Urolithiasis

Revision as of 06:07, 18 August 2011 by Jswartz (talk | contribs)

Background

  • 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)
  • Types
    • Calcium (75%)
      • Hyperparathyroidism, hypercalcemia of malignancy, sarcoidosis, increased absorption, thiazides, IBD
    • Struvite (magnesium-ammonium-phosphate) (15%)
      • Proteus, klebsiella, pseudomonas, staph
    • Uric Acid (10%)
      • 25% of pts w/ gout develop kidney stones
  • Pass Rate
    • <5mm - 98% will pass w/in 4wk
    • 5-7mm - 60% will pase w/in 4wk
    • >7mm - 39% will pass w/in 4wk

The risk factors for a poor outcome with stones include three categories: renal function is at risk (diabetes, hypertension, preexisting renal insufficiency, single kidney or transplant), history of difficulty with stones (extractions, stents, ureterostomy tubes), and infection (fever, systemic illness, and UTI symptoms; Table 97-2). Two mimickers that are very important to exclude are abdominal aortic aneurysm (AAA) and renal artery infarction. Nephrolithiasis is the most common misdiagnosis given to patients with a rupturing or expanding AAA. Recall that stones don't usually present in men older than age 60 and do not cause hypotension, even transiently. Renal artery thrombosis can mimic stone symptoms due to swelling of the infarcted kidney and can also be associated with hematuria. However, early in the course, CT will not necessarily show inflammation around the kidney, and, because no contrast is used, the function of the kidney is not assessed.


Risk Factors for Poor Outcome

  1. Renal function at risk
    1. DM
    2. Hypertension
    3. Renal insufficiency
    4. Single kidney
    5. Horseshoe kidney
    6. Transplanted kidney
  2. History of difficulty with stones

Extractions Stents Ureterostomy tubes Lithotripsy Symptoms of infection Fever Hypotension Systemic illness Urinary tract infection


Diagnosis

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)

Work-Up

Labs

  1. UA
  2. UCx (obtain if UA c/w infection)
  3. Urine pregnancy
  4. Chemistry
  5. CBC (if concern for infection)

Imaging

  • Consider CT for:
    • 1st time stone
  • Consider US for:
    • Pregnant pt
    • Repeat stone (to avoid CT)



DDx

  1. Vascular
    1. Aortic dissection
    2. AAA
    3. Renal artery embolism
    4. Renal vein thrombosis
    5. Mesenteric ischemia
  2. Renal
    1. Pyelonephritis
    2. Papillary necrosis
    3. Renal cell carcinoma
    4. Renal infarct
    5. Renal hemorrhage
  3. Ureter
    1. Blood clot
    2. Stricture
    3. Tumor (primary or metastatic)
  4. Bladder
    1. Tumor
    2. Varicose vein
    3. Cystitis
  5. GI
    1. Biliary colic
    2. Pancreatitis
    3. Perforated peptic ulcer
    4. Appendicitis
    5. Inguinal hernia
    6. Diverticulitis
    7. Cancer
    8. Bowel obstruction
  6. Gynecologic
    1. Ectopic pregnancy
    2. PID/TOA
    3. Ovarian cyst
    4. Ovarian torsion
    5. Endometriosis
  7. GU
    1. Testicular torsion
    2. Epididymitis
  8. Other
    1. Shingles
    2. Retroperitoneal hematoma/abscess/tumor


Treatment

  • Pain
    • NSAIDs are agent of choice
      • Ketorolac 30mg IV
    • Morphine
    • Metoclopramide (provides pain relief equivalent to morphine)
  • 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
    • Alpha blockers a/w increased rate of expulsion, decreased time to expulsion, and decreased pain
      • Tamsulosin 0.4mg PO daily up to 4wk
  • Surgery
    • Consider for:
      • Persistent obstruction
      • Failure of stone progression
      • Increasing or unremitting colic
      • Staghorn calculi (abx penetration is poor)


Patients who have a known stone who return for continued pain should be evaluated for worsening renal function (blood urea nitrogen/creatinine), evidence of obstruction (US to limit radiation exposure), evidence of infection (repeat urinalysis and review for systemic symptoms), movement of stone (repeat KUB), and clear evidence that a stone was the original cause of the pain. If all of these issues do not suggest a urologic emergency, the patient's pain management regimen should be altered. Consider metoclopramide, NSAIDs, opioids, -blockers, and, possibly, steroids. 



In severe concurrent underlying disease (e.g., angina or chronic obstructive pulmonary disease) or in the fragile elderly who may be unable to tolerate the stress of renal colic, a lower admission threshold is indicated. There is also a subset of patients who may require emergent decompression. Examples include those with a solitary kidney and complete obstruction, ureterolithiasis with hydronephrosis and fever, and urosepsis with obstruction. In addition, disposition should be discussed with a urologist and follow-up within 1 week obtained if there is (1) renal insufficiency, (2) severe underlying disease, (3) an IV urogram showing extravasation or complete obstruction, (4) multiple ED visits, (5) a stone >6 mm, (6) sloughed renal papillae, or (7) associated UTI without sepsis.

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)

Discharge

  • Stone w/ associated UTI but no e/o obstruction, fever, or systemic illness can be treated as outpt
    • Provide urologic follow-up in 48 to 72 hours
  • Consider d/c for:
    • Small stone
    • Adequate analgesia
  • Arrange urology f/u w/in 7d


See Also

EBQ Medical Treatment for Nephrolithiasis

Source

Tintinalli

Retrieved from "https://www.wikem.org/w/index.php?title=Urolithiasis&oldid=5370"