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Journal of Postgraduate Medicine, Vol. 48, Issue 4, 2002 pp. 314-316 Gradenigo's Syndrome: Findings on Computed Tomography and Magnetic Resonance Imaging Mathew L, Singh S, Rejee R*, Varghese AM* Departments of Radiodiagnosis and Imaging and Otorhinolaryngology,* Christian
Medical College and Hospital, Vellore - 632 004, India. Code Number: jp02105 A 25-year old man presented with history of right-sided otorrhoea for 3 weeks. It was accompanied with headache, vomiting and diplopia. On examination, this afebrile patient was noted to have ipsilateral sixth nerve palsy and a pinpoint perforation in the tympanic membrane of the right ear. The right mastoid was tender. However, there was no evidence of papilloedema or neck stiffness. The leucocyte count was 11000/ mm3 [polymorphs 73%, lymphocytes 19% and monocytes 6%] while the ESR was 87 mm at the end of 1 hour. The computed tomography showed obliteration of the right mastoid air cells with sclerosis of the mastoid antrum and petrous bone (Figure 1A). The external and middle ear structures also showed obliteration of normal definition. The external auditory canal was widened and a small soft tissue density area was seen around it. There was destruction of the ipsilateral petrous apex. Mildly enhancing soft tissue mass was seen indenting the adjacent pons (Figure 1B). The mastoid antrum, the middle and inner ear structures and the brain parenchyma on the contralateral side were normal. On magnetic resonance imaging, the T2 and proton density-weighted and Fluid Attenuated Inversion Recovery (FLAIR) images showed hyperintense petrous and mastoid parts of the right temporal bones with a small ill-defined high signal intensity lesion surrounding them (Figure 2). The middle ear structures and the external auditory canal were also hyperintense. The pre-contrast T1-weighted images demonstrated small isointense component in the petrous apex (Figure 3A). On post contrast imaging, the MRI showed marked heterogeneous enhancement of the involved petrous apex and surrounding meninges (Figure 3B). The clinical, laboratory and radiological findings helped to establish the diagnosis of Gradenigo's syndrome. The patient was treated with intravenous antibiotics [crystalline penicillin, chloramphenicol, and metronidazole]. Cortical mastoidectomy was done with exteriorisation of the cell tracts above the superior semicircular canal going towards petrous apex. No organisms were grown in the exudates from the middle ear and histopathological examination of the mastoid antrum revealed non-specific inflammatory tissue. At follow-up one month later, the patient showed clinical improvement in the form of absence of otorrhoea, healing of the tympanic membrane and improvement in the lateral rectus palsy. Case 2 A 12-year-old boy presented with history of otorrhoea from the left ear, headache and diplopia for one month. On examination, central perforation was noted in the tympanic membrane of the left ear. Ipsilateral sixth nerve palsy was present, too. The total leucocyte count was 13,000/mm3 with 70% neutrophils, 1% band forms, 15% lymphocytes, 5% eosinophils, and 5% monocytes. The erythrocyte sedimentation rate was 45mm at the end of first hour. The computed tomography showed sclerosis of the left mastoid antrum and petrous bone, loss of aeration of the mastoid air cells and destruction of the petrous apex with an enhancing mass around the petrous apex and the left parasellar region. On magnetic resonance imaging, T2, proton density-weighted and FLAIR images, the petrous and mastoid parts of the left temporal bone and the left middle ear structures appeared heterogeneously hyperintense (Figure 4a, 4b). Moderately enhancing soft tissue structures were seen to surround the petrous apex and parasellar region. He was treated with intravenous antibiotics [crystalline penicillin, chloramphenicol, and metronidazole]. The patient obtained dramatic relief from symptoms after mastoidectomy and drainage of pus from the petrous apex. He was treated with anti-tuberculous drug regime as an empirical treatment.
Discussion Gradenigo's syndrome, characterised by persistent otorrhoea, pain in the region innervated by the first and second divisions of the trigeminal nerve and ipsilateral abducens nerve palsy, is one of the complications of middle ear infection. CT and MRI scans provide evidence of this complication. However, there are only a few reports1-6 in the literature describing these findings. Gradenigo's syndrome consist of abducens nerve paralysis, retroorbital pain and middle ear infection. Although classically attributed to petrositis, the syndrome has also been described in association with extradural abscess, pachymeningitis overlying the petrous apex6 and lateral sinus phlebitis.6 It is thought that the manifestations of the syndrome result from the extension of the inflammatory process, that begins in the middle ear, to the top of the petrous part of the temporal bone.6 The raised intracranial pressure itself is, probably due to, a combination of lateral sinus thrombosis and superior sagittal sinus obstruction. The former impedes the cranial venous outflow while the latter impedes the CSF absorption by pacchionian bodies.6 The CT scans demonstrate fluid-filled mastoid air cells and sclerosis of the bones and one can assess the degree of periosteal reaction and status of the middle ear structures based on CT scan findings.2 The MRI scans are best for assessing the soft tissue lesions. These lesions appear hypointense on T1-weighted images and hyperintense on T2 weighted images and enhance following contrast.2 Management consists of administration of appropriate anti-microbial agents and surgical intervention. However, improvement without the administration of anti-microbial agents has also been described. McHugh et al reported a case of Gradenigo syndrome, where CT scan showed a small mass in the left IAC and MRI showed evidence of petrositis. These lesions showed marked improvement without treatment.6 The report also underlined the utility of gadolinium enhanced MRI in identifying soft tissue inflammation and intra-osseus disease in the absence of bone destruction.5 Complications like brain abscess have been described.5 Homer et al,6 reported three cases with middle ear infection and sixth nerve palsy without petrositis and raised intracranial pressure. Erosion of the malleus and incus, a loculus of gas in the sinodural angle, opacification of the left mastoid antrum and clouding of the mastoid antrum were the lesions demonstrated in these patients on the CT scan. As otitic hydrocephalus, another complication of the middle ear infection is also associated with abducens nerve palsy, neuroimaging should be employed to differentiate between these two conditions.
References
This article is also available in full-text from http://www.jpgmonline.com/ © Copyright 2002 - Journal of Postgraduate Medicine The following images related to this document are available:Photo images[jp02105f3b.jpg] [jp02105f1b.jpg] [jp02105f1a.jpg] [jp02105f2.jpg] [jp02105f4b.jpg] [jp02105f4a.jpg] [jp02105f3a.jpg] |
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