Best Dx/Best Rx: Nephrolithiasis

From: Subject: Best Dx/Best Rx: Nephrolithiasis Date: Wed, 3 Jun 2009 21:24:32 -0700 MIME-Version: 1.0 Content-Type: multipart/related; type="text/html"; boundary="----=_NextPart_000_01AB_01C9E491.AFB36410" X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_01AB_01C9E491.AFB36410 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Content-Location: http://www.acpmedicine.com/acp/newrxdx/rxdx/dxrx1012.htm Best Dx/Best Rx: Nephrolithiasis

Nephrolithiasis

Fuad N. Ziyadeh, M.D.
Stanley=20 Goldfarb, M.D., F.A.C.P.
University of Pennsylvania School of=20 Medicine

Defin= ition/Key=20 Clinical Features
Diffe= rential=20 Diagnosis
Best = Tests
Best = Therapy
Best = References

Definition/Key Clinical=20 Features

Acute nephrolithiasis (renal colic)=20
- Severe pain, abrupt in onset=20
  - Constant, rather than colicky=20
  - Localized to flank or radiating from flank = to=20 groin=20
  - May be associated with nausea and = vomiting=20
- Microscopic or macroscopic hematuria=20
- Atypical presentations=20
  - Midanterior abdominal pain=20
  - Obstruction without pain or = hematuria=20
  - Progressive renal failure=20
  - Urosepsis=20
  - Adynamic paralytic ileus
- Passage of most kidney stones < 5 mm = diameter=20 within 48 hr
- Intervention to effect passage of stone = required in=20 20% of patients
Chronic and recurrent nephrolithiasis=20
- Recurrence in 40% of males within 5 yr of = first stone;=20 60% within 10 yr=20
- Recurrence rate in females about two thirds = of the=20 rate in males=20
- Chronic nephrolithiasis often = asymptomatic=20
  - Cumulative occurrence of a symptomatic = event is 50%=20 over 5 yr
- Calcium stones most common (calcium oxalate = >=20 calcium phosphate)

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Differential = Diagnosis

Acute = Nephrolithiasis=20

Sloughed renal papilla=20
Clot=20
Fungal ball

Chronic=20 and Recurrent Nephrolithiasis=20

Calcium-containing stones=20
- Tubular disorders (renal tubular = acidosis)=20
- Hypercalcemia and hypercalciuria=20
- Hyperoxaluria=20
- Hyperuricosuria=20
- Reduced urine volume=20
- Abnormalities in excretion of inhibitors of = stone=20 formation=20
- Presence of promoters of stone = formation=20
Uric acid stones=20
- Persistently acid urine=20
- Gout
Struvite stones=20
- Urinary tract infection by ectoenzyme = urease-secreting=20 organisms=20
  - Proteus=20
  - Pseudomonas=20
  - Klebsiella=20
  - Providentia=20
  - Serratia=20
  - Staphylococcus
- Cystine stones=20
  - Cystinuria
- Drug-induced stones=20
  - Indinavir=20
  - Nelfinavir =

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Best=20 Tests

Acute = Nephrolithiasis=20

Laboratory studies=20
- Urinalysis=20
  - Stones or gravel
  - Crystalluria=20
  - Hematuria
- Urine culture and sensitivity =
Imaging studies=20
- Flat abdominal film=20
- Helical CT scan=20
  - Obtain if hematuria absent or stone not = seen on=20 abdominal film=20
  - Superior to intravenous urography in = diagnosing=20 acute nephrolithiasis
- Ultrasonography=20
  - May fail to identify stones < 5 mm=20 diameter=20
  - Cannot define degree or site of = obstruction=20
- Intravenous urography (IVU) =

Chronic and Recurrent = Nephrolithiasis=20

Laboratory studies=20
- Urinalysis=20
  - Crystallographic analysis =
- Urine and stone culture=20
- Fasting urinary pH=20
- 24-hr urine levels
  - Calcium=20
  - Phosphate=20
  - Uric acid=20
  - Sodium=20
  - Citrate=20
  - Oxalate=20
  - Cystine=20
  - Creatinine=20
  - Urea nitrogen=20
  - Urine volume
- Plasma levels=20
  - Calcium=20
  - Phosphate=20
  - Uric acid=20
  - Creatinine=20
  - Bicarbonate=20
  - Urea nitrogen
Imaging studies=20
- Flat abdominal film=20
  - Initial study of choice=20
  - Useful for monitoring in situ = stones
- Non=96contrast-enhanced spiral CT=20
- IVU=20
  - Shows site of obstruction=20
  - Allows assessment of urine flow =
- Ultrasonography

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Best=20 Therapy

Acute=20 Nephrolithiasis=20

Emergent care=20
- Suspected stone with fever, urinary tract = infection,=20 or both=20
  - Hospital admission=20
  - Intravenous antibiotics=20
  - Removal of stone after infection = stabilized=20
Supportive therapy=20
- Analgesia=20
- Hydration=20
- Hospital admission=20
  - Urinary tract obstruction=20
  - Severe pain=20
  - Intractable vomiting =
Therapy for confirmed nephrolithiasis with = total=20 obstruction=20
- Nephrostomy and percutaneous = lithotripsy=20
- Extracorporeal shock wave lithotripsy = (ESWL)=20
- Retrograde basket removal=20
- Surgery

Chronic and Recurrent = Nephrolithiasis=20

Prevention of renal stone formation and = growth=20
- Specific treatment of underlying = disorders=20
- Adequate hydration=20
- Reduction of concentration of stone-forming=20 constituents in urine=20
  - Dietary modification=20
  - Drugs
- Urinary alkalinization/acidification=20
- Correction of mechanical or structural = abnormalities=20 associated with urinary tract stasis
Invasive therapy=20
- ESWL=20
  - First choice for most renal and proximal = ureteral=20 stones
- Percutaneous nephrostolithotomy/open = surgery=20
  - Stones > 2 cm diameter or complex = calculi=20
  - Cystine stones that are relatively = resistant to=20 ESWL=20
  - Anatomic abnormalities (e.g., horseshoe = kidney,=20 ureteropelvic junction obstruction)=20
  - Stones within caliceal diverticula=20

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Best References

Bihl G, et al: Lancet 358:651, 2001 [PMID=20 11530173]

Coe FL, et al: N Engl J Med 327:1141, 1992 [PMID=20 1528210]

Consensus Conference: JAMA 260:977, 1988 [PMID=20 3294456]

Delvecchio FC, et al: Curr Opin Urol 13:229, 2003 = [PMID=20 12692447]

Rivers K, et al: Urol Clin North Am 27:203, 2000 = [PMID=20 10778464]

October=20 2006