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Chronic rhinosinusitis i

Chronic rhinosinusitis presents with sinonasal inflammation lasting >12 weeks, affecting approximately 15% of the general population but only ~5% when strict endoscopic/CT criteria are applied. Common in young to middle-aged adults with risk factors including smoking, asthma, allergy, and anatomical obstruction.
Look For First
  • Sclerotic thickened bone (hyperostosis) involving sinus walls indicating prolonged mucoperiosteal reaction
  • Mucosal thickening and/or opacification of the osteomeatal complex region
  • Anatomical variants obstructing normal drainage pathways (concha bullosa, septal deviation, uncinate process variation, Haller cells)
Key Image Findings
  • CT is the gold standard for evaluating chronic rhinosinusitis; plain radiographs are not indicated and have poor diagnostic utility.
  • Sclerotic thickened bone (hyperostosis) of sinus walls is a characteristic feature reflecting chronic mucoperiosteal reaction and distinguishes chronic from acute sinusitis.
  • Intrasinus calcification may be present as a manifestation of chronic inflammatory changes within the affected sinuses.
  • Mucosal thickening and opacification patterns vary depending on drainage pathway obstruction, necessitating classification into five distinct anatomical patterns.
  • Osteomeatal complex (OMC) pattern affects maxillary, anterior ethmoidal, and frontal sinuses due to OMC obstruction; infundibular pattern isolates ethmoid infundibulum and/or maxillary ostium.
  • Sphenoethmoidal recess pattern involves isolated or combined sphenoid and posterior ethmoidal inflammation; sinonasal polyposis pattern shows extensive polyps throughout nasal cavity and sinuses.
  • Sporadic pattern exhibits random mucosal thickening and polyps without clear anatomical distribution; Lund-Mackay scoring is the most validated CT grading system.
  • High diagnostic correlation exists between endoscopy and CT findings, with endoscopic findings of nasal polyps, middle meatal mucopurulent discharge, or mucosal edema supporting CT diagnosis.
Differential Diagnosis
  • Acute sinusitis: lacks sclerotic bone thickening/hyperostosis and shows acute mucosal changes rather than chronic inflammatory pattern; absence of prolonged symptoms and underlying anatomical obstruction.
  • Sinonasal polyposis (isolated): distinguished by extensive polyps without additional mucosal inflammatory changes typical of chronic rhinosinusitis; may be associated with CRS in some cases.
  • Cystic fibrosis: presents with chronic rhinosinusitis but characterized by diffuse nasal polyposis and distinctive viscous secretions; requires clinical history and genetic confirmation.
  • Fungal sinusitis (chronic): can mimic CRS but shows characteristic bone erosion and hypodensity or hyperdensity depending on fungal type (aspergillus shows calcification).
  • Mucocele: presents as expansile lesion with smooth bony erosion and fluid signal intensity, typically in frontal or sphenoid sinus; lacks the sclerotic thickening of CRS.
  • Odontogenic sinusitis: maxillary sinus involvement with dental pathology evident on imaging; history of dental disease and unilateral pattern help distinguish from idiopathic CRS.
Discussion

Chronic rhinosinusitis results from complex interplay of environmental and immune factors, with anatomical variants (concha bullosa 30%, septal deviation 25%, uncinate variation 25%) acting as predisposing factors for recurrent/persistent disease.

Poor correlation exists between clinical symptoms and imaging findings, making CT assessment necessary for diagnosis despite variable symptomatic presentation; imaging findings help guide surgical planning rather than symptom severity.

Five anatomical patterns of CRS are classified by drainage pathway obstruction (OMC, infundibular, sphenoethmoidal, polyposis, sporadic), with pattern recognition critical for surgical planning and FESS approach selection.

Sclerotic bone thickening (hyperostosis) reflects chronic mucoperiosteal inflammation and is a key distinguishing feature from acute sinusitis, indicating chronicity and remodeling rather than acute infiltration.

Functional endoscopic sinus surgery (FESS) has revolutionized CRS treatment, requiring detailed preoperative CT analysis to identify anatomical variants that may predispose to recurrent disease or complicate surgical approach.

Associated systemic conditions including asthma, COPD, GERD, N-ERD, and hypogammaglobulinemia increase CRS risk and should guide comprehensive clinical evaluation beyond imaging findings.

Reporting Pearls

Report chronic rhinosinusitis using the validated Lund-Mackay scoring system, specifically identifying the pattern of inflammation (OMC, infundibular, sphenoethmoidal, polyposis, or sporadic), noting sclerotic bone changes, anatomical variants affecting drainage (with specific locations), and laterality; clearly document extent of mucosal disease to guide surgical candidacy and approach.

Pitfalls
  • Confusing acute sinusitis with chronic rhinosinusitis based on opacification alone; sclerotic bone thickening and hyperostosis are essential features of chronicity and distinguish CRS from acute infection.
  • Overrelying on symptoms to establish diagnosis—poor symptom-imaging correlation means imaging findings (endoscopy/CT criteria) are mandatory for diagnosis despite variable clinical presentation.
  • Failing to identify and document anatomical variants predisposing to CRS (especially in FESS candidates); concha bullosa, septal deviation, and Haller cells must be characterized to predict surgical success.
  • Using plain radiographs for diagnosis or staging; CT is the gold standard and provides superior anatomical detail necessary for surgical planning, rendering plain films obsolete for CRS evaluation.
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