Pediatric Urolithiasis Workup

Author: Sahar Fathallah-Shaykh, MD; Chief Editor: Craig B Langman, MD more...

Updated: May 4, 2012

What would you like to print?

Approach Considerations
Lab Studies
Imaging Studies
Retrieval and Evaluation of Stones
Show All

Approach Considerations

In children, laboratory studies only provide suggestive evidence of a kidney stone; however, certain laboratory studies (eg, calcium or uric acid excretion) may be very helpful in identifying risk factors for additional stone formation. Imaging studies are valuable. Direct assessment of stones is vital.

Lab Studies

In children with identified or strongly suspected stone disease, obtain the following laboratory studies:

Complete blood count (CBC)
Electrolyte, blood urea nitrogen (BUN), creatinine, calcium, phosphorus, alkaline phosphatase, uric acid, total protein, albumin, parathyroid hormone (PTH), and vitamin D metabolite levels
Spot urinalysis and culture, including ratio of calcium, uric acid, oxalate, cystine, citrate, and magnesium to creatinine
Urine tests, including a 24-hour urine collection for calcium, phosphorus, magnesium, oxalate, uric acid citrate, cystine, protein, and creatinine clearance

Imaging Studies

Renal ultrasonography is very effective for identifying stones in the urinary tract. Generally, ultrasonography should be used as a first study. If no stone is found but symptoms persist, helical (spiral) computed tomography (CT) scanning is indicated. Noncontrast spiral CT scanning is the most sensitive test for identifying stones in the urinary system. It is safe, rapid, and has been shown to have 97% sensitivity and 96% specificity.

Many radiopaque stones can be identified with a simple abdominal flat-plate examination. Intravenous pyelography is rarely used in children.

Go to Imaging Urinary Calculi for complete information on this topic.

For hypercalcinuria, hypercystinuria, or hyperoxaluria, please refer to Hypercalciuria and Hyperoxaluria for further evaluation.

Retrieval and Evaluation of Stones

Attempting to obtain a stone for histologic and crystallographic evaluation is essential. It is usually obtained by straining urine in older children or examining diapers in young children (see image below). The content of the stone (ie, cysteine versus calcium versus uric acid) may be the most important element in developing a treatment program to prevent further stone formation (see the image below).

Three groups of kidney stones are shown. Groups at left and center contain varying concentrations of calcium, phosphate, and oxalate. The group of stones on the right is composed of cysteine.

Proceed to Treatment & Management

Contributor Information and Disclosures

Author

Sahar Fathallah-Shaykh, MD Assistant Professor in Pediatric Nephrology, University of Alabama at Birmingham School of Medicine; Consulting Staff, Division of Pediatric Nephrology, Medical Director of Pediatric Dialysis Unit, Children's of Alabama

Sahar Fathallah-Shaykh, MD is a member of the following medical societies: American Society of Nephrology and American Society of Pediatric Nephrology

Disclosure: emedecine Honoraria Other

Coauthor(s)

Richard Neiberger, MD, PhD Director of Pediatric Renal Stone Disease Clinic, Associate Professor, Department of Pediatrics, Division of Nephrology, University of Florida College of Medicine and Shands Hospital

Richard Neiberger, MD, PhD is a member of the following medical societies: American Academy of Pediatrics, American Federation for Medical Research, American Medical Association, American Society of Nephrology, American Society of Pediatric Nephrology, Christian Medical & Dental Society, Florida Medical Association, International Society for Peritoneal Dialysis, International Society of Nephrology, National Kidney Foundation, New York Academy of Sciences, Shock Society, Sigma Xi, Southern Medical Association, Southern Society for Pediatric Research, and Southwest Pediatric Nephrology Study Group

Disclosure: The Osler Institute Honoraria Speaking and teaching

Specialty Editor Board

Deogracias Pena, MD Medical Director of Dialysis, Department of Pediatrics, Cook Children's Medical Center; Clinical Associate Professor, Texas Tech University School of Medicine

Deogracias Pena, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, and American Society of Pediatric Nephrology

Disclosure: Nothing to disclose.

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Luther Travis, MD Professor Emeritus, Departments of Pediatrics, Nephrology and Diabetes, University of Texas Medical Branch School of Medicine

Luther Travis, MD is a member of the following medical societies: Alpha Omega Alpha, American Federation for Medical Research, International Society of Nephrology, and Texas Pediatric Society

Disclosure: Nothing to disclose.

Chief Editor

Craig B Langman, MD The Isaac A Abt, MD, Professor of Kidney Diseases, Northwestern University, The Feinberg School of Medicine; Division Head of Kidney Diseases, Children's Memorial Hospital

Craig B Langman, MD is a member of the following medical societies: American Academy of Pediatrics, American Society of Nephrology, and International Society of Nephrology

Disclosure: NIH Grant/research funds None; Raptor Pharmaceuticals, Inc Grant/research funds None; Alexion Pharmaceuticals, Inc. Grant/research funds None

References

Borghi L, Schianchi T, Meschi T, et al. Comparison of two diets for the prevention of recurrent stones in idiopathic hypercalciuria. N Engl J Med. Jan 10 2002;346(2):77-84. [Medline].
Taylor EN, Curhan GC. Fructose consumption and the risk of kidney stones. Kidney Int. Jan 2008;73(2):207-12. [Medline].
Avci Z, Koktener A, Uras N, et al. Nephrolithiasis associated with ceftriaxone therapy: a prospective study in 51 children. Arch Dis ChildNov. 2004;89(11):1069-72. [Medline].
Khositseth S, Gillingham KJ, Cook ME, Chavers BM. Urolithiasis after kidney transplantation in pediatric recipients: a single center report. Transplantation. 2004;78(9):1319-23. [Medline].
Bergsland KJ, Coe FL, White MD, Erhard MJ, Defoor WR, Mahan JD, et al. Urine risk factors in children with calcium kidney stones and their siblings. Kidney Int. Feb 22 2012;[Medline].
Routh JC, Graham DA, Nelson CP. Epidemiological trends in pediatric urolithiasis at United States freestanding pediatric hospitals. J Urol. Sep 2010;184(3):1100-4. [Medline].
Bush NC, Xu L, Brown BJ, Holzer MS, et al. Hospitalizations for pediatric stone disease in United States, 2002-2007. J Urol. Mar 2010;183(3):1151-6. [Medline].
Bove P, Kaplan D, Dalrymple N, et al. Reexamining the value of hematuria testing in patients with acute flank pain. J Urol. Sep 1999;162(3 Pt 1):685-7. [Medline].
Schwaderer AL, Cronin R, Mahan JD, Bates CM. Low bone density in children with hypercalciuria and/or nephrolithiasis. Pediatr Nephrol. Dec 2008;23(12):2209-14. [Medline].

Three groups of kidney stones are shown. Groups at left and center contain varying concentrations of calcium, phosphate, and oxalate. The group of stones on the right is composed of cysteine.

Table 1. Stone Formation

Table 1. Stone Formation

Mechanism of Stone Formation	Drug	Primary Stone Composition
Crystallization of highly excreted, poorly soluble drug or metabolite causes stone formation.	Phenytoin, triamterene, sulfonamides, felbamate, ceftriaxone, indinavir, ciprofloxacin, guaifenesin/ephedrine	Drug or its metabolites
Drug may increase the concentration of stone-forming minerals.	1. Anti-cancer drugs 2. Glucocorticoid 3. Allopurinol (if used in tumor lysis) 4. Loop diuretics 5. Calcium and vitamin D	1. Uric acid 2. Calcium 3. Xanthine 4. Calcium oxalate 5. Calcium
Drug inhibits activity of carbonic anhydrase enzymes in the kidney, causing metabolic acidosis, hypocitraturia, and elevated urine pH.	Topiramate, zonisamide, acetazolamide	Calcium phosphate

View Table List

Read more about Pediatric Urolithiasis on Medscape