A Case Report of Mycetoma and Cranial Osteomyelitis by Nocardia nova

Mycetoma is a chronic, localized, slowly progressive, granulomatous infection of the skin that may progress to subcutaneous tissue, muscle and bone. It is an infrequent manifestation of Nocardia infection that predominantly occurs on the lower extremities. A previously healthy, 17-year-old boy presented with a 3-month history of scalp abscesses. On physical examination he had numerous, large left parietal and occipital inflammatory nodules on the scalp covered by alopecic skin and several sinuses discharging a purulent and serosanguinous material. He underwent a CT-scan and an MRI of the skull that revealed signs of cranial osteomyelitis and epidural empyema. Polymerase chain reaction assay of the purulent exudate was performed and identified Nocardia nova. The patient was discharged from the hospital after 8 weeks of antibiotherapy with meropenem and TMP-SMX with clinical, laboratorial and imaging improvement. He completed 12 months of outpatient oral therapy with TMP-SMX, after which cranial CT-scan showed a significant reduction of soft tissue thickening and bone reconstitution, with no relapses after stopping the treatment. The best antibiotic regimen and length of treatment are not established for the management of nocardiosis. This is an unusual and severe presentation of infection by Nocardia nova with extent to the bone and epidural space, with full recovery under standard antibiotic therapy. This case shows that a good outcome may be achieved with prolonged antimicrobial treatment in an immunocompetent patient.