Uric acids, products of purine metabolism, are considered unwanted wastes inside the body that need to be eliminated through the urine or stool. When there's a high concentration of uric acid in the urine, formation of uric acid stones or calculus, may occur. Most uric acid stones are found in the kidneys, in the urinary bladder, and some may get stuck in the ureter. The ureters are thin tubes that carry urine from the kidneys down to the urinary bladder for storage, and eventually for excretion.
Uric acid stones are frequently formed due to overproduction of uric acid, and defects in the reabsorption and secretion of uric acid in the kidneys. Taking in excessive amounts of purine will also lead to greater concentration of uric acid in the blood. Dehydration or inadequate amount of fluid in the body usually increases uric acid concentration in the urine, thus leading to stone formation. Some drugs also tend to increase uric acid levels.
Individuals with uric acid stones in their urinary tract frequently complain of excruciating pain on either side of the abdomen, particularly on the back region. They may also experience pain in the testicles and groin area. These symptoms mostly occur when a uric acid stone blocks urine flow or when it moves along the urinary tract. Other manifestations of uric acid stones include nausea, vomiting, chills, and fever. Presence of blood in the urine as well as changes in urine color are also observed.
Nephrologists are doctors who treat patients with urinary tract problems. They may request the patient to undergo an ultrasound of the kidneys for diagnosis. Analysis of the patient's urine as well as examination of blood may also be done for further evaluation of patients showing signs and symptoms of uric acid stones.
Treatment includes the use of citrate or bicarbonate, which are often effective in dissolving the uric acid stones. There are also medications given to lower the amount of uric acid in the blood. Other patients may have to undergo surgery for removal of larger stones. Most patients are advised to drink plenty of water to dilute the urine, and to avoid foods that are high in purine content such as organ meats, fish, nuts, and colas. They are also advised to minimize consumption of dehydrating fluids such as alcohol, coffee, and tea.
Several complications can develop due to uric acid stones. These include renal failure, pallor, insomnia, obstruction, and infection of the urinary tract. Studies have shown that men are more likely to develop uric acid stones than women. Also, white children are more prone compared to children of other races.