The increased use of novel and powerful immunosuppressive drugs in kidney diseases may concomitantly expose the patients to higher risk of opportunistic infections, some of which still remain underdiagnosed thus mishandled. As such, we recently had a less prepared encounter of pulmonary nocardial infection in an ANCA-associated renal vasculitis patient under steroid therapy. Despite the use of broad-spectrum antimicrobials including micafungin, the infection was still unbridled and eventually culminated in lethal brain abscess. We thus chose to renew the knowledge of the clinical features, imaging manifestations, differential diagnosis, specific laboratory tests and unique treatment about this rare infection in kidney diseases patients under immunosuppressive therapy. In addition, CT images of easily confused pulmonary lesions superimposed on kidney diseases were also retrieved from our depository. Moreover, impaired renal function as a risk factor for infection and pharmacological options for the treatment were also focused. By sharing our hard-learnt experience and reviewing the literatures, our report may contribute to the awareness among the clinicians in general and nephrologists in particular of this rare disease in susceptible patients and facilitate a swift thus life-saving treatment.