Urolithiasis

Background[1]

  • Peptic Ulcer Disease (PUD) increases risk for development
    • 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[3]

Pass Rate

  • <5mm - 98% will pass within 4wk
  • 5-7mm - 60% will pase 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)
  • N/V (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

  1. UA
  2. UCx
    1. Consider for all patients[4]
  3. Urine pregnancy
  4. Chemistry
  5. CBC (if concern for infection)

Imaging

  • Bedside Ultrasound
  • Consider CT for:
    • 1st time stone
  • 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

first line agents

Infection

  • Inpatient:
    • Gentamicin 1-2.5mg/kg + ampicillin 1-2gm q4hr OR
    • Piperacillin-tazobactam 3.375 gm q6hr OR
    • Cefepime 2gm q8hr OR
    • Ciprofloxacin 400mg q12hr (if local sensitivities do not predict treatment failure)
  • Outpatient:
    • Ciprofloxacin 500mg PO BID x10-14d OR
    • Levofloxacin 500mg PO daily x10-14d OR
    • Cefpodoxime 200mg PO BID x10-14d

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).[6][7]

  • Tamsulosin 0.4mg PO daily up to 4wk

Surgery

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

Disposition

Admission

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

Consultation

  1. Renal insufficiency
  2. Severe underlying disease
  3. Stone >6 mm
  4. Sloughed renal papillae
  5. Associated UTI without sepsis
  6. Infected stone

Discharge

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

See Also

EBQ:Medical Treatment for Nephrolithiasis

References

  1. ↑ Coe, F et al.The Pathogenesis and Treatment of Kidney StonesNew England Journal of Medicine, 1992; 327:1141-1152
  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. ↑ 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
  4. ↑ 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
  5. ↑ 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.
  6. ↑ 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
  7. ↑ 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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