17794 Cystine Stones

Overview

A cystine stone is a type of kidney stone that forms when there is too much of an amino acid called cystine in the urine. Cystine is a waste product that normally passes into the urine, but in some people it does not stay dissolved and forms hard crystals that can grow into stones.

No, cystine stones are uncommon. They make up about 1% of all kidney stones in adults and about 6% in children.

They affect people who inherit the cystinuria gene from both parents. Anyone can be affected, but symptoms often begin in the teens or twenties. Men and women are affected about equally.

Symptoms

Common symptoms

• Sharp pain on one side of the back or lower belly
• Pain that comes and goes and can move toward the groin
• Blood in the urine (pink, red, or brown)
• Burning sensation when urinating
• Feeling the need to urinate often
• Nausea or vomiting

Symptoms in children

• Children may have the same symptoms as adults, but they may find it hard to describe the pain.
• A child who suddenly seems uncomfortable, cries during urination, or has blood in the diaper or urine should be checked.
• Recurrent urinary tract infections in a child can sometimes be a clue.

Symptoms in older adults

• Older adults may have less typical pain, such as vague belly discomfort or a sense of tiredness.
• They may also have confusion or weakness if a stone blocks the kidney.
• Urinary symptoms such as pain or blood may be less obvious.

Causes

Main causes

• Cystinuria, a genetic condition that prevents the kidneys from reabsorbing cystine properly
• High levels of cystine in the urine, which can crystallize and form stones
• Low urine volume, which makes the urine more concentrated
• Urine that is more acidic than normal, which makes cystine crystals more likely to form

Risk factors

• Family history of cystine stones or cystinuria
• Personal history of kidney stones, especially at a young age
• Living in a hot climate or not drinking enough fluids
• Certain diets that are high in salt or animal protein

When to see a doctor

See a doctor urgently if:

• You have sudden, severe pain in your back, side, belly, or groin.
• You have pain with a fever or chills.
• You are unable to pass urine.
• You feel very nauseated or are vomiting.

Book a routine appointment if:

• You notice blood in your urine.
• You have burning or pain when urinating.
• You have repeated pain in your back or belly that you cannot explain.
• You have passed a stone before and would like to prevent more.

Diagnosis

Your doctor will take a detailed history and ask about any kidney stones in your family. They will likely order urine and blood tests to look for cystine and other substances. If a stone has already passed, it can be sent to a laboratory to check what it is made of.

Tests that may be done

• Urine test to check for cystine, crystals, and blood
• Blood test to check kidney function
• Imaging scan, such as a CT or ultrasound, to find stones in the kidney or urinary tract
• Stone analysis if a stone is passed or removed

What to expect at your appointment

Your doctor may refer you to a kidney specialist (a nephrologist) or a urologist. The first visit may take an hour. You should bring a list of your symptoms, any medicines you take, and any family history of stones. Tests may take a few days or weeks, and the doctor will explain the results and work with you on a plan.

Treatment

The main goals are to remove any stones that are causing problems, prevent new ones from forming, and protect your kidney function. Your doctor will tailor your treatment to your symptoms, stone size, and overall health. The most important part of long-term care is drinking plenty of fluids and following a plan that reduces cystine in your urine.

Self-care at home

• Drink enough water so your urine stays pale and clear. Many people with cystine stones need to drink a lot — often more than 3 liters (about 12 glasses) each day.
• Drink fluids evenly through the day, including in the evening, to keep your urine dilute overnight.
• Cut down on salt in your diet, as too much salt can increase cystine in the urine.
• Eat a balanced diet with normal amounts of protein, unless your doctor advises otherwise.
• Take all prescribed medicines exactly as directed, even if you feel well.

Medical treatments

Your doctor may prescribe medicines that help the body remove less cystine or that make the urine less acidic, so cystine is less likely to form crystals. These medicines come as tablets or liquids, and the right one for you depends on your test results and overall health. Always follow your health care provider's instructions. Never start, stop, or change any treatment on your own.

When is surgery considered?

If a stone is very large, is blocking urine flow, or causes strong pain or infection, a specialist may need to remove it. Common procedures include breaking the stone with shock waves, or removing it with a scope through the urinary tract. For very large stones, a small tube may be placed into the kidney to break up and remove the stone. Your doctor will explain which approach is suitable for you.

Living with this condition

Living with cystine stones means making hydration a daily habit. Carry a water bottle with you, and keep an eye on how much urine you pass. Regular checkups with your doctor will help catch new stones early before they cause severe pain.

Lifestyle tips

• Set reminders to drink water throughout the day.
• Keep a record of any stones you pass, and ask your doctor about sending them for testing.
• Avoid becoming dehydrated, especially during hot weather or after exercise.
• If you get a kidney stone, ask what your next steps should be and follow them.

Diet and exercise

Most people with cystine stones should aim for a balanced diet. Eating too much salt can make the condition worse, so choose fresh foods and use herbs and spices instead of salt. Regular, moderate exercise is generally safe and good for overall health, but be sure to replace fluids after sweating. Your doctor or a dietitian can give you advice specific to your needs.

Mental health and emotional wellbeing

Living with a chronic condition that can cause pain can be stressful. It is normal to worry about when the next stone may come. Talk to your doctor if you feel overwhelmed or anxious. Support from friends, family, or a counselor can also help.

Prevention

Yes, but it takes regular effort. The single most important way is to drink enough fluids every day, ideally enough to produce more than 2.5 to 3 liters of urine. Your doctor may also recommend medicines to reduce cystine levels. Preventing stones reduces the risk of injury to your kidneys.

Vaccines

There is no vaccine for cystine stones. Keeping up with your regular vaccinations is always a good idea for your overall health.

Screening programmes

If you have a family history of cystine stones, your doctor may suggest testing your urine for cystine, even if you have no stones yet. Screening can help start preventive steps early.

Complications

If left untreated

• Repeated stones can block urine flow and cause severe pain.
• Stones can lead to infections in the urinary tract or kidneys.
• Over time, untreated cystine stones can damage the kidneys and reduce kidney function.
• In rare cases, a complete blockage can lead to acute kidney failure.

Long-term outlook

With proper care and good hydration, most people with cystine stones live full, active lives. It may take time to adjust, but sticking to your treatment plan and having regular checkups can greatly reduce the chance of problems. You are not alone, and your health care team is there to help you.

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