Renal colic (literally, kidney pain), also known asureteric colic (literally, pain in the ureters), is characterized bysevereabdominal pain that is spasmodic in nature. This pain is primarily caused by an obstruction of one or bothureters from dislodgedkidney stones. The most frequent site of obstruction is at the vesico-ureteric junction (VUJ), the narrowest point of theupper urinary tract. Acute (sudden onset) obstruction of a ureter can result in urinary stasis - the disruption or cessation ofurine flow into the bladder. This, in turn, can cause distention of the ureter, known as a (hydroureter). The obstruction and distention of the ureter(s) results inreflexiveperistalticsmooth musclespasms or contractions, which then cause very intense and diffuse (widespread)visceral pain affecting the organs of the pelvis, abdomen and even the thoracic area. This intense, diffuse pain is transmitted via theureteric plexus, a branching network of intersecting nerves that cover and innervate the ureters.

Renal colic
Localization of pain caused by kidney stones
Specialty	Urology
Complications	Acute kidney injury

Renalcolic typically begins in theflank and often radiates to below the ribs or thegroin. It typically comes in waves due touretericperistalsis, but may be constant. It is often described as one of the most severe pains.^[1]

Although this condition can be very painful, most ureteric stones under 5 mm size will eventually pass into the bladder without needing treatments, and cause no permanent physical damage. The experience is said to be traumatizing due to the severe pain, and the experience ofpassing blood and clots as well as pieces of stone. In most cases, people with renal colic are advised to drink more water to facilitate passing; in other instances,lithotripsy orendoscopic surgery may be needed. Preventive treatment can be instituted to minimize the likelihood of recurrence.^[2]

The diagnosis of renal colic is the same as the diagnosis for renal calculus and ureteric stones.^{[citation needed]}

A renal colic must be differentiated from the following conditions:^[3]

• biliary colic andcholecystitis
• aortic and iliacaneurysms (in older patients with left-side pain, hypertension or atherosclerosis)
• interstitial:appendicitis,diverticulitis orperitonitis (in this case patients prefer to lie still rather than being restless^[3])
• gynaecological:endometriosis,ovarian torsion andectopic pregnancy
• testicular torsion

Most small stones are passed spontaneously and onlypain management is required. Above 5 mm (0.20 in) the rate of spontaneous stone passage decreases.^[4]NSAIDs (non-steroidal anti-inflammatory drugs), such asdiclofenac^[5] oribuprofen, andantispasmodics likebutylscopolamine are used. Althoughmorphine may be administered to assist with emergency pain management, it is often not recommended as morphine is addictive and raises ureteral pressure, worsening the condition. Vomiting is also considered an important adverse effect of opioids, mainly withpethidine.^[6] Oral narcotic medications are also often used.^{[citation needed]}

There is typically noantalgic position for the patient (lying down on the non-aching side and applying a hot bottle or towel to the area affected may help). Larger stones may require surgical intervention for their removal, such asshockwave lithotripsy,laser lithotripsy,ureteroscopy orpercutaneous nephrolithotomy. Patients can also be treated withalpha blockers^[7] in cases where the stone is located in theureter.

A 2019 review found three cases of renal colic werehydronephrosis caused by malpositionedmenstrual cups pressing on a ureter. When the cups were removed, the symptoms disappeared.^[8]