Sinus infections can be complicated by ocular infections and, in late phases, by brain parenchyma infection. The article debates the case of a 12-year-old patient suffering from paucisymptomatic maxillo-spheno-ethmoidal rhinosinusitis, which was later complicated by orbital cellulitis, ending with the development of a brain abscess. The treatment is complex, initially targeting the source of the infection through draining the collection by middle maxillary antrostomy and anterior posterior ethmoidectomy, then the ablation of the brain abscess and postoperatively with prolonged massive antibiotherapy. Keywords: orbital cellulitis, rhinosinusitis, brain abscess, E. Coli Abbreviation: URI = upper respiratory infection, CT = computer tomography, MRI = magnetic resonance imaging, BA = brain abscess, VAS = visual scale of pain, ENT = ear, nose, throat, RE VA = right eye visual acuity, RE = right eye, CSF = cerebrospinal fluid