Etiologic distribution of isolated abducens nerve palsy: Analysis of 807 patients and literature review.

BACKGROUND AND PURPOSE: The etiologies of abducens nerve palsy have shown a large variability among studies. This study aimed to establish the clinical features and underlying etiologies of isolated abducens nerve palsy by recruiting patients from all departments in a referral-based university hospital. METHODS: We reviewed the medical records of 807 patients with a confirmed diagnosis of isolated abducens nerve palsy at all departments of Seoul National University Bundang Hospital, Seongnam, Republic of Korea, from 2003 to 2020. We also compared the proportion of etiology with that of the patients pooled from the previous studies. RESULTS: The most common etiology was microvascular (n = 296, 36.7%), followed by idiopathic (n = 143, 17.7%), neoplastic (n = 115, 14.3%), vascular anomalies (n = 82, 10.2%), inflammatory (n = 76, 9.4%), and traumatic (n = 35, 4.3%). Patients were mostly managed by ophthalmologists (n = 576, 71.4%), followed by neurologists (n = 479, 59.4%), emergency physicians (n = 278, 34.4%), neurosurgeons (n = 191, 23.7%), and others (n = 72, 8.9%). The proportion of etiology significantly differed according to the age and sex of the patients and the specialties involved in the management (p < 0.001). Compared to the pooled data from the previous reports, the current study showed a higher prevalence of microvascular cause but a lower occurrence of traumatic and neoplastic causes. CONCLUSIONS: The results of previous studies on etiologic distribution of isolated abducens nerve palsy should be interpreted with consideration of the demographic features of patients recruited and the specialties involved.

Aetiologies of acquired pediatric sixth nerve palsies in a U.K. based population.

Due to the low incidence of sixth cranial nerve palsies in children, there has been limited evidence published on this subject, especially from a population based within the UK. The incidence of etiologies has been found to vary significantly within the literature, especially with regard to neoplasms. The main aim of this study is to present the etiologies of newly diagnosed pediatric sixth nerve palsies in a UK-based population. We also take into consideration if the palsies were isolated or associated with other neurological signs or symptoms. Retrospective data collection was carried out on the medical records of 50 pediatric patients with a new-onset sixth nerve palsy. They all presented to a large tertiary referral hospital in the South of the UK between 1 January 2007 and 31 December 2017. Data collected for each patient included age, gender, ethnicity, unilateral versus bilateral, other signs and symptoms, etiology, where the patient first presented, and whether the palsy was the first presenting feature. Thirty-three (66%) patients had a new-onset sixth nerve palsy in conjunction with other neurological signs or symptoms and were considered non-isolated. Seventeen cases (34%) were found to be isolated. Etiologies included high intracranial pressure (18%), neoplasm (14%), surgery for neoplasm (14%), viral (14%), infection (12%), trauma (8%), idiopathic (6%), benign space-occupying lesion (4%), congenital (2%), inflammation (2%), Alexander's disease (2%), Kawasaki syndrome (2%), and diabetes (2%). Our study found non-isolated sixth nerve palsies to be the most common presentation. These patients had a high number of potentially sinister etiologies, the most common being high intracranial pressure followed by post-surgery for neoplasm and neoplasm. Isolated sixth nerve palsies were more commonly due to viral or idiopathic etiology; however, two cases of benign space-occupying lesion and one of neoplasm were identified.

Association of Obesity and Incidence of Third, Fourth, and Sixth Cranial Nerve Palsies.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To assess the association between obesity and the development of third, fourth, and sixth cranial nerve palsy (CNP). METHODS: We analyzed a cohort of 4,067,842 adults aged between 20 and 90 years who underwent health checkups within the National Health Insurance Service between January 1 and December 31, 2009. The participants were followed until December 31, 2017. Cox proportional hazards regression analysis was used to determine the adjusted hazard ratios (HRs) for CNP. Model 3 (the main analysis model) was adjusted for age, sex, smoking status, alcohol consumption, and physical activity. Model 4 was additionally adjusted for hypertension, dyslipidemia, and diabetes mellitus in the setting of model 3. RESULTS: A total of 5,835 individuals were diagnosed with CNP during the follow-up period (7.3 years). General obesity (body mass index [BMI] ≥25 kg/m2) was associated with an increased risk of CNP compared to individuals without general obesity (model 3, HR 1.248, 95% CI 1.184-1.315; model 4, HR 1.162, 95% CI 1.102-1.227). Abdominal obesity (waist circumference [WC] ≥90 cm in men and ≥85 cm in women) also showed an increased HR compared to individuals without abdominal obesity (model 3, 1.239, 95% CI 1.170-1.313; model 4, HR 1.127, 95% CI 1.062-1.196). Compared to the group without either type of obesity, the group with only abdominal obesity (model 3, HR 1.167, 95% CI 1.035-1.317), the group with only general obesity (HR 1.19, 95% CI 1.14-1.24), and the group with both obesity types (HR 1.317, 95% CI 1.236-1.404) showed increased HRs for CNP. CONCLUSION: Based on our population-based cohort study, both general and abdominal obesity increased the risk of CNP. Also, the combination of general and abdominal obesity may further increase the risk of CNP.

Incidence of symptomatic vertical and torsional diplopia after superior rectus transposition for esotropic Duane syndrome and abducens nerve palsy.

PURPOSE: To report the incidence of symptomatic vertical and torsional diplopia after superior rectus transposition (SRT) for esotropic Duane syndrome and abducens nerve palsy. METHODS: The medical records of patients with esotropic Duane syndrome or abducens nerve palsy seen at Boston Children's Hospital (2006-2018) and treated with unilateral SRT with or without augmentation was performed. The primary outcome was incidence of postoperative vertical or torsional diplopia in primary position. The secondary outcome was induced vertical deviation in affected side gaze. RESULTS: A total of 69 patients met inclusion criteria: 32 with abducens nerve palsy and 37 with esotropic Duane syndrome. Vertical alignment changed in both hyper- and hypotropic directions. Median pre- and postoperative vertical deviation in primary gaze was 1.1Δ (10th-90th percentile, 0Δ-6Δ hypertropia) and 0.4Δ (10th-90th percentile, 6Δ hypotropia to 8 Δ hypertropia), respectively. Postoperative vertical diplopia occurred in 7%, including 4 of 49 treated with loop myopexy (8%), 1 of 13 without augmentation (8%), and 0 of 7 treated with sclera-fixated augmentation. All but one was successfully treated with prism or secondary surgery. Intorsional change predominated, but no patient had torsional diplopia post adjustment. Vertical misalignment in affected side gaze increased from 19% to 45% after SRT (P = 0.01). CONCLUSIONS: In this largest-to-date review of patients treated with SRT, with or without MR recession, no patient developed persistent torsional diplopia, while 7% developed symptomatic vertical diplopia in primary position, similar to the reported incidence after balanced vertical rectus transposition. Vertical misalignment in affected side gaze increased, however fusion is already limited by unresolved esotropia in this field.

The Multiple Cranial Nerve Palsies: A Prospective Observational Study.

BACKGROUND: Neurological presentation with isolated multiple cranial nerve palsies is common and its diverse causes include infectious, neoplastic, and inflammatory pathologies. The aetiological spectrum may depend upon geographical regions. We undertook this study to explore clinical spectrum and aetiological profile of multiple cranial nerve palsies. METHODS: This hospital-based prospective observational study was conducted from August 2015 to August 2017. All the consecutive patients of multiple cranial palsies presenting to the neurology department were included in the studies. Primary objectives were to define anatomical syndromes/cranial nerve combinations and to establish aetiology. Secondary objectives were to study associated factors. The multiple cranial nerve palsy was defined as involvement of two or more non-homologous nerves. Patients of neuromuscular junction disorders, anterior horn cell disorders, myopathies, brain stem syndromes were excluded. All patients underwent structured protocol of clinical evaluation, investigations and few specialized investigations in accordance with clinical suspicion to establish the diagnosis. RESULTS: Fifty-four patients with a mean age of 39.9 ± 14.2 years were included. Commonest cranial nerve involved was the abducens (75.9%) among all nerve combinations. The cavernous sinus syndrome (37%), orbital apex syndrome (22.2%) and jugular foramen syndrome (11.1%) were the most frequent anatomical patterns. Infections (40.7%) were the commonest aetiology followed by neoplastic and idiopathic in four patients. CONCLUSION: Cavernous sinus syndrome was the commonest anatomical syndrome of multiple cranial nerve palsies and infections were the commonest cause in this study.

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.

Infectious ocular motor neuropathies.

PURPOSE OF REVIEW: Describe the range of infectious causes of ocular motor neuropathies, from common presentations to unusual manifestations of diseases less frequently seen in the developed world. Provide information on recent developments in diagnostic testing for pathogens that may cause ocular motor neuropathies. RECENT FINDINGS: Antigen detection in serum or CSF has improved the diagnosis of cryptococcal disease. Cartridge PCR testing for tuberculosis has increased diagnostic accuracy, though tuberculous meningitis remains difficult to diagnose. Rapid, multiplex PCR and unbiased sequencing allow for diagnosis of a wider range of organisms. SUMMARY: Infectious ocular motor neuropathies can occur anywhere along the length of cranial nerves III, IV, and VI. Characteristic clinical findings and imaging can be used to localize infections. Infectious causes may have characteristic clinical, laboratory, or imaging findings, but must still be carefully separated from inflammatory or neoplastic conditions.

Third, Fourth, and Sixth Cranial Nerve Palsies in Pituitary Apoplexy.

BACKGROUND: Pituitary apoplexy (PA) often presents with acute headache and neuro-ophthalmic manifestations, including ocular motility dysfunction (OMD) from cranial nerve palsies (CNPs). Our goal was to describe the epidemiology and outcomes of OMD in a large, single-center series of patients with PA. METHODS: We conducted a retrospective chart review of all patients with PA seen in our pituitary center between January 1995 and December 2012. Presenting neuro-ophthalmic, endocrine, and radiologic data, as well as neuro-ophthalmology follow-up data, were collected. RESULTS: We identified 235 patients with PA, 59 of whom (25%) had OMD. Twenty-seven of those 59 patients underwent neuro-ophthalmic evaluation. Preoperatively, 23 of these 27 patients had unilateral OMD, 18 (78%) with a single CNP and 5 (22%) with multiple CNPs. Bilateral OMD was present in 4 of the 27 patients. Postoperatively, 24 of the 27 patients with OMD had follow-up (median duration, 7 months; interquartile range [IQR], 3-17 months). At the last postoperative follow-up, 7 of these 24 patients (29%) had OMD (5 unilateral, 2 bilateral). OMD resolved in 3 of the 24 patients (12%) within 1 month, in 13 of 21 patients (62%) within 6 months (3 lost to follow-up), and in 17 of 19 patients (89%) within 1 year (2 lost to follow-up). Surgery was performed at ≤14 days after presentation in 16 of 18 (89%) resolved cases and in 4 of 6 (67%) unresolved cases. Patients with OMD were more likely than those without OMD to have larger tumors (2.6 vs. 2.0 cm; P < 0.001), panhypopituitarism (31% vs. 14%; P = 0.005), and necrosis (58% vs. 37%; P = 0.03). CONCLUSIONS: OMD from CNPs is common in PA, occurring in one-quarter of patients, and is frequently associated with certain radiologic, endocrinologic, and pathological features. The prognosis is excellent, with 90% of cases of OMD resolving by 1 year after early pituitary surgery.

Strategy for the surgical treatment of vestibular schwannomas in patients with neurofibromatosis type 2.

OBJECTIVE: Guidelines for appropriate management of vestibular schwannomas in NF2 patients are controversial. In this paper we reviewed our experience with patients with NF2 for the results of surgical treatment with particular reference to hearing and facial nerve preservation. METHODS: We included in the study 30 patients (16 women and 14 men) with the diagnosis of NF2 treated in our department between 1998 and 2014 who underwent surgery for vestibular schwannoma removal with a follow-up for at least 1 year. In 3 cases, the vestibular schwannomas were unilateral. Six patients with bilateral vestibular schwannomas underwent unilateral procedure. Therefore, 51 acoustic tumors were studied in 30 patients. RESULTS: No operative death we noted. Significant deterioration to the non-functional level occurred in 19 out of 22 cases with well-preserved preoperative hearing. Only three ears maintained their preoperative good hearing. Hearing was preserved in cases of small schwannoma not exceeding 2 cm. Among 21 patients who underwent bilateral operations hearing was preserved in 3 out of 7 cases when smaller tumor or better hearing level side was attempted at first surgery. In contrary none of the 14 patients retained hearing when the first operation concerned the worse-hearing ear. Among 14 tumors up to 2 cm there was only one case of moderately severe facial nerve dysfunction (House-Brackmann Grade IV) in the long follow-up. CONCLUSION: Early surgical intervention for vestibular schwannoma in NF2 patient is a viable management strategy to maintain hearing function and preserve facial nerve function.

Risk factors and prognosis of isolated ischemic third, fourth, or sixth cranial nerve palsies in the Korean population.

BACKGROUND: To investigate the risk factors and prognosis for ischemic third, fourth, and sixth cranial nerve palsies in a Korean population. METHODS: A pair-matched case-control study of 54 Korean patients who were diagnosed with ischemic third, fourth, or sixth cranial nerve palsies was performed to evaluate their risk factors. Using conditional logistic regression analysis, prevalence of potential risk factors in patients and controls, included diabetes mellitus, hypertension, hyperlipidemia, ischemic heart disease, left ventricular hypertrophy (LVH), and smoking were examined retrospectively. A cohort study by Kaplan-Meier method was performed to analyze the recovery period in relation to the number of risk factors or intracranial abnormalities detected by brain computed tomography or magnetic resonance imaging. RESULTS: The mean age of onset was 64.5 years. Of the 54 patients, 16 (29.6%) developed a third nerve palsy, 19 (35.2%) a fourth nerve palsy, and 19 (35.2%) a sixth nerve palsy. The risk factors of diabetes mellitus, hypertension, and hyperlipidemia were significantly more prevalent than other risk factors of heart disease, LVH, and smoking. The mean number of risk factors was 2.3 ± 0.6 in the third nerve palsy group, 1.7 ± 0.9 in the fourth nerve palsy group, and 1.6 ± 1.0 in the sixth nerve palsy group. Patients with 2 or more risk factors showed a longer recovery period (9.0 ± 5.1 weeks) than did patients who had 1 risk factor (6.1 ± 2.2 weeks). Patients with intracranial abnormalities on neuroimaging showed a longer recovery time (10.4 ± 2.7 weeks) than did those without intracranial abnormalities (7.5 ± 4.8 weeks). CONCLUSIONS: Ischemic ocular motor cranial nerve palsy is closely related to diabetes mellitus, hypertension, and hyperlipidemia in Korean patients. Compared with the fourth or sixth nerve palsy groups, the third nerve palsy group showed a tendency to have multiple risk factors. Recovery takes longer when 2 or more risk factors were present or when abnormal findings were observed on neuroimaging.

Incidence, associations, and evaluation of sixth nerve palsy using a population-based method.

PURPOSE: To determine the incidence of sixth nerve palsy in a population-based study, with particular emphasis on associated coexisting medical conditions and to use these data to develop a management algorithm. DESIGN: Retrospective, population-based case series. PARTICIPANTS: All residents of Olmsted County, Minnesota, USA, diagnosed with sixth nerve palsy between January 1, 1978 and December 31, 1992. METHODS: All cases were identified by using the Rochester Epidemiology Project medical records linkage system, which captures all patient-physician encounters in Olmsted County. The entire medical record of each patient was reviewed to confirm the diagnosis, document county residency, and to determine associated medical conditions. We used stringent predetermined criteria to define diabetes mellitus and hypertension as associations. Incidence rates were adjusted to the age and gender distribution of the 1990 white population in the United States. MAIN OUTCOME MEASURES: Etiology or systemic associations of the palsy. RESULTS: We identified 137 new cases of sixth nerve palsy over the 15-year period. The age- and gender-adjusted annual incidence of sixth nerve palsy was 11.3/100 000 (95% confidence interval, 9.3-13.2/100 000). Causes and associations were: undetermined (26%), hypertension alone (19%), coexistent hypertension and diabetes (12%), trauma (12%), multiple sclerosis (7%), neoplasm (5%), diabetes alone (4%), cerebrovascular accident (4%), postneurosurgery (3%), aneurysm (2%), and other (8%). When sixth nerve palsy was the presenting sign in cases of neoplasm (n = 1) and aneurysm (n = 3), history and examination revealed the presence of other neurologic symptoms or signs. CONCLUSIONS: We provide population-based data on the incidence of sixth nerve palsy with a notably lower incidence of neoplasm and higher incidence of diabetes and hypertension than previous institution-based series. We suggest that patients with nontraumatic neurologically isolated sixth nerve palsy may undergo a focused medical evaluation followed by close observation, whereas non-neurologically isolated cases warrant a full neurologic evaluation, including prompt neuroimaging.