The acute phenomenon of renal stones migrating down the ureter is referred to as renal colic. Adults and children can develop kidney stones. In adults, the condition is 3 times more common in males than in females; kidney stones usually occur in the third to fifth decade of life. Children under the age of 16 years old constitute 7% of cases seen, with the distribution being equal between the sexes.
Patients usually present with an acute onset of severe pain, which may be associated with nausea, vomiting, and diaphoresis. Patients are frequently anxious, pacing, or writhing and are unable to hold still or converse. The pain is sharp and episodic in nature due to the intermittent obstruction of the ureter and is relieved after the stone passes. The pain typically originates in either flank with subsequent radiation around the abdomen toward the groin. However, as the stone passes into the distal ureter, where 75% of stones are diagnosed, the pain may be located in the anterior abdominal or suprapubic area. Vesicular stones may present with intermittent dysuria and terminal hematuria. Children may present in a similar fashion, but up to 30% have only painless hematuria. Vital signs may demonstrate tachycardia and an elevated blood pressure, which are secondary to pain. Pyrexia may be present if there is a concomitant urinary tract infection. Examination may show costovertebral tenderness or abdominal tenderness, guarding, or rigidity. Hematuria may be present in 85% of patients with renal colic.
The diagnosis of urologic stones and renal colic is based on clinical judgement. A urinalysis will help rule out infection and assess for microscopic hematuria.
All females of childbearing age should have a pregnancy test. Imaging is controversial. It allows confirmation of the ureteral stone, rules out other diagnoses, identifies complications, establishes the location of the stone, and assists with the management if the stone fails to pass spontaneously. The use of noncontrast helical computed tomography is the mainstay of diagnosis in the emergency department (ED). Positive findings include changes in the ureteral caliber, suspicious calcifications, stranding of perinephric fat, and dilation of the collecting system (Fig. 56-1). It has a PPV of 96% and a NPV of 93% to 97%. The greatest advantage is the speed at which it can be performed, no need for intravenous contrast administration, and the benefits of excluding other diagnoses. The disadvantages are that it does not evaluate renal function and has radiation exposure.
CT image shows 5-mm stone (arrow) at left ureterovesical junction. Other calcifications are seen in the pelvis, unrelated to the urinary outflow system.
The use of plain kidney-ureter-bladder film (KUB) is limited by the visibility of the stone; the KUB cannot rule out a ureteral stone. The KUB is useful in following the progression of a stone, if visualized, in the outpatient setting.