Gas-containing renal stones.

Gas-containing renal stones is a rarely described complication of emphysematous pyelonephritis. Most of these patients are diabetic and almost all have urinary obstruction and stasis. Management of these patients may be associated with several complications. Copyright:

INTRODUCTION

Gas-containing renal stones is a rare sequel of serious renal infections, often linked with emphysematous pyelonephritis[1] due to gas-producing organisms such as Escherichia coli or Klebsiella.[2] Majority of the patients are diabetic and have obstructive uropathy. So far, only 11 cases have been reported.

CASE REPORT

A 68-year-old male presented with left flank pain, fever, breathlessness, and oliguria. His medical history included coronary artery disease, hypertension, and left hemiparesis. Urine microscopic examination showed Gram-negative bacteria. Urine culture grew E. coli. Creatinine was 3.7 mg/dL. Ultrasonography revealed moderate left hydroureteronephrosis and perinephric collection with multiple calculi in the renal pelvis and lower pole. X-ray kidney, ureter, and bladder revealed a staghorn calculus containing gas, involving the entire left pelvicalyceal system [Figure 1]. Noncontrast computed tomography scan confirmed left-sided staghorn calculus containing gas with perinephric collection [Figure 2]. The patient underwent percutaneous surgery for stone removal. The stone culture grew Klebsiella.

Figure 1

X-ray kidney, ureter, and bladder showing gas-containing left staghorn calculus

Figure 2

Noncontrast computed tomography kidney, ureter, and bladder showing gas inside the left renal calculus (white arrow mark)

DISCUSSION

Gas-containing renal stones are usually associated with emphysematous pyelonephritis by gas-producing organisms. Seven out of eleven cases reported had E. coli infection in urine, whereas two had Klebsiella and one had Staphylococcus infection. E. coli can ferment sugars, particularly glucose. E. coli is also isolated from the renal calculi. Electron microscopy or culture of stones showed a much higher rate of infection than urine culture.[3]

Intracalculus metabolism by the bacteria is the main mechanism producing gas inside the stone. In most of the reported cases, the stone was infected with E. coli. E. coli is the most common gas-producing organism. Gases liberated due to rapid catabolism of tissues are also contributory.[2] Gases produced in emphysematous pyelonephritis may be entrapped within the stones during its formation. On analysis of emphysematous pyelonephritis cases, the gases isolated included 4.1% carbon di oxide, 10.5% oxygen, 67.3% nitrogen, and 18.1% unknown gases.

Presence of gas inside the stones illustrates a combination of two pathologies, namely metabolic activity of the bacteria inside the stone and tissue metabolism.[4] Urinary stasis likely decreases the renal perfusion, impairing the washout of formed gases, and also promotes stone formation and aggregation.

Gas-containing renal stones is a fatal sign.[5] These patients usually develop serious complications such as septicemia and septic shock and even deaths have been reported in them.[5]

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

CONCLUSION

Gas-containing renal stones is a rare complication of emphysematous pyelonephritis. It is associated with urinary stasis and diabetes and hence may lead to perioperative sepsis and death. Gas-containing renal stones is a harbinger of mortality.