particularly in patients with contraindications to CT

scan ( eg, pregnancy). It is highly sensitive for hydronephrosis,

but only moderately sensitive for detecting stones, and

provides no information regarding stone size or location.

Abdominal plain film radiography is occasionally used

to diagnose kidney stones, particularly in patients with a

long history of kidney stones and multiple prior imaging

studies. It has similar sensitivity to renal ultrasound, with

similar limitations .

MEDICAL DECISION MAKING

Although the clinical presentation of a patient with acute

flank pain and suspected kidney stones may seem straightforward, particularly in a patient with a history of kidney

stones, it is important to consider a broad differential

diagnosis and perform a thorough history and physical

exam. Immediate life-threatening conditions, such as ruptured AAA and aortic dissection, must be considered, particularly in older, hypertensive patients with no history of

kidney stones. Other diagnoses to consider include biliary

colic, pyelonephritis, musculoskeletal back pain, diverticulitis, and bowel obstruction. Pay specific attention to the

GU exam, as both testicular/ovarian torsion and ectopic

pregnancy can present with isolated flank pain and with

similar clinical appearance to kidney stones (Figure 39-2).

TREATMENT

Management of suspected nephrolithiasis includes aggressive

pain control, and this intervention should not be delayed

pending diagnostic confirmation. Opioid analgesics are the

mainstay of treatment for acute symptomatic nephrolithiasis.

Nonsteroidal anti-inflammatory drugs are an excellent

adjunct to opiates, but should be avoided in patients with

baseline renal impairment, as this class of drugs may worsen

renal insufficiency. Anti emetics are also useful in treating the

nausea and vomiting often present in these patients. N fluids

are often beneficial in patients with nausea and vomiting;

CHAPTER 39

Acute flank pain

Focused history & physica l exam: rule out

immediate life th reats and alternate diagnoses

IV analgesia

Ketorolac 30 mg IV

or

Morphine 4 mg IV

D

• Oral ana lgesia

• Urology follow-up

• Urine stra iner

• Clear discharge

instructions with

reasons for return

La b studies:

UA, BUN/CR

Search for alternate

diag nosis

.&. Figure 39-2. Nephrol ithiasis diagnostic algorithm. BUN, blood urea nitrogen;

CR, creatin ine; CT, computed tomography; UA, urina lysis.

however, saline boluses are no longer routinely recom ­

mended, as they do not help "flush out'' the kidney stone.

Additional therapeutic intervention includes antibiotics in

those patients with coexisting urinary tract infections.

DISPOSITION

..... Admission

Patients with intractable pain and/or inability to tolerate

oral intake after aggressive ED management should be

admitted to the hospital. Patients with kidney stones and

concomitant urinary tract infection are at high risk for

developing urosepsis and require urology consultation for

consideration of ureteral stenting or percutaneous neph ­