Introduction:

Given the characteristic imaging findings and markedly elevated inflammatory markers, a diagnosis of skull base osteomyelitis was established.. The patient’s neurological manifestations were therefore attributed to right-sided skull base osteomyelitis secondary to zona, resulting in Collet-Sicard syndrome.

The patient was initially treated with intravenous IV acyclovir and switched to oral 14 days later to complete the course. Because of her severe dysphagia and aspiration risk, a percutaneous gastrostomy tube was placed

At follow-up 2 months after, the patient demonstrated complete resolution of her neurological symptoms and auricle lesions. her swallowing function had also significantly improved, allowing her to resume oral intake. The gastrostomy tube was therefore subsequently removed.

Discussion:

This case represents an unusual disease course, particularly given that only a few similar cases have been reported to date. The patient's symptoms developed following an outbreak of herpes zoster oticus affecting the pinna and external auditory canal, with vesicular lesions preceding the onset of otologic symptoms. The resulting viral-induced tissue damage and local immunosuppression likely created a favorable environment for secondary bacterial superinfection, leading to the development of otitis externa, with Pseudomonas aeruginosa identified as the causative pathogen. The infection subsequently progressed locally to involve the right lateral skull base, resulting in skull base osteomyelitis. The patient’s poorly controlled diabetes mellitus likely contributed to the persistence and progression of the infection.

The infectious process also extended to the right internal auditory canal and cerebellopontine angle, which may explain the patient’s right-sided facial weakness through involvement of cranial nerve VII. Although internal carotid artery stenosis has been reported in other cases of infectious Collet-Sicard syndrome [3], this was unlikely to be responsible for the neurological manifestations in our patient. The patient developed palsies involving cranial nerves IX, X, XI, and XII, consistent with Collet-Sicard syndrome resulting from skull base osteomyelitis extending to the jugular foramen and hypoglossal canal.

An additional distinctive feature of this case is that the skull base infection developed secondary to zona, which typically originates in the auricle [4]. In contrast, previously reported cases of infectious Collet-Sicard syndrome have more commonly been attributed to otitis media. Sibai et al. described a patient who developed a cranial base infection with mass effect following incompletely treated otitis media [4]. Similarly, Blazina et al. reported a case of Collet-Sicard syndrome secondary to chronic otitis media caused by Pseudomonas aeruginosa [5].

Other infectious etiologies were also considered in our patient. Testing for herpes simplex virus (HSV), human immunodeficiency virus (HIV), Borrelia burgdorferi, and varicella-zoster virus was performed, given that these infections have previously been associated with cranial nerve palsies. Kahane et al. described a patient with jugular foramen syndrome associated with a palatolaryngeal herpetic eruption, aseptic meningitis, and elevated serum antibodies against varicella-zoster virus [7]. Kondo et al. reported a case of herpes zoster presenting as meningoencephalitis with involvement of cranial nerves IX to XI [8]. Miyazaki et al. described a patient with hoarseness and dysphagia resulting from pharyngeal and vocal cord palsies associated with Ramsay Hunt syndrome [9]. In another case, a young patient with Lyme disease developed lower cranial nerve palsies [10].

Conclusion:

As illustrated by this case, Ramsey hunt syndrome may progress to skull base osteomyelitis with subsequent involvement of multiple cranial nerves. Recognizing this infectious etiology is crucial, as the neurological manifestations may mimic cerebrovascular disease or other more common neurological conditions, potentially resulting in delayed diagnosis and initiation of appropriate treatment. Clinicians should therefore consider Collet-Sicard syndrome and other cranial neuropathies as potential complications of herpes zoster oticus and skull base osteomyelitis, particularly in elderly patients with poorly controlled diabetes mellitus.