|Year : 2019 | Volume
| Issue : 2 | Page : 173-175
Isolated superior oblique palsy as a complication of pansinusitis following root canal treatment – An unusual scenario
Muthukrishnan Vallinayagam1, Tintu Susan Joy1, Shravya Choudhary Balla1, Srikanth Krishnagopal1, P Karthikeyan2
1 Department of Ophthalmology, Mahatma Gandhi Medical College and Research Institute, Sri Balaji Vidyapeeth, Puducherry, India
2 Department of ENT, Mahatma Gandhi Medical College and Research Institute, Sri Balaji Vidyapeeth, Puducherry, India
|Date of Web Publication||10-Sep-2019|
Dr. Muthukrishnan Vallinayagam
Department of Ophthalmology, Mahatma Gandhi Medical College and Research Institute, Sri Balaji Vidyapeeth, Puducherry
Source of Support: None, Conflict of Interest: None
Isolated superior oblique (SO) palsy has been reported in cavernous sinus thrombosis, pituitary microadenoma, tuberculous meningitis, following intraoral local anesthesia, and inferior alveolar nerve block. A 14-year-old boy presented with right SO palsy. There was a history of facial cellulitis, following dental root canal treatment (RCT) 2 weeks back. Magnetic resonance imaging revealed right pansinusitis and breach of the lamina papyracea, with extension of inflammation into the orbit. Complete recovery was noted 1 week after functional endoscopic sinus surgery. The association of SO palsy with sinusitis can be explained by the anatomical proximity of the trochlear nerve to the paranasal sinus or by the extension of infection into the superior orbital fissure. Trochlear nerve is particularly vulnerable due to its location outside the annulus of Zinn. Although multiple ocular nerve palsy following sinusitis is well recognized, isolated SO palsy in pansinusitis following dental RCT has not been reported. An inflammatory etiology carries a favorable prognosis.
Keywords: Isolated superior oblique palsy, pansinusitis, root canal treatment
|How to cite this article:|
Vallinayagam M, Joy TS, Balla SC, Krishnagopal S, Karthikeyan P. Isolated superior oblique palsy as a complication of pansinusitis following root canal treatment – An unusual scenario. TNOA J Ophthalmic Sci Res 2019;57:173-5
|How to cite this URL:|
Vallinayagam M, Joy TS, Balla SC, Krishnagopal S, Karthikeyan P. Isolated superior oblique palsy as a complication of pansinusitis following root canal treatment – An unusual scenario. TNOA J Ophthalmic Sci Res [serial online] 2019 [cited 2020 Jun 1];57:173-5. Available from: http://www.tnoajosr.com/text.asp?2019/57/2/173/266393
| Introduction|| |
Superior oblique (SO) palsy is commonly associated with microvascular ischemia, head injury, brain stem infarction, and tumors. Isolated SO palsy has also been reported in frontal sinus surgery, cavernous sinus thrombosis, pituitary microadenoma, tuberculous meningitis, following intraoral local anesthesia and inferior alveolar nerve block. Although multiple ocular motor nerve palsy following sinusitis is well recognized, isolated SO palsy is a rare occurrence in pansinusitis following dental infection.
| Case Report|| |
A 14-year-old male presented with complaints of diplopia for 1 week. The patient underwent root canal surgery of the right upper second molar 2 weeks back, following which he developed cellulitis of the right half of the face [Figure 1]. It was associated with fever and headache, which subsided after treatment with systemic antibiotics for a week.
Examination showed left-sided head tilt. The Hirschberg's test revealed right hypertropia in the primary position, which worsened on the left gaze and right head tilt [Figure 2]. There was the limitation of levodepression [Figure 3]. Other extraocular movements were normal. Park's three-step test was positive. Diplopia charting showed maximal separation in levodepression. Visual acuity was 6/6. There was no proptosis, congestion, or chemosis. The pupillary reactions were brisk, and corneal sensation was normal. There were no abnormalities of other cranial nerves. Fundus examination was unremarkable. A clinical diagnosis of right SO palsy was made. Magnetic resonance imaging revealed right pansinusitis with polypoidal mucosal thickening and a breach of the lamina papyracea. There was intraorbital extension of inflammatory edema, involving the medial and inferior extraconal fat and abutting the medial and inferior rectus muscles [Figure 4].
|Figure 4: Magnetic resonance imaging showing right pansinusitis with polypoidal mucosal thickening and a breach of the lamina papyracea|
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The patient was referred to the otorhinologist. Functional endoscopic sinus surgery with debridement of inflammatory tissue was done. Systemic steroids and antibiotics were continued for a week postoperatively. There was a complete resolution of diplopia and head tilt after 1 week [Figure 5]. There was the full range of depression on adduction [Figure 6].
|Figure 6: Postoperative follow-up at 1 week showing full range of depression on adduction|
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| Discussion|| |
The trochlear nerve is a somatic motor nerve, with its nucleus in the dorsal mesencephalon. The nerve emerges from the dorsal aspect of the brainstem and enters the subarachnoid space. It passes between the superior cerebellar artery and the posterior cerebral artery and pierces the dura to enter the cavernous sinus. It enters the orbit through the superior orbital fissure, above the annulus of Zinn and innervates the SO.
Palsy of the fourth cranial nerve may result from lesions anywhere along the anatomical course of the nerve. The most common causes are ischemic microvasculopathy, head trauma, infarction, tumors, and aneurysm.
Multiple cranial nerve palsy involving third, fourth, and sixth cranial nerves has been reported in sphenoidal sinusitis and dental procedures. Isolated third and sixth cranial nerve paresis secondary to sinusitis has been well documented., To the best of our knowledge, this is the first report of isolated fourth nerve palsy due to sinusitis, which occurred as a complication of root canal treatment (RCT).
Maxillary sinusitis of dental origin was first described by Bauer in 1943. 10%–12% of maxillary sinusitis is odontogenic. Despite the high prevalence, it is often missed on routine examination and radiography. Depending on the dental pathogenicity, anatomical factors, sinus ostial patency, and extent of mucosal edema, inflammation may progress beyond the antral floor causing obstruction of the maxillary sinus. It may further extend into the ethmoid, frontal, and sphenoidal sinus. The presence of pansinusitis, in this case, could be the result of such an unfortunate conglomeration.
Infection of the paranasal sinus often spreads to adjacent structures by direct extension or through hematogenous spread. The medial wall of the orbit constitutes the lacrimoethmoidal and sphenoethmoidal foramina, which may allow the transmission of infection from the ethmoidal sinuses into the orbit. The walls of sphenoid can be extremely thin, and roof of the sphenoid sinus is related to the posterior nasal cavity, posterior ethmoid cells, and cribriform plate. This explains the spillover of infection from the sphenoidal sinus into the orbit.
The complications of sinusitis include multiple cranial nerve palsies, orbital cellulitis, osteomyelitis, subperiosteal abscess, optic neuritis, papilledema, meningitis, subdural empyema, brain abscess, and cavernous sinus thrombosis.,, The fourth nerve is more laterally placed than the third and sixth cranial nerves and is particularly vulnerable due to its location outside the annulus of Zinn. The association of SO palsy with sinusitis can, therefore, be explained by the anatomical proximity of the trochlear nerve to the paranasal sinuses or by extension of infection into the superior orbital fissure. Furthermore, chronic sinusitis may cause erosion of orbital bone, leading to subacute inflammation in the region of the superior orbital fissure.
In unusual circumstances, cranial nerve palsies have been reported following the injection of local anesthetics for dental procedures. This complication is usually temporary and spontaneously wares off with subsidence of anesthetic effect. The underlying mechanism is due to the proximity of the middle meningeal artery and inferior alveolar artery to the inferior alveolar nerve, which facilitates the entry of anesthetic solution by diffusion. This phenomenon is unlikely to be the attributing cause in this patient due to the delayed onset of diplopia after dental surgery and the lack of tendency to resolve spontaneously.
Isolated trochlear nerve palsy secondary to sinusitis triggered by RCT in this patient could be multifactorial, as discussed above. An inflammatory etiology carries a favorable prognosis, and a vigilant approach coupled by urgent imaging is warranted.
| Conclusion|| |
Although multiple ocular motor nerve palsy following sinusitis and after alveolar nerve blocks are well recognized, isolated SO palsy in pansinusitis following dental RCT is a rare occurrence, which has not been reported in the literature. Although isolated SO palsy following RCT is rare, clinicians should keep in mind that the inflammatory etiology could be the precipitating event. The urgency of neuroimaging as an aid in the early diagnosis cannot be overemphasized. Prompt diagnosis and treatment hasten visual recovery.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]