Neurobrucellosis Mimicking Primary CNS Vasculitis-Should We Perform CSF Metagenomics Before Brain Biopsy?: A Case Report.

Objective: To report a patient with neurobrucellosis mimicking primary CNS vasculitis (PCNSV) diagnosed by CSF metagenomic next-generation sequencing (mNGS). Methods: A 32-year-old male patient with a prior stroke developed headache, dizziness, fever, and memory complaints in the past 30 days. Physical examination was unremarkable except for slight apathy. He was investigated with brain MRI, cerebral digital angiography, CSF analysis with mNGS, and brain biopsy. Results: An examination of the brain MRI showed a left nucleocapsular gliosis compatible with prior stroke; MR angiogram showed circular enhancement of distal branches of the middle cerebral arteries. Digital angiogram revealed stenosis of intracranial carotid arteries and the left middle cerebral artery. The CSF disclosed 42 cells/mm3, 46 mg/dL of glucose, and 82 mg/dL of protein. Brain biopsy showed a chronic leptomeningeal inflammatory process, not fulfilling criteria for PCNSV. mNGS revealed the presence of Brucella sp. genetic material. He was treated with antibiotics with full remission of systemic and neurologic symptoms. Discussion: Brucellosis is an endemic disease in developing countries and may mimic PCNSV. Our patient fulfilled the criteria for possible PCNSV; however, brain biopsy was inconsistent with PCNSV, and CSF mNGS disclosed neurobrucellosis. This case illustrates the importance of CSF mNGS in the differential diagnosis of CNS vasculitis.