Orbital apex syndrome associated with cranial nerve V neuritis complicating bacterial maxillary sinusitis.

Maxillary sinusitis is a common pathology of the paranasal sinuses, most frequently caused by bacterial infections. Although typically benign, it can occasionally lead to severe complications when the infectious process extends beyond the sinus cavity. One such rare but serious complication is orbital apex syndrome (OAS), also known as Jacod syndrome, characterized by dysfunction of multiple cranial nerves at the orbital apex. OAS may result from various etiologies, including infectious, traumatic, and neoplastic causes. Among infectious origins, bacterial maxillary sinusitis is an uncommon yet clinically significant contributor. Involvement of the trigeminal nerve (cranial nerve V), manifesting as neuritis, adds further complexity to the clinical presentation. Accurate diagnosis and timely management of OAS rely heavily on advanced radiological imaging, particularly magnetic resonance imaging (MRI). MRI plays a pivotal role in confirming the diagnosis, excluding differential diagnoses, and delineating the extent of sinus infection, orbital inflammation, and perineural involvement, including neuritis of cranial nerve V. These imaging findings are essential for guiding appropriate therapeutic strategies. In this case report, we describe a rare instance of orbital apex syndrome associated with cranial nerve V neuritis complicating bacterial maxillary sinusitis. The objective is to underscore the crucial role of MRI in both diagnosis and therapeutic decision-making, and to illustrate the characteristic radiological features observed in such cases.