Urinalysis, ultrasound analysis, and renal dynamic scintigraphy in acute appendicitis

The influence of acute appendicitis (AA) on the right kidney and urinalysis was investigated. Permanent damage of the urinary tract and abnormal urinalysis have been previously reported in AA.

Appendectomy was performed in 84 patients with no previous urogenital, retroperitoneal, or pelvic disease, trauma, or operation. AA was confirmed in 66 of them. Control groups were the remaining 18 patients and 40 patients with varicocele repair. Renal sonography and urinalyses were done prior to operation, on days 1, 3, and 6 postoperatively. Pentetic acid renal scintigraphy was done on postoperative day 1 in patients with abnormal urinalysis. An obstructive radiographic curve indicated furosemide renography.

Abnormal urinalysis was found in 48% of patients with AA before appendectomy and in 12% on day 6 postoperatively. Sonography showed pyelocaliceal dilation of the right kidney in 38% of patients with AA prior to appendectomy and in none on day 6 postoperatively. Patients with AA had pyelocaliceal dilation of the right kidney more frequently than those in the control groups (P < 0.001). It was more frequent in patients having abnormal urinalysis (P < 0.01). Scintigraphy confirmed pyelocaliceal dilation of the right kidney in 38% of patients with abnormal urinalysis. Furosemide renography excluded an obstruction in all of them.

Inflammation is the major cause of abnormal urinalysis and transitory pyelocaliceal dilation in some patients with AA. Erythrocyturia, pyuria, proteinuria, and pyelocaliceal dilation detected by sonography or scintigraphy can frequently be found in patients with AA, but should not mislead the surgeon in the diagnosis of AA.