Nephrolithiasis affects nearly 1.2 million people each year and can progress to a debilitating renal colic requiring inpatient care. Treatment depends on the type and size of the stone.
Patients with underlying renal disease are at higher risk for acute injury when a complete obstruction occurs. Given that the management of stones varies with their etiology, even first time kidney stones should be identified and their source addressed. Recurrent obstructions can stimulate the fibrogenic cascade, leading to renal parenchymal injury.
Recurrence rates for stone formation increase with each passing year. Reports have calculated this risk of recurrence to over 50% at a 10 year period. This recurrence rate has been reported to decrease with some simple preventative measures. These measures are usually dietary modifications and increased fluid intake.
Pathophysiology and Presentation
The term nephrolithiasis specifically refers to renal calculi, but is often used to also describe both ureteral and renal calculi. For stones to form, the components must be present in the urine at a high enough concentration to precipitate out of solution.
To be of clinical consequence, these initial clots must grow. There are several types of stones that may develop calcium, struvite, uric acid, and cysteine. Calcium stones are the most common. Knowledge of the stone composition helps identify the appropriate dietary modification. Its location will dictate the potential therapeutic interventions.
Often times, renal colic is the presenting symptom of nephrolithiasis. Renal colic is an acute, incapacitating pain due to the dilation, stretch and spasm caused by a complete ureteral obstruction. The pain is often described as the worst pain the patient has ever felt. This pain presents differently at different locations.
At the ureteropelvic junction, neophrolithiasis can present as an ipsilateral deep flank pain without radiation. In the ureter, it can present as a severe colicky pain in the flank and lower abdomen. Unlike the ureteropelvic location, this pain radiates to the ipsilateral groin and can be associated with severe nausea. It initiates in the deep flank on the same side as the obstruction, without radiation to the groin.
At the ureterovescial junction, the symptoms consist more of voiding difficulties; including increased frequency and painful urination. Furthermore, this location is associated with a suprapubic location of pain. Unique to this location are associated gastrointestinal symptoms such as diarrhea and tenesmus.
Other potential symptoms include those associated with nausea and vomiting, a urinary tract infection, or hematuria. When the stones are too large to pass through the system, such as the case with staghorn calculi, they often do not present with pain. Instead, they present as infection or hematuria.
Untreated stones may develop into perinephric hematomas, kidney infections, urinary obstruction from stone impactions, stomach or intestinal ulcerations, and post procedural kidney impairment.