Miliary cerebrospinal lesions caused by Nocardia beijingensis in an immunocompetent patient.

The genus Nocardia usually infect immunocompromised patients. Pulmonary nocardiosis is the most common Nocardia-induced infection while central nervous system (CNS) is the most common extrapulmonary site to develop nocardial disease. Approximately 54 % cases of previously reported nocardial brain abscesses were solitary lesions, while 38 % cases had multiple lesions; but miliary-like ring enhancing lesions have not been reported previously. We present a case of immunocompetent patient with miliary-like cerebrospinal lesions caused by Nocardia beijingensis. A 68-year-old Japanese man presented with acute-onset headache, vomiting, and progressive disturbance of consciousness. A contrasted magnetic resonance imaging (MRI) scan showed countless miliary-like ring-shaped enhancing lesions on the patient's whole brain, brain stem, and cervical spinal cord. A brain biopsy was performed and Kinyoun stain suggested that the brain lesions were abscesses caused by Nocardia species. 16S ribosomal RNA sequencing identified Nocardia beijingensis as the causative microorganism. The trimethoprim/sulfamethoxazole regimen was continued for 7 months and the patient showed good improvement with recovery of consciousness. Clinical manifestation of Nocardia beijingensis infection is poorly studied. Further cases are needed to be accumulated.