.
• Organ meats.
• Shellfish.
• Shrimp.

Talk to a urologist to review food choices and restrictions.

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 can vary in size from specks, to stones as big as golf balls.

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 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?

For the most part, patients may not know that they have a kidney stone until it moves. Once it moves, it can cause excruciating pain along with other symptoms, including:

• Intense pain that can radiate.
• Chills.
• Fever.
• Changes in urination – Frequent urination or a reduction in urine due to a blockage.
• Nausea.
• Vomiting.
• Painful urination.
• Cloudy urine.
• Urine that appears to be pink or red in color (blood in the urine).

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. Individuals may stand, sit, pace, or recline, 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?

When visiting a urologist for evaluation, the provider will use several tools to make a kidney stone diagnosis. This diagnostic tools will include:

• Physical examination – A Urologist will ask questions about the patient’s medical and family history and perform a physical examination. A physical examination may be difficult if the patient is experiencing severe pain.
• Urinalysis – This lab test is conducted to detect the presence of blood and/or bacteria.
• Blood tests – Blood tests are used 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 – Imaging may include Ultrasound, X-rays or a CT Scan. A CT Scan is the most common and precise imaging test 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 a 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.

Kidney stones can be an emergency condition depending on the size of the stone and how it is impacting the urinary system. When kidney stone patients are in unbearable pain, and detecting blood in their urine, they should proceed to an emergency room for evaluation and treatment.

If you have a history of kidney stones, or believe you are experiencing a non-emergency kidney stone, contact Urology Austin to schedule an appointment with one of our urologists.