Sixth Nerve Palsy Research Articles

RADT-42. DISSEMINATED TUMORAL AMYLOIDOSIS OF THE CRANIAL NERVES IN THE ABSENCE OF SYSTEMIC DISEASE: CASE REPORT

Abstract Tumoral amyloidosis, characterized by tumor-like deposits without systemic disease, is rare in the central nervous system. Most often located in the periventricular white matter, tumoral amyloidosis typically consist of immunoglobulin light chains (AL). While prior reports describe cases of tumoral amyloidosis isolated to the trigeminal nerve, we report herein a first known case of diffuse cranial nerve involvement. The patient is a 43-year-old man who presented with left trigeminal dysesthesias, which led to self-excoriation and erosion of the left naris. On exam, he had absent sensation in the V1-V3 distributions, left trochlear nerve palsy, and bilateral abducens nerve palsies. Imaging demonstrated significant thickening of the left trigeminal nerve and diffuse cisternal contrast enhancement of the other cranial nerves, including the oculomotor, abducens, facial, and glossopharyngeal nerves. Work-up began with a lumbar puncture that found elevated protein with otherwise benign results, including flow cytometry. He was therefore recommended to undergo open biopsy of the left trigeminal nerve and cavernous sinus. Pathology from this surgery demonstrated congo red- positive AL amyloid deposits. Following this pathologic diagnosis, he subsequently underwent a full workup for systemic amyloidosis including bone marrow biopsy, abdominal fat pad biopsy, and a PET CT scan. Biopsy of a long nodule was negative for amyloidosis. Systemic amyloid testing did not demonstrate non-CNS sites of amyloid deposition. Medical therapy with daratumumab, cyclophosphamide, bortezomib, and dexamethasone was started but then discontinued due to ineffectiveness. He underwent radiation treatment of 4500 cGy to the left cavernous sinus where the tumoral amyloidosis was most severe. He has had no further progression of his disease. Tumoral amyloidosis of the cranial nerves remains a rare and poorly-understood disease. Prior reports have described the disease isolated to the trigeminal nerve. This report raises attention to this diagnosis in cases of rare multi-nerve involvement and suggests that radiation may be a useful first-line treatment.

An evaluation of 30 years’ experience in the use of botulinum toxin injections in the management of sixth nerve palsies

ABSTRACT Intrroduction Sixth nerve palsy is the most common type of extraocular muscle palsy. The therapy options in sixth nerve palsies include monitoring with or without conservative treatment, botulinum toxin injections or strabismus surgery. The aim of this retrospective study was to compare botulinum toxin (BT) injections into the medial rectus to conservative treatment in sixth nerve palsies. The rate of patients improved after intervention and treatment outcomes for the two treatment options were be evaluated at a German tertiary referral center. Methods A service evaluation was conducted on adult patients with sixth nerve palsy. Patient files were reviewed and data including abduction deficit and size of deviation were collected retrospectively. Patients which presented between January 1987 and April 2022 were considered. Patients were allocated into two treatment groups: BT injected into medial rectus or conservative treatment, which included observation, providing occlusion and Fresnel prisms. Inclusion criteria were attendance of two visits with orthoptic assessment. Exclusion criteria included presence of further oculomotor palsies, strabismus, strabismus surgery and suppression. Non-parametric statistical analysis was conducted using IBM® SPSS Statistics. Results A total of 606 adult patients with unilateral or bilateral sixth nerve palsy attended during the named period. A total of 137 adult patients met the inclusion criteria. Of which, 36 had a bilateral palsy, 101 had a unilateral palsy. 45.26% (n = 62) were treated with BT injections and 54.75% (n = 75) were treated conservatively. The median initial abduction deficit was greater in the BT group, (−4 to −5 after Scott and Kraft) than in the conservative treatment group (−1). The initial angle of deviation at distance was significantly larger in the BT group than in the conservative treatment group (p = <0.001). The rate of improvement in the BT group was 24.19% (n = 15) and 20% (n = 15) in the conservative treatment group. When excluding longstanding palsies rates of improvement in both groups increased to 28.85%. The improvement of the angle of deviation at distance in all patients was greater in the BT group (p = <.001). The improvement of abduction in bilateral palsies were greater in the BT group (p = .016), but in unilateral palsies, there was no significant difference in abduction improvement in the two treatment groups (OD p = .3, OS p = .406). Conclusion This service evaluation found that BT injection into medial rectus in unilateral and bilateral sixth nerve palsies did not increase the rate of improvement compared to conservative treatment. But BT injections reduced the angle of deviation to a greater extent than conservative treatment. Additionally, BT was able to improve abduction in bilateral palsies to a greater extent than conservative treatment. It is recommended a BT injection is considered in symptomatic bilateral sixth nerve palsies to enable fixation and improved ocular motility. More research is needed to verify reliable clinical guidelines for the use of BT in sixth nerve palsies.

Isolated Sixth Cranial Nerve Palsy in Patients with Pituitary Apoplexy.

Pituitary apoplexy is an acute clinical syndrome constituted by headache, visual impairment, ophthalmoplegia, and altered mental status. Abducens nerve palsy due to pituitary apoplexy is a significant clinical manifestation in pituitary apoplexy cases.This study aims to investigate the rare occurrence of isolated sixth cranial nerve palsy in patients with pituitary apoplexy, a condition characterized by sudden hemorrhagic or ischemic infarction of the pituitary gland. A search was conducted on major databases, including PubMed, Web of Science, and ScienceDirect, to identify cases of isolated sixth cranial nerve palsy in patients with pituitary apoplexy. Only six cases were found in the available literature. Descriptive statistics were used to summarize the data, and relevant clinical features were compared between the cases. Among the six identified cases, isolated sixth cranial nerve palsy in patients with pituitary apoplexy predominantly affected middle-aged adults, with a prominent male preponderance. Clinical manifestations included acute-onset diplopia and headache, with the most common radiologic finding being pituitary gland enlargement or hemorrhage. Laboratory investigations revealed hormonal dysregulation in some cases. Treatment approaches varied and included conservative management and surgical intervention. Outcomes were generally favorable, with most patients experiencing partial or complete resolution of their cranial nerve palsy. Isolated sixth cranial nerve palsy in patients in the context of pituitary apoplexy is an exceptionally rare occurrence, with only six documented cases in the available literature. Further research and case reporting are essential to better understand this rare clinical entity and guide optimal management strategies.

Accuracy of the Image Interpretation Capability of ChatGPT-4 Vision in Analysis of Hess Screen and Visual Field Abnormalities.

OpenAI, the owner of ChatGPT, publicly released the GPT-4 Vision in September 2023. This multimedia chatbot has the capability to receive and analyze various images presented to it by the user. We assessed the accuracy of its interpretation of 2 of the images commonly used in neuro-ophthalmology, namely Hess screen and automated visual field images. We separately uploaded typical images of 5 abnormal Hess screen charts related to third, fourth, and sixth cranial nerve palsy, Brown syndrome, and inferior orbital wall fracture with entrapment of the inferior rectus muscle. Likewise, 5 classic images of automated visual field grayscale maps related to lesions of the optic nerve, the chiasma, the optic tract, the optic radiations, and the occipital lobe were presented. The chatbot was instructed to select the best option among the 5 choices presented in each question. The GPT-4 Vision was able to select the right choice in 2/5 questions on Hess screens and 3/5 of the visual field questions. Despite selection of the correct option, qualitative evaluation of GPT-4 responses revealed flawed analysis of certain aspects of some image findings, such as the side of involvement or the misinterpretation of the physiologic blind spot as a central scotoma. The performance of GPT-4 Vision in the interpretation of abnormalities of Hess screen and visual field involvement was highly variable, even with simple typical cases of classic disorders. As the chatbot's image recognition is currently evolving, its capacity to accurately interpret ophthalmologic images is still limited at this time.

Neuro-leishmaniasis with cauda equina syndrome and cranial nerve palsy: a rare manifestation of recurrent atypical visceral leishmaniasis

BackgroundVisceral leishmaniasis (VL) is a neglected tropical disease primarily affecting Brazil, East Africa, and India, with India accounting for 18% of the global burden. While VL typically presents with systemic symptoms like fever, weight loss, and splenomegaly, it can occasionally manifest atypically, posing significant diagnostic challenges. Neurological presentations of VL are extremely rare, making them difficult to suspect and diagnose. Cases where VL predominantly presents with neurological symptoms are particularly novel, underscoring the need for heightened awareness of such atypical manifestations in endemic regions.Clinical caseA 38-year-old man with history of recurrent atypical VL presented with diffuse lower back pain, progressive tingling, numbness, weakness in the lower extremities, and double vision for one month. Clinical and radiological evaluations suggested cauda equina syndrome and cranial nerve palsy, accompanied by generalized lymphadenopathy, subcutaneous nodules, and skin papules. The differential diagnosis initially included disseminated tuberculosis, histoplasmosis, and lymphoma. Cerebrospinal fluid (CSF) analysis revealed an inflammatory syndrome. Histopathology of lymph node and bone marrow revealed Leishmania amastigotes and subcutaneous nodule and skin biopsy revealed inflammatory cells with granulomas. Furthermore, the qPCR test on DNA from a subcutaneous nodule, lymph node, and CSF was positive for Leishmania kinetoplast DNA. The species was further confirmed as Leishmania donovani through ITS-based PCR amplification and sequencing. Finally, a diagnosis of relapse of VL with lymph node, cutaneous, and neurological involvement, including abducens nerve palsy and cauda equina syndrome, was established. He was treated with combination of liposomal amphotericin B and miltefosine, along with intrathecal hyaluronidase, resulting in significant improvement.ConclusionUnlike previously reported cases with both systemic and neurological symptoms, our patient predominantly presented with neurological manifestations, making this a unique and novel presentation of VL. This case highlights diagnostic challenges and management of atypical VL, emphasizing neurological involvement and successful therapeutic strategies.

Navigating the Mysteries of CLIPPERS Syndrome: A Case Report of Long-Term Follow-Up.

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) syndrome is a rare central nervous system inflammatory disorder with an unknown pathophysiology. We present the case of a 51-year-old female exhibiting clinical and radiological features consistent with CLIPPERS syndrome. She manifested diplopia, vertigo, gait ataxia, and lower limb asthenia, accompanied by impaired tandem gait, right sixth nerve palsy, and coarse horizontal nystagmus during the physical examination. Magnetic resonance imaging (MRI) revealed punctate and curvilinear lesions centered in the pons. Treatment with glucocorticoids resulted in significant clinical improvement, and the patient was discharged with a maintenance dose of prednisolone. Throughout a four-year follow-up period, the patient remained symptom-free without any relapses using the low-dose corticosteroid. The CLIPPERS syndrome diagnosis remains challenging, but recent evidence supports an autoimmune pathogenesis. Although corticosteroid treatment has shown significant clinical improvement, there are no established guidelines or clinical trials on the optimal therapeutic regimen. Despite its rarity, clinicians should consider CLIPPERS syndrome in patients with compatible clinical and radiological features to prevent irreversible neurological damage.

Isolated fungal sphenoid sinusitis with unilateral lateral rectus palsy six years post lung transplant

Rhino-orbital-cerebral mucormycosis (ROCM) infections are rare and usually occur in patients with diabetes, malignancy, or organ transplantation. The most common presenting symptoms include facial pain and swelling, fever, and rhinorrhea. Mortality rates reach nearly 50%. Those with previous organ transplants typically present with sinus symptoms a few weeks to months after transplantation. A 75-year-old man presented with headache. His history was significant for bilateral lung transplantation in 2017. On his fourth presentation, he was admitted to the hospital for work up. Imaging showed small fluid levels within the right maxillary and sphenoid sinuses. Infectious work-up revealed no meningitis. On day three, the patient complained of diplopia on the right. His examination was significant for right lateral rectus palsy. Repeat imaging was performed and showed increasing fluid levels of the right maxillary and sphenoid sinuses, and the otolaryngology consultation service was consulted. Nasal endoscopy was significant for pink, vascularised mucosa with no obvious regions of pallor or necrosis. Endoscopic sinus surgery was performed. There were no findings suggestive of fungus but purulence of the right sphenoid grew Rhizopus. The patient’s nerve palsy did not resolve and progressed to the contralateral orbit. Repeat nasal endoscopy continued to show healthy mucosa while MRI showed enhancement worrisome for meningitis. To our knowledge, this is the only reported case of fungal sphenoid sinusitis resulting in meningitis and death six years after transplant. Current literature documents fungal infection in post-transplant patients up to four years after surgery, with most occurring within the first year. Suspicion for fungal infection should remain high in this patient population. Keywords: mucormycosis, lung transplant, sinusitis, lateral rectus palsy

Embolization of posterior fossa meningiomas supplied with meningohypophyseal trunk by using n-BCA and dual balloon protection.

Efficacy of tumor embolization for posterior fossa meningioma is controversial due to the lack of adequate embolization for dangerous feeders. Of these, a meningohypophyseal trunk (MHT) has high therapeutic value despite the high risks associated with embolization. To analyze the utility of preoperative MHT embolization for posterior fossa meningiomas using n-BCA with dual balloon protection, a single center retrospective record review was performed on eight consecutive patients who underwent preoperative tumor embolization via the MHT for posterior fossa meningiomas between 2020 and 2024. All patients successfully embolized the MHT using n-BCA. Complete obliteration was achieved in five cases, which is related to the tentorial artery alone as the feeding vessel. None of the patients had cerebral infarction associated with distal embolization. One patient experienced worsening of preoperatively observed abducens nerve palsy due to cranial nerve ischemia. Gross total resection was achieved in seven of eight cases. The mean estimated blood loss during surgical resection was 186 mL (range, 39-392 mL). The mean operative time was 431 min (range, 317-767 min). The MHT embolization of posterior fossa meningiomas by using n-BCA is technically feasible with a high success rate and an acceptable complication rate. MHT=meningohypophyseal trunk; ILT=inferolateral trunk; CPA=Cerebellopontine angle; BGC=balloon guide catheter; PVA=polyvinyl alcohol; GTR=Gross Total Resection; CN=Cranial nerve.

Sphenoclival fibrous dysplasia with cyst formation causing abducens nerve palsy in an older patient: illustrative case.

Fibrous dysplasia (FD) is typically asymptomatic but is known to occasionally cause neurological symptoms such as visual disturbances. However, FD-associated abducens nerve palsy is extremely rare. A 76-year-old woman had a left abducens nerve palsy due to mass effect on the abducens nerve at Dorello's canal caused by FD and its associated cyst, which was resolved by resection of the cyst through an endoscopic transnasal route. Although FD is generally an asymptomatic lesion occurring in younger patients, it can occasionally cause abducens nerve palsy even in older patients. In particular, cystic degeneration within FD tends to trigger a mass effect and thus can require surgical decompression. https://thejns.org/doi/10.3171/CASE24424.

Delayed Pontomesencephalic and Cervical Cord Venous Drainage Followed by Contralateral Carotid-Cavernous Fistula after Craniofacial Fractures: A Case Report.

A 24-year-old male was admitted with progressive cervical hypesthesia, tetraparesis, dyspnea, and a history of craniofacial fracture. Spinal magnetic resonance imaging (MRI) showed brainstem edema extending to the thoracic spine with multiple prominent perimedullary vascular structures. Cerebral digital-substraction angiography revealed Barrow type A carotid-cavernous fistula. Total occlusion with preservation of internal carotid artery flow was achieved using 1 detachable balloon and 6 coils. Postoperatively, immediate respiratory recovery, gradual extremities strength improvement, and right abducens nerve palsy were found. One month follow-up cervical MRI showed good recovery of spinal cord edema and perimedullary veins.

Seronegative brucella meningitis diagnosed by CSF PCR: report on seven cases

IntroductionNeurobrucellosis (NB) can be associated with meningitis and present as a headache with or without meningeal signs. Pseudotumor presentation of NB has been reported to be accompanied by lymphocytic predominant cerebrospinal fluid(CSF) pleocytosis. NB is diagnosed by means of isolation of Brucella from blood or CSF and/or the presence of anti-Brucella antibodies in the CSF. Molecular techniques have been used in chronic or challenging cases of NB.Clinical findingsWe report on seven cases of NB presenting with different types of headache and signs of meningeal involvement. In five cases, signs of intracranial hypertension were evident in the form of papilledema, sixth nerve palsy and blurred vision.DiagnosisMRIs of the brain revealed signs of intracranial hypertension in three patients, basal meningeal enhancement in one patient and white matter lesions in one patient. Brucella serology in the blood and CSF was negative in all patients. It was interesting that four patients had normocellular CSF analysis with normal glucose and protein results. The diagnosis was made by Brucella PCR in all patients.ConclusionNB should be considered in the differential diagnoses of pseudotumor cerebri syndrome in endemic areas. It is important to employ molecular techniques using sterile CSF samples in the investigation of Brucella.

Cranial neuropathy following coronavirus disease 2019 vaccination in kidney transplant recipients.

Understanding of adverse reactions to coronavirus disease 2019 vaccines remains limited. Case 1: A 52-year-old woman, post-kidney transplantation, experienced sudden vision loss in her left eye after receiving a second dose of coronavirus disease 2019 vaccine. She was diagnosed with ischemic optic neuropathy.Case 2: A 53-year-old woman, post-kidney transplantation, presented with worsening diplopia and left eye pain following the second dose of coronavirus disease 2019 vaccine. She was diagnosed with left abducens nerve palsy. Vigilance is essential for recognizing the potential for delayed cranial neuropathy in immunocompromised individuals after coronavirus disease 2019 vaccination.

Endoscopic transorbital approach for recurrent spheno-orbital meningiomas: single center case series

Endoscopic transorbital approaches (ETOAs) are finding wide application for skull base lesions, particularly for spheno-orbital meningiomas (SOMs). These tumors have high recurrence rates, and second surgery can often represent a challenge. In this study we analyze our experience of management of recurrent SOMs through a slightly modified eyelid crease approach. Between May 2016 and September 2023, in the Department of Neurosurgery of Fondazione IRCCS Policlinico San Matteo (Pavia, Italy), five consecutive recurrent SOMs have been treated using an endoscopic transorbital approach. Demographic data, preoperatory deficits, lesions characteristics, histology, grade of resection, eventual adjuvant treatments, complications, outcome in terms of symptoms improvement and cosmesis, and hospitalization are described. One patient maintained a right lateral rectus muscle palsy that was already present in the preoperatory, no cerebrospinal fluid (CSF) leaks were reported. All patients had postoperative periorbital edema, but no other systemic complication was found. All patients had proptosis improvement, two had visual acuity improvement, and best cosmetic outcome was obtained in all cases. Hospitalization varied between 4 and 6 days. ETOAs in the management of recurrent SOMs are safe and have good outcome. Right selection of patients is mandatory, but when feasible, endoscopic surgery can allow a virgin route to a previously operated tumor, guaranteeing a good strategic option.

Differential Diagnoses for Isolated Right Sixth Nerve Palsy in the High Altitude Setting: A Case Report.

This case report describes the presentation and management of a patient with an isolated right sixth nerve palsy while trekking in Nepal. Consideration is made of the anatomy of the sixth nerve and the differential diagnoses afforded to this isolated sign, including high altitude cerebral edema. The case stresses the need to exclude life-threatening pathologies for any symptoms associated with altitude and includes decision-making processes on whether to monitor the patient in the field or evacuate them to a definitive care facility.

Etiological and Prognostic Factors of Acquired Sixth Cranial Nerve Palsy

Etiological and Prognostic Factors of Acquired Sixth Cranial Nerve Palsy

Outcomes and Factors Associated with Successful Strabismus Surgery for Abducens Nerve Palsies: A Retrospective Study and Literature Review [Letter]

Outcomes and Factors Associated with Successful Strabismus Surgery for Abducens Nerve Palsies: A Retrospective Study and Literature Review [Letter]

Carotid-cavernous fistula due to contralateral orbital trauma

Abstract: Direct carotid cavernous fistula is an abnormal arterio-venous connection from the carotid artery to the cavernous sinus (CS), resulting in high-pressure arterial blood entering the low-pressure venous CS. Most often, it occurs posttrauma and presents with ipsilateral orbital signs. In this report, we describe the case of a 54-year-old man, who presented with a late-onset right-sided red eye and diplopia following contralateral (left sided) orbital trauma (road traffic accident 7 months ago). Ocular examination revealed signs of Lateral rectus palsy, axial proptosis, and elevated intraocular pressure with dilated episcleral vessels in the right eye. Clinical findings were consistent with the diagnosis of right-sided direct CCF. To our surprise, digital subtraction angiogram revealed a left CCF with prominence of signs on the contralateral side. He underwent near-total endovascular coiling of the fistula, with initial aggravation of symptoms followed by near-total resolution.

Sixth cranial nerve palsy in giant cell arteritis: A systematic review.

This study aimed to review and describe isolated sixth cranial nerve or abducens nerve palsy that may present with subtle ophthalmoplegia in patients with giant cell arteritis (GCA). In this systematic review following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) Extension for Scoping Reviews, MEDLINE and EMBASE were searched for all peer-reviewed articles using the keywords "cranial nerve six," "abducens nerve," and "giant cell arteritis" from their inception to December 22, 2022. Twenty-five articles, including seven observational studies and 18 cases, were included. While the incidence and prevalence of sixth nerve palsy in GCA were variable, up to 48% of diplopia in GCA were attributed to the sixth cranial nerve palsy, according to the observational studies included. While 88.2% had a resolution of symptoms with 40-50 mg/day of prednisone-equivalent corticosteroids, it took a median of 24.5 days until the resolution of symptoms from the initiation of treatment. This review summarizes the current understanding of the characteristics of sixth nerve palsy in GCA. While most patients may have reversible clinical courses, a few can suffer from persistent ophthalmoplegia, which is a potentially missed yet crucial clinical finding in GCA. Increased awareness of the sixth nerve palsy in GCA is crucial.

CHALLENGE IN TREATING OPTIC NEURITIS IN PATIENT WITH CEREBRAL TOXOPLASMOSIS RELATED TO IMMUNOCOMPROMISED CONDITION

Introduction: This study aimed to discuss the prognosis of optic neuritis in a patient with cerebral toxoplasmosis related to an immunocompromised condition. Case Report: A 28-year-old female complained of blurred vision and double vision 2 weeks before admission, accompanied by headache, low extremities weakness, dysphonia, and dysphagia. Visual acuity of both eyes was 6/30 and worsened to 6/60 in a couple of days. Anterior segment examination revealed anisocoria pupil, and RAPD was positive in the left eye. Funduscopic examination showed a blurry margin and hyperemia of the optic nerve head. There was impaired eye movement, indicating oculomotor and abducens nerve palsies. High titer of IgG Antibody Toxoplasma (264) and very low titer of CD4 (&lt;50) with non-reactive HIV rapid test were found in laboratory findings. Multiple ring enhancement was shown in MRI finding. Unfortunately, patient passed away during hospitalization due to respiratory failure. Discussion: Toxoplasmosis-associated optic neuritis is rare and usually becomes potentially serious. Although parasite detection by microscopy and bioassay is considered the gold standard for the diagnosis of toxoplasmosis, clinical diagnosis relies more on serological examination methods. The high proportion of deaths from this disease is mostly caused by late diagnosis of the infection. Conclusion: Optic neuritis that accompanied by systemic disorders needs special attention and comprehensive treatment among multidisciplinary divisions, especially in the immunocompromised condition. Early detection and primary prevention are important to improve prognosis and survival rate.

Case Report: Tolosa-Hunt syndrome, a neuroinflammatory origin of painful ophthalmoplegia

Background Tolosa-Hunt syndrome is a rare neuroinflammatory disease that affects the cavernous sinus and superior orbital fissure, resulting in symptoms of neuropathy. Case presentation We report a case of a 35-year-old male patient with no past medical history who presented to the emergency department (ED) complaining of a four-day history of progressively increasing headaches associated with right eye pain and double vision. A physical examination showed findings suggestive of abducens nerve palsy. A computed tomography (CT) scan showed subtle asymmetric thickening of the right cavernous sinus, which prompted further investigation by magnetic resonance imaging (MRI) scan. The MRI scan showed intensely enhanced soft tissue thickening in the right cavernous sinus region, slightly extending to the right orbital apex, which caused enlargement of the cavernous sinus and appeared isointense to the adjacent muscles on T1 and T2. The diagnosis of Tolosa-Hunt syndrome was made after the exclusion of all other possible pathologies. The patient received prednisolone therapy; his symptoms improved, and he was discharged after three days. Two weeks later, the patient presented again to the ED with the same symptoms and was treated symptomatically. Conclusions This case highlights a very rare etiology for painful ophthalmoplegia, which is Tolosa-Hunt syndrome. Thickening of the cavernous sinus on MRI images with a background history of painful ophthalmoplegia and headache should raise clinician’s suspicion towards the disease. In addition, exclusion of other possible causes is very important, as Tolosa-Hunt syndrome is a diagnosis of exclusion.