Problems in the initial diagnosis of renal infarction.

We retrospectively analyzed 20 cases of renal infarction to identify the problems in tentatively diagnosing renal infarction. The subjects consisted of 12 outpatients and 8 inpatients whose diagnosis was confirmed by renal scintigram and/or contrast computed tomography. Renal infarction was tentatively diagnosed in only 4 of the 12 outpatients. Causes of hospitalization were cerebral emboli in 5 cases, peripheral emboli in the extremities in 2 cases and one case involved percutaneous transmitral commissurotomy. On initial urinalysis, 11 cases (55%) showed less than 2+ hematuria using dipsticks to test for occult blood. The mean lactic dehydrogenase value was as high as 2,096 IU while the mean aspartate aminotransferase and mean alanine aminotransferase were 83.1 IU and 78.6 IU. Abdominal ultrasonography revealed abnormalities in only one of 18 cases. In conclusion, since only a moderate degree of hematuria was seen in about half the cases and it was difficult to detect renal abnormalities by ultrasonography, a tentative diagnosis of renal infarction may be difficult in some cases.