Author: Anna Haugg, medical author
Last update: July 03, 2020
Urinary stones (bladder stones) are salts that crystallize in the urinary tract. These can have different sizes. Depending on their location, they cause different complaints.
Urinary stones consist of the following stone-forming, poorly soluble substances: calcium oxalate, uric acid, calcium phosphate, magnesium ammonium phosphate, calcium, protein and cystine. Urinary stones can be very small (e.g. kidney semolina), but they can also fill parts or the entire kidney pelvis (e.g. four-centimeter kidney stones).
Stone suffering in humans becomes medically relevant due to the pinching and sudden obstruction of urine outflow in the urinary tract (urinary drainage system). The urinary tract begins at the kidney, passes the urine through the ureters to the bladder and on through the urethra.
At a glance:
These symptoms occur with urinary stones
The classic symptom of ureter stones is kidney colic, caused by a pinched ureter stone. With renal colic, patients experience sudden cramp-like pain. This colic-like pain can go from the flank to the testicles or the large labia. The pain is not caused, as is often assumed, by the stone itself, but by the urine build-up and the associated overstretching of the urinary system above the stone.
These colic complaints are often accompanied by other symptoms such as nausea, vomiting, constipation and wind, blood in the urine and urinary disorders. If there is a fever in addition to the colic-like pain – if the immune system heats up the body and / or chills, an infection of the urine above the stone can be assumed. This is an emergency situation, immediate medical attention is necessary.
Symptoms of kidney stones
The stone resting in the kidney pelvis or calyx can be without symptoms. It is often discovered accidentally during a routine ultrasound examination. If this stone gets bigger, it can cause dull discomfort and promote or maintain inflammation. If the kidney stone moves and enters the ureter, it typically results in kidney colic.
Symptoms of bladder stones
Bladder stones, which primarily arise in the bladder when there are drainage disorders, generally cause little discomfort, but if there is an inflammation, there must be a strong feeling of urination (urge complaints). Inflammation of the bladder can usually only be effectively treated by removing the bladder stone.
Blood poisoning as the most dangerous consequence
If the infected urine is not discharged to the outside, there is a great risk of kidney suppuration and a general bacterial blood contamination, a so-called uro-sepsis. Since this severe clinical picture can be fatal, every patient with flank pain and fever should immediately seek urological help.
Causes and risk factors for urinary stones
The causes of urinary stones are processes of crystallization in the urine, favored by disturbances in the flow of urine between the kidney cup and bladder.
The urinary stones can consist of the following stone-forming substances:
These stone-forming substances (poorly soluble substances in urine) are absorbed through food. After digestion, they get into the blood – and through the kidneys into the urine. If too many of these substances are ingested, a crystallization process occurs and urinary stones form in the urinary tract.
Another important cause of urinary stone formation is reduced urine flow. In this case, the stone-forming substances remain in the urinary tract over a long period of time and can also react with one another and crystallize out over a long period.
Risk factors for urinary stones
Despite some unanswered questions, it is now certain that the following factors promote urinary stone formation:
Improper diet, resulting in increased protein intake
low fluid intake, thereby reduced urine flow
lack of movement, thereby disturbed metabolism and an increased amount of stone-forming substances
recurrent infections of the urinary tract, resulting in increased crystallization of magnesium ammonium phosphate as a result of bacterial changes
Diseases of the urinary tract, which may result in narrowing and reduced urine flow
Disorders of the parathyroid glands, resulting in increased calcium levels in the blood and urine
The risk factors for urinary stones include general risk factors such as an older age, professions with a lot of stress and belonging to a rather higher social class. Patients with urinary stone problems are common in industrialized countries and hot areas. About six percent of all patients with urinary stones suffer from a genetic predisposition.
Diagnosis of urinary stones
Urinary stones are identified by questioning and examining the patient as well as urine analysis, ultrasound and X-ray diagnostics. The typical medical history (anamnesis) with sudden cramp-like pain and the results of the clinical examination usually allow the symptoms to be assigned to urinary stones. Urine analysis completes this first part of the examination.
Ultrasound examination of urinary stones
The heart of diagnostics for urinary stones is ultrasound. Ultrasound can be used to visualize and measure a urinary stone in the area of the kidney.
A ureteral stone cannot usually be visualized directly with ultrasound, because the air-containing intestine often hinders the imaging. In contrast, the build-up of urine in the kidney pelvis caused by the stone can be recognized very well. It is a clear diagnostic sign of a ureteral stone.
X-ray examinations if urinary stones are suspected
The X-ray examination of the entire urinary tract can show all radiopaque urinary stones in the urinary system. Uric acid stones are not radiopaque and therefore cannot be visualized with this examination.
By giving contrast medium through a vein, the urinary drainage disorder can be exactly represented – this examination is also called urogram. The injected contrast medium is distributed in the blood and reaches the urine directly through the kidneys. This makes the kidney pelvis and the ureter visible – urinary stones are shown on the X-ray images as a contrast medium recess.
After clarification and exclusion of allergies and an untreated thyroid disease, an X-ray overview is first taken. The urologist or radiologist then injects a contrast medium over the vein. This contrast medium is then excreted into the urinary tract via the kidneys. This excretion is documented with X-rays after different times (after five to seven and ten to 15 minutes). If there is a stone-related urinary drainage disorder, so-called late shots after 30, 60 or even 120 minutes are often necessary.
In very rare cases, special urological X-ray procedures are necessary for the stone detection – so-called retrograde ureter imaging with contrast agent or ureter reflection.
Treatment of urinary stones: what therapies are there?
The treatment of urinary stones is divided into measures for pain relief and measures for stone removal.
Kidney colic is an emergency situation. Immediate pain therapy is required. This includes the administration of pain relieving and antispasmodic medication. As a rule, it is possible to control the pain situation. After the diagnosis has been confirmed, further medical therapy is determined.
General procedures for urinary stone removal
Urinary stones up to about seven millimeters are generally considered to be spontaneously capable of leaving, i.e. one tries to reach a stone exit without surgery. This is achieved by drinking or infusing large amounts of fluids. In addition, medication to expand the ureter is given. In almost 80 percent of all patients, the urinary stone can be removed within a few days. However, colic may occur again and again in the meantime.
Special urinary stone removal procedures
Modern methods of stone destruction and removal today include extracorporeal shock wave lithotripsy (ESWL, non-contact stone destruction in the area of the kidney, ureter, bladder), the so-called percutaneous nephrolitholapaxy (minimally invasive stone removal from the kidney pelvic system using a special instrument) and the endoscopic stone removal by means of a stone removal Bladder and ureter using a special endoscope). If these minimally invasive methods are unsuccessful, the indication for open surgery should be critically examined.
Diet and drink: Use these tips to prevent urinary stones
General preventive measures include:
Abundant hydration: At least two and a half liters of liquid (e.g. mineral water or fruit tea) within 24 hours are recommended to flush the urinary tract sufficiently.
Varied, high-fiber and low-fat diet: It makes sense to eat five different types of fruit or vegetables every day (an example of a daily ration: an apple, a banana, a kiwi, a pepper, a kohlrabi). High-fiber foods are: oatmeal, muesli, lentils, beans and other legumes: healthy protein packages – plus a list and recipe, but also fresh fruits and vegetables. Low-fat foods are all types of fruit and vegetables.
Cutlet, cabbage and co .: Caution, these delicacies can lead to an uncomfortable bloated stomach!
Abundant physical activity (For example, twice a week for 30 minutes of walking, running or swimming) and the reduction of excess weight (with a BMI over 30) are recommended, as this can change the human metabolism positively – for example, less stone-forming substances get into the urinary tract .
Diet and Co.: Individual measures against urinary stones
Because of the high rate of recurrence of urinary stones (it is about 60 percent if there is no follow-up care), besides regular follow-up care by the urologist, individual preventive measures are also important. Knowing the patient about the composition of the removed urinary stone can be important for individual nutritional adjustment.
Today, radical compliance with the previous nutritional guidelines has been abandoned. It is particularly important to have a balanced diet, exercise and, if necessary, weight loss.
People with magnesium-ammonium-phosphate stones (infection stones) and cystine stones should take medical aftercare particularly seriously, because these stones in particular are likely to come back.
People with calcium oxalate stones
- Reduction of animal foods, such as meat and sausages
- Reduction of calcium-rich foods such as cheese, milk and curd
- Avoid foods rich in oxalate, such as rhubarb, spinach and tomato
- Reduction of salt consumption, if possible completely dispensing with the salt shaker
- Avoid purine-containing food, for example contained in the offal of meat, sausage, lentils, sardines
People with uric acid stones
- Body weight reduction
- Refraining from food containing purine, for example contained in the offal of meat, sausage and lentils, sardines (the purine content of the food should be below 300 milligrams of purine per day)
- Reduction of animal foods, such as meat and sausages
- Refrain from alcohol
People with calcium phosphate stones
- animal foods such as meat and sausages
- calcium-rich foods such as cheese, milk and curd
- Foods high in phosphates such as cheese, milk, curd cheese, meat, wheat bran and nuts.