All you need to know about kidney stones

The pain of having kidney stones is often described as one of the worst you can experience. But what are kidney stones, why can they have the potential to cause a lot of pain, and is there anything you can do to minimise your chances of getting them?

Here, we speak to Mr Ken Anson, Consultant Urological Surgeon and kidney stone specialist, who works at The Princess Grace Hospital, part of HCA Healthcare UK, to answer the common questions around kidney stones.

What are kidney stones made up of?

Kidney stones are crystallisations of metabolites in the urine that congregate together and create stones. Typically, they look like small pieces of gravel and come in a number of different colours and consistencies – from small soft stones that can almost crumble in your hand, to very hard and solid. They can also range in size and can fill the whole of the drainage system of the kidney – the so called ‘staghorn’ stone.

The role of the kidney is to filter any waste products from the blood into the urine which then passes from our body when we urinate. Whilst some stones might be small enough to pass in our urine without us knowing, some can cause excruciating pain when they pass down the tube between the kidney and the bladder (the ureter) and sometimes they can become stuck on this journey.

What are the symptoms of kidney stones?

Nowadays one of the commonest ways kidney stones are detected is during imaging of the body that the patient has for other conditions - these stones are considered incidental findings but need to be discussed with a urologist. However, sometimes, when a kidney stone moves down from your kidney to the ureter, it can cause severe pain, often described as one of the worst pains you can experience – this is known as ureteric or renal colic. 

Kidney stones are common – more than 1 in 10 people will experience it at some point in their lifetime, so it’s important you’re aware of the symptoms. Common symptoms can include:

• Lower back or stomach pain
• Blood in the urine
• Urinary infections
• Nausea and vomiting
• Frequent urination
• Burning sensation when urinating
• Pain in the tip of the penis

How are kidney stones diagnosed?

If your doctor suspects you have a kidney stone, they may conduct tests such as:
•  Urine test to check for any infections or presence of blood 
•  Blood test to check kidney function, calcium and uric acid
•  Chemical examination of any stones that have been passed

If you are referred to a urologist due to suspicion of kidney stones, they might do further tests, which include:
•  Ultrasound to assess the kidney for any stones and evidence of kidney obstruction
•  CT scan to further assess for stones in more detail

How do you treat kidney stones?

In the majority of cases, small kidney stones (and those that have moved into the ureter) will pass spontaneously and are managed with supportive measures such as pain relief and medication. The stones which need treatment are the ones which are too large to pass spontaneously or those that are causing the patient persistent pain or if there is evidence to suggest an infection.  

For these kinds of stones, the treatments include:

• Extracorporeal shockwave therapy (ESWL) - a minimally invasive treatment that involves using ultrasound or X-ray to pinpoint the stone, before shockwaves are directed at the stone to break it up into smaller pieces to be passed naturally. This can be done in one session or several sessions depending on the size of the stone.
• Ureterorenoscopy – this is where a long, thin telescope-like camera is inserted through the urethra into the bladder and along the ureter and into the kidney to reach the stone. The surgeon may then use a laser to break the stone into smaller pieces to pass naturally or remove them all at the same time.
• Percutaneous kidney surgery – this is performed through a small incision in the back to enable much larger stones to be removed.

If someone has kidney stones once, are they more prone to getting them again?

It has been reported that between 30% and 50% of the population will experience a second episode of kidney stone disease in five years.
 

Can you do anything to prevent kidney stones?

In the majority of people, we do not know why they form stones, so we offer general advice to reduce the risk of further stones forming. The simplest yet most important thing is to ensure you regularly produce clear, dilute urine. You can tell if you are drinking enough by the colour of the urine – if it’s champagne colour then you’re doing something right! 

You should also avoid adding salt at the table (you can cook with it in moderation) and enjoy a healthy diet, with perhaps a maximum of five servings of meat a week. If you have a high intake of oxalate containing foods such as coffee, tea, chocolate, peanuts, spinach and rhubarb, then these should be reduced. It’s important however that you don’t drastically change your diet in a short space of time, as this can also increase the risk of stones forming.

Book an appointment with Mr Ken Anson at The London Kidney Centre here