Elsevier

Urology

Volume 80, Issue 6, December 2012, Pages 1203-1208
Urology

Endourology and Stones
Gas-containing Renal Stones: Findings From Five Consecutive Patients

https://doi.org/10.1016/j.urology.2012.08.035Get rights and content

Objective

To describe the clinical course, microbiology, and metabolic findings of 5 patients presenting to our institution with gas-containing renal stones.

Materials and Methods

During a 20-month period beginning in 2009, 5 patients were identified by computed tomography scanning to harbor gas-containing renal calculi. Despite similar imaging and referral practice patterns, no such cases had been seen at our institution in the preceding 20 years. The records of these patients were reviewed to better characterize this unique condition.

Results

All 5 subjects were premenopausal women. One patient presented with urosepsis and 4 presented with flank pain. All had urinary tract infections, and Escherichia coli was isolated from a voided urine specimen in 3. Stone culture was positive in 2 and was concordant with the voided specimen in 1. The stones were solitary in 4 and multiple in 1 patient. All the stones were composed of calcium phosphate. Of the 5 patients, 3 had pure calcium phosphate stones and 2 had stones with calcium oxalate monohydrate components. Also, 3 subjects had diabetes mellitus, 3 had hypertension, and 1 had a history of gout. Two subjects underwent 24-hour urine metabolic testing, and abnormalities were identified in both. All patients were rendered stone free: 4 with percutaneous nephrostolithotomy and 1 using robotic pyelolithotomy.

Conclusion

Gas-containing renal stones are rare but might be increasing in prevalence. The pathophysiology is unknown but is most likely influenced by a combination of metabolic and infectious factors.

Section snippets

Material and Methods

After gaining approval from our institutional review board, the records of 5 patients with gas-containing renal calculi treated at our institution from November 2009 to July 2011 were reviewed. Data on demographics, comorbidities, clinical course, surgical intervention, urinary microbiology, stone composition and culture, and metabolic evaluation were extracted and characterized.

Results

All 5 patients were premenopausal women ranging in age from 31 to 47 years (mean 40.4 ± 6.5; Table 1). The mean body mass index was 28.4 ± 8.3 kg/m2. The initial manifestations included flank pain in 4 patients and sepsis in 1. The youngest patient was referred 4 weeks postpartum; her stone had initially been identified during the third trimester of pregnancy. Three subjects had diabetes mellitus, two poorly controlled. Three subjects had hypertension, and one had a history of gout. Two

Comment

Renal stones containing gas are very rare. A total of 9 cases, including the present series, have been reported. The characteristics of the previous cases are listed in Table 2. Most of the patients have been women. This is not unexpected because women are more susceptible to developing urinary tract infections (UTIs). Coexistent medical comorbidities were common, including some associated with stone risk such as diabetes mellitus, gout, hyperparathyroidism, and sarcoidosis. Of the 9 subjects,

Conclusion

Gas-containing renal stones are rare and are likely due to a combination of metabolic and infectious factors. Female patients with diabetes mellitus might be the most susceptible. Proper patient preparation, including both targeted and broad-spectrum antibiotic therapy, initial renal drainage in those with any signs of sepsis, and eventual PCNL, appear to be the steps of successful management.

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Financial Disclosure: The authors declare that they have no relevant financial interests.

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