Brain abscess is the most common CNS infection. The lesions are often multilocular and can occur in any region of the brain. CT or MRI with contrast demonstrates ring-enhancing lesions, as observed with other causes of pyogenic brain abscess. In AIDS patients, brain abscess is often accompanied by an abnormal chest x-ray, which suggests the diagnosis. With other patients, abnormalities on chest x-ray are not always present.
Patients undergoing surgical drainage of their abscesses have a higher survival rate.
Patients typically have subacute to chronic meningitis characterized by fever, stiff neck, and headache. CSF analysis demonstrates a predominance of polymorphonuclear neutrophils, a low CSF glucose level, and an elevated protein level. CSF cultures are often negative, particularly in the first three days, and patients fail to fully respond to empirical antibiotic therapy. Cutaneous Infection Cutaneous involvement is uncommon and is generally caused by N. brasiliensis. A pustule or a moderately erythematous, nonfluctuant nodule develops at the site of inoculation.