A Comprehensive Review of Skull Base Osteomyelitis: Diagnostic and Therapeutic Challenges among Various Presentations

Abstract

Skull base osteomyelitis (SBO) is a complex and fatal clinical entity that is often misdiagnosed for malignancy. SBO is commonly a direct complication of otogenic, sinogenic, odontogenic, and rhinogenic infections and can present as central, atypical, or pediatric clival SBO. This review describes the clinical profile, investigational approach, and management techniques for these variants. A comprehensive literature review was performed in PubMed, MEDLINE, Research Gate, EMBASE, Wiley Online Library, and various Neurosurgical and Neurology journals with the keywords including: SBO, central or atypical SBO, fungal osteomyelitis, malignant otitis externa, temporal bone osteomyelitis, and clival osteomyelitis. Each manuscript's reference list was reviewed for potentially relevant articles. The search yielded a total of 153 articles. It was found that with early and aggressive culture guided long-term intravenous broad-spectrum antibiotic therapy decreases post-infection complications. In cases of widespread soft tissue involvement, an early aggressive surgical removal of infectious sequestra with preferentially Hyperbaric Oxygen (HBO) therapy is associated with better prognosis of disease, less neurologic sequelae and mortality rate. Complete resolution of the SBO cases may take several months. Since early treatment can improve mortality rates, it is paramount that the reporting radiologists and treating clinicians are aware of the cardinal diagnostic signs to improve clinical outcomes of the disease. It will decrease delayed diagnosis and under treatment of the condition. However, due to rarity of the condition, complete prognostic factors have not fully been analyzed and discussed in the literature.

Keywords: Central skull base osteomyelitis; clival osteomyelitis; fungal osteomyelitis; malignant ostitis externa; pediatric osteomyelitis; skull base osteomyelitis; temproal bone osteomyelitis.

Figure 1

Skull base osteomyelitis and its variants

Figure 2

Axial computed tomography images following intravenous contrast administration (a) Soft-tissue window settings demonstrate the fullness of the posterior nasal space and posterior nasopharynx with abnormal soft tissue along the course of the Eustachian tube (red arrow). (b) Bone window settings demonstrate opacification of mastoid air cells on the left with erosive bone loss involving the inferior petrous bone. Loss of clarity of the cortical outline of the basisphenoid (green arrows) and the proximity to the carotid vessel can be noted

Figure 3

(a) Contrast-enhanced computed tomography of the skull base shows erosion of the anterior cortex of the left occipital condyle (yellow arrows), anterior displacement of the left internal carotid artery (orange arrow). A normal right internal jugular vein is visible (purple arrow), whereas the left internal jugular vein is completely occluded. (b) Magnetic resonance imaging of the skull base shows pathological contrast enhancement in the clivus extending into the soft tissues surrounding the left internal carotid artery (blue arrow) and jugular foramen (green arrow). There is thickening and enhancement of the clival dura (red arrows)

Figure 4

A contrast-enhanced computed tomography scan (a) axial and (b) sagittal views in a child with pediatric clival osteomyelitis demonstrates destruction within the anterior aspect of the clivus bone (red and green arrows in a and b) posterior to the spheno-occipital synchondrosis (orange arrow) associated with anterior soft-tissue prominence extending close to the cephalic most portion of the adenoids along with some prevertebral soft-tissue thickening (blue arrows)