Clinical Course and Prognostic Factors of Acquired Third, Fourth, and Sixth Cranial Nerve Palsy in Korean Patients

Clinical spectrum and its association with recovery patterns in patients with acquired isolated ocular motor nerve palsies - an observational study

Purpose: To study the clinical spectrum and recovery patterns in patients of acquired isolated ocular motor nerve palsies (OMNPs). Methods: Patients above 5 years of age with various etiologies of OMNPs were included. Demographic and ocular details were recorded, and a squint assessment was performed. Recovery patterns at 3 and 6 months were noted. Results: OMNP was more common in adults, in the order VI > III > IV nerve. Ischemic cause (35%) was followed by idiopathic (26.3%). III nerve palsies were all unilateral, of which all ischemic palsies were pupil-sparing. By 6 months, >50 patients showing complete recovery had ischemic and idiopathic palsies. Smaller baseline deviation correlated with better recovery. Conclusion: Acquired isolated OMNPs are mostly ischemia-related, with >80% of cases fully recovering by 6 months. VI nerve palsy of ischemic or idiopathic etiology and small baseline deviation were associated with self-recovery.

A protocol to quantify cross-sectional and longitudinal differences in duction patterns

Currently, there is no established system for quantifying patterns of ocular ductions. This poses challenges in tracking the onset and evolution of ocular motility disorders, as current clinical methodologies rely on subjective observations of individual movements. We propose a protocol that integrates image processing, a statistical framework of summary indices, and criteria for evaluating both cross-sectional and longitudinal differences in ductions to address this methodological gap. We demonstrate that our protocol reliably transforms objective estimates of ocular rotations into normative patterns of total movement area and movement symmetry. This is a critical step towards clinical application in which our protocol could first diagnose and then track the progression and resolution of ocular motility disorders over time.

Etiological distribution of isolated oculomotor nerve palsy: analysis of 633 patients and literature review

BACKGROUND AND PURPOSE

The etiological distribution of oculomotor nerve palsy has varied amongst the studies. This study aimed to define the clinical features and underlying etiologies of isolated oculomotor nerve palsy by recruiting patients from all departments in a referral-based university hospital.

METHODS

The medical records of 672 patients who had a confirmed diagnosis of isolated oculomotor nerve palsy at all departments of Seoul National University Bundang Hospital, Seongnam, South Korea, from 2003 to 2020 were reviewed. A proportion of the etiology of isolated oculomotor nerve palsy was also compared with that of patients pooled from the previous studies that were searched on PubMed in May 2022.

RESULTS

The most common etiology was microvascular (n = 168, 26.5%), followed by vascular anomalies (n = 110, 17.4%), neoplastic (n = 86, 13.6%), inflammatory (n = 79, 12.5%), idiopathic (n = 60, 9.5%) and traumatic (n = 53, 8.4%). Neurologists were mainly involved in the management of microvascular and inflammatory oculomotor nerve palsies whilst ophthalmologists mainly participated in the care of idiopathic, neoplastic and traumatic palsies. Neurosurgeons mostly took care of oculomotor nerve palsy due to vascular anomalies.

CONCLUSIONS

The proportion of etiologies of isolated oculomotor nerve palsy may differ according to the specialties involved in the management. The results of previous studies on the etiological distribution of isolated oculomotor nerve palsy should be interpreted with this consideration.

Early-Onset Ocular Motor Cranial Neuropathy Is a Strong Predictor of Dementia: A Nationwide, Population-Based Cohort Study

PURPOSE

To assess the risk of dementia in individuals with newly diagnosed ocular motor cranial neuropathy (OMCN).

DESIGN

A nationwide, population-based cohort study using authenticated data from the Korean National Health Insurance Service (KNHIS).

PARTICIPANTS

This study included 60 781 patients with OMCN who received a diagnosis between 2010 and 2017 and were followed up through 2018, with an average follow-up of 3.37 ± 2.21 years with a 1-year lag. After excluding patients with disease related to oculomotor dysfunction preceding the OMCN diagnosis, a total of 52 076 patients with OMCN were established. Of these, 23 642 patients who had participated in the National Health Screening Program (NHSP) within 2 years before the OMCN diagnosis were included. After applying the exclusion criteria, the final cohort comprised 19 243 patients and 96 215 age and sex-matched control participants without OMCN.

METHODS

We identified patients with newly diagnosed OMCN in the KNHIS database and collected participant characteristics from the health checkup records of the NHSP. The study end point was determined by the first claim with a dementia diagnostic code and antidementia medications. The association of OMCN with dementia risk was examined using Cox proportional hazards regression analysis, adjusting for potential confounding factors.

MAIN OUTCOME MEASURES

The main outcome measures were hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause dementia (ACD), Alzheimer's disease (AD), and vascular dementia (VaD) development in patients with OMCN relative to those without OMCN.

RESULTS

Patients with newly diagnosed OMCN demonstrated higher metabolic comorbidities than those without OMCN. New OMCN was associated with an elevated risk of ACD (HR, 1.203; 95% CI, 1.113-1.300), AD (HR, 1.137; 95% CI, 1.041-1.243), and VaD (HR, 1.583; 95% CI, 1.286-1.948), independent of potential confounding factors. The younger age groups exhibited a stronger association between OMCN and ACD (HR, 8.690 [< 50 years] vs. 1.192 [≥ 50 years]; P = 0.0004; HR, 2.517 [< 65 years] vs. 1.099 [≥ 65 years]; P < 0.0001).

CONCLUSIONS

This nationwide population-based study assessed the association between OMCN and dementia risk. Our results demonstrated a robust relationship between OMCN and the risk of dementia, particularly in the younger population.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Retrospective Analysis of Factors Related to the Long-Term Recovery of Third, Fourth, and Sixth Cranial Nerve Palsy with Etiologies and Clinical Course in a Tertiary Hospital

Purpose

Although various studies have explored the causes and clinical aspects of cranial nerve palsies, there remains a significant gap in understanding the prognostic factors that influence outcomes. In this study, we sought to address this gap by investigating the incidence, etiologies, clinical courses, and factors associated with long-term recovery, with the aim of enhancing the knowledge base in this field and providing valuable insights for improved patient care.

Patients and Methods

This retrospective study evaluated the data gathered from subjects who had third, fourth, and sixth cranial nerve palsy at the ophthalmology outpatient clinic of Phramongkutklao Hospital between April 1, 2012, and April 30, 2022.

Results

Among the three nerves, abducens nerve palsy was the most prevalent finding by most commonly involved. Our study revealed that ischemic and compressive lesions were the most common etiology of oculomotor nerve palsy, comprising 24.6% each. In addition, the most common etiology of trochlear and abducens nerve palsy was trauma, at 31.6% and 27.1%, respectively. Compared with the other nerves, oculomotor nerve palsy was associated with a shorter duration onset of symptoms and recovery period. The best recovery outcomes among the various etiologies were inflammation, ischemic events, and trauma in oculomotor, trochlear, and abducens nerve palsy, respectively. Logistic regression revealed that an onset of <7 days and isolated nerve involvement were significantly associated with good long-term outcomes, with an adjusted odds ratio of 1.73 (95% confidence interval, 1.03-2.89) and 2.56 (95% confidence interval, 1.21-5.39) adjusted for the type of cranial nerve palsy, aged at 50 years, sex, diabetes mellitus, hypertension, dyslipidemia, onset at 7 days, and number of cranial nerves involved, respectively.

Conclusion

The onset of symptoms in less than 1 week and isolated nerve involvement were associated with better prognosis in subjects with third, fourth, and sixth cranial nerve palsy.

The profiles and clinical significance of extraocular muscle-expressed lncRNAs and mRNAs in oculomotor nerve palsy

Introduction

Oculomotor nerve palsy (ONP) arises from primary abnormalities in the central neural pathways that control the extraocular muscles (EOMs). Long non-coding RNAs (lncRNAs) have been found to be involved in the pathogenesis of various neuroparalytic diseases. However, little is known about the role of lncRNAs in ONP.

Methods

We collected medial rectus muscle tissue from ONP and constant exotropia (CXT) patients during strabismus surgeries for RNA sequencing analysis. Differentially expressed mRNAs and lncRNAs were revealed and included in the functional enrichment analysis. Co-expression analysis was conducted between these differentially expressed mRNAs and lncRNAs, followed by target gene prediction of differentially expressed lncRNAs. In addition, lncRNA-microRNA and lncRNA-transcription factor-mRNA interaction networks were constructed to further elaborate the pathological changes in medial rectus muscle of ONP. Furthermore, RT-qPCR was applied to further validate the expression levels of important lncRNAs and mRNAs, whose clinical significance was examined by receiver operating characteristic (ROC) curve analysis.

Results

A total of 618 differentially expressed lncRNAs and 322 differentially expressed mRNAs were identified. The up-regulated mRNAs were significantly related to cholinergic synaptic transmission (such as CHRM3 and CHRND) and the components and metabolism of extracellular matrix (such as CHI3L1 and COL19A1), while the down-regulated mRNAs were significantly correlated with the composition (such as MYH7 and MYL3) and contraction force (such as MYH7 and TNNT1) of muscle fibers. Co-expression analysis and target gene prediction revealed the strong correlation between MYH7 and NR_126491.1 as well as MYOD1 and ENST00000524479. Moreover, the differential expressions of lncRNAs (XR_001739409.1, NR_024160.1 and XR_001738373.1) and mRNAs (CDKN1A, MYOG, MYOD1, MYBPH, TMEM64, STATH, and MYL3) were validated by RT-qPCR. ROC curve analysis showed that lncRNAs (XR_001739409.1, NR_024160.1, and NR_002766.2) and mRNAs (CDKN1A, MYOG, MYOD1, MYBPH, TMEM64, and STATH) might be promising biomarkers of ONP.

Conclusions

These results may shed light on the molecular biology of EOMs of ONP, as well as the possible correlation of lncRNAs and mRNAs with clinical practice.

Identification and characterization of differentially expressed circular RNAs in extraocular muscle of oculomotor nerve palsy

BACKGROUND

Oculomotor nerve palsy (ONP) is a neuroparalytic disorder resulting in dysfunction of innervating extraocular muscles (EOMs), of which the pathological characteristics remain underexplored.

METHODS

In this study, medial rectus muscle tissue samples from four ONP patients and four constant exotropia (CXT) patients were collected for RNA sequencing. Differentially expressed circular RNAs (circRNAs) were identified and included in functional enrichment analysis, followed by interaction analysis with microRNAs and mRNAs as well as RNA binding proteins. Furthermore, RT-qPCR was used to validate the expression level of the differentially expressed circRNAs.

RESULTS

A total of 84 differentially expressed circRNAs were identified from 10,504 predicted circRNAs. Functional enrichment analysis indicated that the differentially expressed circRNAs significantly correlated with skeletal muscle contraction. In addition, interaction analyses showed that up-regulated circRNA_03628 was significantly interacted with RNA binding protein AGO2 and EIF4A3 as well as microRNA hsa-miR-188-5p and hsa-miR-4529-5p. The up-regulation of circRNA_03628 was validated by RT-qPCR, followed by further elaboration of the expression, location and clinical significance of circRNA_03628 in EOMs of ONP.

CONCLUSIONS

Our study may shed light on the role of differentially expressed circRNAs, especially circRNA_03628, in the pathological changes of EOMs in ONP.

Isolated Pupillary-sparing Cranial Nerve III Palsy from a Subgaleal Abscess

Cranial nerve (CN) III palsy is rarely caused by intraorbital compression, let alone from a subgaleal abscess. We present a case of a hypertensive 55-year-old man with an acute isolated pupillary-sparing left CN III palsy from a left subgaleal abscess with associated pterional osteomyelitis and frontotemporal mass. This is the first reported such case and the third reported case of a chronic spontaneous subgaleal abscess. A seemingly routine case of an acute, pupillary-sparing, isolated CN III palsy from hypertension turned out to be a rare case in terms of etiology of the palsy and of the source of the abscess.

What you need to know about assessing a patient with diplopia

Diplopia occurs when two images are subjectively seen of a single object. It has a variety of causes, which range in severity from benign to sight or life threatening if left untreated. Clinical assessment of diplopia includes taking a comprehensive history to delineate the exact type of visual disturbance experienced by the patient and examination to pinpoint the aetiology, which is crucial for further management. This article discusses the causes of diplopia, along with risk factors and other associated symptoms, to facilitate diagnosis and management. Efficient and effective diagnosis is important, as some pathologies require immediate treatment to save the eyesight and/or life of the patient. This article will concentrate solely on binocular diplopia.

Intraocular vascular analysis using optical coherence tomography angiography in patients with vascular paralytic strabismus

Purpose

To investigate changes in peripapillary and macular vessel density (VD) in vascular paralytic strabismus using optical coherence tomography angiography (OCTA).

Methods

Medical records of patients who recovered from monocular vascular paralytic strabismus were retrospectively analyzed. Age, sex, presence of underlying diseases, strabismus type and severity, time to recovery, and visual acuity at diagnosis were evaluated. VD in the optic disc area and macular capillary plexus density were estimated using OCTA. The effect of paralytic strabismus on intraocular VD was investigated by comparing VD between the paralysis and contralateral eyes. To analyze hemodynamic changes, VD changes in the paralysis eye during the attack and recovery were compared.

Results

Thirty-one patients (mean age, 64.1±13.0 years; 21 males, 10 females) were included and mean recovery time was 3.0±1.6 months. The most common paralysis was sixth nerve palsy (54.8%). When comparing OCTA results between the paralysis and contralateral non-paralysis eyes, foveal VD in the superficial capillary plexus (SCP) was significantly lower in the paralysis eye (P = 0.034); however, VD in the optic disc area was not different. In the paralysis eye, foveal VD in the SCP significantly increased after paralysis recovery (P = 0.04). During attack, the maximal deviation angle and severity of duction limitation were significantly related to foveal VD in SCP. The greater the deviation angle and the more severe the eye movement restriction, the lower the foveal VD in SCP.

Conclusions

Transient retinal ischemia of the paralysis eye was observed in a patient with paralytic strabismus, which corresponded to the degree of deviation angle and ocular motor restriction. Ischemic factors, which are the etiology of vascular paralytic strabismus, affect intraocular blood flow.

Facial Asymmetry: A Narrative Review of the Most Common Neurological Causes

Symmetry of the face is one of the most important features for the perception of attractiveness. Asymmetry of the face means that the right and left sides of the face are not identical. Subclinical facial asymmetry is very common in the general population. Most people have some slight facial asymmetry, and this is the normal biological situation in humans. Abnormalities from soft tissue, dental, and skeletal elements lead to facial asymmetry. Asymmetry has many causal factors, and its aetiology includes both congenital and acquired conditions. Neurological facial asymmetry is scarcely addressed in the dental literature. In this narrative review, we focus on the most common neurological causes of facial asymmetry. From a neurological point of view, facial asymmetry can result from disturbances of the cranial nerves, developmental disorders, or myopathies. In the broad range of differential diagnostics of facial asymmetry, neurological abnormalities should be taken into consideration. The treatment must be related to the underlying cause. Complete knowledge of the aetiological factors and the character of the asymmetry plays a crucial role in formulating a treatment plan.

Clinical outcomes and etiology of acquired sixth cranial nerve palsy

ABSTRACT

The objective of this study was to investigate the difference in clinical features according to age and factors affecting recovery of acquired sixth cranial nerve (CN6) palsy.A total of 156 patients with acute CN6 palsy between March 2016 and August 2021 who were followed up for at least 3 months were included in this study. Etiology, rate of recovery, and factors associated with recovery were retrospectively investigated.The average age of patients with CN6 palsy was about 60years and the mean duration of recovery was about 2.5 months. Of 156 patients, 72 (46.15%) had a microvascular etiology and 25 (16.03%) patients had a brain vascular lesions. Brain neoplasm, trauma, and "others" were found in 10 (6.41%), 11 (7.05%), and 15 (9.62%) patients, respectively. Among the total of 156 patients, 28 (17.95%) failed to completely recover. Non-isolated CN6 palsy with other cranial nerve palsies were recorded in 29 (18.59%) cases. Comparison of age (<50years vs ≥50years), between recovery and non-recovery groups showed that etiology was significantly different.The recovery rate of acquired CN6 palsy was about 82% and about 27% of patients had brain lesions. Also, varying rates and duration of recovery were found according to etiology, so we should be pay attention to diagnosis of causative disease in CN6 palsy patients.

A Review of Transposition Techniques for Treatment of Complete Abducens Nerve Palsy

Purpose:

To review various types of extraocular muscle transposition procedures for management of strabismus in sixth cranial nerve palsy with little lateral rectus (LR) muscle function, along with their pros and cons.

Methods:

We performed a comprehensive review of transposition procedures in sixth cranial nerve palsy, based on literature published anytime up to March 2021. A thorough search through PubMed and Cochrane databases was performed. All types of clinical studies on different transposition procedures in LR palsy, were included.

Results:

Eighty-six original articles in English, with full text or abstracts available, were included in the review, among which 16 are prospective studies, 48 retrospective, 3 review articles, 1 randomized clinical trial, 17 case reports, and 1 letter. Vertical rectus transposition has demonstrated promising results, especially in abduction improvement and expansion of binocular diplopia-free visual field, albeit the possible adverse effects such as anterior segment ischemia, especially in the presence of medial rectus contracture, and induced vertical deviation may become troublesome. Partial muscle transposition, single muscle transposition, and also transposition without tenotomy have all been introduced to reduce the risk of multiple muscle manipulation and ischemia. On the other hand, different adjustable transpositions are being utilized to manage concomitant or induced vertical deviations.

Conclusion:

Transposition procedures are highly effective in the treatment of esotropia caused by complete LR palsy. Various techniques for vertical muscle transposition have been proposed, with each of them having certain advantages and disadvantages.

Clinical Characteristics for Predicting Recovery of Acquired Fourth Cranial Nerve Palsy

BACKGROUND

Fourth cranial nerve palsy is the most common disease diagnosed in patients with vertical diplopia. Although it is reported to present a good prognosis, there are currently no agreed on prognostic factors that anticipate the recovery of the palsy other than the etiology. The purpose of this study was to investigate the prognostic factors of acquired fourth cranial nerve palsy.

METHODS

The medical records of consecutive patients diagnosed with acquired unilateral fourth cranial nerve palsy from 2010 to 2020 and followed up for ≥6 months were retrospectively reviewed. The cause and degree of palsy, ocular deviation (horizontal, vertical, and cyclo), and fundus torsion were reviewed. The cause of palsy was classified as ischemic, traumatic, intracranial mass, others, or idiopathic. Patients were divided into 2 groups according to palsy recovery: complete recovery (group CR) or not CR (group NCR). The clinical characteristics of the 2 groups were compared, and the risk factors for incomplete recovery were investigated.

RESULTS

Thirty-five patients (25 men) were included in the study. The average age was 55.94 ± 16.11 years. CR was achieved in 23 patients (65.7%), and the time to recovery was 3.91 ± 4.03 months. The most common cause was traumatic (40.0%), followed by ischemia (37.1%), intracranial mass (11.4%), others (8.6%), and idiopathic (2.9%). The degree of palsy and fundus torsion was significantly higher in group NCR (P = 0.010 and P = 0.001). Severe oculomotor limitation, large fundus torsion, and intracranial mass cause rather than ischemic cause indicated a higher risk of incomplete or no recovery (P = 0.016, P = 0.009, and P = 0.043).

CONCLUSION

Identifying whether a patient has an intracranial mass, severe oculomotor limitation, or large fundus excyclotorsion may be useful for predicting the recovery of acquired unilateral fourth cranial nerve palsy.

The spectrum and differential diagnosis of acquired ocular motor nerve palsies: a clinical study of 502 patients

Background

Ocular motor nerve palsies (OMNP) frequently cause patients to present in an emergency room. In the following study, we report the differential diagnosis of OMNP by use of magnetic resonance imaging (MRI) and CSF examination as a standard.

Method

We performed a data analysis of N = 502 patients who presented with oculomotor, trochlear, and/or abducens nerve palsy in the emergency room of the Department of Neurology, University of Ulm, between January 2006 and December 2019. We report clinical and MRI scan findings in all patients; furthermore, the CSF of 398 patients has been analysed.

Results

Abducens nerve palsies were most common (45%), followed by palsies of the oculomotor (31%) (CNP III) and trochlear nerve (15%). Multiple OMNPs were seen in 9% of our cohort. The most common causes included inflammations (32.7%), space-occupying lesions, such as aneurysms or neoplasms (17.3%), diabetes mellitus (13.3%), and brainstem infarctions (11%). Still 23.4% of the patients could not be assigned to any specific cause after differential diagnostic procedures and were described as idiopathic. One of three patients with an inflammation and 39% of the patients with space-occupying lesions showed additional cranial nerve deficits.

Conclusion

Inflammation and space-occupying processes were the most frequent causes of OMNP, although brainstem infarctions also play a significant role, in particular in CNP III. The presence of additional CNPs increases the probability of an inflammatory or space-occupying cause.

Clinical Factors Affecting Recovery Periods of Vascular and Idiopathic Acquired Paralytic Strabismus

Purpose: Clinical factors affecting the recovery period in patients with vascular or idiopathic paralytic strabismus were evaluated.Methods: This study involved a retrospective review of medical records of patients diagnosed with vascular and idiopathic acquired paralytic strabismus. Vascular paralysis was defined in cases of hypertension, diabetes mellitus, or cardiovascular disease. The angle of deviation and limitation of extraocular movement were evaluated at each visit. Recovery was defined as the absence of diplopia and complete resolution of limitation of extraocular movement. Factors affecting recovery success and recovery period were analyzed.Results: We retrospectively reviewed data of 145 patients consisting of 87 with vascular paralytic strabismus (cranial nerve [CN] III: 21, CN IV: 28, CN VI: 38) and 58 with idiopathic paralytic strabismus (CN IV: 20, CN VI: 24, CN III: 14). The recovery rate did not significantly differ between vascular (60.9%) and idiopathic (63.8%) groups (p = 0.15). The recovery period was longer in the vascular group (130.1 ± 145.1 days) than in the idiopathic group (92.6 ± 76.6) (p = 0.02). Age at onset was significantly associated with the recovery period in both vascular and idiopathic groups. In the vascular group, the recovery periods were 107.4 ± 74.8 days in CN III palsy, 97.2 ± 51.9 days in CN IV palsy, and 159.3 ± 194.1 days in CN VI palsy. The recovery period was significantly longer in patients with CN VI palsy (p = 0.03). Hypertension was significantly influencing the recovery period in patients with vascular CN VI palsy (odds ratio = 2.54, p = 0.01).Conclusions: The recovery period was longer in patients with vascular paralytic strabismus than in patients with idiopathic paralytic strabismus. Recovery rates were not significantly different between groups. In patients with vascular CN VI palsy, a history of hypertension was significantly associated with the recovery period.

A rare case of Meckel's cave primary lymphoma: a case report and elaboration of the diagnostic algorithm

Management of lesions involving Meckel's cave can represent a challenge for neurosurgeons, because of the deep-seated location and the surrounding complex neurovascular structures. Very small lesions arising from MC are generally asymptomatic and radiological follow-up with head MRI and PET-CT is sufficient to control these lesions. In rare cases, the rapid increase in the size of lesions and the alteration of the neurologic status make early histological characterization mandatory in the plethora of lesions arising from Meckel's cave; a very small percentage is represented by central nervous system lymphomas. Primary diffuse large B-cell lymphoma is the most commonly found. Aggressive surgery, in case of suspicious Meckel's cave lesions, is strongly discouraged, because this procedure may increase the risk of postoperative deficit and provides no survival benefit compared with biopsy alone. The aim of the present paper is to report a very rare case of primary Meckel's cave diffuse large B-cell lymphoma (only seven cases were described in literature) and standardize an operative algorithm to avoid the risks of an incorrect surgical conduct.

Third Cranial Nerve Palsy Due to COVID-19 Infection

Coronavirus disease 2019 (COVID-19) is known to be primarily a viral infection affecting the pulmonary system leading to severe pneumonia and acute respiratory distress syndrome. COVID-19 has also been found to affect the neurological system causing various nerve palsies. While some studies have suggested these neurological manifestations may indicate severe disease, cranial nerve palsies in the setting of COVID-19 infection have been linked to improved patient outcomes and mild viral symptoms. We present a case of a 55-year-old male with confirmed COVID-19 infection presenting with third cranial nerve palsy. Since his hospital course remained unremarkable, he was treated supportively for his COVID-19 infection and remained stable on room air during his hospitalization. No causative factors other than COVID-19 were identified as a cause for his cranial three nerve palsy which resolved spontaneously during outpatient follow-up. Although different cranial nerve palsies associated with COVID-19 infection have been identified in the literature, the pathogenesis and prognosis of cranial nerve palsy is still unclear. This case emphasizes the need for continued symptom monitoring and identification in patients diagnosed with COVID-19.

Idiopathic unilateral oculomotor nerve palsy: A case report

Cranial nerve III palsy, also known as oculomotor nerve palsy, may result from various causes; however, the etiology remains unknown in some instances. The aim of this case report is to present the authors' experience with two cases of idiopathic cranial nerve III palsy, together with a review of the literature. Case 1 is a 78-year-old woman and case 2 is a 75-year-old man, both having no history of trauma and no vascular risk factors. They presented to the authors' hospital with diplopia and palpebral ptosis and were diagnosed with idiopathic unilateral cranial nerve III palsy. They received oral steroids for treatment. One patient recovered completely within 3 months, while the other patient did not recover regardless of long-term follow-up. Idiopathic cranial nerve III palsy can occur in otherwise healthy individuals and often recover in several months. Careful examinations to rule out other causes and then steroid treatment should be considered after early diagnosis.

Aetiology, clinical features and surgical outcomes of isolated medial rectus palsy

IMPORTANCE

Isolated medial rectus palsy is extremely rare in clinical practice.

BACKGROUND

To report demographics, aetiology, clinical findings, imaging features and surgical outcomes in patients with isolated medial rectus palsy.

DESIGN

Retrospective study.

PARTICIPANTS

All patients treated for isolated medial rectus palsy at Zhongshan Ophthalmic Center, Sun Yat-sen University, between September 2003 and March 2019.

METHODS

Review of patient records.

MAIN OUTCOME MEASURES

Aetiology, clinical findings, imaging features and surgical outcomes.

RESULTS

A total of 32 patients (22 males, 10 females) were included. Mean age was 33.19 ± 19.78 years. The right eye was involved in 17 patients, the left eye was involved in 14 patients, and both eyes were involved in one patient. The most common causes were iatrogenic injury (43.75%), followed by trauma (37.50%) and congenital (18.75%). The most common clinical findings included outward deviation, diplopia and limited adduction. Six patients showed combined small-angle vertical strabismus, and 10 patients experienced a scale of -1 motility defect in other directions. After individualized strabismus surgery, preoperative exotropia of 60 ± 25 prism diopters (PD) was significantly reduced to 12 ± 13 PD (t = 10.938, P < .0001). Ocular motility improved in 21 patients, and five patients achieved normal ocular motility. Successful correction was obtained in 20/32 (62.50%) patients, with under-correction in 12/32 (37.50%) patients. Twenty-eight patients had only one surgery, three patients had two surgeries and one patient had three surgeries.

CONCLUSIONS AND RELEVANCE

The most common cause of isolated medial rectus palsy was local injury. Satisfactory results were obtained after individualized surgical interventions based on personalized preoperative evaluations.

The Incidence and Etiologies of Third Cranial Nerve Palsy in Koreans: A 10-year Nationwide Cohort Study

PURPOSE

This study aimed to determine the incidence, prevalence, and etiologies of third cranial nerve (CN3) palsy in Koreans.

METHODS

Data were collected from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) database of South Korea and analyzed. Incident CN3 palsy subjects in the cohort population were defined as cases occurring after the initial 4-year or longer washout period. The incidence and prevalence were analyzed by sex, age group, and year. The etiologies of CN3 palsy were evaluated using comorbidities.

RESULTS

Of 1,108,253 subjects, 387 patients were newly diagnosed with CN3 palsy between 2006 and 2015. The incidence of CN3 palsy was 3.71 per 100,000 person-years (95% confidence interval, 3.35-4.09). The incidence of CN3 palsy increased with age and accelerated after the age of 60 years. The mean male-to-female incidence ratio was 1.16. The main cause was presumed to be vascular disease (52.7%), followed by idiopathic causes (25.8%), intracranial neoplasm (7.8%), unruptured cerebral aneurysm (5.4%), and trauma (5.2%).

CONCLUSIONS

The incidence of CN3 palsy in Koreans increased with age and peaked between 75 and 79 years. The main cause of CN3 palsy was vascular disease.

The incidence and etiology of sixth cranial nerve palsy in Koreans: A 10-year nationwide cohort study

We aimed to investigate the incidence, prevalence, and etiology of sixth cranial nerve (CN6) palsy in the general Korean population. The nationally representative dataset of the Korea National Health Insurance Service–National Sample Cohort from 2006 through 2015 was analyzed. The incidence and prevalence of CN6 palsy were estimated in the cohort population, confirming that incident cases of CN6 palsy involved a preceding disease-free period of ≥4 years. The etiologies of CN6 palsy were presumed using comorbidity conditions. Among the 1,108,256 cohort subjects, CN6 palsy developed in 486 patients during the 10-year follow-up. The overall incidence of CN6 palsy was estimated to be 4.66 per 100,000 person-years (95% confidence interval [CI], 4.26–5.08) in the general population. This incidence increased with age, accelerating after 60 years of age and peaking at 70–74 years of age. The mean male-to-female incidence ratio was estimated as 1.41 in the whole population, and the incidence and prevalence of CN6 palsy showed an increasing trend over time in the study period. Surgical incidence for CN6 palsy was only 0.19 per 100,000 person-years (95% CI, 0.12–0.29). The etiologies were presumed to be vascular (56.6%), idiopathic (27.2%), neoplastic (5.6%), and traumatic (4.9%). In conclusion, the incidence of CN6 palsy increases with age, peaking at around 70 years, and shows a mild male predominance in Koreans.