What are kidney stones and how are they treated?

Kidney stones are fairly common and affect around one in 10 people in the UK. They typically affect people aged between 30 and 60 and can develop in one or both kidneys. 

Kidney stones are made of minerals and salts that collect in your kidneys as crystals and form hard deposits — the type of kidney stones you have is determined by the type of crystals they’re made of. Kidney stones can affect any part of your urinary tract and often form when urine becomes concentrated, which allows minerals to form crystals. 

While most kidney stones are small — about the size of a grain of sand — and can be passed out in your urine without you noticing, they can become larger. If a kidney stone is fairly big, it can cause pain when you are passing it or it can get stuck, which leads to complications. 

What causes kidney stones?

Kidney stones are caused by waste products collecting in the kidneys and forming crystals. These crystals can build up into a lump similar to a stone. While this can happen to anyone, some factors mean you’re more likely to develop kidney stones, including:

• Certain medications
• Dehydration
• Gastric bypass surgery
• Hyperparathyroidism
• Inflammatory bowel diseases eg ulcerative colitis or Crohn’s disease
• Obesity

You’re also at greater risk of kidney stones if your diet is high in salt, protein or glucose, which is why it is important to maintain a balanced diet if you have a history of kidney stones. 

What are the symptoms of kidney stones?

Small kidney stones often don’t cause any symptoms and you’re unlikely to notice them as they pass out of your body. However, if kidney stones get to be a few millimetres or even centimetres big, they can cause symptoms as your body tries to pass them out. 

Symptoms of larger kidney stones can include:

• Chills
• Fever
• Nausea and/or vomiting
• Pain in the side of your stomach or back
• Strong smelling or discoloured urine

The pain caused by large kidney stones is severe and can radiate from the side of the abdomen and/or back down to your groin.

When should you seek medical attention for kidney stones?

While most kidney stones will pass on their own, you should see your GP if any of your symptoms are concerning you. 

Larger kidney stones can get stuck, which can lead to complications and the following symptoms:

• Blood in your urine
• Difficulty passing urine
• Pain accompanied by fever and chills
• Pain accompanied by vomiting
• Pain that is so severe that you can’t find a comfortable position

In these cases, you should seek immediate medical attention. 

How are kidney stones diagnosed?

In some cases, your GP can diagnose kidney stones based on your symptoms and medical history. 

However, you may also need to undergo tests to check for kidney stones and also to make sure your kidneys are functioning properly. Tests can include:

• Analysing the stones you pass
• Blood tests to check your kidney function
• Imaging, such as a CT scan or X-ray to check for kidney stones
• Urine tests to check for infections

How are kidney stones treated?

The type of treatment you’ll receive for kidney stones will depend on the type of stones you have. If you have recurrent kidney stones, their composition will be tested so that your doctor can prescribe the most effective treatment.

Treatment for kidney stones can include:

• Intravenous fluids ie fluids passed directly into your bloodstream 
• Medication to break down the stones and for pain relief
• Lithotripsy — using sound waves to break up large stones so they can be passed more easily
• Tunnel surgery to remove the stones if they are too large, are damaging your kidneys or have caused an obstruction or infection
• Ureteroscopy to remove stones stuck in the bladder or the tube connecting your kidneys to your bladder (ureter)

How can you prevent kidney stones?

If you have had kidney stones once, you are more likely to get them again, so it is important to take steps to reduce the chances of them forming. 

Try to:

• Avoid fizzy drinks
• Drink plenty of fluids
• Drink water with fresh lemon juice
• Reduce your salt intake

You can tell if you’re staying hydrated enough by the colour of your urine. Ideally, your urine should be light in colour. If it is dark, it means it is more concentrated, which increases the chances of crystals and then stones forming. 

Depending on the type of stones you have, your GP may also suggest altering your diet to cut down on certain foods.