Computer tomography findings in necrotizing otitis externa based on the offending pathogens.

Area of Science:

• Radiology
• Otolaryngology
• Infectious Diseases

Background:

• Necrotizing otitis externa (NOE) is a severe infection often assessed initially with high-resolution temporal bone computer tomography (HRTBCT).
• Understanding pathogen-specific radiological manifestations is crucial for effective treatment.

Purpose of the Study:

• To compare the extent of NOE on HRTBCT across different causative pathogens (fungal, Pseudomonas aeruginosa [PA], and sterile).
• To determine if HRTBCT findings can suggest the pathogen in sterile NOE cases.

Main Methods:

• Retrospective analysis of 30 NOE patients hospitalized between 1990 and 2018.
• Random selection of 10 patients each for fungal-NOE, PA-NOE, and sterile-NOE groups.
• Reevaluation of HRTBCT scans by a senior radiologist, focusing on 13 predefined subsites.

Main Results:

• Otaliga was most frequent in fungal-NOE (100%) compared to sterile-NOE (90%) and PA-NOE (60%).
• External ear canal edema and granulation tissue were common in all groups.
• Temporomandibular joint (TMJ) bone erosion was significantly more prevalent in fungal-NOE (4/10) than PA-NOE (1/10).

Conclusions:

• Temporomandibular joint (TMJ) involvement on HRTBCT may indicate fungal etiology in NOE.
• The distinct pattern of TMJ involvement in fungal NOE suggests a different disease spread compared to PA-NOE.
• HRTBCT findings of TMJ erosion could support initiating antifungal therapy in culture-negative NOE.