A cystine stone is a special type of urinary stone that occurs with lower frequency. Cystine stones are also known as cystine stones and are characterized by a roughly round shape. In some cases, the contours of the cystine stone also conform to its location in the renal pelvis. The surface of the cystine stone is smooth and resembles wax. While the coloration of cystine stones tends to be yellowish, the stones have visual similarities to milk glass.
What is a cystine stone?
Cystine stones are comparatively rare in the general population. The stones develop as a result of a congenital and genetically caused disease of the metabolism. However, only one to three percent of all urinary stones are cystine stones. The stones are formed primarily because patients suffer from urolithiasis. The underlying disease is cystinuria, which is inherited in an autosomal recessive manner. Healthy individuals hardly accumulate proportions of the substance cystine in their urine that exceed the urine’s potential to dissolve it. Individuals with cystinuria accumulate significantly elevated concentrations of cystine in the urine, especially homozygous patients.
Causes
The main factor in the development of cystine stones is the presence of hereditary cystinuria, which is passed on in an autosomal recessive manner and is rare. Individuals with cystinuria suffer from a metabolic disorder so that an enormous amount of cystine accumulates in the urine. The organism excretes increased amounts of amino acids in the urine. Healthy people excrete on average about 40 to 80 milligrams of cystine per liter of urine. Persons with cystinuria, on the other hand, often have concentrations of more than 1000 milligrams per liter of urine. Cystinuria refers not only to the substance cystine, but also to ornithine, arginine and lysine. However, cystine dissolves much more heavily in urine than the other amino acids. The excessive cystine is therefore not completely soluble in urine and crystallizes. As a result, the typical cystine stones form in sufferers.
Symptoms, complaints, and signs
Cystine stones cause typical symptoms and symptoms of illness. Patients notice the first cystine stone mainly by sudden, severe pain. The pain sensation results from the cystine stone moving within the urinary tract. In particular, smaller stones or individual fragments slide, starting from the kidney, first into the bladder and finally into the ureter. In some cases, the cystine stone almost completely blocks the ureter. As a result, patients experience acute intense pain in the flank area. The pain often extends to the spine and groin. Most individuals seek emergency medical attention in this condition, as the pain is almost unbearable. In addition, drainage of urine from the kidneys is no longer possible due to the blockage. The urine accumulates, triggering further pain. At the same time, the risk of inflammation of the urinary tract increases.
Diagnosis
Patients with cystine stones usually seek medical attention immediately, as soon as the first stone becomes noticeable through pain. The medical history may already bring to light that the person suffers from cystinuria. In some cases, however, the rare hereditary disease is not diagnosed until the first stone causes acute pain. The physician analyzes the patient’s genetic disposition by means of family history. The clinical examination is based on different procedures. The physician uses imaging methods and performs blood and urine analyses. This allows the increased excretion of amino acids to be detected, which, together with the acute symptoms of cystine stones, indicates the disease.
When should you see a doctor?
If severe pain suddenly occurs during urination, a physician should be consulted. The physician can use a clinical examination to determine if a cystine stone is present and, if necessary, remove it directly. Occasionally, cystinuria can also be corrected by measures such as drinking plenty of fluids and climbing stairs. If the stone remains untreated, it may continue to obstruct the urinary tract. As it progresses, there is intense pain in the flank area that can spread to the spine and groin. At this stage, self-treatment is no longer possible and an emergency doctor must be called immediately.At the latest when symptoms of a urinary tract infection are noticed, a medical professional must be consulted. Since cystinuria is a hereditary disease, medical clarification and treatment are absolutely necessary in the long term. Otherwise, new stones will continue to form over the course of a lifetime, impairing well-being and gradually damaging the urinary tract and kidneys as well.
Treatment and therapy
A causal cure for cystine stones is not possible. First, it is important for patients to consume a larger amount of water. In addition, surgical procedures are usually required to remove the cystine stones. This removal of the stones is done in different ways. In percutaneous nephrolitholapaxy, the doctor punctures the kidney with a hollow needle. An instrument is pushed through this needle that destroys and removes the cystine stones. Snare extraction is also possible, although it is rarely used nowadays. This method can only be used if the cystine stone is located in the lower part of the ureter. With the help of an inserted snare, the physician pulls the cystine stone outward. The risk of injury to the ureter during this procedure is relatively high, which is why the method is considered obsolete. Alternatively, surgical removal of the cystine stones is possible. In most cases, the patient receives a general anesthetic. Surgeons then open the person’s abdomen and remove the cystine stones from the kidneys or urinary tract. In all methods, once the cystine stones have been removed, new formation of stones should be prevented if possible.
Outlook and prognosis
About 90 percent of cystine stones that are less than five millimeters in size are washed out on their own with urine. This can cause severe pain and, in some circumstances, injury to the urethra. If the cystine stones are not treated, serious complications such as injuries to the urethra and kidney can develop. The quality of life decreases sharply, and the formation of further stones also increases the original symptoms. In the absence of treatment, the prognosis tends to be negative, since larger cystine stones cannot be broken down by the body. With surgical treatment, the prognosis is generally good. Consequential damage rarely occurs and removal by puncture needle is symptom-free for the affected person. Since the formation of stones is based on genetic causes, a causal therapy is not possible. Cystine stones can therefore recur after treatment. In this case, further surgical treatment is necessary. If this is done early, the prognosis is usually good. Despite repeated surgery, cystine stones have no permanent consequences for the health of the person affected. In the long term, however, the recurring complaints can lead to mental discomfort and permanently impair well-being.
Prevention
Prevention of cystine stones requires effective control of the underlying condition, cystinuria. Patients consume reduced levels of certain amino acids. In addition, an intake of vitamin C is helpful in minimizing the concentration of cystine. In any case, it is important that individuals drink sufficient water. Drinking water that contains a relatively high proportion of bicarbonate is recommended.
Follow-up
In most cases, no special measures of aftercare are available to the patient in the case of a cystine stone. In this case, the affected person is primarily dependent on rapid and, above all, early detection and diagnosis of this disease, so that further complications or complaints do not occur. Early diagnosis has a very positive effect on the further course of the disease, so that the affected person should contact a doctor at the first symptoms and signs of the disease. In most cases, the cystine stones can be excreted through the urine. The affected person should drink a lot to increase the likelihood of excretion. In many cases, however, surgical intervention is also necessary to remove the cystine stone. After such an operation, the affected person should in any case rest and not exert his body. Physical and strenuous activities should be refrained from. Even after a successful operation, regular examinations by a doctor should be performed in order to detect further damage possibly at an early stage.Usually, a cystine stone does not reduce the life expectancy of the affected person.
