Kidney stones, also known as renal lithiasis, are small crystals that form in the urinary tract. The stones can be composed of several different types of minerals and may be caused by medical conditions or disorders. The body often excretes small kidney stones with no signs or symptoms, but large kidney stones can remain in the body for years.
In the short term, kidney stones may cause symptoms of excruciating pain, nausea, vomiting and blood in the urine. If left untreated, kidney stones can cause serious long-term health complications, according to Medline Plus.
Kidney Damage
The greatest risk to the kidney from long-term kidney stones is permanent damage, which can eventually lead to chronic kidney disease, explains DaVita.com. Kidney stones that remain in the kidneys for a long time can prevent urine from flowing properly through the kidneys, thereby reducing the ability of kidneys to filter wastes from the blood.
The kidney stones may also damage the delicate, tiny blood vessels within the kidney, causing scarring. Build-up of scar tissue in the kidneys can causes chronic kidney disease, a progressive condition of worsening kidney function. Chronic kidney disease can lead to complete renal failure, a life-threatening condition.
Urinary Tract Blockage
Large kidney stones may become stuck in the urinary tract and block the flow of urine. The most common sites of blockage are the ureters, the slender tubes that connect the kidneys to the bladder. A blockage of the ureter is known as unilateral obstructive uropathy. When the ureter is blocked, the kidney that it is connected to it can no longer excrete urine. The blocked kidney will begin to swell, which can cause severe pain, fever, vomiting, high blood pressure and changes in mental status, according to Georgia Health Info.gov.
Infection
The long-term presence of kidney stones within the urinary tract increases the risk of bacterial infection in all components of the urinary tract, including the kidneys, ureters and bladder. People with untreated kidney stones often develop repeated urinary tract infections. In some cases, the infection may spread to the rest of the body, causing systemic infections leading to fever, chill, nausea and vomiting, according to the University of Illinois Medical Center.
Urinary Fistula
In rare cases, a long-term kidney stone may result in a urinary fistula, which is an opening that connects the urinary tract with some other organ in the body, Loyola Medicine explains. Fistulas may occur between the urinary tract and the vagina, uterus, colon or rectum.
This opening between the two organs causes urine to leak, which can cause urine to drain from body openings other than the urethra. The presence of urine in other organs can cause complications including diarrhea, abdominal pain, nausea, vomiting, fever and weight loss.
