Kidney stones, also referred to as “nephrolithiasis”, are quite common among men, women, and to a lesser extent, children.
Kidney stones are more common in the Southern United States due to warmer climates and the propensity for dehydration. Substances in urine, such as calcium, oxalate, cystine or uric acid, form “crystals” in the kidney which can ultimately grow in size to form a kidney stone. Stones can also develop in the bladder (bladder stones) and are usually seen in men who have difficultly urinating due to an enlarged prostate obstructing the flow of urine.
Symptoms of Kidney Stones
When a kidney stone forms, it may travel from the kidney down the “ureter”, the tiny tube that carries urine from the kidney to the bladder. When this happens, excruciating flank or back pain ensues. The pain varies in severity from individual to individual; however, most rate the pain as a 10/10 – the worst possible pain.
Pain may be accompanied by nausea, vomiting, hematuria (blood in the urine), as well as fever.
Evaluation and Treatment
Individuals who are suspected of having kidney stones undergo a urinalysis and urine culture. These lab tests often demonstrate “microscopic hematuria” (blood in the urine that is seen with a microscope).
When significant pain is present, along with microscopic hematuria, a CT scan of the abdomen and pelvis is usually obtained. This internal examination demonstrates the location of the stone and any other associated findings such as “hydronephrosis”, or swelling of the kidney due to an obstructing stone.
Treatment of the stone can vary between conservative management (pain medication and increased fluids to help the stone pass out of the body) to surgery (lithotripsy) to remove or fragment the stone to facilitate passage out of the body.
The decision to treat an individual conservatively or with surgery to remove the stone is based on the size of the stone and its location within the urinary system. In general, stones less than 5 millimeters in size have a 50% chance of passing out of the body with conservative therapy alone.
Kidney stones that are larger than 5 mm are often treated surgically.
When an individual has a fever, and a stone is obstructing the urinary system, surgery is advised to allow elimination of the obstruction that allows the individual to improve clinically. The stone is then removed several days later after the individual is clinically stable.
It is important to undergo a thorough metabolic evaluation following the diagnosis of kidney stones. Dietary modification, including increase in fluid intake to prevent dehydration, is important in the management and prevention of kidney stones.
A 24-hour urine test may be performed that allows the physician to better understand a specific individual’s risk of stone formation, and aid in future therapy to prevent kidney stones.
It is important that any stones retrieved be evaluated to determine the chemical composition of the stone. This allows for treatment recommendations that help prevent future stones.
Some stone types allow for individuals to take oral medications to reduce the chance of future stone formation.