Flank pain

Background

  • This page outlines the general approach to flank pain in the ED
  • The most common cause is nephrolithiasis, but vascular emergencies (AAA, renal infarction) must be considered
  • Flank pain may also be referred from intra-abdominal or retroperitoneal pathology

Classification by Abdominal pain location

Side-by-side comparison of quadrants and regions.
Chart of commonly reported referred pain sites.
RUQ pain Epigastric pain LUQ pain
Flank pain Diffuse abdominal pain Flank pain
RLQ pain Pelvic pain LLQ pain

Clinical Features

  • Location: Pain between the costal margin and iliac crest, typically lateral to the paraspinal muscles
  • Classic renal colic: sudden onset, severe colicky pain radiating from flank to groin/testicle/labia
  • Associated symptoms may help differentiate cause:
    • Dysuria, frequency, hematuria → urologic cause
    • Fever, chills → pyelonephritis, perinephric abscess
    • Pulsatile abdominal mass, hemodynamic instability → AAA
    • Sudden onset with atrial fibrillation or recent MI → renal infarction
    • Nausea, vomiting common with both renal and GI causes
  • Physical exam:
    • CVA tenderness
    • Abdominal exam for peritoneal signs, masses, or pulsatile mass
    • Testicular exam in males
    • Pelvic exam in females of childbearing age if gynecologic cause suspected

Differential Diagnosis

Flank Pain

Evaluation

  • Urinalysis — hematuria supports urologic cause but absence does not exclude it (up to 15% of kidney stones have no hematuria)[1]
  • Pregnancy test in females of childbearing age
  • BMP/Cr — evaluate renal function, especially if obstruction suspected
  • CBC — if infection or hemorrhage suspected
  • Lactate — if concern for ischemia or sepsis
  • CT abdomen/pelvis without contrast — gold standard for nephrolithiasis and can identify most alternative diagnoses
  • CT with IV contrast or CT angiography — if vascular emergency suspected (AAA, renal infarction, aortic dissection)
  • Bedside ultrasound — can identify hydronephrosis, AAA; first-line in pregnancy
  • Renal ultrasound — alternative to CT, especially in young patients or pregnancy

Management

  • Pain control is the priority for renal colic:
    • Ketorolac 15-30 mg IV or IM — first line (NSAIDs are superior to opioids for renal colic)[2]
    • IV lidocaine 1.5 mg/kg IV over 10 min — emerging evidence as adjunct[3]
    • Opioids (e.g., morphine, hydromorphone) for refractory pain
  • IV fluids — for hydration; aggressive IV fluids do NOT speed stone passage
  • Alpha-blockers (tamsulosin 0.4 mg PO daily) for medical expulsive therapy of stones 5-10 mm[4]
  • Pyelonephritis: Antibiotics per guidelines (see Pyelonephritis)
  • Emergent urology consult for: obstructed infected kidney (pyonephrosis), bilateral obstruction, solitary kidney with obstruction, or urosepsis
  • If AAA suspected: emergent surgical consultation

Disposition

  • Admit:
    • Infected obstructed kidney / urosepsis
    • Intractable pain or vomiting
    • Acute kidney injury
    • Vascular emergency (AAA, renal infarction)
  • Discharge with follow-up:
    • Uncomplicated renal colic with adequate pain control
    • Stone <10 mm without complicating factors
    • Strain urine, urology follow-up within 1-2 weeks
    • Return precautions: fever, intractable pain/vomiting, inability to urinate

See Also

External Links

References

  1. ↑ Bove P, Kaplan D, Dalrymple N, et al. Reexamining the value of hematuria testing in patients with acute flank pain. J Urol. 1999;162(3):685-687.
  2. ↑ Holdgate A, Pollock T. Systematic review of the relative efficacy of non-steroidal anti-inflammatory drugs and opioids in the treatment of acute renal colic. BMJ. 2004;328(7453):1401.
  3. ↑ Soleimanpour H, et al. Effectiveness of intravenous lidocaine versus intravenous morphine for patients with renal colic. BMC Urol. 2012;12:13.
  4. ↑ Hollingsworth JM, et al. Alpha blockers for treatment of ureteric stones: systematic review and meta-analysis. BMJ. 2016;355:i6112.
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