Name a common complication of untreated acute bacterial sinusitis.

Orbital cellulitis is a recognized complication of untreated acute bacterial sinusitis due to the proximity of the sinuses to the orbit of the eye. When the sinus cavities become infected, the inflammation can extend to the surrounding areas, including the orbit. This can lead to swelling and infection of the soft tissues around the eye, resulting in symptoms such as redness, swelling, and pain in the eye area, as well as potential vision changes.

The risk of developing orbital cellulitis increases especially when the infection is in the frontal or ethmoid sinuses, as these are directly connected to the orbit. If not treated promptly, orbital cellulitis can lead to more severe complications, such as abscess formation, vision loss, or intracranial spread of the infection.

While meningitis, sepsis, and pneumonia are potential complications associated with severe systemic infections, they are less directly linked to acute bacterial sinusitis compared to orbital cellulitis, which is specific to the anatomical relationship between the sinuses and the eye. Thus, the selection of orbital cellulitis highlights the importance of timely management of sinus infections to prevent such localized complications.