Single photon emission computed tomography/computed tomography for malignant otitis externa: lesion not shown on planar image

Necrotising Otitis Externa: A Review of Imaging Modalities

Necrotising Otitis Externa (NOE) has often posed some challenges in view of diagnosis and management by clinicians. One such challenge is the appropriate and timely use of imaging techniques since its use is critical not only in diagnosis but also in determining the extent and resolution of the disease. Hence, doctors in both primary and secondary health care need to be familiar with presenting symptoms while specialists need to be appraised of advances in imagining techniques in diagnosis and management of NOE. Whilst there is a general consensus amongst clinicians on some aspects of management of NOE, there is very limited consensus on the use of imaging modalities. There is no single modality of imaging that can provide a complete picture of diagnosis, disease progression and resolution. This review aims to highlight the strengths and weaknesses of various imaging techniques used in the diagnosis and management of NOE over the years and whether a multi-modal imaging technique at particular stages of the disease may provide better management outcomes.

The challenging diagnosis and follow-up of skull base osteomyelitis in clinical practice

PURPOSE

The disease activity of skull base osteomyelitis can be challenging to assess by means of conventional imaging methods and renders monitoring of the disease difficult, especially in areas with restricted access to nuclear medicine imaging. Here, we provide clinically relevant data on the management of skull base osteomyelitis including assessment, treatment, and follow-up strategies with regards to the role of imaging.

METHOD

A chart review was performed including 30 patients treated for SBO from 1993 to 2015. Clinical findings, treatment procedures, and complication rates were assessed. Special attention was paid to imaging procedures.

RESULTS

The overall mortality rate was 36.7% and increased to 45% when cranial nerve palsies were present. An initial computed tomography (CT) scan was performed in all patients, MRI in 60% and nuclear imaging in 33%. CT scans failed to detect progression or regression in up to 80% after four to nine months. MRI examinations could reveal changes at a higher rate compared to CT. Nuclear medicine functional imaging was most likely to assess disease activity.

CONCLUSION

A combination of different imaging modalities is recommended for diagnosing SBO. For the follow-up, MRI is preferable to CT as changes can be detected more readily with MRI. If available, nuclear medicine imaging should guide the decision of treatment discontinuation.

Necrotizing Otitis Externa-Analysis of 83 Cases: Clinical Findings and Course of Disease

OBJECTIVES

Evaluate the relationship between clinical findings and course of disease among patients with necrotizing otitis externa (NOE).

STUDY DESIGN

Retrospective case series review.

SETTING

Tertiary referral center.

PATIENTS

Adult patients with no previous history of chronic ear disease, hospitalized due to NOE between the years 1990 to 2015.

MAIN OUTCOME MEASURES

1) Duration of hospitalization and 2) necessity for surgery.

RESULTS

Eighty-one patients were included in the study, corresponding to 83 effected ears. Thirty-two patients (38.5%) were hospitalized longer than 20 days and 20 patients (24.0%) underwent surgery. Otalgia was the most common complaint (n = 71, 85.5%). Pseudomonas Aeruginosa (PA) was the most common isolated bacteria (n = 40, 48.1%). Shifting incidence of culture results was noted, as rates of PA NOE decreased and rates of sterile culture and fungal NOE increased. Duration of complaints and presence of aural discharge at admission were associated with prolonged hospitalization (p = 0.010, p = 0.011, respectively). Advanced age, duration of hospitalization, and rates of readmission were associated with surgery (p = 0.037, p < 0.001, p < 0.001 respectively).

CONCLUSIONS

Duration of complaints and presence of aural discharge may indicate advanced NOE and require longer in-hospital treatment. Elderly patients are at increased risk for conservative treatment failure and are more likely to require surgery. With shifting incidence of pathogens, a wider empirical treatment covering nontraditional pathogens should be considered.

Imaging in the Diagnosis and Management of Necrotizing Otitis Externa: A Survey of Practice Patterns

OBJECTIVE

To survey neurotologists and head and neck radiologists regarding use of imaging in the diagnosis and management of necrotizing otitis externa (NOE).

STUDY DESIGN

Cross-sectional survey study.

SETTING

Online survey distributed through email to specialty society membership lists.

PARTICIPANTS

Neurotologists and head and neck radiologists with membership in either the American Neurotology Society or The American Society of Head and Neck Radiology.

MAIN OUTCOME MEASURES

Responses to survey consisting of two demographic and seven clinically oriented questions related to the use of imaging in the diagnosis and management of NOE.

RESULTS

One hundred thirty-six participants responded to the survey. The imaging modality of choice in establishing the diagnosis of NOE selected by the respondents was computed tomography (CT) (37.5%) followed by technetium scintigraphy (21.3%). Magnetic resonance imaging (MRI) was the preferred investigation by 41.9% of participants for determining extent of disease. Gallium scanning was the imaging modality preferred by 32.4% of respondents for determining when to cease medical therapy. Ninety-five percent of participants responded that CT scans were always or frequently used in the diagnosis and management of NOE compared with 72.8% for MRI, 34.5% for gallium scans, and 34.2% for technetium scans.

CONCLUSIONS

There is considerable heterogeneity in the preferred imaging modalities used in the diagnosis and management of NOE. CT and MRI are the preferred contemporary modalities used by many physicians, demonstrating a shift away from the historic use of nuclear medicine scans.

Efficacy of HRCT Imaging vs SPECT/CT Scans in the Staging of Malignant External Otitis

OBJECTIVE

The prognosis of patients with malignant external otitis (MEO) depends on the extent of the inflammatory changes in the temporal bone and skull base. The efficacy of high-resolution computed tomography (HRCT) imaging in accurately assessing the extent of disease is compared with that of single-photon emission computed tomography/computed tomography (SPECT/CT) scan.

STUDY DESIGN

A clinical chart review was conducted with medical records and radiologic images.

SETTING

Tertiary care medical college hospital.

SUBJECTS AND METHODS

This study involved patients with clinically diagnosed MEO who underwent both modalities of imaging of the skull base. Staging of the disease extent was compared between the imaging systems among patients. Symptom control and survival rates were analyzed with respect to the SPECT/CT staging of MEO.

RESULTS

Out of 28 patients included in this study, 72% had SPECT/CT scans showing higher staging than the HRCT imaging. Four patients had mild uptake (stage 1), and 15 had disease confined to the mastoid/temporal bone, not reaching midline (stage 2). All patients in stages 1 and 2 were surviving with good symptom control. Five patients with petrous involvement reaching midline (stage 3) had persistent symptoms, and all 4 cases with SPECT/CT showing sphenoid involvement and crossing midline (stage 4) died within a year of diagnosis.

CONCLUSIONS

SPECT/CT scan is more sensitive than HRCT imaging in detecting the extent of disease and is a better prognosticator for patients with MEO.

Additive value of 99mTechnetium methylene diphosphonate hybrid single-photon emission computed tomography/computed tomography in the diagnosis of skull base osteomyelitis in otitis externa patients compared to planar bone scintigraphy

The aim of this study was to evaluate the additive value of ^99mtechnetium methylene diphosphonate (^99mTc-MDP) hybrid single-photon emission computed tomography/computed tomography (SPECT-CT) in the diagnosis of skull base osteomyelitis (SBO) compared to planar bone scintigraphy (PBS). This was a single institution; prospective study included 23 patients with otitis externa, clinically suspected of SBO, all of them were diabetic. Three-phase bone scintigraphy and SPECT/CT were performed to all patients. The imaging modalities which had the most equivocal results were PBS (9/23) followed by SPECT (3/23). No equivocal results were detected with CT or SPECT-CT. SPECT-CT had the highest sensitivity (100%) and highest accuracy (95.7%) in diagnosis of SBO, whereas, PBS showed the lowest sensitivity (50%) and lowest accuracy (52.2%). In this study, SPECT-CT considered the best modality for accurate localization of the site of SBO involvement, followed by CT. SPECT and planar BS were less accurate in this consideration. When comparing the sensitivity of planar BS, CT, SPECT and SPECT/CT, statistical significance difference was detected between planar BS and SPECT (P = 0.057), planar BS and SPECT/CT (P = 0.001), and between CT and SPECT/CT (P = 0.031). No statistically significant difference was detected between SPECT and SPECT/CT (P = 0.250), CT and planar BS (P = 0.125), and between CT and SPECT (P = 0.508) In conclusion, ⁹⁹Tc-MDP SPECT/CT has high sensitivity in the diagnosis of SBO and also provide accurate localization of the site of SBO.

Diagnosis and treatment of necrotising otitis externa and diabetic foot osteomyelitis - similarities and differences

OBJECTIVE

Necrotising otitis externa is a severe inflammatory process affecting soft tissue and bone, mostly in diabetic patients. Diabetic patients are also at risk of diabetic foot osteomyelitis, another inflammatory condition involving soft tissue and bone. This review aimed to describe the similarities and differences of these entities in an attempt to further advance the management of necrotising otitis externa.

METHOD

A PubMed search was conducted using the key words 'otitis externa', 'necrotising otitis externa', 'malignant otitis externa', 'osteomyelitis' and 'diabetic foot'.Results and conclusionThe similarities regarding patient population and pathophysiology between necrotising otitis externa and diabetic foot osteomyelitis raise basic questions concerning the effects of long-standing diabetes on the external ear. The concordance between local swabs and bone cultures in diabetic foot osteomyelitis is less than 50 per cent. If this holds true also to necrotising otitis externa, the role of deep tissue cultures should be strongly considered. Similar to diabetic foot osteomyelitis, magnetic resonance imaging should be considered in selected necrotising otitis externa subgroups.

[The infections of the ear]

In front of external otitis in spite of a well-conducted treatment, especially in immunodeficient patient, it is always necessary to look for an osteomyelitis of the skull base that requires an urgent parenteral antibiotic treatment of several weeks. Acute otitis media (AOM) is the most common bacterial infection of the child. In children under 2 years with purulent AOM, antibiotic therapy with amoxicilline is systematic for a period of 8-10 days. After 2 years of age and with mild symptoms of AOM, symptomatic treatment may be justified as first-line treatment. Chronic otitis media is frequent after an episode of AOM and becomes chronic only after 3 months of evolution. Grommets reduce the frequency of AOM episodes. All AOM complicated with meningitis requires monitoring by audiogram and MRI of the ear.

Malignant external otitis: Factors predicting patient outcomes

OBJECTIVE

Malignant external otitis (MEO) is an aggressive infection, primarily affecting elderly diabetic patients. It begins in the external ear canal and spreads to adjacent structures. This study investigated the clinical characteristics of patients diagnosed and treated for MEO and analyzed factors affecting patient outcomes.

STUDY DESIGN

Historical cohort.

SETTING

Tertiary medical center.

METHODS

Medical records of all patients diagnosed and treated for MEO from 1990 to 2013, were retrospectively reviewed. Clinical features, laboratory, imaging and outcomes were analyzed.

RESULTS

88 patients were included, mean age was 73±11.5years, 61 (69%) were male. Of these, 75% had diabetes. Mean follow-up was 60months. The most common presenting symptoms were otalgia (89%), external ear canal edema (86%) and otorrhea (84%). Pseudomonas aeruginosa was isolated in 61% of ear cultures. All patients were treated with antibiotics, 22% had surgery and 8% hyperbaric oxygen. Overall survival rate was 38% in 5years, with disease specific mortality 14%. DM, facial nerve palsy, positive CT scan and age above 70 were found to correlate and predict disease-specific mortality.

CONCLUSIONS

MEO carries a grave prognosis. The presence of two or more of the following features, DM, facial nerve palsy, positive CT scan and age above 70, predicts poor outcome, and highlights the need for prolonged, vigorous treatment.