British Journal ofUrology (1995), 75, 71-74

Emphysematous pyelonephritis in diabetic patients A . R . PONTIN, R.D. BARNES, J . JOFFE and D. KAHN Departments of Urology and General Surgery, Groote Schuur Hospital and the University of Cape Town, South Africa

Objective To determine the clinico-pathological profile of patients with emphysematous pyelonephritis (EPN).

Patients and methods The records of 22 diabetic patients who presented with EPN were reviewed.

Results EPN occurred predominantly in female diabetic patients without evidence of ureteric obstruction. The ages of the patients and the duration of the diabetes were variable. EPN occurred in insulin-dependent as well as non-insulin-dependent patients. The patients presented following a prodromal illness of urinary sepsis, with an acute severe illness with symptoms and signs on the affected side. Dehydration and keto-

acidosis were common. The diagnosis was made by recognizing gas in the kidney on an X-ray or ultra- sound. Eighteen patients were subjected to emergency nephrectomy .

Conclusions EPN is an uncommon, life-threatening con- dition characterized by the production of intraparen- chymal gas. We believe that vigorous resuscitation and emergency nephrectomy is the treatment of choice.

Keywords Emphysematous pyelonephritis, diabetes mellitus

Introduction

The causes of gas in the upper urinary tract include a fistula, iatrogenic causes, and the local production of gas due to fermentation. The gas may be seen within the renal collecting system, in the perinephric space or within the renal parenchyma. Intraparenchymal pro- duction of gas is the hallmark of emphysematous pyelo- nephritis (EPN). This is an uncommon, life-threatening condition which usually occurs in diabetic patients. In this study we reviewed the hospital records of diabetic patients seen with EPN over a 15-year period at this institution. Many of the features described are at variance with the impression gained from previous overviews and isolated case reports.

Patients and methods

All diabetic patients presenting with emphysematous pyelonephritis to Groote Schuur Hospital between 19 78 and 1993 were included in the study. There were 21 women and one man, whose ages ranged from 21 to 82 years (mean 5 5 ) . The hospital records were reviewed retrospectively and the clinical features, radiological and biochemical findings, treatment, subsequent course and outcome noted.

Accepted for publication 29 September 1994

Results Eight patients had insulin-dependent diabetes mellitus. The remaining 14 patients were being treated with oral hypoglycaemic agents. The mean duration of the diabetes mellitus was 10 years (range 2-30). Two patients had been insulin-dependent for more than 20 years and five had been diabetic for less than 5 years. In none of the patients was EPN the presenting symptom of diabetes. Five of the 22 patients could be classified as compliant while 13 were known to be poorly compliant with several prior admissions for the control of their diabetes.

All patients initially presented with a urinary tract infection. This was followed by features of severe sepsis despite treatment with antibiotics. There was often a delay of up to 4 days in hospital before the diagnosis was made. The symptoms and signs were referable to the affected loin. A mass was rarely palpable. Crepitus was not present except in one patient who had crepitus in the neck and groin. The diabetes was out of control in 18 patients and ketoacidosis was present in 16.

The diagnosis of EPN was made by detecting intrapar- enchymal gas on the abdominal X-ray or ultrasound, and was confirmed by a computed tomography (CT) scan in some patients. The various gas patterns are listed in Table 1. In two patients the gas was localized to a pole of the kidney and one patient also had gas within the bladder. Ureteric obstruction, due to a radio-opaque calculus in the mid ureter, was present in one patient. The lesion was on the left in 14 patients and on the right in eight. Abnormal renal function was noted in 20

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72 A.R. PONTIN et ul.

Table 1 Gas patterns in emphysematous pyelonephritis

No. of patients

Parenchymal gas only 8 3

9

Parenchymal plus collecting system gas Parenchymal plus perinephric gas 2 Parenchymal plus collecting system plus perinephric gas

patients. In 12 patients the serum creatinine was over 200 mmol/L. Urinary tract sepsis was confirmed in all patients and Escherichia coli and Klebsiellu were the organisms most commonly cultured. In some patients the culture revealed a mixed growth.

Initial treatment consisted of urgent resuscitation with intravenous fluids, control of the diabetes with insulin and broad spectrum antibiotic cover. Eighteen patients had emergency nephrectomy. One patient had an incision and drainage, one patient had a delayed neph- rectomy after failure to respond to conservative therapy, and the patient with the ureteric obstruction had a percutaneous nephrostomy and subsequent ureterolitho- tomy. One patient had a cardiac arrest en route to theatre for an intended emergency nephrectomy and could not be resuscitated.

Simple nephrectomy was performed through a loin incision and an extraperitoneal approach. Audible release of gas occurred on entering some perinephric collections. The kidneys varied in consistency from firm with necrotic areas to totally necrotic and some had even liquefied.

There were three deaths in this series of 22 patients. One patient died en route to the operating theatre and two patients died post-operatively, one 5 days after nephrectomy from a myocardial infarction and one 60 days post-operatively from a hospital-acquired staphylo- coccal septicaemia and multi-organ failure.

The surgical morbidity is listed in Table 2 . Five patients had wound sepsis requiring incision and drainage and

Table 2 Morbidity in patients subjected to nephrectomy

No. of patients

Duodenal injury Splenic injury Wound abscess Hypoglycaemia Pleural effusion Prolonged septicaemic shock No morbidity

one patient required an intercostal drain for a sympto- matic pleural effusion.

Apart from the patient who died 2 months after nephrectomy, the length of the post-operative hospital stay ranged from 8 to 22 days. At the time of discharge from hospital the serum creatinine was normal in 11 patients and 200 mmol/L in one patient.

Discussion

The term emphysematous pyelonephritis was first used by Schultz and Klorfein to describe the intraparenchymal production of gas in patients in whom there was a high mortality in the absence of surgical intervention [l]. Gas in the collecting system only is termed emphysematous pyelitis [2].

EPN predominantly affects females [3,4], although in Japan it appears to be commoner in males [S]. The condition usually occurs in patients with established diabetes mellitus but can be the presenting feature of diabetes [6]. The severity of the condition was not related to whether the patient was insulin-dependent or not. In fact, insulin dependence had no prognostic significance. The age of the patient was also not a prognostic indicator as the three deaths occurred in patients who were less than 60 years of age.

The development of the necrotiiing infection with the production of gas heralded the acute clinical deterior- ation [6]. It seems unlikely that the necrotizing infection can run an indifferent course for weeks or months, as previously suggested [4].

Previous reports have suggested that ketoacidosis is uncommon. However, it occurred in 1 6 of our patients. Despite the acute necrotizing process, four patients still had normal diabetic control.

We believe that the initial investigation of a diabetic patient with a urinary tract infection associated with pain and tenderness in either loin should include an abdominal X-ray and an ultrasound investigation. In this series there was a significant delay in the diagnosis being made. The abdominal X-ray invariably showed the presence of intraparenchymal renal gas (Figs. 1 and 2). Although ultrasonography usually confirms the pres- ence of intraparenchymal gas, its main value is to exclude ureteric obstruction. Since many of tht: patients are obese, it is often difficult to distinguish the necrotic gas-filled kidney from gas in the bowel on ultrasound.

Gas within the kidney parenchyma may be of a generalized honeycomb pattern (Figs 1 and 3) or localized (Figs 2 and 4). Gas in the renal pelvis or upper ureter does not necessarily imply ureteric obstruction. In diffuse disease, the earliest place for the gas to form is around the papilla where the vascularity is poor and it may rupture into the collecting system. It may also

British Journal of Urology (1995). 75

EMPHYSEMATOUS PYELONEPHRITIS IN DIABETIC PATIENTS 73

Fig. 1* Diffuse honeycomb me emphysematous pyelonephritis Fig. 2. Localized collection of gas in upper pole of kidney, Gas also with parenchymal perinephric and collecting system gas. Note loss of mid zone substance of kidney.

in ureter.

track along the pyramids and rupture into the peri- nephric space. Gas in the perinephric space was not associated with a worse prognosis, as previously sug- gested [l].

The CT scan is the best confirmatory test since it accurately defines the position and pattern of the gas, as well as the presence of gas in other tissues. Gas has also been noted in the renal vein [7] and hepatic vein [8]. The reason for delineating the gas pattern is that a localized collection may be more amenable to conserva- tive surgery. The gas produced in EPN is due to fermen- tation of necrotic tissue as well as glucose [9.10] and has been described in association with Candida and pneumocystis infection [ 11,121.

Conservative treatment is associated with a mortality rate of over 75% [4]. In this study vigorous resuscitation and emergency simple nephrectomy were associated with an acceptable mortality rate. It has been suggested that a modified radical nephrectomy approach with early ligation of the pedicle in an attempt to remove all septic tissue may be associated with fewer POSt-OPeratiVe Septic complications [6]. sematous pyelonephritis.

Fig. 3. Computed tornogram showing honeycomb type emphy-

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74 A.R. PONTIN et aI.

Fig. 4. Computed tornogram showing localized type emphy- sematous pyelonephritis.

Conservative or percutaneous surgery has been advo- cated for the treatment of EPN, especially in patients who are too ill to undergo general anaesthesia or if there is a localized area of EPN [13,14]. However, conservative surgery in the hope of salvaging function of that kidney is ill advised since the whole kidney is usually involved and there is little or no chance of renal recovery [6]. If conservative surgery is considered, a pre-operative scan is mandatory [ 111.

Patients with EPN usually present with advanced pathology. Prevention of EPN is preferable and we rec- ommend early and vigorous management of diabetic patients with upper urinary tract sepsis.

Acknowledgement

The authors thank Dr D.R. Barnes for stimulating an interest in this subject and for his advice and guidance.

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Authors A.R. Pontin. MBChB, FRCS, FCS, Consultant Urologist. R.D. Barnes, MBChB, FCS, Consultant Urologist. J. Joffe, MBChB, FCS, Consultant Urologist. D. Kahn, MBChB, FCS. ChM, Consultant Transplant Surgeon. Correspondence: Dr A.R. Pontin. Ward F26, Groote Schuur Hospital, Observatory, Cape Town, Republic of South Africa.

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