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A case of emphysematous pyelonephritis A 40-year-old Asian man admitted for treatment of diabetic ketoacidosis was referred to the on-call general surgical team with pain and tenderness over the right loin and renal angle. He had recently returned from India. The patient had a white cell count of 16.9 × 109/L, platelet count of 76 × 109/L, creatinine of 139 umol/L and C-reactive protein of 172 mg/L. Plain film radiography of the abdomen revealed a gas density on the outline of the right kidney (Fig. 1). An urgent non-contrast computed tomography (CT) scan of the abdomen demonstrated a large amount of gas within the right renal parenchyma with right-sided hydronephrosis and hydroureter (Fig. 2a,b). The diagnosis of emphysematous pyelonephritis was made. An 8-French locking pigtail nephrostomy was inserted percutaneously under ultrasound guidance. A 14-French locking pigtail catheter was inserted into the emphysematous region superiorly within the right kidney. Pus and urine were aspirated and cultures subsequently grew Enterobacter aerogenes. He was treated conservatively with intravenous antibiotics and supportive therapy within an intensive care setting and made a successful recovery. Emphysematous pyelonephritis is a rare, but life-threatening condition characterized by infection with gas-forming gram-negative bacteria within the renal parenchyma, most commonly by Escherichia coli. It is most frequently seen in women in the fourth or fifth decade and the majority of case series originate from Asia.1,2 The condition often presents on the background of poorly controlled diabetes.3 Loin pain is typical and patients may also complain of nausea, vomiting, dysuria and rigours. In this case, there was throm-
bocytopenia, acute kidney injury and decreased consciousness. Such features, as well as severe hypotension, hyponatremia and bilateral disease, have been associated with higher mortality rates.4,5 CT imaging is required for diagnosis and evaluation of the extent of disease. Emphysematous pyelonephritis may be treated conservatively with supportive therapy and antibiotics alone, with percutaneous drainage or through emergency nephrectomy. In 2008, a systematic review of available data, mostly retrospective reports of case series, demonstrated a 13.5% mortality in patients treated with percutaneous drainage compared with 25% and 50% mortality for conservative therapy and emergency nephrectomy, respectively.6 Further, those treated through percutaneous drainage may show up to 92%
Fig. 1. Plain film radiography of the abdomen demonstrating a gas density on the outline of the right kidney.
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Fig. 2. (a) Computed tomography scan (coronal view) of the abdomen showing gas in the right renal parenchyma. (b) Computed tomography scan (axial view) of the abdomen showing gas in the right renal parenchyma.
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renal salvage at 18 months post-treatment compared with around 67% in the cohort as a whole.4 Emergency nephrectomy is generally reserved for severe cases as it is associated with higher mortality rates and an increased risk of developing chronic kidney disease.3 Evidence-based protocols for management of this condition should be developed to optimize outcomes. Emphysematous pyelonephritis is a rare, but life-threatening necrotizing infection of the renal parenchyma seen most commonly in poorly controlled diabetics. Although most case series originate from Asia, this disease is likely to present increasingly in Western countries as the global community becomes further integrated through affordable air travel.7
References 1. Khaira A, Gupta A, Rana DS, Bhalla A, Khullar D. Retrospective analysis of clinical profile prognostic factors and outcomes of 19 patients of emphysematous pyelonephritis. Int. Urol. Nephrol. 2009; 41: 959–66. 2. Kolla PK, Madhav D, Reddy S, Pentyala S, Kumar P, Pathapati RM. Clinical profile and outcome of conservatively managed emphysematous pyelonephritis. ISRN Urol. 2012; 2012: 931982.
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3. Lin YC, Lin HD, Lin LY. Risk factors of renal failure and severe complications in patients with emphysematous pyelonephritis-a single-center 15-year experience. Am. J. Med. Sci. 2012; 343: 186–91. 4. Kapoor R, Muruganandham K, Gulia AK et al. Predictive factors for mortality and need for nephrectomy in patients with emphysematous pyelonephritis. BJU Int. 2010; 105: 986–9. 5. Falagas ME, Alexiou VG, Giannopoulou KP, Siempos II. Risk factors for mortality in patients with emphysematous pyelonephritis: a metaanalysis. J. Urol. 2007; 178: 880–5; quiz 1129. 6. Somani BK, Nabi G, Thorpe P, Hussey J, Cook J, N’Dow J. Is percutaneous drainage the new gold standard in the management of emphysematous pyelonephritis? Evidence from a systematic review. J. Urol. 2008; 179: 1844–9. 7. Bjurlin MA, Hurley SD, Kim DY et al. Clinical outcomes of nonoperative management in emphysematous urinary tract infections. Urology 2012; 79: 1281–5.
Simon P. Rowland, MBBS, BSc (Hons) Hemant Sheth, FRCS, MD Ealing Hospital NHS Trust, London, UK doi: 10.1111/ans.12224
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