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Hyperuricosuria and Gouty Diathesis: Differential Diagnoses & Workup

Author: Bijan Shekarriz, MD, Director, Laparoscopy and Minimally Invasive Surgery, Associate Professor of Urology, Department of Urology, State University of New York Upstate Medical University
Coauthor(s): Marshall L Stoller, MD, Medical Director of Urinary Stone Center, Professor, Department of Urology, University of California at San Francisco; Brian H Eisner, MD, Instructor in Surgery, Department of Urology, Massachusetts General Hospital-Harvard Medical School; Fellow in Endourology, Department of Urology, University of California
Contributor Information and Disclosures

Updated: Jul 28, 2008

Differential Diagnoses

Abdominal Aortic Aneurysm
Ileus
Acute Abdomen and Pregnancy
Inflammatory Bowel Disease
Appendicitis
Pancreatitis, Acute
Crohn Disease
Pancreatitis, Chronic
Diverticulitis
Pelvic Inflammatory Disease
Gastroenteritis, Bacterial
Salpingitis
Gastroenteritis, Viral

Other Problems to Be Considered

Musculoskeletal disorders
Herniated disc
Renal artery embolism

Workup

Laboratory Studies

  • Laboratory evaluation should include urinalysis and urine culture. In patients with known uric acid stones, urinary pH should be recorded using pH paper. Blood chemistry tests should include calcium, phosphorus, electrolyte, creatinine, uric acid, and parathormone levels.

Imaging Studies

  • All patients with questionable urinary calculi should undergo a baseline radiologic evaluation, including a scout film (ie, kidneys, ureters, bladder [KUB]). The scout film is useful not only as a baseline for tracking radiopaque calculi, but also for establishing radiolucency of possible uric acid stones.
  • Pure uric acid stones are relatively radiolucent and are a bright-white signal on noncontrast CT scans (Images 1-2). The diagnosis of uric acid stones can be suggested by a persistent urinary pH of less than 5.5, uric acid crystals visible on microscopic urinalysis, hyperuricemia, a KUB study that fails to show a calcific stone, or a history of gout or previous uric acid calculi.
  • Intravenous urography (ie, intravenous pyelography [IVP]) or renal ultrasonography may be useful. Contrast is used for IVP, which can make a uric acid stone appear as a filling defect, especially in the renal pelvis. Ultrasonography is a very good tool for identifying and tracking larger uric acid calculi, especially in the renal pelvis, because their radiolucency does not affect sonograms. This modality is less useful for ureteral calculi.
  • Noncontrast CT scanning is the imaging modality of choice for the differential diagnoses of urinary calculi. With noncontrast CT scanning, uric acid calculi, despite being radiolucent on conventional radiographs, appear as bright-white images, as do other calculi. The average density readings of uric acid stones on CT scans are substantially less than calcium-containing stones but are still well above the threshold of optical visualization as anything but a bright-white spot. In these cases, performing KUB imaging at the same time as CT scanning is essential to help indicate that the stone is relatively radiolucent and therefore likely to be composed of uric acid. If the stone is located in the kidney, ultrasonography can be particularly useful for tracking the progress or dissolution of the stone.
  • In rare circumstances (eg, intravenous contrast allergy, unavailability of CT scanning), retrograde pyelography may help to confirm the diagnosis.

Other Tests

  • Perform a 24-hour urine collection for volume, pH, calcium, uric acid, oxalate, citrate, phosphorus, sodium, and creatinine analysis after the acute stone event has resolved. This test should help elucidate the metabolic abnormality associated with stone formation. The most common urinary abnormalities in patients with uric acid stones are persistently acidic urine (<5.5), low volume, and hyperuricosuria.

Staging

  • Staghorn calculi are stones in the renal pelvis that extend into at least 2 calyceal groups. A complete staghorn calculus fills the entire renal collecting system.
  • Proximal ureteral calculi are stones in the ureter distal to the ureteropelvic junction and anterior to the superior edge of the sacroiliac joint.
  • Midureteral calculi are stones in the ureter that overlie the sacroiliac joint as seen on KUB images.
  • Distal ureteral calculi are stones in the ureter below the inferior margin of the sacroiliac joint down to the ureterovesical junction.

More on Hyperuricosuria and Gouty Diathesis

Overview: Hyperuricosuria and Gouty Diathesis
Differential Diagnoses & Workup: Hyperuricosuria and Gouty Diathesis
Treatment & Medication: Hyperuricosuria and Gouty Diathesis
Follow-up: Hyperuricosuria and Gouty Diathesis
Multimedia: Hyperuricosuria and Gouty Diathesis
References
Further Reading
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References

  1. Sakhaee K, Maalouf NM. Metabolic syndrome and uric acid nephrolithiasis. Semin Nephrol. Mar 2008;28(2):174-80. [Medline].

  2. Asplin JR. Uric acid stones. Semin Nephrol. Sep 1996;16(5):412-24. [Medline].

  3. Bernardo NO, Smith AD. Chemolysis of urinary calculi. Urol Clin North Am. May 2000;27(2):355-65. [Medline].

  4. Cameron MA, Sakhaee K. Uric acid nephrolithiasis. Urol Clin North Am. Aug 2007;34(3):335-46. [Medline].

  5. Coe FL, Kavalach AG. Hypercalciuria and hyperuricosuria in patients with calcium nephrolithiasis. N Engl J Med. Dec 19 1974;291(25):1344-50. [Medline].

  6. Low RK, Stoller ML. Uric acid-related nephrolithiasis. Urol Clin North Am. Feb 1997;24(1):135-48. [Medline].

  7. Moe OW, Abate N, Sakhaee K. Pathophysiology of uric acid nephrolithiasis. Endocrinol Metab Clin North Am. Dec 2002;31(4):895-914. [Medline].

  8. Pak CY. Medical management of urinary stone disease. Nephron Clin Pract. 2004;98(2):c49-53. [Medline].

  9. Pak CY, Moe OW, Sakhaee K, Peterson RD, Poindexter JR. Physicochemical metabolic characteristics for calcium oxalate stone formation in patients with gouty diathesis. J Urol. May 2005;173(5):1606-9. [Medline].

  10. Pak CY, Poindexter JR, Peterson RD, Koska J, Sakhaee K. Biochemical distinction between hyperuricosuric calcium urolithiasis and gouty diathesis. Urology. Nov 2002;60(5):789-94. [Medline].

  11. Pak CY, Sakhaee K, Moe O, Preminger GM, Poindexter JR, Peterson RD, et al. Biochemical profile of stone-forming patients with diabetes mellitus. Urology. Mar 2003;61(3):523-7. [Medline].

  12. Shekarriz B, Stoller ML. Uric acid nephrolithiasis: current concepts and controversies. J Urol. Oct 2002;168(4 Pt 1):1307-14. [Medline].

  13. Steele TH. Hyperuricemic nephropathies. Nephron. 1999;81 Suppl 1:45-9. [Medline].

  14. Stoller ML. Gout and stones or stones and gout?. J Urol. Nov 1995;154(5):1670. [Medline].

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Further Reading

For additional information, See Medscape's Stone Disease Resource Center.

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Keywords

hyperuricosuria, gouty diathesis, uric acid stones, nephrolithiasis, hyperuricemia, gouty arthritis, urolithiasis, uric acid calculi, purine, purine-rich food, endogenous uric acid overproduction, urinary stones, primary gout, gout, Lesch-Nyhan syndrome, myeloproliferative disease

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Contributor Information and Disclosures

Author

Bijan Shekarriz, MD, Director, Laparoscopy and Minimally Invasive Surgery, Associate Professor of Urology, Department of Urology, State University of New York Upstate Medical University
Bijan Shekarriz, MD is a member of the following medical societies: American Urological Association and Endourological Society
Disclosure: Nothing to disclose.

Coauthor(s)

Marshall L Stoller, MD, Medical Director of Urinary Stone Center, Professor, Department of Urology, University of California at San Francisco
Marshall L Stoller, MD is a member of the following medical societies: American Urological Association
Disclosure: Nothing to disclose.

Brian H Eisner, MD, Instructor in Surgery, Department of Urology, Massachusetts General Hospital-Harvard Medical School; Fellow in Endourology, Department of Urology, University of California
Brian H Eisner, MD is a member of the following medical societies: American Urological Association and Endourological Society
Disclosure: Nothing to disclose.

Medical Editor

Allen Donald Seftel, MD, Professor, Department of Urology, Case School of Medicine
Allen Donald Seftel, MD is a member of the following medical societies: Ohio State Medical Association
Disclosure: lilly Consulting fee Consulting; sanofi-aventis Consulting fee Consulting; auxilium Consulting fee Consulting; solvay Consulting fee Consulting; plethora Grant/research funds clinical trial; indevus Consulting fee Consulting; nature publishing  journal editor

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

CME Editor

J Stuart Wolf Jr, MD, FACS, David A Bloom Professor of Urology, Director of Division of Minimally Invasive Urology, Department of Urology, University of Michigan
J Stuart Wolf Jr, MD, FACS is a member of the following medical societies: American College of Surgeons, American Urological Association, Catholic Medical Association, Endourological Society, Society for Urology and Engineering, Society of Laparoendoscopic Surgeons, Society of University Urologists, and Society of Urologic Oncology
Disclosure: Terumo Corporation Consulting fee Consulting; Gyrus-ACMI Honoraria Speaking and teaching

Chief Editor

Bradley Fields Schwartz, DO, FACS, Professor of Urology, Director, Center for Laparoscopy and Endourology, Department of Surgery, Southern Illinois University School of Medicine
Bradley Fields Schwartz, DO, FACS is a member of the following medical societies: American College of Surgeons, American Urological Association, Association of Military Osteopathic Physicians and Surgeons, Endourological Society, Society of Laparoendoscopic Surgeons, and Society of University Urologists
Disclosure: Nothing to disclose.

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