Urolithiasis

Background

Urolithiasis comprises 3 similar clinical entities:

  • Nephrolithiasis
  • Ureterolithiasis
  • Cystolithiasis

The most common cause is infection of residual bladder urine with urea-spliting organisms (proteus, pseudomonas, klebsiella, staphlococcus and mycoplasm)

Renal damage
  • Irreversible renal damage can occur within 3 weeks in patients with a complete obstruction
  • Most have no rise in creatinine because unobstructed kidney functions at up to 185% of its baseline capacity

Infection
  • 8-15% of kidney stones have urinary co-infection[1]
    • Fever, pyuria >10 WBC/hpf, and peripheral WBC >11.3 (any one) best predictors of concomitant UTI[1]

Stone Expulsion Rate
Stone Size Passage Rate[2]
1-4 mm78%
5 -7 mm60%
>8mm39%

Types

Risk Factors for Complications
  • 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
Diagram showing the classic location of renal colic.
  • 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

Evaluation

Labs
  • Urinalysis: hematuria
    • Hematuria cannot be used to rule-out or rule-in stone (sensitivity 71-95%; specificity 18-49%)[3]
    • The absence of pyuria cannot exclude a complicating UTI (sensitivity 86%; specificity 79%)[3]
  • Urine culture :
    • Consider for all patients[1] OR those at higher risk (female, pyuria, or cystitis symptoms)[3]
  • Urine pregnancy
  • Chemistry
  • CBC: If concern for infection (>15k concerning)

Imaging
  • Consider tailoring your choice of imaging based upon the patient's age, clinical likelihood of stones, risk factors, and prior history of stones[4]
    • In young patients, even with no prior history of kidney stones, reasonable approaches may be bedside ultrasound or no imaging
    • In middle aged patients with prior history of stones, it may be reasonable to perform a bedside ultrasound although no imaging can be appropriate as well
    • In middle aged patients with no prior history of stones, CT imaging is reasonable
    • In elderly patients, even with prior history of stones, CT is recommended in order to avoid missing alternative etiologies such as dissection, AAA, or diverticulitis.
Axial CT scan of abdomen without contrast, showing a 3-mm stone (marked by an arrow) in the proximal ureter.
Renal ultrasound of a stone located at the pyeloureteral junction with accompanying hydronephrosis.
  • Consider non-contrast CT abdomen and pelvis (KUB protocol) for:
    • 1st time stone
    • Older patients with other possible diagnosis
    • Avoid CT in young (<50 years old), health patients with known history of nephrolithiasis with presentation consistent with renal colic[5]
  • Consider formal ultrasound for:
    • Pregnant pt
    • Repeat stone (to avoid CT)
  • In comparison of diagnosis by CT vs. U/S (by EP) vs. U/S (by radiologist):[6]
    • 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
  • Ketorolac 15mg IV or Ibuprofen 600mg PO Q6hrs PRN if the patient can tolerate oral medications[7]
    • Avoid high dose NSAIDS in patients with renal failure or insufficiency.
    • Ketorolac 15 mg has similar effects to traditional 30 mg dosage. [8]
  • Morphine or other Opioids are often needed due to severe pain

Antiemetic

Expulsion Therapy
  • Consider Tamsulosin 0.4mg PO QHS (discontinued after successful expulsion; average 1-2 weeks)
    • See EBQ:Alpha-blockers for ureteral stone expulsion discussion of evidence
    • 76% vs 48% passage rates in tamsulosin vs no treatment, respectively[9]
      • Only patients with stones ≥ 5 mm benefited
      • Review of 55 RTCs, with NNT of 4
    • Tamsulosin 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]

Infected Urolithiasis

Inpatient observation is often the safest disposition for patients with infected stones due to the risk of progressing to sepsis. All antibiotics should take into account patient's previous sensitivities and local antibiograms Treatment is targeted at E. coli, Enterococcus, Klebsiella, Proteus mirabilis, S. saprophyticus

Outpatient

Consider one dose of Ceftriaxone 1g IV or Gentamycin 7mg/kg IV if the regional susceptibility of TMP/SMX or Fluoroquinolones is <80%

Adult Inpatient Options

Pediatric Inpatient Options

Surgical Removal

Considered for ureterolithiasis with:

  • Persistent obstruction
  • Failure of stone progression
  • Increasing or unremitting colic
  • Staghorn calculi

Disposition

Admission

Recommended for any of the following:

Also consider admission for patients with:

  • 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 follow up within 7d

See Also

References
  1. 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.
  2. Coll DM et al. Relationship of spontaneous passage of ureteral calculi to stone size and location as revealed by unenhanced helical CT. AJR Am J Roentgenol 2002 Jan; 178:101-3.
  3. Wang RC. Managing Urolithiasis. Annals of EM. April 2016. 67(4):449-454
  4. Imaging in suspected renal colic: systematic review of the literature and multispecialty consensus Moore CL, Carpenter CR, Heilbrun ME, et al. Ann Emerg Med. 2019;74(3):391-399.
  5. Part of Choosing wisely ACEP
  6. Smith-Bindman R, Aubin C, Bailitz J, et al. Ultrasonography versus computed tomography for suspected nephrolithiasis. NEJM. 2014; 371(12):1100–1110.
  7. Pathan, SA et al. Delivering safe and effective analgesia for management of renal colic in the emergency department: a double-blind, multi-group, randomised controlled trial. Lancet. 2016 May 14;387(10032): 1999-2007
  8. Motov S, et al. Comparison of Intravenous Ketorolac at Three Single-Dose Regimens for Treating Acute Pain in the Emergency Department: A Randomized Controlled Trial. Ann Emerg Med. 2017 Aug;70(2):177-184. doi: 10.1016
  9. Hollingsworth JM et al. α-blockers for treatment of ureteric stones: systematic review and meta-analysis. BMJ 2016;355:i6112.
  10. Gupta K, Hooton TM, Naber KG, et al. International Clinical Practice Guidelines for the Treatment of Acute Uncomplicated Cystitis and Pyelonephritis in Women. Clinical Infectious Diseases. 2011;52(5):e103-e120. doi:10.1093/cid/ciq257
  11. Colgan R, Williams M. Diagnosis and treatment of acute uncomplicated cystitis. Am Fam Physician. 2011 Oct 1;84(7):771-6.
  12. Acute Pyelonephritis in Adults. Johnson, JR and Russo, TA. New England Journal of Medicine 2018; 378:48-59.
  13. Sandberg T. et al. Ciprofloxacin for 7 days versus 14 days in women with acute pyelonephritis: a randomised, open-label and double-blind, placebo-controlled, non-inferiority trial. Lancet. 2012 Aug 4;380(9840):484-90.
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