Objectives To investigate the clinical and pathological
characteristics of Mutong (a Chinese herb, caulis aristolochiae
manshuriensis ) induced tubulointerstitial nephropathy (MT-TIN), and analyze the related to renal fuction decline and clinical prognosis. Methods 51 patients with MT-TIN were studied retrospectively. They were divided into acute, mildchronic and severechronic groups according to the pathological lesion. Clinical and pathological data were semi-quantitatively assessed. Correlation and regression of the parameters were further tested. Relationship between medication and the illness, incidence, clinical
characteristics, therapy and regression of the disease were analyzed. The results of the acute group of MT-TIN were compared with those of the antibiotics-induced acute tubular necrosis (A-ATN) and acute intersitial nephritis (A-AIN). Results The common clinical symptoms of MT-TIN were fatigue, polyuria, nocturia, usually acommpanied by renal tubular dysfunction with or without an elevated serum creatinine (Scr) level. It was rare to find urine abnormality and anemia in the acute and mildchronic groups. The pathological examination of MT-TIN revealed that there were severe degradation, necrosis and collapse of the renal epithelial cells leaving the basement membrane naked. Regeneration was rarely seen as in A-ATN. Cellular infiltrate in the interstitium was also rarely seen as in A-AIN. However, marked tubular atrophy and early occurrence of diffuse interstitial fibrosis were detected in the chronic groups. Correlation and regression tests showed that the level of Scr correlates obviously with the degree of anemia and renal interstitial fibrosis. After withdrawal of medication containing MT, most patients' Scr level becamesteady within 2 months. Both the clinical and pathological characteristics were different with those of A-ATN or A-AIN. Most of the patients suffering from MT-TIN got the disease by over-dose or long-term taking of medicines containing Mu-Tong. Few patients had it when taking regular dose of the medicine. Conclusion MT-TIN is a special type of drug-induced tubulointerstitial nephropathy, which is mainly related to over-dose or long-term taking of Mu-Tong, which contains
aristolochic acid. One should try to avoid using Mu-Tong containing aristolochic acid and pay attention to monitor the renal function if the medication has to be given.