Clinical characteristics of renal infarction in an Asian population.

INTRODUCTION: Renal infarction is a rare and easily missed disease. There is even less meaningful information on renal infarction in the Asian population. Thus, the aim of this study was to clarify the clinical characteristics of the disease in Asian patients.

CLINICAL PICTURE: Over a period of 10 years, 38 Chinese patients with renal infarction diagnosed by contract-enhanced CT or angiography were enrolled in this study. Their demographic data, clinical characteristics, laboratory and image results, risk factors or suspected causes, treatment and final outcomes were retrospectively reviewed. The results were also compared with the analogous Western data. The mean age of the sample population was 60.8 +/- 17.6 years, with patients aged over 50 years and males predominating. The most common symptoms/signs were abdominal (57.9%) and flank pain/tenderness (50%). Only 23.7% of patients had suffered previous thromboembolic events such as coronary or peripheral artery diseases, or cerebral infarction. Cardiogenic factors, such as atrial fibrillation, intra-cardiac thrombus, infective endocarditis and valvular heart disease, were the main causes of renal infarction (57.9%). The most common laboratory abnormalities were elevated serum LDH (92.1%) and proteinuria (76.3%). Only half of the cases involved haematuria at initial presentation.

TREATMENT AND OUTCOME: One-third of the sample suffered renal impairment after the renal infarction. Overall mortality rate during admission was 13.2% (n = 5). The cause of death was usually not the renal infarction itself but rather the underlying disease and its complications. There was no difference in outcome for anticoagulation treatment with or without thrombolytics. Compared to their Western counterparts, the proportion of males (71.1% versus 48.3%) and bilateral renal infarctions (31.6% versus 12.4%) were significantly higher, and the percentage of leukocytosis (50% versus 85%) significantly lower in our Asian patients.

CONCLUSION: Clinical presentation of renal infarction is usually non-specific and differs for Asian and Western populations. In our Asian patients, the most common clinical characteristics were abdominal pain/tenderness, flank pain/tenderness, elevated serum LDH and proteinuria. Early diagnosis and treatment are imperative because of the high rate of renal impairment and associated mortality. If this disease is suspected, contrast-enhanced CT is suggested to exclude or confirm renal infarction and anticoagulation alone is currently the favored treatment.