Petroapicitis as a Severe Complication of External Otitis—Strategy and Prognosis

Introduction: Inflammation of the external ear canal is a very common diagnosis in the ENT surgeon's daily practice. Pseudomonas aeruginosa infection bears the risk of malignant external otitis, which can lead to an infection of the lateral skull base in the region of the apex of the petrous bone.

Patients and Methods: We diagnosed petroapicitis in three cases within 6 months. The patients had been treated for Pseudomonas infection of the outer ear canal. Extraordinarily severe pain and cranial nerve palsies resulted in further investigation and diagnosis. We present the three cases and their 9- to 15-month follow-up results. Diagnostic steps and different therapeutic options are discussed.

Results: One of the patients developed mastoiditis from malignant otitis externa and had to undergo mastoidectomy. Despite the radical operative approach, the infection later affected the lateral skull base. Petroapical osteomyelitis could then be successfully treated conservatively. The second patient's CT and MRI scans suggested malignancy of the lateral skull base. Operative biopsies showed evidence of osteomyelitis which was then treated conservatively. The patient had to undergo tracheostomy because of the risk of aspiration due to vagal and glossopharyngeal palsy. The third patient was successfully treated with subtotal petrosectomy.

Conclusion: If external otitis with evidence of Pseudomonas aeruginosa proves to be resistant to therapy and is unbearably painful, we strongly recommend CT and MRI of the lateral skull base and detailed analysis of cranial nerve function. If the diagnosis of osteomyelitis of petrosal apex is confirmed, the surgeon must thoroughly evaluate a radical-surgical against a conservative therapeutic approach—depending on the patient's general health condition and age, previous illnesses, and severity of symptoms.