Case report: diagnosis of neurobrucellosis in a non-endemic area child using metagenomic next-generation sequencing.

Brucellosis with neurological symptoms at onset is rare in children and is frequently misdiagnosed or overlooked due to nonspecific clinical presentations, particularly in non-endemic areas. We report a case of neurobrucellosis in a child from a non-pastoral area, diagnosed via metagenomic next-generation sequencing (mNGS). The patient presented with headache and altered consciousness, accompanied by fever, projectile vomiting, seizures, and urinary incontinence. Physical examination indicated possible nuchal rigidity. Cerebrospinal fluid (CSF) analysis showed colorless and clear fluid, with a white blood cell count of 259 × 10⁶/L, 4.6% polymorphonuclear cells, positive protein qualitative test, protein level of 0.78 g/L, and glucose level of 1.66 mmol/L. Initial diagnosis suggested central nervous system infection, and empirical treatment led to improvement in consciousness. However, after a few days of stable body temperature, the patient experienced recurrent fever. Ultimately, mNGS of CSF identified Brucella melitensis, confirming neurobrucellosis. Following treatment with ceftriaxone, doxycycline, and rifampin, the patient's clinical symptoms improved significantly, and follow-up CSF analysis showed normalization of cell counts. This case highlights the early diagnostic utility of mNGS in CSF for neurobrucellosis and its role in differential diagnosis.