Nocardiosis (central nervous system manifestations)

Central nervous system (CNS) nocardiosis is a rare infection that may affect both the brain and the spine in patients with immunodeficiency. 

Epidemiology

CNS nocardiosis has been reported to represent ~2% of all cerebral abscesses, and to be present in 15-50% of patients with systemic infection ^2-3. 

Clinical presentation

Symptoms may vary according to the type of presentation and its extension in the CNS: headache, nausea, vomiting, focal neurological deficit and seizures are reported as the most common ^2-3. 

Pathology

Nocardia spp. are aerobic gram-positive bacilli which are ubiquitous saprophytic organisms ^1-3. The infection is acquired primarily by inhalation of the bacillus from the environment, from where it can spread hematogenouslyhaematogenously to other organs and tissues ^1-2. In the CNS the infection manifests as meningitis, granuloma with giant cells or cerebral abscesses ². 

Identification of Nocardia spp.in the clinical laboratory can be challenging: the organism may grow on cultures in intervals between 4 days to 2–4 weeks ¹.

Radiographic features

This infection has no specific features to aid in suggesting the diagnosis. It typically manifests as a parenchymal abscess in any part of the brain, though spinal cord abscesses and meningitis have also been described ^1,2.

Treatment and prognosis

Medical and surgical opinions should be sought ^4,5. Empiric antibiotic treatment consists of trimethoprim-sulfamethoxazole plus either a carbapenem class antibiotic and/or amikacin ⁴, while surgical management includes craniotomy or aspiration of abscesses ^4,5. Both craniotomy and aspiration have been found to be equally effective ⁵.