Abstract

Introduction: Acute pyelonephritis and acute renal infarction have several of the same aspects of symptoms and presentation easily be misidentified. This study aimed to find the difference in clinical presentation between renal infarction and acute pyelonephritis.

Methods: We retrospectively searched the database in MacKay Memorial Hospital from Jan 1, 2011, to Sep 30, 2021. Twenty cases of acute renal infarctions (ARI) and 20 of 1600 cases of acute pyelonephritis (APN) were obtained.We analyze the visiting time, the initial vital signs, the clinical symptoms, and the
laboratory data. Both Student's t-test and chi-square test were used in the statistical analyses, and a p-value of < 0.05 indicated a statistically significant difference.

Results: In laboratory exam, hematuria and pyuria are more common in APN group (hematuria 80% vs. 40%, p = 0.01, pyuria 75% vs. 15%, p < 0.001). More  patients presented with abdominal pain in ARI group (70% vs. 30%, p = 0.001). There are 20% of the APN group has bilateral flank pain and none of the ARI group has bilateral flank pain (p = 0.035).

Conclusion: ARI is male-predominant, and APN is female-predominant. APN patients have 2-fold hematuria and 5-fold pyuria than ARI. The ARI patients presented more abdominal pain and bilateral flank pain than APN patients. A relatively small number of APNs enrolled in this study.Maybe a multi-center study is a better way to have enough sample numbers to explain these findings well.