Urolithiasis

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Backgroun

  • Peptic Ulcer Disease (PUD) increases risk for developmentd[1]
    • Elevated oral calcium intake with calcium based treatments
  • Renal damage
    • Irreversible renal damage can occur w/in 3wk w/ complete obstruction
    • Most pts have no rise in Cr b/c 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

  • Calcium (75%)
    • Hyperparathyroidism, hypercalcemia of malignancy, sarcoidosis, increased absorption, loop diuretics, IBD
  • Struvite (magnesium-ammonium-phosphate) (15%)
    • Proteus, klebsiella, pseudomonas, staph
  • Uric Acid (10%)
    • 25% of pts w/ gout develop kidney stones

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
    • 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%)
    • Cannot be used to rule-in or rule-out stone (25% of pts w/ flank pain and hematuria do not have stone)

Differential Diagnosis

Nephrolithiasis is most common misdiagnosis given to patients with rupturing AAA

Flank Pain

Lower Back Pain

Diagnosis

Labs

  • UA
  • UCx
    • Consider for all patients[2]
  • Urine pregnancy
  • Chemistry
  • CBC (if concern for infection)

Imaging

  • Bedside Ultrasound
  • Consider non-contrast CT abdomen and pelvis for:
    • 1st time stone
    • Avoid CT in young (<50 years old), health patients with known history of nephrolithiasis with presentation consistent with renal colic
    • Part of ACEP Choosing wisely
  • 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):[3]
    • 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

Infection

Expulsion

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).[4][5]

Surgery

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

Disposition

Admission

  • Absolute
    • Intractable pain or vomiting
    • Urosepsis
    • Single or transplanted kidney with obstruction
    • Acute renal failure
    • Hypercalcemic Crisis
    • Severe medical comorbidities
  • Relative
    • Fever
    • Solitary kidney or transplanted kidney without obstruction
    • Obstructing stone with signs of urinary infection
    • Urinary extravasation
    • Significant medical comorbidities
    • Stone unlikely to pass (large stone (>5mm) in proximal ureter)

Consultation

  • Renal insufficiency
  • Severe underlying disease
  • Stone >6 mm
  • Sloughed renal papillae
  • Associated UTI without sepsis
  • Infected stone

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 StonesNew England Journal of Medicine, 1992; 327:1141-1152
  2. ↑ 2.0 2.1 2.2 Abrahamian FM, et al. "Association of Pyuria and Clinical Charateristics with Presence of Urinary Tract Infection Among Patietns with Acute Nephrolithiasis." Annals of EM. Novomber 2013. 62(5):526-533
  3. ↑ Smith-Bindman R, Aubin C, Bailitz J, et al. Ultrasonography versus Computed Tomography for Suspected Nephrolithiasis. N Engl J Med. 2014;371(12):1100–1110.
  4. ↑ Singh A, et al. A systematic review of medical therapy to facilitate the passage of ureteral calculi. Annals of Emerg Med. 2007; 552-563. fulltext
  5. ↑ Pickard, R et al. Medical expulsive therapy in adults with ureteric colic: a multicentre, randomised, placebo-controlled trial. 2015; epub. [www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(15)60933-3.pdf full text]
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