Kidney stones
They are among the most severe pains
What are kidney stones?
Kidney stones are solid deposits that form from crystallised components of urine. They can develop in various parts of the urinary system, such as the renal tubules, the renal pelvis and the urinary tract. The size of kidney stones varies widely: they can be as small as a grain of rice or large enough to fill the entire renal pelvis.
Because kidney stones often move along the urinary tract, they are named according to their location. Common terms include ureteral stones, bladder stones or urethral stones. Pain usually occurs when a stone reaches the ureter, which can cause a painful renal colic.
What symptoms can kidney stones cause?
Kidney stones can produce a variety of symptoms, and many people initially have no complaints. Stones are often found incidentally, for example during a routine check. A mild ache in the kidney area can be an early sign but is not always immediately linked to kidney stones.
Symptoms typically appear when a stone blocks the renal pelvis or travels through the ureter. The most characteristic symptom is pain, which can range from mild discomfort to severe, cramp-like episodes. These pains, also called renal colics, are sudden and come in attacks, often radiating from the flank into the lower abdomen. The pain is particularly severe when a stone passes a natural narrowing in the ureter, for example at the point where the ureter enters the bladder.
Pain during a renal colic often fluctuates in waves and may be accompanied by nausea and vomiting. People affected often try to relieve the pain by changing position. A renal colic can last between 20 and 60 minutes.
Other possible symptoms of a stone in the ureter include blood in the urine, pain when urinating and increased urinary frequency. The pain can also radiate to the genital area. Small stones often cause no symptoms and may only be noticed when they are passed in the urine.
editorial.facts
- In Sri Lanka a 62-year-old patient had an 801 Gramm kidney stone removed that is considered the largest in the world. The stone was 13.372 Zentimeter long. The Guinness Book of Records officially confirmed this.
- About 5 percent of the adult population in Germany are affected by kidney stones, men twice as often as women. Kidney stones generally occur between the ages of 30 and 60.
- In up to 50 out of 100 affected people kidney stones recur within five years. Therefore it is important to take preventive measures.
What causes kidney stones and what are the risk factors?
The formation of kidney stones is influenced by both genetic factors and lifestyle.
A genetic predisposition increases the risk of developing stones. Metabolic disorders, such as overactivity of the parathyroid glands, can lead to increased calcium excretion and promote stone formation. Likewise, disorders of uric acid metabolism due to enzyme defects or a purine-rich diet and alcohol misuse can lead to uric acid stones.
Another important factor is fluid intake. Drinking too little results in higher concentrations of stone-forming substances in the urine, which promotes crystallisation and stone formation. Dehydration from excessive sweating, chronic bowel disease or a hot climate further increases the risk.
The urine pH also plays a role. Acidic urine (pH below 5.5) favours uric acid stone formation, while alkaline urine (pH above 7.0) favours phosphate stones.
Other risk factors include urinary transport disorders caused by malformations, scarring or narrowing of the kidneys or lower urinary tract, as well as frequent urinary tract infections. Certain medications, such as sulfonamides or high doses of acetylsalicylic acid (ASA), can also increase the risk. Excessive body weight and a family history likewise contribute to stone formation.
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What role does diet play in causing kidney stones?
Diet plays an important role in the development of kidney stones, especially calcium-oxalate and uric acid stones. A high-protein diet and consumption of oxalate-rich foods such as chocolate, rhubarb, beetroot and spinach increase the concentration of stone-forming substances in urine. This promotes crystallisation and can lead to stone formation. A lack of citrate, a stone-inhibiting substance in urine, also accelerates this process.
Excessive intake of supplements rich in calcium and vitamin D can increase the risk of stones. A purine-rich diet, especially high in meat, raises uric acid concentration in urine and favours the formation of uric acid stones.
How are kidney stones treated?
Treatment of kidney stones depends on their size, location and the symptoms they cause. For small stones that do not cause symptoms, it may be appropriate to wait for them to pass naturally in the urine. Pain can be relieved with common analgesics such as diclofenac, ibuprofen, paracetamol or metamizole; for severe pain, stronger medications such as opioids may be used.
For ureteral stones between 5 and 10 millimetres in size, medications can be given to relax the urinary tract muscles and facilitate stone passage.
Larger stones usually require active treatment. Litholytic therapy can, in certain cases, dissolve renal sand and stones using special substances administered orally or via a catheter.
Extracorporeal shock wave lithotripsy (ESWL) is another procedure in which mechanical pressure or shock waves directed from outside break the stone into fragments. These fragments can then be passed spontaneously in the urine.
For bigger stones, a percutaneous nephrolitholapaxy (PCNL) may be performed, where a percutaneous channel to the kidney is created to fragment and remove the stone.
Effective prevention of kidney stones: practical tips
- Drink at least two litres of fluid daily, preferably water, to keep urine diluted and avoid mineral deposits.
- Eat little salt by cooking fresh and avoiding ready-made meals, which often contain too much salt.
- Avoid or reduce overweight, as this can lower the risk of stone formation.
- Regular exercise helps prevent small kidney stones. If you exercise and sweat a lot, make sure to drink enough fluids.
- Avoid purine-rich foods. These include certain fish such as herring, mackerel or anchovies, as well as offal.
- Eat plenty of fresh vegetables and fruit for a balanced diet. As a rule of thumb: “Five a day”, i.e. three portions of vegetables and two portions of fruit.
- Reduce refined carbohydrates where possible. Choose wholegrain bread, wholegrain pasta or brown rice, which provide healthy fibre.
- Monitor your daily calcium intake: consume about 1000 to 1200 milligrams per day, coming from two to three portions of milk or dairy products.
- Use high-quality vegetable oils for cooking and reduce animal fats, which contain the pro‑inflammatory arachidonic acid.
- Eat meat no more than twice a week and choose lean cuts. Avoid processed meats and pork.
- Reduce consumption of oxalate-rich foods such as rhubarb, beetroot, spinach and nuts to lower the risk of kidney stones.
Kidney stone formation is a complex process influenced by factors such as genetics, lifestyle and diet. Symptoms range from mild discomfort to severe renal colics that require immediate treatment. It is important to pay attention to the body's signals and take preventive measures.
