Kidney and ureteral stones are very common, but it is difficult to get an accurate figure for the number of sufferers in Europe.
Kidney or ureter stones often pass without any discomfort but this disease can be amongst the most painful experiences known. In the past, this was seen as a “Cinderella disease”, a disease which was reasonably common but with little public visibility. Today, however, more people are likely to form stones because of the changes in the Western diet and lifestyle.
What is a stone?
A stone is a hard, solid mass that can form in the gallbladder, bladder, and kidneys. These types of stones have different causes and are treated in different ways.
Kidney and ureteral stones develop in the kidney and either stay there or move to the ureter (Fig. 1).
Kidney stones form when minerals or acid salts in your urine crystalise. Most stones leave your body while you urinate. However, sometimes stones get stuck in the ureter, block the normal flow of urine, and cause symptoms. Stones can also be too big to leave the kidney. In both cases you may need treatment to remove the stone.
What are the causes of kidney stones?
Anyone may develop a kidney stone during his or her lifetime. Stones can form if there is an imbalance in the way your body produces urine. This may be connected to how much you drink and whether there are substances in your urine which trigger stone formation.
Stones can have other causes as well.
People often associate kidney and ureteral stones with pain. However, symptoms can vary from severe pain to no pain at all, depending on stone characteristics – such as the size, shape, and location of the stone in the urinary tract (Fig. 2).
Severe pain (renal colic)
If the stone blocks the normal urine flow through the ureter you will experience severe pain, known as renal colic. This is a sharp pain in the loin and the flank (the side of your body, from the ribs to the hip) (Fig. 3). If the stone is not in your kidney but in your ureter, you may feel pain in the groin or thigh. Men can even have pain in their testicles.
Renal colic is caused by a sudden increase of pressure in the urinary tract and the ureteral wall. The pain comes in waves and does not decrease if you change positions. It is described as one of the most painful experiences, similar to giving birth.
Other symptoms that may accompany renal colic are:
- Blood in the urine (urine appears pink)
- Painful urination
Renal colic is an emergency situation and you should contact your family doctor or nearest hospital to relieve the pain. In case of high fever you must seek medical help immediately.
Stones that do not block the ureter can cause a recurrent, dull pain in the flank. This kind of pain may also point to other diseases, so you will need to take medical tests to find out if you have kidney or ureteral stones.
Some stones do not cause any discomfort. These are called asymptomatic stones and are usually small. They do not block the flow of urine. In general asymptomatic stones are found during x-ray or similar imaging procedures for other conditions.
The doctor does a series of tests to understand what causes your symptoms. This is called a diagnosis. First, the doctor or nurse will take your medical history and do a physical examination. Then, they will take images of your body and perform other tests if needed.
To locate your stone the doctor needs to take images of your internal organs. You will get an ultrasonography (also known as ultrasound), which uses high-frequency sounds to create an image.
The doctor can see whether the stone causes an obstruction by checking if the urinary collecting system is enlarged. In addition to ultrasonography, you may need an x-ray of the urinary tract.
Another common method of diagnosis is a CT-scan (computed tomography). For stone disease a non-contrast- enhanced computed tomography (NCCT) is done. This scan can clearly show the size, shape, and thickness of the stone.
In some situations your doctor may decide to do a contrast-enhanced CT-scan or an intravenous urography. These images give additional information about your kidney function and your anatomy.
Stone analysis and other tests
In case of renal colic, your urine and blood are tested to see if you have an infection or kidney failure.
If your stone is expected to pass with urine, your doctor may recommend that you filter your urine to collect the stone. The doctor will analyse it in order to understand what type of stone you have. This information is important because it helps to select the best options for treatment and prevention.
If you have a high risk of forming more stones, you will get additional tests known as metabolic evaluation.
You have been diagnosed with a kidney or ureteral stone. This section describes the different treatment options which you can discuss with your doctor. Together you can decide which approach is right for you.
Factors that influence the decision include:
- Your symptoms
- Stone characteristics
- Your medical history
- The kind of treatment available at your hospital and the expertise of your doctor
- Your personal preferences and values
Not all stones require treatment. You need treatment if your stone causes discomfort and does not pass naturally with urine. Your doctor may also advise treatment if you have pre-existing medical conditions. There are different treatment methods for emergency and non-emergency situations.
If you have a kidney or ureteral stone which does not cause discomfort, you will generally not receive treatment. Your doctor will give you a time schedule for regular control visits to make sure your condition does not get worse.
If your stone is likely to pass with urine, your doctor can prescribe drugs to ease this process. This is called conservative treatment.
If your stone continues to grow or causes frequent and severe pain, you will get active treatment.
Conservative stone treatment
Most kidney or ureteral stones will leave your body while you urinate. However, depending on the size and location of the stone, it will take you some time to pass the stone. You may suffer from renal colic when the stone moves. If you have a very small stone there is a 95% chance of passing this stone within 6 weeks.
In general, you can keep this in mind:
- The closer the stone is to the bladder, the higher the chance of passing it
- The bigger the stone, the smaller the chance of passing it
There are 2 common conservative treatment options: Medical Expulsive Therapy (MET) and dissolving uric acid stones. In both cases you get medication.
Active stone treatment
Kidney or ureteral stones should be treated if they cause symptoms. There are 3 common ways to remove stones:shock-wave lithotripsy (SWL), ureteroscopy (URS), and percutaneous nephrolithotomy (PNL).
Which active treatment option is best for you depends on many aspects. The most important factor is the symptoms the stone causes. Based on whether the stone is in your kidney or your ureter, the doctor may recommend different treatment options.
If you don’t have symptoms you may still get treatment in case:
- The stone continues to grow
- You are at high risk of forming another stone
- You have an infection
- Your stone is very large
- You prefer active treatment
Your doctor will recommend to remove a stone in the ureter if:
- It seems too big to pass with urine
- You continue to suffer from pain while you take medication
- Your kidneys have stopped or may stop to function properly
Acute renal colic
Renal colic is an acute, painful situation caused by a stone that blocks the ureter. Go to the family doctor or the nearest emergency room as soon as possible to relieve the pain.
Pain is usually relieved with NSAIDs (non-steroidal anti-inflammatory drugs), which you can take as a tablet or a suppository. If this first step of treatment does not help, you will get stronger painkillers called opioids. Usually, they are injected directly into the vein. The disadvantage of opioids is that they can make you nauseous.
On a rare occasion, drugs do not work. In this case the doctor may need to drain urine from your kidney. This is called decompression.
There are two methods of decompression:
- By placing a ureteral JJ-stent in your ureter through your urethra (Fig. 3)
- By inserting a percutaneous nephrostomy tube into your kidney directly through the skin (Fig. 4a and 4b)
Both methods are equally effective.
Obstructed and infected kidney
If you have renal colic together with a fever or if you feel unusually tired, you should go to the closest urological department at once. You will get blood and urine tests to check if you have an infected, obstructed kidney.
If you have an infected, obstructed kidney, you need immediate decompression to relieve the pressure in your kidney. After the decompression you will get antibiotics to clear the infection. You can only be treated to have your stone removed after the infection is gone.
Prevention of stone recurrence
Some patients who have had kidney or ureteral stones may form more stones in the future. After your stone passes or is removed, your doctor will determine if you are at high risk of recurrence. To do so, he or she will need to analyse the stone. In addition, the doctor will consult the results of your blood and urine tests which were done before treatment.
If your risk of recurrence is low, general lifestyle changes will be enough to cut the risk of forming another stone.
If you have a high risk of recurrence, the doctor will run a series of specific blood and urine tests called metabolic evaluation (See Metabolic Evaluation for Kidney and Ureteral Stones). Depending on the test results, the doctor will recommend preventive measures or further tests.
General lifestyle advice to prevent stones
Even if you have a low risk of forming another stone, your doctor and nurse will advise you to make some lifestyle changes. These measures reduce the risk of you getting another stone and improve your health in general. The following advice is for adults.
- Make sure you drink 2.5 to 3 litres every day
- Drink evenly throughout the day
- Choose pH-neutral drinks such as water or milk
- Monitor how much you urinate. It should be 2 to 2.5 litres every day
- Monitor the colour of your urine: it should be light
- Drink even more if you live in a hot climate or do a lot of physical exercise. This will help you to balance your fluid loss
Adapt your diet
Depending on your individual situation, your doctor may recommend that you adapt your diet. It is important to discuss this with the doctor first.
- Have a balanced and varied diet
- Avoid excessive consumption of vitamin supplements
- Eat lots of vegetables, fibres, and fruits (especially citrus fruits)
- Try to eat more low-oxalate foods like eggs, lentils, white rice, peeled apples, grapes, cauliflower, squash, etc
- Make sure your diet contains a sufficient amount of calcium (about 1,000 milligrams a day). However be careful with calcium supplements and always ask your doctor or nurse for advice
- Reduce the amount of salt in your diet (no more than 3 to 5 grams a day)
- Do not eat too much animal protein, especially meat from young animals. Instead, eat more vegetable protein, found for example in avocado, cauliflower, or peas
- Maintain a healthy weight (your Body Mass Index should be between 18-25 kg/m2)
Adopting a healthy lifestyle is always a good idea.
- Try to exercise 2 or 3 times a week
- Avoid stress
Read more about how to adapt your diet in these Litholink brochures
If you have a high risk of forming more stones (See Causes of Kidney and Ureteral Stones), your doctor will do a metabolic evaluation. This is a series of blood and urine tests to determine which additional treatment you may need.
Depending on the test results, you may get medication. Generally, the medication will cause little or no side effects. In addition, it may be helpful to consider lifestyle changes (See Prevention of Stone Recurrence). Your doctor will discuss your individual situation and treatment options with you.
As part of the metabolic evaluation your doctor will ask you to collect your urine in 2 separate periods of 24 hours. This is done some 3 weeks after your stone has passed or has been removed. The amount of urine is measured and so are the levels of different substances in the urine.