MO091BILATERAL EMPHYSEMATOUS PYELITIS: A CASE REPORT AND ULTRASONOGRAPHY FEATURES
Authors: Pellegrino Angela Maria , Vergura Michele , Prencipe Michele antonio , Gatta Giuseppe , Aucella Filippo 
Published: May 2021

Abstract

Background and Aims
Emphysematous pyelitis is a rare urinary infection with gas formation in the excretory system. Diabetes mellitus and urinary tract obstruction are the main risk factors. Most patients are women over 60 years old. The pathogenesis is unknown. Diabetes mellitus and the elevated glucose levels may create a favorable microenvironment for gas-forming microbes, but it does not exhaustively explain clinical and pathological symptoms. Escherichia Coli and Klebsiella Pneumoniae are the most involved bacteria. Clinical features are the same as other forms of pyelonephritis e.g. fever, chills, flank abdominal pain, nausea and vomiting. Ultrasonography, and especially computed tomography (CT) are important diagnostic tools for demonstration of gas within pelvicalyceal system, urethers or even in bladder. Use of parenteral antibiotic, relief of urinary tract obstruction if present, percutaneous catheter drainage of gas and purulent material and nephrectomy are the mainstays of therapy. This report introduces a case of bilateral emphysematous pyelitis with emphasis on its ultrasound presentation. This is one of the few cases of bilateral emphysematous pyelitis reported in literature.

Method
A 49-year-old female presented to the emergency with asthenia, epistaxis, orthostatic hypotension and nocturnal cramps. Two months before she was referred to Department of Nephrology for proteinuria. In that occasion, renal ultrasound showed normal kidneys and renal biopsy was performed. She started oral therapy with corticosteroid for ANCA-negative vasculitis and iatrogenic diabetes mellitus occurred.
She was admitted again to our Department of Nephrology, blood test was performed and revealed: white cell count 20.500/ml; glucose 243 mg/dl; serum creatinine 2.3 mg/dl; C-reactive protein, 0.65 mg/dl ( &lt; 0.5), procalcitonin 2.05 µg/l (nv &lt; 0.5). Urine culture was positive for E. Coli.

Results
Renal ultrasound revealed the presence, in both kidney pelvises, of multiple and diffuse hyperechogenic images associated with some reverberation artefacts. The ultrasound findings were unusual and of doubtful interpretation: staghorn calculi, encrusted pyelitis, gas? (Fig. 1, 2).
Reverberation artifacts give rise the suspicion of gas presence in kidney pelvises, usually absent in case of staghorn calculi and encrusted pyelitis. CT confirmed the diagnosis of bilateral emphysematous pyelitis due to the diffuse presence of gas within the renal calyces, also extending to the ureters and bladder lumen (Fig. 3).
We promptly started parental antimicrobial therapy with cefalosporine. After one week we observed a clinical and laboratory improvement, and the renal ultrasound revealed the resolution of bilateral pelvises alteration (Fig. 4).

Conclusion
In emphysematous pyelitis, renal ultrasound is characteristic due to the presence of diffuse hyperechogenic images located in the renal pelvis associated with some reverberation artifacts, usually absent in case of renal stones.
Therefore, the renal ultrasound in association with clinical and laboratory findings, especially in patient with positive urine culture, should arouse the suspicion of emphysematous pyelitis to start promptly antimicrobial therapy, even when CT examination is not immediately available.