Abstract
Procalcitonin (PCT) is a useful biomarker for bacterial infection. However, several cases of an elevated PCT level in patients without infection have been reported. A 66-year-old man with Goodpasture's syndrome was found to have a high anti-glomerular basement membrane antibody (anti-GBM antibody) level (111 EU) and was transferred to our ICU because of acute respiratory failure due to pulmonary alveolar hemorrhage. Even after steroid pulse therapy and plasma exchange (PE), the patient's renal function remained aggravated. Hemodialysis (HD) had already been started prior to ICU admission. On the 30th hospital day, an elevated serum PCT level of 50.32 ng·ml−1 was noted, although no other evidence of infection was seen. Steroid pulse therapy and PE were continued, and the patient's serum PCT level decreased to 3.72 ng·ml−1 and his anti-GBM antibody titer became negative. On the 40th hospital day, he developed methicillin-resistant Staphylococcus aureus (MRSA) pneumonia and his PCT level once again increased (22.5 ng·dl−1). However, his anti-GBM antibody titer remained negative. His clinical conditions improved, and he returned to the general ward on the 75th hospital day. In the present case, the PCT level might have reflected tissue damage of the lungs and kidneys caused by the anti-GBM antibody and the presence of Goodpasture's syndrome. Therefore, in cases with Goodpasture's syndrome and a high PCT level, the possibility of not only bacterial infection, but also lung and/or renal injury caused by the anti-GBM antibody should be considered.
