Renal colic and kidney stones

Kidney stones, also known as renal calculi or urolithiasis, are a common disorder affecting 10 percent of the population. Recurrence is frequent, occurring in 50 percent of patients within five years. Our Stone Center offers multidisciplinary care at all stages of the disease.  

Patients suffering from renal colic can visit our Emergency Care Center 24/7 for pain relief and to undergo an initial set of laboratory and imaging tests.

Our Urology Department offers latest-generation techniques to treat kidney stones, including extracorporeal lithotripsy, laser surgery via the urinary tract and percutaneous or laparoscopic robotic surgery for the most severe forms of the disease.

Our Nephrology Department and dieticians help patients by identifying the nature of the imbalance in their urine composition and correcting the issue in order to prevent the kidney stones from recurring.

A patient’s first bout of renal colic is the most frequent indicator of kidney stone disease. It is caused by a “moving” stone which prevents urine from flowing from the kidney to the bladder. Kidney stones are hard deposits of minerals and salts that form inside the kidneys due to an imbalance in urine composition. When they occur, urine collects in the kidney, which becomes swollen. This sudden swelling causes renal colic.

Renal colic is characterized by acute, sudden pain in the back or side which radiates to the lower abdomen and groin. The patient may have other symptoms including blood in the urine, nausea and vomiting. No position brings relief, and the pain is so intense that emergency medical care is generally necessary.

While renal colic is benign in most cases, it can lead to complications (in less than five percent of cases) and be life-threatening in the short term, particularly if it is combined with a urinary tract infection (UTI) or occurs in patients with only one kidney.

Other clinical signs may indicate the presence of stones in the urinary tract: blood in the urine, recurrent UTIs, or chance discovery thanks to x-rays performed for a different reason.

The condition can also lead to chronic kidney disease or even to end-stage renal failure, particularly if recurrences are poorly managed or if a diagnosis is not made or is incorrect. Kidney stones are responsible for two to three percent of the cases of end-stage renal failure in France.

Several types of stones may develop in response to urinary composition imbalances. Each case is different and necessitates highly individualized care.

Several risk factors have been clearly identified : 

Dietary factors

Adjusting one’s diet is often key to preventing the recurrence of kidney stones.

Genetic factors

Family antecedents exist in nearly 40 percent of cases.

Infectious factors

The enzymatic activity of certain UTI-causing bacteria such as Proteus mirabilis, Klebsiella and Pseudomonas can cause kidney stones to form.

Abnormal urinary pH

Overly acidic or alkaline urinary pH contributes to the development of various types of kidney stones.

Anatomical defects in the urinary tract

Certain anatomical defects in the kidneys or urinary tract contribute to urinary stasis and therefore to the formation of stones.

The patient’s care pathway begins with identifying the cause of stone formation. This is achieved through the coordinated collaboration of several health professionals: emergency physician, urologist, nephrologist, radiologist, endocrinologist and dieticians. Exams are conducted during and after a renal colic emergency for long-term treatment and monitoring purposes. Laboratory tests conducted at the American Hospital of Paris are helpful for determining dietary recommendations as well as the prescription of appropriate medications.

It is also extremely important to collect the stone(s), whether they are naturally eliminated or removed by a urologist, in order to conduct a spectrophotometry analysis and gain a better understanding of why the stones formed. Certain specific compositions will enable a definitive diagnosis. If the stone cannot be retrieved, testing for crystals in the urine can facilitate the diagnosis in some cases and very often pinpoints metabolic abnormalities as the cause of stone formation. The presence of urine crystals is a useful indicator when assessing stone formation and the risk of recurrence.

After the first occurrence of kidney stones, a blood and urine laboratory workup is necessary. Urine is collected over a 24-hour period and analyzed in order to measure volume and pH as well as the levels of calcium, oxalate, uric acid, citrate, magnesium, sodium and phosphate. Blood tests will be done to measure kidney function and the serum concentration levels of calcium, uric acid, phosphate, potassium, chloride and bicarbonate. Calcemia (a high level of calcium in the blood) indicates a parathyroid disorder.

The nephrologist will interpret the results of these tests and define preventive measures and specific treatment if necessary.

In most cases, the type of stone, the lab and imaging results and a review of the patient’s history make it possible to determine the cause and contributing factors of the kidney stones. It is often a question of diet and lifestyle.

Following this assessment, an initial therapeutic strategy should be determined, combined with the appropriate monitoring to limit the risk of recurrence.

Kidney stones can be a symptom of other, more complex pathologies and contribute to the accurate diagnosis of a monogenic disorder, bone disease or metabolic syndrome.

Emergency care is typically reserved for renal colic, in order to provide relief to the patient. When medications are insufficient, or in severe forms of the disease with complications, emergency hospitalization may be necessary to de-obstruct the kidney. In this case, an endoscopic procedure under general anesthesia is required, in which an internal drain is inserted allowing urine to flow from the kidney to the bladder.

Afterwards, long-term care will consist in medication and surgery to treat the stone and prevent recurrence.

Kidney stone disease treatment is essentially based on prevention. It consists in preventing recurrence with minor lifestyle and dietary adjustments. If the disease continues to progress despite these measures, medication may be proposed. In all cases, regular monitoring is necessary.

The nephrologist will identify the causes and consequences of the kidney stones and set specific goals to prevent recurrence and protect the kidney. Through consultations, the dietician’s role is to help identify the causes and prevent recurrence by exploring the range of nutritional options available to the patient. Certain general dietary measures apply to all patients with kidney stones. Certain medications are reserved for very specific cases of the disease.

Surgical treatment of the stones by the urologist will depend on the patient’s morphology and co-morbidities, on the stone's location, size and composition, and on the anatomy of the urinary tract.

Extracorporeal lithotripsy

Extracorporeal lithotripsy is a non-invasive procedure in which shock waves are delivered externally. These waves go through the tissues without damaging them, and converge on the stone. The cumulative energy of the shock waves becomes powerful enough to fragment the stone into tiny pieces or dust which can then be easily eliminated through the urine.

Ureteroscopy

Ureteroscopy is a procedure that involves the passage of a small scope (camera) through the urethra, bladder and up the ureter to the point where the stone(s) is located. Depending on their size, the stones are either removed whole or broken down using a laser, after which the fragments can be extracted.

For very large stones: Percutaneous nephrolithotomy surgery consisting in a three-centimeter incision, or laparoscopic surgery (generally robot-assisted), may be proposed.

• The prevalence of kidney stone disease has been rising constantly in industrialized countries, and is estimated to affect 10% of the general population in France.
• Today, 70 to 80% of renal calculi are calcium oxalate stones that form in the kidney. Renal calculi affect men approximately twice as often as women, generally between the ages of 20 and 60.
• Within this population, the recurrence rate is around 50% within five to ten years following the first diagnosis.
• Acute renal colic accounts for 1 to 2% of emergency room visits.
• Less than 8% of renal colic emergencies require hospitalization due to complications.