How the kidney senses acidosis

Kidney stones

Causes & Symptoms

What are kidney stones?

Kidney stones are hard stones that are formed from crystalline matter in the urine in the kidney. Most of these tiny crystals leave the body without even being noticed. However, any crystals that are left behind can act as nuclei and turn into kidney stones. Urolithiasis is the medical term for stones in the urinary tract. Men are more often affected than women. The typical age of onset is between 20 and 40 years.

Struvite or infection stones are less common, they are often caused by a urinary tract infection. Uric acid or cystine stones are rare. If a kidney stone is washed into the ureter, it is also referred to as a ureteral stone. Gallstones and kidney stones are not related, they are formed in different regions of the body.

Kidney stones: causes of the disease

Often the cause of kidney stones remains in the dark. In susceptible people, certain eating habits can lead to this. Urinary tract infections, changes in the kidneys and metabolic diseases can also be the trigger. Seventy percent of people with rare hereditary renal tubular acidosis also develop kidney stones. Two other rare hereditary metabolic diseases that can be responsible for kidney stone disease are cystinuria and hyperoxaluria.

In the absorptive form of hypercalciuria, the body removes too much calcium from the food and releases it again in the urine. Due to the high concentration of calcium in the urine, crystals of calcium oxalate and calcium phosphate form, which turn into stones in the urinary tract.

Other causes include hyperuricosuria, a uric acid metabolic disorder, gout, excessive intake of vitamin D and blockages within the urinary tract. Certain diuretics or calcium-based antacids can increase the amount of calcium in the urine, causing kidney stones to develop. Patients with chronic inflammation of the bowel, intestinal bypass or stoma are also at increased risk. Urinary stones can form in people who have a urinary tract infection. Those treated with the drug indinavir for HIV infection and AIDS also have an increased risk of developing kidney stones.

Kidney stones: symptoms of the disease

Usually the first sign of kidney stones is severe pain. As the stone is in motion, it causes blockages and irritations - the pain therefore appears suddenly. Typically it is described as a sharp, cramping pain in the back and side in the kidney area or lower abdomen. You may also feel nauseous and vomit. Later the pain can spread to the groin area. If the stone is too big to pass easily, the pain will remain as the ureter tries to move the stone into the bladder via muscle movements. Movement of the stone can also cause urine to change color from small bleeding. If the stone moves closer to the bladder, there may be an increased urge to urinate and a burning sensation when urinating. If fever or chills are accompanying symptoms, there may also be a urinary tract infection.


Diagnosis: This is how we diagnose kidney stones

Some stones that are not causing discomfort are discovered by accident, for example during a routine X-ray examination. In a patient with acute pain, a stone is usually found on an ultrasound or X-ray examination. We can also determine the size and position of the stone at the same time. With blood and urine tests, we try to find information about the possible causes of stone formation. In order to be able to recommend the best possible treatment, a so-called low-dose computed tomography may be necessary. A particularly low radiation dose is used and all information about the location and the surrounding organs is immediately obtained. An intravenous pyelogram (IVP) is rarely used. A contrast agent is injected into the vein and excreted in the urine so that the kidney stones can be seen on the X-ray.

Laboratory, blood and urine tests to find the cause

If a patient has had more than one kidney stone, they are more likely to have more stones. To prevent this, it is important to find the cause of the stone formation. This is done on the one hand through laboratory, blood and urine tests. On the other hand, medical history, occupation and eating behavior also play a role. Sometimes urine collected over 24 hours is also tested.