Acute Renal Colic

Acute renal colic is a severe and sudden flank pain that typically originates at the costovertebral angle and extends anteriorly and inferiorly toward the groin or testicle. This condition is usually caused by an acute urinary tract obstruction due to calculus and is often associated with nausea and vomiting. Urolithiasis, commonly known as kidney stones, is a prevalent condition affecting approximately 1 in 11 individuals in the United States at some point in their lives. Urolithiasis typically occurs when a crystal or crystalline aggregate travels from the kidney through the genitourinary system, becoming lodged and obstructing urinary flow, usually in the ureter. This obstruction leads to proximal ureteral and renal pelvic dilation (hydroureteronephrosis), which is the primary cause of the intense pain known as renal colic.  The intensity of pain is related to the degree of obstruction, rather than the size of the stone, although stone size can help predict the likelihood of spontaneous passage. Although kidney stones are not the only cause of flank pain, their prevalence and the severity of the pain they cause make ureterolithiasis the most likely presumptive diagnosis when sudden, severe flank pain occurs, particularly when associated with hematuria. The nature, onset, location, and severity of the pain vary depending on the underlying cause. However, for most patients, the pain typically peaks 1 to 2 hours after its initial onset. Underlying causes of urolithiasis include inadequate hydration, aciduria, chronic urinary infections, hypercalciuria, hyperoxaluria, hyperuricosuria, and hypocitraturia. The initial evaluation of a patient presenting with acute renal colic involves laboratory testing, urinalysis, and appropriate imaging studies. The immediate treatment of acute renal colic due to urolithiasis includes pain control, intravenous (IV) hydration, antiemetics, and antibiotics (if indicated). Patients with severe or refractory symptoms may require hospital observation or admission. In some cases, urgent surgical intervention is necessary, such as in obstructive pyelonephritis (pyonephrosis), where emergent drainage of the infected renal pelvis is required. Definitive treatment for obstructing ureteral stones may involve conservative or procedural approaches. Surgical options include cystoscopy with double J stenting, extracorporeal shockwave lithotripsy (ESWL), ureteroscopy with stone basketing, and laser therapy, as open surgery for ureteral stones is rarely necessary. Please see StatPearls' companion resource, "Ureterolithiasis," for more information. Quality of life scores typically decrease as the frequency of kidney stone attacks increases. This decline is most noticeable when a patient experiences 5 or more lifetime episodes of renal colic, indicating that preventive measures, such as 24-hour urine testing, should be considered at that point, if not earlier.