Lacrimal Sac Pneumatocele Following Blunt Nasal Trauma

Abstract

Pneumatocele of the lacrimal sac is an uncommon entity and has been rarely reported in literature. The valvular function of the Hasner's valve at the lower end of nasolacrimal duct is presumed to prevent the retrograde reflux of air into the lacrimal sac with increased intranasal pressure as in valsalva maneuver. Loss of this valvular function as noted with persistent positive airway pressure ventilation can cause retrograde air reflux into lacrimal sac. The authors report a case of lacrimal sac pneumatocele which developed following blunt nasal trauma involving the bony nasolacrimal duct.

Retrograde Air Flow through the Lacrimal Drainage System with Valsalva Maneuver

“…However, this is rarely clinically significant, because in most patients, the remaining valves are competent, the sac is widely opened (preventing pressure build up), and the pressure generated in a wide cavity such as the intranasal space, may be different than that in a smaller space, such as the lacrimal sac. Other causes of pneumatocele include trauma as illustrated by a recent case in which blunt nasal trauma resulted in fracture of medial wall of the NLD and sac-NLD junction, in which Valsalva-augmented CT-dacryocystography revealed a hypodense filling defect within a distended sac [2]. Other causes of lacrimal pneumatocele include congenital mucocele, persistent…”