What are cystine stones?
Cystine stones are a type of kidney stones. Kidney stones happen when collections of chemicals come together to create a hard mass. These stones can be formed by several different chemicals in the body. Cystine stones are made of a chemical called cystine, a product of a condition called cystinuria. Stones can be a variety of sizes. Cystine stones tend to be larger and sometimes need to be removed surgically to prevent damage to the kidneys or urinary tract. This is a rare condition that is passed down through families (an inherited condition).
What is cystinuria?
Cystinuria is an inherited condition that causes the chemical cystine (an amino acid in your body) to build up in the urine. Collection of cystine in your urine can cause a type of kidney stone. This condition can cause multiple stones to occur throughout your life.
Who gets cystinuria?
Cystinuria is an inherited condition (runs in families) that impacts people in all age groups. Children, teens, people in their 20s and 30s, as well as older adults can all develop cystine stones.
Symptoms and Causes
What causes cystine stones?
Cystine stones are caused by a collection of the amino acid cystine. This occurs in people with a condition called cystinuria. Cystinuria is passed down through a family.
Cystine forms crystals that combine to create stones in the urine.
What are the symptoms of cystine stones?
The symptoms of cystine stones are similar to those of kidney stones.
Symptoms can include:
- Painful urination.
- Vomiting and upset stomach.
- Seeing blood in your urine.
- Feeling a sharp pain in your side or back (this is typically on one side of the body).
- Feeling pain in your groin or abdomen.
In some cases, a urinary tract infection (UTI) may occur because a cystine stone is stuck. Cystine stones tend to be larger than other types of kidney stones, causing complications like UTIs.
Diagnosis and Tests
How are cystine stones diagnosed?
Cystine stones can be diagnosed in several ways, including:
- Identifying symptoms of kidney stones. In cases where a stone has not left the body, the symptoms can help your healthcare provider determine if more testing is needed. Cystine stones can be larger than other types of kidney stones, causing them to get stuck in the urinary tract. Your healthcare provider may need to use imaging tests (ultrasounds and CT scans) as well as urine tests to diagnosis cystine stones.
- Discussing a family history of cystine stones. Your family history can be very helpful when diagnosing cystine stones because cystinuria is an inherited condition.
- Taking a stone in for testing. If you can collect a stone that has passed out of the body with your urine, it can be brought into the lab to be analyzed. Once the chemical structure of the stone is identified, your healthcare provider can better treat it.
Management and Treatment
How are cystine stones treated?
A major part of treating cystine stones is preventing stones from forming in the first place. Dietary changes such as drinking plenty of liquids, limiting the amount of sodium in your diet and cutting back on alcohol can all help prevent cystine stones from forming. Your doctor may also give you a medication to alkalize your urine. This may help prevent cystine from forming together into a stone.
Because cystinuria is an inherited condition, multiple stones can form throughout your life.
If a stone does form, treatment options can include:
- Surgical removal of the stone. Large stones can cause damage if they cannot pass out of the body through the urinary tract. These stones can be very painful and may prevent the flow of urine out of the body. There are several options your healthcare provider may use to remove a stone, including:
- Inserting a small, flexible camera up the urethra (where urine leaves the body), locating the stone and removing it.
- Using shockwave lithotripsy to crush the stone with high-frequency sound waves. Once broken into smaller pieces, the stone can pass out of the body with urine.
- Making a small incision in the back and inserting a tube into the kidney to remove the stone.
Can cystine stones be prevented?
Cystinuria is an inherited condition (passed down through a family) that cannot be prevented. However, you can prevent the formation of cystine stones by drinking plenty of liquids, reducing the amount of sodium in your diet and limiting alcohol consumption. Maintaining a healthy diet may reduce the chance of developing future cystine stones.
Outlook / Prognosis
What is the outlook for cystine stones?
Cystine stones can happen multiple times in your life. If you have cystinuria, dietary changes and medication may be needed to prevent the formation of cystine stones. Cystine stones must be treated and monitored to prevent damage to your urinary tract, kidneys and bladder.