Malignant otitis externa clinical features and management

1. MALIGNANT OTITIS EXTERNA-
CLINICAL FEATURES AND MANAGEMENT
--DR.JINORAJ
ENT POST GRADUATE

2. INTRODUCTION
 Malignant otitis externa is an aggressive and potentially
life-threatening infection of the soft tissues of the external
ear and surrounding structures, quickly spreading to
involve the periosteum and bone of the skull base.
• Synonyms :
 Necrotizing Otitis Externa
 Skull Base osteomyelitis

3. MICROBIOLOGY:
 Bacterial :
Pseudomonas aeruginosa (95%)
Staphylococcus aureus , S.epidermidis
 Fungus
Aspergillus Fumigatus(m/c), A. Flavus, A. Niger
Associated with worse prognosis.

4. PREDISPOSING FACTORS
 Diabetes in elderly
• Defect in immunity
• Microangiopathy and endarteritis
• Change in cerumen Ph
 HIV/AIDS
 Pharmacological immunosuppression
• Chemotherapy
• Steroid use
• States like Leukemia and lymphoma

5. CLINICAL MANIFESTATIONS
 Otalgia (75-100% cases) Severe throbbing and non-remitting pain extending to TMJ, more
at night.
 Purulent fetid otorrhea (45-100% cases)
 Hearing loss
 Fever: rare
 Hallmark finding: granulation tissue
on floor of the ear canal at the bony cartilaginous
junction.

6. CONT..
 Facial Nerve Paralysis (in up to 25% of
patients).

7. CONT..
 As bony destruction and inflammation
progresses medially through the skull base to the
foramina, cranial neuropathies ensue.
 Children with skull base osteomyelitis
usually develop facial nerve palsies earlier.

8. CONT..
 Further spread of disease can affect abducens and trigeminal nerves
around the petrous apex, and also the optic nerve.
 Meningitis, cerebral abscess and sigmoid sinus thrombosis are late
signs.
 Parotitis and trismus due to masseter myositis and
temporomandibular joint involvement is a rare clinical feature.

9. EXAMINATION SHOWS:
 Purulent otorrhoea in tender and edematous EAC.
 Floor of the ear canal may reveal granulation
tissue or exposed bone.
 Patients with HIV infection often lack granulation
tissue.

10. DIAGNOSIS
 The diagnosis is based on the constellation of
clinical, laboratory and radiographic findings.
 Clinical Findings.
 Laboratory Findings
• ESR
• Bacterial and Fungal Culture
• Biopsy

11. RADIOLOGY
 High-resolution Computed Tomography (CT)
- Bone erosion
- Reduced bone density
- Soft tissue abnormalities inferior to the temporal
bone

12. MAGNETIC RESONANCE IMAGING (MRI)
 • Soft tissue differentiation
 • Bone marrow edema.

13. TECHNETIUM-99M-METHYLENE-DIPHOSPHONATE
(99MTC-MDP) SCINTIGRAPHY
 Almost 100% sensitivity.
 Radiotracer accumulates in areas of high osteoblastic activity.
 Has low specificity as it is also positive in
Malignancy.

14. SINGLE PHOTON EMISSION COMPUTED
TOMOGRAPHY (SPECT) PROVIDES
 Good anatomic localization
 May highlight areas of bony involvement
before the CT scan.

15. GALLIUM-67-CITRATE SCANNING
 Utilized to monitor treatment response
 Specific and Sensitive
 Accumulates in Granulocytes and Bacteria
 Active Osteomyelitis Tc-99m (+), Ga-67 (+)
 Non-active Osteomyelitis Tc-99m (+), Ga-67 (-)

16. TREATMENT
 Aural Toileting-It enables control of
granulations and pain.
 Aggressive Glycemic Control.
 Use of Topical Anti-microbial Therapy in these
cases is controversial as it may make culture of the
pathological organism difficult.

17. SYSTEMIC ANTI-MICROBIAL THERAPY:
 Long term systemic culture-directed antimicrobial therapy is the
mainstay of treatment.
 Duration of therapy
-- Depends upon the resolution of symptoms (6-8weeks)
--Depends upon Gallium-67 Scan.
 Fluoroquinolone (Ciprofloxacin) is the initial treatment of choice due
to its antipseudomonal activity and good bone penetration in
osteomyelitis.

18.  Pseudomonas resistant to fluoroquinolones
Cephalosporins like ceftazidime, cefepime can be given.
 Penicillin (i.e. ticarcillin)
 Aminoglycosides
 Amphotericin B is the most common treatment for
fungal MOE.
 Voriconazole and Itraconazole have also been
used on a more limited basis.

19. HYPERBARIC OXYGEN
 Adjunct to systemic antimicrobial therapy increases
the partial pressure of oxygen.
 Relieving hypoxia.
 Enhancing the oxidative killing of microbes.

20. Surgery has a limited role in the management of
MOE.
 To obtain specimens for culture
 To locally debride dead necrotic tissue.
 To exclude malignancy.
 To decompress Facial nerve for complete facial
palsies