Dacryocystitis is an infection of which anatomical structure?

• A. Dacryadenitis
• B. Lacrimal sac
• C. Conjunctiva
• D. Cornea

Answer: (B)

Dacryocystitis involves infection of the lacrimal sac, which sits along the tear drainage pathway at the medial canthus. When the drainage system is obstructed, bacteria can proliferate in the lacrimal sac, leading to localized swelling and purulent discharge that may be expressed through the punctum with pressure over the lacrimal sac. This specific location helps distinguish it from other structures: infection of the lacrimal gland (dacryoadenitis) causes swelling in the lateral upper eyelid; conjunctivitis is an infection of the conjunctiva with diffuse redness and discharge; keratitis is an infection of the cornea with corneal staining and pain. Thus, the infection is in the lacrimal sac.