Beware of covert enemies: Candida orthopsilosis malignant otitis externa with base of the skull osteomyelitis, a case report and review of literature

Abstract

Background: Malignant otitis externa (MOE) is a serious infection of the external auditory canal that is frequently associated with skull base osteomyelitis (SBO) as well as secondary neurological sequelae. Patients with poorly controlled diabetes mellitus or immunosuppression are at increased risk of developing such critical infection for multiple local and systemic factors. While most cases are secondary to bacterial infections particularlyPseudomonas aeruginosa, fungal infections are also occasionally encountered, often associated with delayed diagnosis and high morbidity and mortality.

Case report: We report a case of a 63 years old man with uncontrolled diabetes mellitus who presented with symptoms and signs of MOE, supported by radiological assessments. The patient was treated presumptively with a prolonged course of antibiotics without clinical improvement, coupled with progression of radiological findings and significant disease extension. Reassessment with biopsies and tissue cultures from external auditory meatus, tempo-mandibular bone, as well as base of the skull grew Candida orthopsilosis. The patient received induction treatment with high dose liposomal amphotericin followed by fluconazole to control disease progression and complications.

Conclusion: Candida MOE with secondary skull base osteomyelitis is rare and difficult to diagnose with no clear guidance on assessment and management. Clinicians should be aware of the unusual presentations where microbiological and histopathological evaluations are essential for proper management.

Keywords: Candida orthopsilosis; MOE; Malignant otitis externa; Osteomyelitis.

Fig. 1

Non contrast axial CT initial scan in the emergency room demonstrated no significant intracranial pathology. However the soft tissue windows demonstrated loss of fat planes in the right parapharyngeal space (blue arrow) and masticator space (red arrow). (For interpretation of the references to colour in this Figure legend, the reader is referred to the web version of this article).

Fig. 2

Axial STIR MRI sequence demonstrates hyperintensity (oedema) in multiple neck spaces including masticator space adjacent to the lateral pterygoid muscle (blue arrow). There is mucosal congestion within the nasopharynx (red arrow) with high signal noted posteriorly in the longus capitis muscle (green arrow) suggestive of extension through the retropharyngeal space. Note fluid secretions within the right mastoid air cells (yellow arrow). (For interpretation of the references to colour in this Figure legend, the reader is referred to the web version of this article).

Fig. 3

Axial and coronal post contrast enhanced MRI scan confirming diffuse multicompartmental involvement with enhancement in the masticator and parapharyngeal spaces as described previously (blue arrows). In addition, there is better delineation of medial and posterior extension including pharyngeal mucosal space of the nasopharynx (red arrow), retropharyngeal space (green arrow) and perivertebral space (yellow arrow). Note the enhanacment in the right carotid space surrounding IJV and ICA (pink arrow). Coronal image delineates extension into right TMJ (purple arrow) explaining erosion or upper condylar head margin. Note no evidence of meningeal enhancement (orange) therefore no convincing intracranial extension. The diffuse nature of disease raises the possibility of an infective cause rather than neoplastic. (For interpretation of the references to colour in this Figure legend, the reader is referred to the web version of this article).

Fig. 4

Axial FDG PET-CT demonstrates mild increased avidity in the right deep neck spaces including carotid and masticator spaces (arrow). The “low grade” nature of the tracer uptake suggests infective cause rather than malignant.