Spontaneous intraventricular rupture of a thalamic abscess: case report and systematic review of a rare neurocritical emergency

Spontaneous intraventricular rupture of a thalamic abscess is a rare, life-threatening neurocritical emergency. A 51-year-old man with a ventriculoperitoneal shunt placed at the referring hospital for acute obstructive hydrocephalus attributed to a presumed thalamic tumour presented with headache, left-sided weakness, altered mental status, and a Glasgow Coma Scale score of 15/15. Magnetic resonance imaging demonstrated a right thalamic abscess with rupture into the lateral ventricle, ventriculitis, and pyocephalus. The shunt was removed, an external ventricular drain was inserted, and prolonged systemic antimicrobial therapy was guided by serial cerebrospinal-fluid findings and neuroimaging. At 8–10 months of follow-up, imaging showed no active infection and the patient remained independently ambulatory, with resolved left little-finger numbness and subjective left-sided hearing loss; a formal modified Rankin Scale or Glasgow Outcome Scale score had not been recorded and could not be retrieved from the available records. A systematic search performed through April 2026 identified seven reports describing eight previous cases. Owing to the small number and clinical heterogeneity of the reports, no quantitative synthesis was performed. This case supports prompt magnetic resonance imaging, early cerebrospinal-fluid diversion when hydrocephalus or ventriculitis is present, and individualized antimicrobial management. Intraventricular antibiotics should be reserved for selected patients with inadequate response to systemic therapy, and the evidence should be interpreted as descriptive rather than comparative.