<b>Methods for Early Diagnosis of Herbal </b><b>Medicine-induced Pneumonitis </b> / 日本東洋医学雑誌

ABSTRACT

Early diagnosis of drug-induced pneumonitis (DP) is important because timely drug withdrawal will significantly reduce the risk of irreversible fibrosis. Although DP is diagnosed based on the patient's history, physical examinations and laboratory data, a definitive diagnosis of DP is difficult because the clinical and laboratory data are often nonspecific. And the diagnostic methods for DP are still an area of debate. Furthermore, DP has characteristics similar to infectious pneumonia and collagen-vascular disease-related pulmonary fibrosis.Thus, infectious pneumonia and collagen-vascular disease-related pulmonary fibrosis are important considerations for the differential diagnosis of DP. The drug-induced lymphocyte stimulation test (DLST) is widely used to diagnose drug-induced pneumonia in Japan. However, the DLST is not reliable for the diagnosis of DP because the false-positive and-negative rates are relatively high and there are other limitations with the DLST.On the other hand, serum KL-6 produced by type II pneumocytes is a useful marker for the diagnosis of DP, because serum KL-6 levels are high in DP but low in bacterial pneumonia, <i>Mycoplasma pneumoniae pneumonia </i>and <i>Chlamydia pneumoniae </i>pneumonia. Other laboratory methods related to DP are also described in this article. Some herbal medicines may also induce DP. However, in several reports of herbal medicine-induced pneumonitis, DP was often diagnosed with DLST and/or infection was not excluded. Once the diagnosis of DP is definite, we should not continue using the causative drug, even if it is useful for the treatment of a specific disease. Clearly, the definitive diagnosis of DP involves careful consideration.