Nocardia brain abscesses

Case contributed by Virginia López
Diagnosis certain


Fever, pancytopenia. Sudden onset headache without other neurological symptoms during admission. Treated with chemotherapy and radiotherapy for a cavum carcinoma two years ago. Recent diagnosis of pulmonary nocardiosis.

Patient Data

Age: 50 years
Gender: Male

Left basal consolidation with subtle nodules in the rest of the lung and small left pleural effusion.


Low-density white matter changes, consistent with vasogenic edema, located in the left centrum semiovale and left frontal lobe with no mass effect.

Contrast-enhanced CT shows a single small nodular lesion with ring enhancement in left hemispheric convexity.


T2/FLAIR sequences show high-intensity areas due to vasogenic edema, with small ring lesions inside.

Well-defined round intra-axial lesions, T1 hypointense and T2 hyperintense, in subcortical white matter, located in the left frontal lobe (convexity, inferior frontal gyrus) and right parietooccipital lobe (cuneus). These lesions have a thick wall with a double rim sign and ring enhancement.

These lesions show marked diffusion restriction.


Multiple consolidations in the upper and lower lobe of the left lung, some with cavitation.

Small left pleural effusion.

Ground-glass changes in both superior lobes.

Case Discussion

A pleural fluid culture was performed, which was positive for Nocardia spp. A biopsy of the brain lesions was not carried out. Cefalo-spinal fluid (CSF) cultures were also positive for Nocardia spp.

Infection is acquired through inhalation or direct inoculation, causing primary pulmonary or cutaneous disease. Involvement of other sites usually occurs through hematogenous dissemination.

Nocardia tends to have a special tropism for the brain, with central nervous system (CNS) involvement in almost half of the patients with systemic infections. Primary pulmonary infection might be subclinical and CNS involvement may be asymptomatic, as in this case.

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.