The recurrence rate is 30% within the first year
and 50% at 5 years. Patients with a family history of
kidney stones are more likely to develop stones, and
include dehydration, hypercalcemia, hyperuricemia
(gout), certain urinary tract infections (Proteus, Klebsiella,
Pseudomonas), and medications (protease inhibitors,
• Noncontrast computed tomography of the abdomen
and pelvis is the test of choice for diagnosing
• Urologic consultation is indicated in patients with
coexisting infection or worsening renal insufficiency.
diuretics, laxatives). The 4 main types of kidney stones
The GU tract has several anatomic areas of narrowing
that may limit passage of a stone. The most common areas
are the renal calyx, the ureteropelvic junction (UPJ), the
pelvic brim (where the ureter passes over the pelvic bone
and iliac vessels), and the ureterovesical j unction (UVJ).
hydronephrosis (dilated renal pelvis and calices).
Timely evaluation, a broad differential, and prompt
administration of appropriate analgesia is paramount to
proper emergency department (ED) management. Although
disposition of these patients is often uncomplicated, certain
factors may warrant more extensive workup, emergent urology consultation, and hospital admission.
Table 39-1 . Kidney stones by type, frequency of occurrence, and precipitants.
Struvite (magnesium-ammoniumphosphate)
Hyperparathyroidism, immobil ization
Infection caused by urea-spl itting bacteria Proteus (most common cause
Hypercystinuria from genetic disorder
Patients often present with rapid onset of severe sharp
pain, which is usually episodic ("renal colic") and lasts
minutes to hours. Pain often originates in the flank and
radiates to the abdomen and groin along the course of the
ureter. Nausea, vomiting, and diaphoresis are common.
Urinary symptoms, such as frequency and urgency, may
vary, depending on where the stone is located, and often
increase in severity when the stone nears the bladder .
Patients with symptomatic nephrolithiasis are often rock
ing or writhing on the stretcher. They are frequently unable
to lie down or find a comfortable position. Elevated blood
pressure and heart rate are common because of pain.
Examination should focus on identifying and/or ruling out
other causes of abdominal and flank pain. It should
include a thorough genitourinary evaluation, including
pelvic or testicular examination, when pain is located in
the lower abdomen. Evidence of a pulsatile abdominal
mass or peritonitis suggests an alternative diagnosis.
Although no single laboratory test is needed to diagnose
hematuria and the presence of concomitant infection. In
15-30% of patients, microscopic hematuria may be absent.
Crystals may be present in the urine and aid in the
diagnosis of stone type. Urine pH >7.6 (normal is 5.5) may
indicate infection with urea-splitting organisms. Urine
pregnancy test should be obtained in all females of
checked to assess renal function, especially in patients at
risk for renal insufficiency (diabetics, elderly) or in patients
who may receive intravenous (N) contrast. Complete
blood count may be helpful when infection is suspected,
but is not routinely necessary .
Computed tomography (CT) scan of the abdomen and
pelvis is the test of choice for diagnosis of nephrolithiasis
(Figure 39-1). It has a sensitivity and specificity of approx
imately 96% for kidney stones. CT scans can visualize all 4
types of kidney stones as well as perinephric stranding,
hydroureter, and hydronephrosis. They can also identify
nonurologic causes of pain (eg, abdominal aortic aneurysm [AAA]) in cases of diagnostic uncertainty.
Noncontrast CT scan does not evaluate renal function or
the presence of complete obstruction.
.&. Figure 39-1 . CT sca n of left ureteral stone (arrow).
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