Acute sinusitis is an acute inflammation of the paranasal sinus mucosa that lasts less than four weeks and can occur in any of the paranasal sinuses. If the nasal cavity mucosa is also involved then the term rhinosinusitis may be used.
Fever, headache, postnasal discharge of thick sputum, nasal congestion and an abnormal sense of smell.
Usually following a viral upper respiratory tract infection. Dental caries, periapical abscess and oroantral fistulation lead to a spread of infection to the maxillary sinus. Cystic fibrosis and allergy are risk factors.
Other anatomical variants that may predispose to the inflammation include nasal septal deviation, a spur of the nasal septum and/or frontoethmoidal recess variants.
Opacification of the sinuses and air-fluid level best seen in the maxillary sinus. It does not allow assessment of the extent of inflammation and its complications.
Better anatomical delineation and assessment of inflammation extension, causes and complications. Peripheral mucosal thickening, air-fluid level, gas bubbles within the fluid and obstruction of the ostiomeatal complexes are recognized findings.
Signal characteristics of the affected regions include
- T1: mucosal thickening is isointense to soft tissue and fluid is hypointense
- T2: both mucosal thickening and fluid are, to a variable degree, hyperintense
- T1 C+ (Gd): inflamed mucosa enhances whilst fluid does not