Emphysematous Pyelonephritis Disparities observed in the use of percutaneous drainage techniques

OBJECTIVES

The recent drop in the mortality rates of emphysematous pyelonephritis, a serious medical condition, is attributable to renal percutaneous drainage (PCD) techniques that have also reduced the necessity for surgery. Since the difference in the objectives of the two specific techniques, i.e. PCD and percutaneous nephrostomy (PCN), is often overlooked, this study aimed to highlight the inconsistencies in the use of these two techniques.

METHODS

A retrospective study of 17 patients was conducted over a 10-year period from January 2008 to December 2017 at The Royal Hospital, Muscat, Oman. All patients had undergone abdominal computerised tomography. The obtained images were reviewed and categorised based on Huang and Tseng's classification.

RESULTS

From the sample, 13 patients (76%) were categorised as class I and II, three (17%) as class IIIA and one (6%) as class IIIB. Five patients from the class I and II categories underwent drainage of the pelvicalyceal system, four by PCN and one by a double-J stent insertion. PCN was performed on all the class IIIA and IIIB patients. One class IIIB patient required PCD for localised gas and fluid collection but later underwent emergency nephrectomy. There were no mortalities.

CONCLUSION

The favourable outcome of this study was in keeping with those of the more recent studies. However, despite the present classifications and guidelines, wide variations were reported in the use of percutaneous drains with PCD, ranging from 2.5-91%. The lack of precise guidelines may be a cause of these disparities in clinical management.

A systematic review and meta-analysis of risk factors and treatment choices in emphysematous pyelonephritis

PURPOSE

Emphysematous pyelonephritis (EPN) is an acute, severe necrotising infection of the kidney. There has been a shift from early nephrectomy to conservative methods. We conducted a meta-analysis to assess the impact of risk factors and treatment choices on outcomes in EPN.

METHODS

We conducted a database search of all studies in English, reporting more than 12 patients of EPN from 1980 to 2020. We compiled the demographics, clinical presentations, risk factors, critical diagnostic results, treatment modalities and outcomes, including mortality.

RESULTS

We identified 37 observational studies, 32 retrospective and 5 prospective. The studies reported on 1146 patients, of which 790(68.9%) were female, and 946 (82.5%) were diabetic. In addition, 184 (16.1%) patients had stones, and 235 (20.5%) had obstructive uropathy. Fever and flank pain were the most frequent symptoms. The most common clinical features were pyuria, fever, flank tenderness, and tachycardia. E. coli, Klebsiella pneumoniae and Proteus were the most frequent organisms isolated. X-ray KUB and ultrasound were used as initial diagnostic modalities, but CT scan was the usual diagnostic and confirmatory investigation. Confusion, shock, thrombocytopenia, sepsis, emergency nephrectomy and hyponatremia were significantly associated with mortality. In particular, confusion and hyponatremia were associated with a sevenfold increase in mortality risk. There was no evidence that diabetes, stones, obstructive uropathy, AKI or proteinuria was associated with higher mortality. Nevertheless, 143 of the total 1146 patients died (12.5%). While 26% of the patients who had upfront emergency nephrectomy died, only 9.7% and 10% of patients with medical management and medical management plus minimally invasive treatments died. However, patients that failed medical and minimally invasive treatments and needed salvage emergency nephrectomy had a mortality of upwards of 27%.

CONCLUSION

The risk factors for mortality in emphysematous pyelonephritis are shock, thrombocytopenia, confusion, hyponatremia and emergency nephrectomy. Conservative and minimally invasive treatment should be the initial management strategy for emphysematous pyelonephritis as they carry lesser mortality risks. The presence of risk factors may help predict the subset of patients who need aggressive treatment and minimally invasive treatment modalities or early nephrectomy.