Role of Positron Emission Tomography Scan in Complicated Ear Infection

Abstract

Introduction: Malignant otitis externa (MOE) can be a potentially life threatening condition. The patient typically presents with pain in the ear with minimal clinical signs. Cranial neuropathies may be present depending upon the extent of the disease. A high index of suspicion is required to diagnose and treat MOE. MOE can be suspected clinically but is often confirmed on investigations including CT scan of temporal bone. Objective: We describe an atypical case of malignant otitis externa (MOE). Clinical and standard CT scan findings were regarded inadequate to make a definitive diagnosis. We discuss the complementary but important role of PET CT to confirm the diagnosis in the presence of equivocal finding on standard skull base CT scan. Methodology: Case report with literature review. Results: A 76 year old male presented with deep seated otalgia. Clinical findings were equivocal. He had ipsilateral hypoglossal nerve palsy. The CT scan showed opacification of the middle ear cleft. The differential included middle ear neoplasm, skull base osteomyelitis and malignant otitis externa. The PET CT showed widespread uptake of the ipsilateral skull base which led to the diagnosis of MOE. Patient was treated with 10 days of intravenous ciprofloxacin followed by oral treatment totalling 10 weeks. The pain improved with IV treatment and a review at 8 weeks revealed complete resolution of pain and hypoglossal nerve palsy. Conclusion: Standard clinical or radiological parameters may not always be adequate to make a definitive diagnosis of MOE. In such setting, we advocate the use of PET CT scan as a complementary investigation to clinch the diagnosis