Impact of Diplopia and Ptosis From Lingering Third Nerve Palsy After Treatment of Cerebral Aneurysms

BACKGROUND

Third nerve palsies (TNPs) may not resolve after intervention for intracranial aneurysms that have compressed the nerve. The disability related to this lingering condition has not been assessed with the support of patient self-report.

METHODS

A single-institutional retrospective study of patients with TNP who had undergone interventions for intracranial aneurysms. We used residual primary-position diplopia, a narrow zone of single binocular vision, and vision-obscuring ptosis to divide TNP recovery into complete, incomplete nondisabling, and incomplete disabling outcomes based on medical record documentation and patient self-report derived from telephonic interviews.

RESULTS

In a cohort of 33 patients, 13 (39%) had complete TNP recovery. There were 11 patients (33%) with lingering visual disability from diplopia or ptosis present before ophthalmic interventions. Of the 6 patients who underwent ophthalmic interventions, visual disability was relieved in only 2 patients, leaving 9 patients (27%) with lingering impairment in instrumental activities of daily living. Telephonic interviews of 23 patients (70% of the cohort) confirmed that the outcome criteria we applied were accurate in assessing visual disability in 17 patients (74%). Univariate analysis using the Fisher exact test showed that aneurysmal clipping as a treatment modality was the only clinical feature associated with a favorable TNP outcome.

CONCLUSIONS

In applying a novel method of assessing disability, this study showed that more than one-quarter of patients undergoing procedures for brain aneurysms had lingering disability from third nerve palsy-associated diplopia or ptosis, despite later ophthalmic interventions. Patient self-report gleaned from telephonic interviews was valuable in largely validating the assessment method derived from medical records and in revealing differences between physician and patient estimation of disability.

Orbital fractures treated in a university hospital of southern Italy: epidemiology, outcomes and prognostic factors resulting from 538 retrospectively analyzed cases

PURPOSE

Orbital fractures are common injuries and represent an interesting chapter in maxillofacial surgery. This retrospective study analyses data collected from 528 patients surgically treated at the University Hospital "Magna Graecia", Catanzaro, Italy, from 1st January 2007 to 31st January 2021.

METHODS

The inclusion criteria were a diagnosis of orbital bone fracture, complete clinical and radiological records, and a minimum follow-up of 12 months. We analyzed gender, age, etiology, fracture type, treatment, timing of repair, and associated complications.

RESULTS

The most frequent cause of trauma was road accidents (37.88%), followed by domestic accidents (25.95%). The manifestation of diplopia (72.35%), infraorbital nerve hypoesthesia (53.41%), extrinsic eye movement limitation (51.70%), and enophthalmos (41.29%), determined the indication for surgery. Our trauma team preferred the sub-eyelid approach (79.36%). The study shows a statistical significance in the correlation between the severity of the herniation of the lower rectus muscle and the presence of preoperative diplopia (p-value = 0.00416); We found the same statistical significance for the post-postoperative diplopia (p-value = 0.00385). Patients treated two weeks after the trauma show a higher rate of diplopia and a greater limitation of long-term post-operative eye movements than those treated within two weeks (diplopia 23.08% vs. 15.56%; eye movements limitation 13.33% vs. 7.69%). Early surgical treatment (> 14 days) reduces the likelihood of functional and structural damage to the lower rectus muscle.

CONCLUSION

Our data will support future maxillofacial traumatology studies, and the education and prevention measures taken will reduce the incidence of orbital trauma.

Diplopia in the Younger Adult (≤65 Years Old) Compared With Older Adult (>65 Years Old) Population-Presentation, Progression, and Outcome

BACKGROUND

Despite the impact of new-onset diplopia on the quality of life, there are few studies concerning new-onset diplopia in seniors. This study aimed to describe the epidemiology, etiology, prognosis, and outcome of different treatments in the older adults compared with younger adult patients presenting with new-onset binocular diplopia.

METHODS

A retrospective chart review of patients ≥18 YO with new-onset binocular diplopia presenting between 2010 and 2021. Data collected included age at presentation, gender, duration of time since diplopia onset, imaging results, known trigger, etiology, treatment, and follow-up.

RESULTS

Two hundred ten patients were included. Of them, 75 patients were ≤65 YO (35.7%, the "younger adult group") and 135 > 65 YO (64.3%, the "older adults group"). The common etiology in both groups was neurogenic (54.7% ≤ 65 vs 62.2% >65, P = 0.29). Cranial nerve palsies were more commonly microvascular in the older adults (96.0% vs 74.1%, P = 0.005), whereas tumor-related cranial nerve palsies were more frequent in younger adults (14.81% vs 2.04%, P = 0.03). A restrictive etiology was observed in 20% of younger adult compared with 11.1% of older adults group ( P = 0.08). Sagging eye syndrome (SES) was the second most common etiology in the older adults group at 11.9%, compared with 1.3% in the younger adult group ( P = 0.01). Decompensated phoria/tropia appeared in 16% of younger adult group compared with 11.9% of older adults ( P = 0.4), with an obvious trigger (mostly cataract surgery) in the latter (80% older adults vs 20% younger adults, P = 0.019). Positive imaging findings were found in 46.7% of patients ≤65 compared with 25.3% of >65 ( P = 0.01) and complete spontaneous resolution of diplopia was noted in 32.1% of the older adults compared with 11.8% of younger adults ( P = 0.003).

CONCLUSIONS

Neurogenic diplopia was the most common etiology for both groups, but is more prominent in the older adults. Noticeable findings in the older adults were SES diagnosis, identification of triggers for impaired fusion/diplopia, and a paucity of positive findings in imaging results. It is important to know these differences not only for managing seniors better, but also to minimize symptoms of binocular diplopia after lens-related procedures.

Acute acquired comitant esotropia associated with Lhermitte-Duclos disease: a case report

BACKGROUND

Acute acquired comitant esotropia caused by prolonged near work, such as the use of digital devices, has been frequently reported in recent years. However, intracranial examination is necessary even for patients with nonparalytic comitant esotropia. Lhermitte-Duclos disease is a rare tumor that grows in layers in the cerebellum. Among those with this disease, cases of esotropia have been reported due to abduction limitation of the eye, but there have been no reports of comitant esotropia. Here, we report the case of a young woman with acute acquired comitant esotropia who was found to have Lhermitte-Duclos disease.

CASE PRESENTATION

A 16-year-old Japanese female patient, whose ethnicity was Asian, was referred to our hospital for acute acquired comitant esotropia. Fundus examination revealed papilledema in both eyes, and magnetic resonance imaging of the head revealed a cerebellar tumor in the right cerebellum with obstructive hydrocephalus. She underwent partial tumor resection, and a histopathological diagnosis of Lhermitte-Duclos disease was obtained. However, comitant esotropia status remained unchanged, and she underwent strabismus surgery. Finally, diplopia disappeared completely.

CONCLUSION

Neurological and intracranial imaging examinations are essential when acute acquired comitant esotropia is observed. Acute acquired comitant esotropia by Lhermitte-Duclos disease did not improve with partial tumor resection and required strabismus surgery, but good surgical results were obtained.

Surgical treatment of unilateral acquired superior oblique muscle palsy in adults by inferior oblique belly transposition: a retrospective analysis

PURPOSE

Evaluate and analyze the efficacy of inferior oblique belly transposition (IOBT) in treating adult patients with diplopia and small-angle hypertropia caused by mild to moderate inferior oblique overaction (IOOA) secondary to acquired superior oblique palsy (SOP).

METHODS

Nine adult patients with diplopia and small-angle hypertropia associated with mild to moderate IOOA secondary to unilateral acquired SOP were included in the current retrospective study. All patients received the IOBT procedure between February 2019 and May 2023 at The Second People's Hospital of Jinan and were followed up for more than 6 months after the surgery. During the procedure, the belly of the inferior oblique muscle was fixed to the sclera at 5 mm posterior to the temporal insertion of the inferior rectus muscle. The following indicators were reviewed pre- and post-surgery: the vertical deviation (VD) in the primary position and in the Bielschowsky test, the fovea disc angle (FDA) of the affected eye, changes in IOOA, and diplopia.

RESULTS

After IOBT, the VD in the primary position decreased from 7.22△ ± 1.72△ (range 4△-10△) to 1.22△ ± 1.30△ (range 0△-3△). The VD in the Bielschowsky test decreased from 13.00△ ± 1.80△ to 3.22△ ± 1.09△. The FDA decreased from 10.02° ± 3.34° to 6.26° ± 1.91°. The grade of IOOA was reduced from 2.00 (1.00, 2.00) to 0.00 (0.00, 1.00). All changes were statistically significant (P < 0.001 or P = 0.006). Diplopia was resolved completely for all patients.

CONCLUSIONS

IOBT can effectively treat adults with diplopia and small-angle hypertropia caused by mild to moderate IOOA secondary to acquired SOP.

Bilateral pneumatic blowout fractures in a patient with silent sinus syndrome while diving

A 37-year-old scuba diver developed sudden severe headache, mid-facial pressure/pain and diplopia while diving. Upon examination, he had signs and symptoms consistent with silent sinus syndrome (SSS), including bilateral enophthalmos, hypoglobus, and diplopia/strabismus in conjunction with CT findings of occluded maxillary sinus ostia, atrophic/collapsed maxillary sinuses, and bilateral orbital floor fractures with fat herniation. As there was no history of trauma or chronic sinusitis, this rare case of bilateral SSS was deemed the cause of the spontaneous fractures (i.e. barotrauma secondary to a lack of equalization to ambient surrounding pressure). Transconjunctival repair of the fractures was successful and maxillary sinus antrostomies re-established aeration of the sinuses. We present this case and its management, as well as review the literature concerning sinus barotrauma as a result of diving and SSS. There have been no reports of orbital fractures primarily caused by scuba diving, nor secondarily from diving with the rare entity, SSS.

Effects of orbital decompression on duction, cyclotorsion and diplopia

BACKGROUND

Orbital decompression is commonly performed to correct proptosis in patients with Graves' orbitopathy (GO). In literature, the incidence of new-onset constant diplopia after orbital decompression varies. Few studies have evaluated changes in duction and cyclodeviation after orbital decompression. We evaluated the changes in duction, cyclodeviation, eye position and degree of diplopia after orbital decompression.

METHODS

We retrospectively analysed data from patients who underwent orbital decompression at our hospital between January 2016 and July 2020. Data regarding the type of decompression, eye position, duction, cyclodeviation and level of diplopia according to the Gorman score were recorded.

RESULTS

Data from 281 eyes/orbits of 156 patients were analysed. Proptosis decreased from 23.8±2.5 to 20.9±2.5 mm. Horizontal and vertical duction range decreased (horizontal d=0.40 and vertical 0.30; p=0.000) after surgery; however, the change was not clinically significant (≤5°). Horizontal deviation changed towards esodeviation (d=-0.45; p=0.000), whereas vertical deviation remained stable (d=0.15; p=0.161). Preoperative cyclotorsion in the primary and downgaze positions changed towards incyclodeviation (primary: d=0.30, p=0.021; downgaze d=0.30, p=0.039). Diplopia improved in 22% (18 patients), whereas new-onset constant diplopia developed in 11% (12 patients). Elevation has an excellent predictive value of causing new-onset constant diplopia when measured preoperatively as <19°, sensitivity 88.0%, specificity 41.7% (area under the curve 0.812 (95% CI 0.660 to 0.963); p=0.000).

CONCLUSION

After orbital decompression, incidence of new-onset constant diplopia was 11% and 22% of the patients had partial or complete improvement of their diplopia. The changes in duction, cyclodeviation and horizontal deviation showed a statistical but not clinical difference. Patients with GO and a preoperatively restricted elevation of <19° are at risk of developing new-onset constant diplopia. In addition, preoperative incyclodeviation may worsen after decompression surgery.

[Myasthenia as the cause of vertical diplopia in the elderly]

Myasthenia gravis is a well-understood autoimmune disease of the neuromuscular synapse that is medicinally treatable with favorable results and therefore should not be overlooked in the differential diagnostic evaluation of vertical diplopia. Myasthenia is primarily a clinical diagnosis. Positive indications include double vision of fluctuating severity, diurnal variations, double vision after lengthy gaze fixation on a distant object and in the primary position as well as diplopia in various visual directions, often associated with a varying extent of ptosis. Clinical tests are the Simpson test, the ice on eyes test and the probatory administration of pyridostigmine. Positive results corroborate this diagnosis but negative results do not exclude myasthenia. The same applies for the determination of specific autoantibodies. In addition to ocular symptoms it is important to search for generalized symptoms and bulbopharyngeal symptoms in particular should prompt immediate neurological diagnostics. In addition to symptomatic treatment a wide range of immunotherapeutic agents are available. Thymectomy is also used for immunomodulatory indications according to the 2023 revised guidelines. Patient-centered treatment goals, patient education and comprehensive information, also via the self-help organization German Myasthenia Society, are essential components of successful treatment of myasthenia.

Surgical Outcomes of Revision Orbital Reconstruction in Patients With Inadequate Primary Orbital Fracture Repair

OBJECTIVE

This study aimed to investigate the clinical characteristics of patients with complications following inadequate primary orbital fracture repair and to evaluate surgical outcomes of secondary revision orbital reconstruction.

METHODS

The authors retrospectively reviewed data from 41 patients who underwent revision orbital reconstruction by a single surgeon following complications from primary orbital fracture repair performed elsewhere. Clinical characteristics, including enophthalmos, exophthalmos, diplopia, ocular motility limitation, epiphora, infraorbital hypoesthesia, infection, eyelid malposition, lagophthalmos, hypoglobus, and compressive optic neuropathy, were assessed. Surgical outcomes of revision surgery were evaluated to determine improvements in clinical deficits and postoperative patient satisfaction.

RESULTS

The most common postoperative complications of primary orbital fracture repair were enophthalmos (n=20/41) and diplopia (n=20/41). The mean time between primary and revision surgeries was 67.2 months (range: 1-276 mo). Revision surgery significantly improved enophthalmos, diplopia (Hess area ratio), epiphora (Munk score), periorbital pain, and exophthalmos ( P =0.003, P =0.001, P <0.001, P <0.001, and P =0.007, respectively) compared to the pre-revision state. In addition, 6 patients experienced improved infraorbital hypoesthesia. Among the 41 patients, 23 were very satisfied, 17 were satisfied, and 1 was neutral after revision orbital reconstruction.

CONCLUSIONS

Our study highlights the positive impact of revision orbital reconstruction in addressing complications from inadequate primary orbital fracture repair. Surgeons should consider revision surgery to address clinical deficits following prior surgery, especially when anatomic abnormalities are evident in imaging studies, regardless of the time lapse since the initial surgery or concerns about tissue fibrosis and fat atrophy.

[Graves' orbitopathy as the cause of diplopia in old age-Differences between young and old]

BACKGROUND

Endocrine orbitopathy (EO) is an autoimmune disease mostly associated with a disease of the thyroid gland, which leads to inflammation, adipogenesis and fibrosis. The severity of EO can vary greatly between individuals, which makes it difficult to exactly predict the natural course of the disease; however, this is important to be able to individually adapt the treatment. The aim of this study was to compare the clinical features, course, treatment and prognosis for patients with EO under 50 years old with older patients. The results of the study with a focus on motility are presented in this special issue.

PATIENTS AND METHODS

The hospital records of a randomly selected sample of 1000 patients from the EO databank in Essen (GODE), which includes 4260 patients, were analyzed. The patients were divided into two groups: group 1 ≤50 years and group 2 >50 years. Only patients with complete data sets were included in the statistical analyses.

RESULTS

Younger patients (n = 484) presented significantly more frequently with milder EO (53% vs. 33%, p < 0.0001), whereas older patients (n = 448) more frequently suffered from moderate or severe forms (44% vs. 64%, p < 0.0001). Older patients showed more severe strabismus, motility and clinical activity scores (5.9 vs. 2.3 prism diopters, PD/310° vs. 330°, both p < 0.0001, CAS 2.1 vs. 1.7, p = 0.001). Proptosis and the occurrence of optic nerve compression showed no significant differences between the groups (3% each). Multiple logistic regression showed that the necessity for a second eye muscle surgery was most strongly associated with a previous decompression (OR = 0.12, 95 % CI 0.1-0.2, p < 0.0001), followed by orbital irradiation and age.

CONCLUSION

In summary, younger patients with EO presented with milder clinical features, such as a lower rate of restrictive motility disorders and weaker expression of signs of inflammation. Therefore, older patients needed steroids, irradiation, eyelid and eye muscle surgery more frequently; however, the risk of dysthyroid optic neuropathy and the necessity of a second eye surgery were not or only slightly associated with age.

Clinical Significance of Diplopia and the Orthoptic Examination in Zygomatic Maxillary Complex Fractures

Literature describes variable rates of diplopia of associated with zygomatic maxillary complex (ZMC) fractures (6% to 40%). The aim of this study was to retrospectively assess the prevalence of diplopia in ZMC fracture patients, the usefulness of the orthoptic evaluation compared with the clinical finger-tracking examination, and to seek possible relations of this symptom with clinical parameters. Data of patients attending the Maxillofacial Surgery Units of the University of Messina and University of Naples "Federico II", between January 2012 and December 2022 were retrieved. Statistical analysis of positive versus negative diplopia at both the clinical examination and the orthoptic evaluation and subgroup analysis were performed. 320 patients were included in the analysis. 50 (15.6%) patients reported diplopia at the clinical examination, whereas 70 (21.9%) resulted positive at the orthoptic evaluation. Statistical analysis for every determinant and subgroup did not show statistical significance ( P >0.05). Performing routine preoperative orthoptic evaluation allowed an increase of 6.3% in positive reports. Although it seems that no basic clinical parameter can predict diplopia, results suggest that the orthoptic evaluation is superior in the assessment of this symptom. Clinical analysis was shown to be a moderate/low efficient test and should not be used as a decisional standard.

[Differential diagnosis of vertical strabismus in the elderly]

Due to the demographic changes, the number of older patients in ophthalmological practices and clinics, including those with diplopia, is increasing. Some of the patients report not only horizontally shifted double images but also or only vertically shifted double images. Vertical double vision often causes significant diagnostic problems for ophthalmologists. The underlying condition could urgently require further neurological, neuroradiological and/or internal medical diagnostics (e.g., skew deviation, 4th nerve palsy, myasthenia, Graves' orbitopathy, orbital floor fracture, orbital mass, 3rd nerve palsy) but the cause of diplopia could also be a condition in which overdiagnosis should be avoided (e.g., sagging eye syndrome, the prevalence of which significantly increases with increasing age; decompensated strabismus due to inferior oblique muscle overaction, myopia-associated vertical tropia). For some diseases early diagnosis is important for a better prognosis, e.g., tumor diagnosis, Graves' disease and stroke. This article presents an overview of the most common and most important differential diagnoses of vertical tropia in patients over 50 years of age.

Characteristics and type of strabismus associated to macular diplopia. Treatment outcomes

OBJECTIVE

To study the clinical characteristics of macular diplopia, treatment, and outcome.

METHODS

Retrospective descriptive study of cases referred to the ocular motility section of a tertiary hospital with diplopia, diagnosed with macular diplopia between 2022-23. The etiology of the macular pathology and the type of associated strabismus were recorded. The result was considered good if the diplopia improved or was eliminated with the medical or surgical treatment. Follow-up time from the onset of diplopia until data collection was recorded.

RESULTS

a total of 19 cases comprised the sample (63.2% women), mean age: 67.16 years. Amblyopia (21.1%), high myopia (47.4%), epirretinal membrane (ERM) (36.8%), neovascular membrane (26.3%), macular hole (10.5%), and lamellar (15.8%), and age macular degeneration (5.3%) were registered. The 47.4% had vertical diplopia, horizontal: 5.3 and 47.4% mixed. The mean horizontal deviation was: 7.3 PD (prism diopters) and vertical: 6.22 PD. Ocular extorsion was observed in 26.3%, and intorsion: 5.3%. Torticollis was present in 15.8%. The treatment consisted of strabismus surgery + Botox (15.8%), strabismus surgery (47.4%), medical treatment with Fresnel prims or Scotch cellophane (36.8%). A 68.4% presented a good result at the end of the study. The mean follow-up was 55.58 months.

CONCLUSIONS

Misregistration of macular photoreceptors is the most common cause of binocular diplopia in patients with ERM or other macular pathologies. Most complains of vertical or mixed diplopia. Sensorimotor evaluation of these patients should be thorough. Early diagnosis prevents unnecessary prescription of prism glasses. Surgical and/or medical treatment achieves good results in most cases.

[Intermittent exotropia complicated with spasm of the near reflex: a case report]

A 21-year-old female patient presented to the Ophthalmology Department of Yunnan University Affiliated Hospital with complaints of "bilateral blurred vision accompanied by diplopia for 3 weeks". The patient's main symptoms included intermittent visual blurring, diplopia, headaches, and ocular discomfort. Ocular examination revealed intermittent exotropia, sometimes accompanied by esotropia or orthotropia, along with signs of pupillary constriction and pseudomyopia. Based on the clinical presentation, a diagnosis of intermittent exotropia complicated by spasm of the near reflex (SNR) was made. The patient underwent bilateral exotropia surgery, which corrected the ocular alignment and resolved the symptoms and signs of SNR postoperatively.

Cranial Nerve Palsies in the Setting of Arachnoid Cysts: A Case Series and Literature Review

BACKGROUND

Arachnoid cysts (ACs) are benign lesions typically believed to not cause neurologic defects in the adult population and are most often found incidentally on imaging. We describe 2 patients with ACs potentially leading to isolated cranial nerve (CN) dysfunction.

METHODS

We describe 2 patients, 1 with a fourth nerve palsy and the other with a sixth nerve palsy found to have ACs on MRI brain imaging in locations that potentially caused a compressive CN palsy. We review previous literature of ACs presenting with CN III, IV, or VI palsy.

RESULTS

Patient 1 was a 62-year-old man who presented with a 22-year history of diplopia with strabismus examination consistent with a congenital CN IV palsy. Despite multiple surgeries, his CN IV palsy insidiously worsened. An AC in the posterior fossa with mass effect on the quadrigeminal plate and asymmetric atrophy of the right superior oblique was identified on imaging. Patient 2 was an 80-year-old man who presented with an 18-year history of diplopia and was found to have a left esotropia and abduction deficit consistent with complete CN VI palsy. An AC in the left cavernous sinus was identified on imaging. He underwent strabismus surgery with satisfactory resolution of diplopia. We identified a total of 18 previously published cases: 8 reports of CN III palsy, 4 reports of CN IV palsy, and 6 reports of CN VI palsy. Patient ages ranged from 1 to 67 with a median of 34.5. In 16/18 (89%) cases, the diagnosis of ACs was made within 1 year of symptom onset. Surgical removal of the AC was successful in resolving diplopia in 7/12 (58%) cases. In no case was strabismus surgery performed as primary treatment.

CONCLUSIONS

Although ACs are typically congenital asymptomatic lesions, we present a case series of 2 patients with ACs in anatomic locations that potentially caused chronic, progressive, isolated CN palsies leading to strabismus. Our literature review revealed that most published cases detailing this clinical scenario resulted in neurosurgical fenestration of ACs with mixed results. Our cases represent 2 patients with AC-associated CN palsy treated with strabismus surgery.

Isolated Abducens Nerve Palsy: A Rare Manifestation of Recurrent Extramedullary Myeloma

Multiple myeloma is a plasma cell neoplasm, which may present as a solitary plasmacytoma and, uncommonly, as an extramedullary plasmacytoma. Intracranial plasmacytomas may manifest in central nervous system involvement as cranial nerve palsies. Cranial nerve six palsy is the most common in cases of malignancy. However, isolated abducens palsy presenting as multiple myeloma recurrence is very uncommon. Here, we detail two cases in which intracranial plasmacytoma lesions were present within the region of the Dorello canal, resulting in acute isolated unilateral diplopia from disease recurrence in the absence of systemic marrow involvement.

Unusual and Rare Causes of Monocular Elevation Deficit

INTRODUCTION

To study the rare and unusual causes of monocular elevation deficit.

METHODS

Five patients presenting to us with diplopia and elevation deficit were thoroughly examined and were found to have monocular elevation deficit due to rare causes.

OBSERVATIONS

All five were found to have different underlying etiologies - iatrogenic, sphenoid wing meningioma, cysticercosis, sarcoidosis and mid brain infarct, and were managed appropriately.

DISCUSSION

Monocular Elevation Deficit can occur due to a variety of causes. Having a high index of suspicion for the more serious etiologies is of utmost importance. Thorough clinical examination and imaging help clinch the diagnosis.

Ocular neuromyotonia: an unusual case after radiotheraphy for nasopharyngeal carcinoma

Ocular neuromyotonia (ONM) is an infrequent disorder characterised by recurrent episodes of binocular diplopia caused by paroxysmal contraction of one or several extraocular muscles innervated by the same cranial nerve. It can be triggered spontaneously or caused by prolonged contraction of specific eye muscle(s) and is usually related to a local intracranial radiotherapy antecedent. We report the case of a 46-year-old woman who developed intermittent episodes of binocular diplopia eight years after radiotherapy for a nasopharyngeal carcinoma. After a complete neuro-ophthalmic assessment we diagnosed the case as an abducens nerve neuromyotonia. Although it is infrequent, radiotherapy to the nasopharynx is a possible cause of ONM, due to the proximity to the base of the skull and extraocular motor nerve pathways, especially that of the VI cranial nerve, as is the case presented in this article, about a patient whose history is a nasopharyngeal carcinoma treated with local radiotherapy.

Accuracy of Repetitive Ocular Vestibular-Evoked Myogenic Potentials to Diagnose Myasthenia Gravis in Patients With Ptosis or Diplopia

BACKGROUND AND OBJECTIVES

We developed repetitive ocular vestibular-evoked myogenic potentials (roVEMP) as an electrophysiologic test that allows us to elicit the characteristic decrement of extraocular muscles in patients with ocular myasthenia gravis (OMG). Case-control studies demonstrated that roVEMP reliably differentiates patients with OMG from healthy controls. We now aimed to evaluate the diagnostic accuracy of roVEMP for OMG diagnosis in patients with ptosis and/or diplopia.

METHODS

In this blinded prospective diagnostic accuracy trial, we compared roVEMP in 89 consecutive patients presenting with ptosis and/or diplopia suspicious of OMG with a multimodal diagnostic approach, including clinical examination, antibodies, edrophonium testing, repetitive nerve stimulation of accessory and facial nerves, and single-fiber EMG (SFEMG). We calculated the roVEMP decrement as the ratio between the mean of the first 2 responses compared with the mean of the sixth-ninth responses in the train and used cutoff of >9% (unilateral decrement) in a 30 Hz stimulation paradigm.

RESULTS

Following a complete diagnostic work-up, 39 patients (44%) were diagnosed with ocular MG, while 50 patients (56%) had various other neuro-ophthalmologic conditions, but not MG (non-MG). roVEMP yielded 88.2% sensitivity, 30.2% specificity, 50% positive predictive value (PPV), and 76.5% negative predictive value (NPV). For comparison, SFEMG resulted in 75% sensitivity, 56% specificity, 55.1% PPV, and 75.7% NPV. All other diagnostic tests (except for the ice pack test) also yielded significantly higher positive results in patients with MG compared with non-MG.

DISCUSSION

The study revealed a high sensitivity of 88.2% for roVEMP in OMG, but specificity and PPV were too low to allow for the OMG diagnosis as a single test. Thus, differentiating ocular MG from other neuro-ophthalmologic conditions remains challenging, and the highest diagnostic accuracy is still obtained by a multimodal approach. In this study, roVEMP can complement the diagnostic armamentarium for the diagnosis of MG.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that in patients with diplopia and ptosis, roVEMP alone does not accurately distinguish MG from non-MG disorders.

TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov: NCT03049956.