ED presentations of acute renal infarction

Objective: The objective of the study was to investigate initial clinical characteristics that can suggest an early diagnosis of patients with acute renal infarction presenting with flank and/or abdominal pain in the emergency department (ED). Methods: From January 1, 1996, through December 31, 2005, 20 adult patients with renal infarction diagnosed by contrast-enhanced computed tomography in the ED were enrolled. Medical records, including demographic data, risk factors for thromboembolism, initial clinical presentations, laboratory data, treatment programs and outcomes, were retrospectively reviewed and analyzed. Results: Mean patient age was 60.3 years (range, 21-80). The estimated incidence of renal infarction was 0.004% (20 of 481 540) among the ED census. The median time of onset of symptoms before the ED visit was 31 hours (range, 1-285). Eighteen patients (90%) had a history of more than 1 risk factor for thromboembolic events. In clinical presentations, all the patients had either abdominal or flank pain and tenderness. Nineteen patients (95%) had an elevated serum lactate dehydrogenase level with a mean ± SD of 812.1 ± 569.4 U/L. Sixteen patients (80%) presented with the triad-persisting flank or abdominal pain/tenderness, elevated serum lactate dehydrogenase level, and proteinuria. Among all 20 patients, 10 patients (50%) were diagnosed as having renal infarction at the initial ED visit. No specific clinical characteristics could be identified to distinguish those patients diagnosed early and those with delayed diagnosis. All 20 patients received medical treatment with coumadin, which was given in combination with heparin treatment in 11, peripheral intravenous and/or local intra-arterial thrombolytics with urokinase in 5, and mitral valve replacement in 1. No patient died. Although 4 patients had a mildly elevated serum creatinine level (>1.5 mg/dL) during hospitalization, none of them needs dialysis after more than 1 year of follow-up. Conclusions: In this study, we delineated specifically clinical features for emergency physicians to raise their suspicion index for an early diagnosis of patients with renal infarction, a disease which is uncommon and is usually delayed or missed at initial ED presentation.