Urolithiasis

Background

  • Urolithiasis comprises 3 similar clinical entities:
    • Nephrolithiasis
    • Ureterolithiasis
    • Cystolithiasis
  • Peptic ulcer disease increases risk for development of kidney stones[1]
    • Elevated oral calcium intake with calcium based treatments
  • Renal damage
    • Irreversible renal damage can occur within 3wk with complete obstruction
    • Most have no rise in Cr because unobstructed kidney functions at up to 185% of its baseline capacity
      • Rise in Cr suggests solitary kidney or preexisting renal disease (such that the unobstructed kidney is unable to compensate)
  • Infection
    • 8-15% of kidney stones have urinary co-infection[2]
    • Fever, pyuria >10 WBC/hpf, and peripheral WBC >11.3 (any one) best predictors of concomitant UTI[2]

Pass Rate

  • <5mm - 98% will pass within 4wk
  • 5-7mm - 60% will pass within 4wk
  • >7mm - 39% will pass within 4wk

Types

Risk Factors for Poor Outcome

  • Renal function at risk
    • DM
    • Hypertension
    • Renal insufficiency
    • Single kidney
    • Horseshoe kidney
    • Transplanted kidney
  • History of difficulty with stones
    • Extractions
    • Stents
    • Ureterostomy tubes
    • Lithotripsy
  • Symptoms of infection

Clinical Features

  • Pain
    • Acute onset, crampy, intermittent, unable to find position of comfort
    • Location of pain depends on location of stone:
      • Upper ureter: flank pain
      • Mid ureter: lower anterior quadrant of abdomen
      • Distal ureter: groin pain
      • UVJ: Can mimic a UTI (frequency, urgency, dysuria)
  • Nausea/vomiting (50%)
  • Hematuria (85%)

Differential Diagnosis

Nephrolithiasis is most common misdiagnosis given to patients with rupturing AAA

Flank Pain

Lower Back Pain

Diagnosis

Labs

  • UA: hematuria
    • Hematuria cannot be used to rule-out or rule-in stone (sensitivity 71-95%; specificity 18-49%)[3]
    • The abscence of pyuria cannot exclude a complicating UTI (sensitivity 86%; specificity 79%)[3]
  • UCx:
    • Consider for all patients[2] OR those at higher risk (female, pyuria, or cystitis symptoms)[3]
  • Urine pregnancy
  • Chemistry
  • CBC: If concern for infection

Imaging

  • Bedside Renal ultrasound
  • Consider non-contrast CT abdomen and pelvis (KUB protocol) for:
    • 1st time stone
    • Avoid CT in young (<50 years old), health patients with known history of nephrolithiasis with presentation consistent with renal colic[4]
  • Consider formal US for:
    • Pregnant pt
    • Repeat stone (to avoid CT)
  • In comparison of diagnosis by CT vs. U/S (by EP) vs. U/S (by radiologist):[5]
    • No difference in rate of missed high-risk diagnoses that resulted in complications (pyelo/sepsis/diverticular abscess)
    • No difference in rate of serious adverse events, pain scores, return emergency department visits, or hospitalizations

Management

Pain

ED & Inpatient

Outpatient

  • Ibuprofen 600mg PO Q6hrs PRN pain, AND
  • Norco 5/325 PO Q6hrs PRN pain x 3 days

Antiemetic

Infection

Expulsion

  • Consider tamulosin 0.4 mg PO QHS (discontinued after successful expulsion; average 1-2 weeks)
    • Current Cochrane Review concludes: "the use of alpha-blockers in adult patients with ureteral stones appears to expedite spontaneous passage, with only minor potential adverse effects."[6][7]
    • There is evidence that the subgroup of large distal stones >5mm benefit from tamulosin (passage rate of 83.3% with tamulosin versus 61.0% with placebo)[8]
    • Although meta-analyses of previous randomized controlled trials concluded that the smooth muscle relaxant drugs tamsulosin and nifedipine assisted stone passage for people managed expectantly for ureteric colic, a randomized placebo-controlled trial demonstrated that no difference was noted between active treatment and placebo (p=0.78), or between tamsulosin and nifedipine (p=0.77).[9][10]
    • Tamulosin number needed to harm (orthostatic hypotension)= 19 (give at night, to reduce side effect rate)[3]
  • Use of IV fluids to "flush out" stone has not been shown to improve clinical outcomes[3]

Surgery

  • Considered for:
    • Persistent obstruction
    • Failure of stone progression
    • Increasing or unremitting colic
    • Staghorn calculi (abx penetration is poor)

Disposition

Admission

  • Absolute
  • Relative
    • Solitary kidney or transplanted kidney without obstruction
    • Urinary extravasation
    • Significant medical comorbidities

Consultation

  • Renal insufficiency
  • Severe underlying disease
  • Stone >10 mm[3]
  • Sloughed renal papillae
  • Unclear/distal UTI
  • Ruptured renal capsule causing urinoma

Discharge

  • Small stone, adequate analgesia, able to arrange urology f/u w/in 7d

See Also

References

  1. ↑ Coe F, et al. The pathogenesis and treatment of kidney stones. NEJM. 1992; 327:1141-1152.
  2. ↑ 2.0 2.1 2.2 Abrahamian FM, et al. Association of pyuria and clinical characteristics with presence of urinary tract infection among patients with acute nephrolithiasis. Annals of EM. 2013; 62(5):526-533.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 Wang RC. Managing Urolithiasis. Annals of EM. April 2016. 67(4):449-454
  4. ↑ Part of Choosing wisely ACEP
  5. ↑ Smith-Bindman R, Aubin C, Bailitz J, et al. Ultrasonography versus computed tomography for suspected nephrolithiasis. NEJM. 2014; 371(12):1100–1110.
  6. ↑ Welch JL and Cooper DD. Systematic review Snapshot. Annals of Emergency Medicine. January 2016. 67(1):117-118.
  7. ↑ Campschroer et al. Alpha-blockers as medical expulsive therapy for ureteral stones. Cochrane Databse Syst Rev. 2014(4):CD008509
  8. ↑ Furyk, JS, et al. Distal Ureteric Stones and Tamsulosin: A Double-Blind, Placebo-Controlled, Randomized, Multicenter Trial. Annals of Emergency Medicine. 2016; 67(1):86-95.e2.
  9. ↑ Singh A, et al. A systematic review of medical therapy to facilitate the passage of ureteral calculi. Annals of Emerg Med. 2007; 552-563.
  10. ↑ Pickard R, et al. Medical expulsive therapy in adults with ureteric colic: a multicentre, randomised, placebo-controlled trial. Lancet. 2015; epub.
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