Kidney stones explained: From symptoms to prevention

Kidney stones (also known as urinary calculi or urolithiasis or nephrolithiasis) are a common health concern that can affect people of all ages, but especially the ones above the age of 45.

In the UK, almost 1 in 10 men and 1 in 12 women will have at least one episode of kidney stones in their lifetime.

Encyclopaedic fact: kidney stones occur in many animals like dogs, cats, horses, pigs, birds, turtles, rodents and dolphins.

Kidney stones are hard mineral deposits that form in the kidneys and can cause anything from mild discomfort to intense pain, especially when they fall into the ureter (the tube that connects the kidneys with the bladder) and blocks the flow of urine causing swelling of the kidney (hydronephrosis). The stones are then called ureteric stones and the severe pain is called Renal Colic or Ureteric Colic.

By understanding the causes, symptoms, and treatments for kidney stones, you can take steps to manage or even prevent kidney stones effectively.

We speak to esteemed consultant urologist Mr Stefanos Almpanos who explains their causes, symptoms and steps to manage or even prevent kidney stones effectively.

What are kidney stones?

Kidney stones are solid clusters of minerals and salts that develop within the kidneys. Our kidneys are the filters of our body, removing waste. When the waste is not diluted enough or it is too much to be cleared or the anatomy of the kidney does not allow it to clear, it then becomes solid tiny crystals, which can attract one another to form solid stones.

They can range in size from tiny, grain-like particles measuring a few millimetres, to larger, pebble-shaped formations, measuring 1 - 2 centimetres or up to very large, so called ‘staghorn’ stones, which are several centimetres. Some stones can be created and grow bigger by urine infections and they are called infectious stones; such stones can cause more urine infections, creating thus a vicious cycle of urine infections and stone growth.

The stones can cause pain and some of them, the ones that block part of or the whole kidney not allowing it to produce the urine properly, can actually damage irreversibly the kidney function.

Are kidney stones all the same or made from different components?

Usually stones are composed of calcium, oxalate, uric acid. The infectious stones are usually composed by magnesium ammonium phosphate, while there are other, more rare stones made of cystine, xanthine and other substances and some stones which are caused by medications (e.g. Indinavir, Triamterene, excess of laxatives, Vit C, Vit D, etc)

Kidney stones can cause no symptoms, can cause mild symptoms like mild loin pain, feeling of heaviness of the right or left flank or can cause more severe pain which can become excruciating when the stone moves into the ureter (the long, thin tube that connects the kidneys to the urinary bladder and allows the urine produced in the kidney to travel into the bladder).

This sudden and severe pain is called Renal or Ureteric Colic. Can cause nausea, vomiting while most patients describe it as the worst pain they have ever felt. It can have gradual or sudden onset and can  last from hours to days causing severe distress if left untreated. Most of the stones that cause Renal Colic will pass spontaneously, but if they do not, they can cause serious urine infection and infection of the kidney, sometimes the infection can become life threatening when it develops into sepsis and septic shock (when a severe infection cannot be managed by our body and deranges all basic functions of our body, including heart, lungs, kidneys and liver).

What causes kidney stones?

There are various factors which can lead to the formation of kidney stones. Dehydration is a common cause, as insufficient water intake leads to concentrated urine, which promotes the build-up of stone-forming substances. Dietary habits also play an important role. Consuming foods high in salt, sugar, fat (especially saturated) or animal protein (lots of meat or protein supplements) may increase your risk.

Certain medical conditions, such as Gout (a form of arthritis caused by high levels of uric acid), or digestive disorders like Crohn’s disease, Ulcerative colitis, can make some individuals more susceptible. Additionally, family history and personal medical history, such as a previous kidney stone, can raise your risk.

Being overweight increases the risk to develop kidney stones and the relationship is directly proportional to the excess weight.

Sedentary life and lack of exercise can also lead to developing kidney stones.

Diabetes, especially if t poorly controlled, is a significant risk factor for kidney stones.

Other more rare conditions include thyroid and parathyroid problems, cancer, osteoporosis, bone metabolism problems, rare forms of hereditary conditions (e.g. primary hyperoxaluria, cystinuria and others ).

It is common to have more than one kidney stones.

How do you know if you have a kidney stone?

Kidney stones may cause no symptoms, can cause mild symptoms like mild loin pain, feeling of heaviness of the right or left flank or can cause more severe pain which can become excruciating when the stone moves into the ureter (the long, thin tube that connects the kidneys to the urinary bladder and allows the urine produced in the kidney to travel into the bladder).

This severe pain is commonly called Renal Colic, it affects the side and back, just below the ribs and can radiate to the lower abdomen and groin. This pain often comes in waves and varies in intensity. Can cause nausea, vomiting, while most patients describe it as the worst pain they have ever felt. It can have gradual or sudden onset and can last from hours to days, causing severe distress if left untreated.

Most of the stones that cause Renal Colic will pass spontaneously, but some may cause serious urine infection, possible infection of the kidney; sometimes the infection can become life threatening when it develops into sepsis and septic shock (when a severe infection cannot be managed by our body and deranges all basic functions of our body, including heart, lungs, kidneys and liver).

Other symptoms of kidney stones can be changes in urination, such as frequent urges to urinate, difficulty passing urine, or cloudy or pink-tinged urine due to blood. Additional signs include nausea, vomiting, and fever, especially if an infection is present.

Blood in the urine can also indicate kidney stones but it can also happen in urine infections and in bladder or kidney cancer, so if you do see blood in your urine speak with your doctor.

If you suspect a kidney stone, consult a urologist promptly for evaluation.

How are kidney stones diagnosed and treated?

Diagnosis usually begins with a physical examination and a review of symptoms. Imaging tests such as an ultrasound or a CT scan help confirm the presence, size, and location of the stone. A urine test and culture may also be conducted to identify any infection or determine what substances are forming the stones.

Special Blood tests can also be used to identify a potential health issue that is responsible for stones.

In specific patients (e.g. with bilateral kidney stones or stones that present at younger age or recurrent stone formation) collection of urine over 24-48 hours is also done. The combination of specialised blood tests and urine tests are called Metabolic Evaluation and allows us to find out if there is a specific health problem that causes the stones.

When the stone passes or after an operation, sample of the stone is sent for analysis so we can identify the type of the stone, an important information for prevention of stones in the future.

In most patients though, there is no specific reason, and the causes of stones are attributed to obesity, dehydration, sedentary life, immobility, fatty and salty diet etc.

The treatment approach for kidney stones varies based on their size, number, location and the intensity of symptoms. Smaller stones often pass naturally with increased hydration and pain relief. However, larger stones may require medical intervention. Treatments can include medications to relax the ureter muscles, allowing the stone to pass more easily, or procedures like shock wave lithotripsy, which uses sound waves to break the stones into smaller fragments. Shock wave treatment is an outpatient procedure that uses only pain killers - no need to be anesthetised and is called an ‘operation without a knife’.

If the stones are bigger or resist shock wave lithotripsy or the patient prefers a quicker resolution, we can utilise endoscopic, minimally invasive, day case procedures like Flexible Ureteroscopy and Retrograde Intrarenal Surgery by using flexible, slim and slender scopes, the ureteroscopes, that can easily enter through the water pipe (urethra) and reach the stones. We then utilise laser fibres, as slim as 0.2 -0.3 mm so to ‘dust’ the stones (laser the stone into tiny dust-size particles or very tiny fragments that then pass spontaneously).

For the largest kidney stones, such as the ‘staghorn’ stones as they are called we utilise a key hole endoscopic technique which is called Percutaneous Nephrolithotripsy (PCNL). It is usually a single key hole at the loin area (left or right, according to which kidney is being treated), which allows a telescopic instrument, the nephroscope, to enter the kidney, so to break the stones into small pieces and through the same hole, the fragments are removed. For this operation we can use thinner instruments (for smaller stones) called Mini PCNL or thicker instruments for larger stones called Standard PCNL.

What is a Ureteric Stent and why is it used?

Ureteric stents also called PigTail stents or Double J or  JJ stents are used to treat obstruction of the ureter (the pipe that drains the kidney into the bladder). Obstruction of the ureter causes the severe pain (renal colic), it can also cause severe infection, fever and sepsis and it can damage the function of the kidney.

Obstruction of the ureter can occur after an endoscopic operation due to temporary swelling of the ureter, a stone can cause obstruction, a tumour of the bladder or the ureter can also cause obstruction. The stent is used to relieve the obstruction and protect the kidney and the patient’s health.

Sometimes, the ureteric stent has to be inserted before we engage to break the stone, so to treat or prevent urine infection, facilitate widening of the urter and reduce any risks for the patient during treatment of more difficult stones.

Can kidney stones be prevented?

Keeping well-hydrated is one of the best ways to reduce the risk of kidney stones. Try to drink enough water to maintain pale yellow urine, which indicates proper hydration.

Exercise and walk regularly are very important as immobility causes stones.

Maintain healthy weight, pay attention to your daily calories. Exercise helps in keeping a healthy weight too.

Dietary adjustments can also help, such as reducing salt, moderating protein intake, and eating more fruits and vegetables.

Saturated and animal fat along with some vegetable oils need to be avoided. One of my first points to make, is to significantly reduce consumption of processed food, crisps, biscuits, fried food, fried oil, butter in cooking and even avoid raw butter, avoid bacon, ham etc.

Reduce significantly the consumption of animal protein and prefer legumes.

The dietary aim is to reduce oxalate and uric acid in someone’s diet, as well as reduce the ability of the components that make stones to bind together

A common misconception is that by reducing calcium intake one can prevent stones, but that is wrong and many times quite the contrary is correct, the lack of calcium in our diet can cause stones. An example is dairy products, which contains three main components of interest: fat, calcium and animal protein. A stone patient can consume dairy products with great moderation, not because of the calcium component, but for the fat and protein they contain.

What I advise my patients to do is to combine calcium rich food with oxalate rich food; an example is to drink half a glass of fat free (0%), skimmed milk with the main meal of the day.

For patients with health conditions that cause stones, optimum control of these conditions reduces significantly the risk to form stones (e.g. optimum control of diabetes in a diabetic patient who suffers from kidney stones).

If you are prone to stones, your doctor may recommend specific changes of your daily habits and diet based on the type of stone you form, as different types have different causes.

If your Metabolic Evaluation (please see paragraph: ‘how are kidney stones diagnosed and treated’) indicates specific abnormality that is responsible for causing stones, your doctor may provide you with medication to prevent or reduce the incidence of stones.

Where can I get more information on kidney stones?

There is plenty of good and some misleading information on internet; a couple of good sites is the European urological association site with advise for patients with kidney stones and the British urological association site; both sites are mentioned below.

PI_Kidney-and-Ureteral-Stones-EN-Q1-2020-1.pdf

Kidney stones | The British Association of Urological Surgeons Limited

If you would like to book a consultation with Mr Almpanis, do not hesitate to do so by visiting his Top Doctors profile today.