Kidney stones, also known as renal stones or nephrolithiasis, are hard, crystalline mineral deposits that form within the kidneys. They are a common urological condition, affecting approximately one in ten people over the course of their lifetime.
Men are more frequently affected than women, and the incidence can increase with age.
Kidney stones can vary greatly in size, from tiny grains of sand to large stones that can obstruct the urinary tract. While some kidney stones are asymptomatic and discovered incidentally during medical evaluations for other issues, others can cause significant discomfort and complications, necessitating medical intervention.
Common symptoms of kidney stones
Kidney stones can manifest with a variety of symptoms, depending on their size, location, and whether they obstruct the flow of urine. Common symptoms include:
- Persistent Back or Side Pain: This is one of the most typical symptoms of kidney stones. The pain is often described as sharp or cramping and can be felt in the lower back or side, beneath the ribs.
- Blood in the Urine (Haematuria): Blood in the urine can range from microscopic (only visible under a microscope) to gross haematuria, where the urine appears pink, red, or brown.
- Recurrent Urinary Tract Infections (UTIs): The presence of stones can irritate the urinary tract, leading to recurrent infections. Symptoms of UTIs include a frequent urge to urinate, pain or burning during urination, and cloudy or foul-smelling urine.
- Pain During Urination: If a stone passes into the ureter or the bladder, it can cause a sharp pain or burning sensation during urination.
- Frequent Urination in Small Amounts: This can occur if a stone is obstructing the lower urinary tract.
Severe symptoms or complications
In more severe cases, particularly when a stone becomes lodged in the ureter (the tube connecting the kidney to the bladder), the following symptoms and complications may occur:
- Severe Pain: The sudden onset of severe, excruciating pain is often the hallmark of kidney stones obstructing the ureter. This pain, known as renal colic, typically starts in the flank (side of the body) and may radiate to the lower abdomen and groin. In men, pain may also radiate to the testicles.
- Nausea and Vomiting: The intense pain can stimulate the nerves that connect the kidneys and digestive tract, causing nausea and vomiting.
- Hematuria: Visible blood in the urine can be a sign of a stone moving through the urinary tract.
- Urinary Urgency: An urgent and frequent need to urinate, often producing only small amounts of urine, can be a symptom of lower urinary tract stones.
- Fever and Chills: If a urinary tract infection develops in conjunction with a kidney stone, it can lead to systemic symptoms such as fever and chills. This is a medical emergency and requires prompt treatment.
What causes kidney stones?
Kidney stones form when there is an imbalance in the substances that make up urine, such as minerals and salts. Several factors can contribute to the development of kidney stones:
- Dehydration: Not drinking enough fluids leads to concentrated urine, which increases the likelihood of stone formation. High levels of certain substances, such as calcium, oxalate, and uric acid, can crystallise and form stones.
- Dietary Factors: Diets high in oxalates (found in foods such as spinach, nuts, and chocolate), high sodium intake, and excessive protein can contribute to the formation of stones.
- Medical Conditions: Conditions such as hyperparathyroidism (which causes elevated calcium levels), gout (which increases uric acid levels), and recurrent urinary tract infections can promote stone formation.
- Genetic Factors: A family history of kidney stones increases the risk of developing them.
- Obesity and Metabolic Syndrome: Obesity and related metabolic conditions can alter the chemical composition of urine, promoting stone formation.
How are kidney stones diagnosed?
Blood and Urine tests
Routine blood tests are undertaken to check for kidney functions and evidence of infection in the bloodstream. These can also provide information regarding calcium and Urea levels in the blood (the two common sources of stone formation). A urine test can indicate the presence of blood or infection in the urine.
CT Scan
This is a quick and reliable investigation. A CT scan provides the most accurate information regarding the site, size, shape and amount of stone burden in order to plan appropriate management.
Treatments for kidney stones
Conservative Management
If ureteric stones are small (less than 5mm), then there is a high chance that they may pass without any surgical intervention. Tablets called alpha blockers (which are usually used in men with difficulties passing urine) help to relax the ureter tube. These are used in conjunction with appropriate pain killers (anti-inflammatories) to increase the rate of spontaneous stone passage.
Emergency Decompression (JJ Stent Insertion or Nephrostomy)
In cases where the stones fail to pass conservatively and/or there is uncontrollable pain, significant blockage to the kidney, damage to kidney function or signs of infection, then urgent action has to be taken.
This often involves the placement of a plastic tube called a JJ stent, which runs from the kidney to the bladder and unblocks the kidney’s drainage system. It is inserted under a general anaesthetic via a telescope that goes down the urethra (water pipe) and into the bladder.
Definitive Stone Treatment
We offer a comprehensive management of kidney stone disease, including:
Extracorporeal Shock Wave Lithotripsy (ESWL)
ESWL is performed on an outpatient basis while the patient is awake. High-energy shock waves are focused on the stone using either X-rays or ultrasound to break it up into smaller pieces. Once fragmented, the pieces will be passed by the patient.
Ureteroscopy (Rigid and Flexible) and Holmium Lasertripsy
Ureteroscopy & Holmium Lasertripsy is performed under a general anaesthetic as a day case procedure. A small telescope is placed via the urethra into the bladder and then up into the ureter and kidney if necessary. The stone is seen directly, often broken up with a laser, and the fragments removed with a basket. A JJ stent is usually inserted at the end of the operation to prevent the kidney from becoming blocked by swelling of the ureter tube, blood, or stone fragments.
Percutaneous Nephrolithotomy (PCNL)
PCNL is a more invasive procedure reserved for the treatment of larger stones in the kidney or upper ureter. It involves being admitted to the hospital and staying in for 2-3 days.
Under a general anaesthetic, a small incision is made in the skin, and the kidney is punctured using a fine needle. This tract is then dilated, and a plastic tube is inserted into the kidney through which a telescope can be passed. The stone is then identified and either removed or broken into small pieces.
Can you prevent kidney stones from occurring?
Preventing kidney stones involves making lifestyle and dietary changes to reduce the risk of stone formation. Here are some preventive measures:
- Hydration: Drinking plenty of fluids, especially water, helps dilute urine and prevents the formation of concentrated urine, reducing the risk of stone formation. Aim for at least 2-3 litres of water per day.
- Dietary Modifications: Reduce intake of oxalate-rich foods (e.g., spinach, rhubarb, nuts), limit salt and animal protein intake, and ensure adequate calcium intake through diet or supplements as advised by your healthcare provider.
- Avoid High Doses of Vitamin C Supplements: Excessive vitamin C can be converted to oxalate, increasing the risk of stone formation.
- Medications: For individuals with a high risk of recurrence, medications such as thiazide diuretics, potassium citrate, or allopurinol may be prescribed.
- Healthy Weight Management: Maintaining a healthy weight and managing underlying conditions like diabetes and hypertension can help reduce the risk of kidney stones.
Frequently asked questions
What types of kidney stones are there?
Kidney stones can be classified into several types based on their composition. The most common types include:
- Calcium Stones: These are the most common type, often in the form of calcium oxalate. They can also occur as calcium phosphate stones.
- Uric Acid Stones: These form when urine is too acidic. A diet high in purines (found in animal proteins) can increase uric acid levels.
- Struvite Stones: Often associated with urinary tract infections, these stones can grow quickly and become quite large.
- Cystine Stones: These are rare and result from a genetic disorder called cystinuria, which causes the kidneys to excrete excessive amounts of certain amino acids.
Can kidney stones recur after treatment?
Yes, kidney stones can recur. Approximately 50% of individuals who have had a kidney stone will develop another within 5-10 years. Taking preventive measures and regularly visiting your healthcare provider can help manage and reduce this risk.
Are there any long-term effects of having kidney stones?
While most kidney stones can be treated without long-term effects, repeated occurrences can lead to chronic kidney disease, kidney infections, and urinary tract damage. It is crucial to manage the condition and prevent recurrence to avoid long-term complications.
Can certain medications increase the risk of kidney stones?
Yes, some medications, such as certain diuretics, calcium-based antacids, and high-dose vitamin D, can increase the risk of developing kidney stones. Discuss any concerns with your healthcare provider, who can adjust your medication regimen if necessary.
Is there a link between kidney stones and other health conditions?
Kidney stones can be associated with other health conditions such as chronic kidney disease, high blood pressure, and metabolic disorders. Managing these conditions effectively can help reduce the risk of stone formation and improve overall health.
