Paralytic strabismus: third, fourth, and sixth nerve palsy

Traumatic oculomotor nerve palsy treated with transnasal endoscopic decompression through the optic strut

Objective

To present a surgical treatment regimen of transnasal endoscopic decompression through the optic strut for traumatic oculomotor nerve palsy based on the anatomical study of the superior orbital fissure and the oculomotor nerve fissure segment.

Methods

The bone structure of the oculomotor nerve fissure segment and the important bone anatomical landmarks of the lateral wall of the sphenoidal sinus were identified on a dried skull and a cadaveric head, respectively, using a nasal endoscope, and a surgical plan was determined. Decompression was conducted on the orbital apex, the superior orbital fissure, the optic canal and the optic strut of the two patients in sequence, after which the degree and range of decompression were identified by three-dimensional (3D) computed tomography (CT).

Results

The oculomotor nerve had a close correlation with the lateral surface of the optic strut. The transnasal endoscope was employed to identify the lateral optic-carotid recess (LOCR), as well as the positions of the optic nerve, internal carotid artery (ICA), and superior orbital fissure, collectively called the "optic strut triangle". The surgical plans for decompression of the orbital apex, superior orbital fissure, optic canal, and optic strut and the necessity of optic strut drilling were determined, and the surgical procedures for safe drilling of the optic strut were elaborated. After surgery, the two patients had significantly improved symptoms, without complications. In addition, their postoperative CT showed that the medial margin of the superior orbital fissure was fully decompressed.

Conclusion

The optic strut triangle is a crucial anatomical landmark in the decompression of the oculomotor nerve, and optic strut drilling is necessary for such decompression. For patients with traumatic oculomotor nerve palsy and fractures of the medial wall of the superior orbital fissure on CT, the oculomotor nerve fissure segment can be decompressed in an effective, complete and safe manner as per the surgical plan of decompressing the orbital apex, superior orbital fissure, optic canal and optic strut in turn under a transnasal endoscope, conducive to the recovery of neurological function of patients.

Evaluation of diplopia as a vital and remarkable ocular finding among cancer patients

BACKGROUND

Diplopia is an important and debilitating symptom of malignancies due to different pathogenetic mechanisms. Data is lacking in the literature because of the rarity of the diplopia in patients with cancer.

AIMS

We aimed to evaluate the etiological and clinical factors of diplopia in patients with different types of cancer.

METHODS

We retrospectively investigated 22 cancer patients with diplopia who were admitted between 2018 and 2021. The diagnosis of primary cancer, the underlying factors causing diplopia, and the life expectancy after diplopia were evaluated.

RESULTS

Among available data of 620 cancer patients applied to our ophthalmology department, 22 (3.55%) had diplopia. Paralytic strabismus was found in 19 patients and restrictive strabismus was found in 3 patients. Among the paralytic cases, 6th nerve palsy was found to be the most common with a rate of 68%. In 18 of 22 (82%) patients, the cause of diplopia was due to orbital or brain metastasis or local invasion. Two patients had diplopia secondary to radiotherapy and 2 had diplopia due to chemotherapy.

CONCLUSION

Metastasis is the most common cause of diplopia in patients with cancer and screening for metastasis is crucial as soon as diplopia begins for a better life expectancy.

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.

Case Report: Unilateral Cranial Nerve IV Palsy Secondary to Trochlear Schwannoma

SIGNIFICANCE

Cranial nerve IV palsy is the most common cranial nerve affected in both pediatric and adult patients with vertical and/or torsional diplopia. The condition has multiple known etiologies, including schwannoma, which is rarely reported in the literature. Schwannoma should be considered when the most common etiologies have been ruled out.

PURPOSE

This report documents a rare case of cranial nerve IV palsy secondary to a trochlear schwannoma. Treatment and management considerations will be discussed.

CASE REPORT

A 57-year-old man presented to the clinic for evaluation of his recent-onset vertical diplopia. He was diagnosed with left cranial nerve IV palsy. MRI of the brain and orbits revealed the presence of a schwannoma along the course of his left fourth cranial nerve. It did not compress any other cranial nerves or the brainstem. The patient was referred to the neuro-ophthalmology clinic for further evaluation. He was managed conservatively with prismatic spectacle correction to relieve his diplopia. Repeat MRI of the brain and orbits was recommended every 6 months.

CONCLUSIONS

Although rare, schwannoma of the fourth cranial nerve should be considered in cases of cranial nerve IV palsies without an obvious etiology. Neuroimaging of the brain and orbits is warranted in cases where more common etiologies have been ruled out or when other cranial nerves and/or the brainstem are involved.

Utility of Magnetic Resonance Imaging (MRI) in Children With Strabismus

PURPOSE

Magnetic resonance imaging (MRI) of the brain can provide valuable information about structural abnormalities in strabismus. The aim of this study was to evaluate the utility of MRI in this regard and to identify risk factors for abnormal MRI results in children with strabismus.

METHODS

A retrospective analysis of children <18 years of age presenting with strabismus, who underwent brain MRI at Pusan National University Hospital (Busan, Korea) between January 2012 and March 2017, was performed. Clinical characteristics, MRI results, and ophthalmologic findings were reviewed. Findings were classified as normal or abnormal according to MRI results. Additionally, patients were divided according to age to compare characteristics of infantile and childhood strabismus.

RESULTS

A total of 90 patients (47 [52.2%] male, 43 [47.8%] female; mean age, 2.19 ± 0.53 years) were enrolled. Of those, 64 (71.1%) presented with normal and 26 (28.9%) with abnormal MRI results. The age at presentation was lower and abnormal findings on fundus examination were more common in the abnormal MRI group (P = .002 and P = .008, respectively). Among the patients, 46 (51.1%) had infantile strabismus and 44 (48.9%) had childhood strabismus. Global developmental delays, speech delays, and MRI abnormalities were more common in patients with infantile than in those with childhood strabismus. Ptosis and headaches were more common in patients with childhood strabismus (P = .025, P = .025, respectively).

CONCLUSION

Brain MRI was helpful for accurate diagnosis and treatment of strabismus in younger children, those with abnormal findings on fundus examination, and infants with developmental, especially speech, delays.

Acquired Ocular Motor Nerve Palsy in Neurology Clinics: A Prospective Multicenter Study

BACKGROUND AND PURPOSE

This study aimed to determine the patterns and etiologies of acquired ocular motor nerve palsy (OMNP) diagnosed in neurology clinics. We also investigated the clinical features that may predict the causes other than microvascular ischemia in isolated OMNP.

METHODS

We performed a prospective multicenter study that had recruited 298 patients with acquired OMNP from the neurology clinics of referral-based 9 university hospitals in Korea. We finally selected 235 patients with isolated OMNP and divided them into older (age ≥50 years, n=188) and younger (age <50 years, n=47) groups. We investigated the underlying etiologies of acquired OMNP. We also estimated the frequency of microvascular ischemia and other causes in isolated OMNP, and sought to determine the clinical features that can predict the causes other than microvascular ischemia.

RESULTS

Abducens nerve palsy was the most common (40%) of the acquired OMNPs, followed by oculomotor nerve palsy (27%), trochlear nerve palsy (23%), and multiple OMNPs (10%). The etiologies included microvascular ischemia (47%), inflammatory (21%), stroke (5%), trauma (5%), neoplasm (3%), and others (2%), with the cause not being determined in 13% of the patients. Microvascular ischemia was the most common cause (83%) in patients aged ≥50 years with isolated OMNP, followed by inflammation (6%), stroke (6%), neoplasm (3%), and aneurysm (1%). Microvascular ischemia was more common in the older than the younger group (83% vs. 49%, p<0.001). The intensity of headache was the only risk factor for causes other than microvascular ischemia in isolated OMNP.

CONCLUSIONS

Vascular and inflammatory disorders are the most common causes of acquired OMNP diagnosed in neurology clinics. Microvascular ischemia was the predominant cause of isolated OMNP. Severe headache indicates causes other than microvascular ischemia in isolated OMNP.

Validity and reliability of the Ocular Motor Nerve Palsy Scale

Objective and accurate assessment of the degree of ocular motor nerve palsy is helpful not only in the evaluation of prognosis, but also for the screening of treatment methods. However, there is currently no comprehensive measure of its severity. In this study, we designed the Ocular Motor Nerve Palsy Scale and investigated its validity and reliability. Six experts were invited to grade and evaluate the scale. The study recruited 106 patients with a definite diagnosis of unilateral isolated ocular motor nerve palsy. Three physicians evaluated the patients using the scale. One of the three physicians evaluated the patients again after 24 hours. The content validity index (CVI) and factor analysis were used to analyze the scale's construct validity. The intraclass correlation coefficient and Cronbach's alpha were used to evaluate the inter-rater and test-retest reliability and the internal consistency. The CVI results (I-CVI = 1.0, S-CVI = 0.9, P = 0.016, K* = 1) indicated good content validity. Factor analysis extracted two common factors that accounted for 85.2% of the variance. Furthermore, the load value of each component was above 0.8, indicating good construct validity. The Ocular Motor Nerve Palsy Scale was found to be highly reliable, with an inter-rater reliability intraclass correlation coefficient of 0.965 (P < 0.01), a test-retest reliability intraclass correlation coefficient of 0.976 (P < 0.01), and Cronbach's alpha values of 0.63-0.70. In conclusion, the Ocular Motor Nerve Palsy Scale with good validity and reliability can be used to quantify the severity of ocular motor nerve palsy. This study was registered at Chinese Clinical Trial Registry (registration number: ChiCTR-OOC-17010702).

Guidelines for radiographic imaging of cranial neuropathies

Disruption of the complex pathways of the 12 cranial nerves can occur at any site along their course, and many, varied pathologic processes may initially manifest as dysfunction and neuropathy. Radiographic imaging (computed topography or magnetic resonance imaging) is frequently used to evaluate cranial neuropathies; however, indications for imaging and imaging method of choice vary considerably between the cranial nerves. The purpose of this review is to provide an analysis of the diagnostic yield and the most clinically appropriate means to evaluate cranial neuropathies using radiographic imaging. Using the PubMed MEDLINE NCBI database, a total of 49,079 articles' results were retrieved on September 20, 2014. Scholarly articles that discuss the etiology, incidence, and use of imaging in the context of evaluation and diagnostic yield of the 12 cranial nerves were evaluated for the purposes of this review. We combined primary research, guidelines, and best practice recommendations to create a practical framework for the radiographic evaluation of cranial neuropathies.

A Window to the Brain: Neuro-Ophthalmology for the Primary Care Practitioner

Visual symptoms, including acute monocular visual loss, papilledema, visual field deficits, anisocoria, limitations of eye movements, and nystagmus, can be the presenting feature of a wide range of important neurologic diseases. It is important for primary care clinicians to be to be able to direct appropriate initial diagnostic assessment, treatment, and referral for further evaluation of these conditions.

End-organ radiographic manifestations of cranial neuropathies: A concise review

BACKGROUND

Cranial neuropathies are a spectrum of disorders associated with dysfunction of one or more of the twelve cranial nerves and the subsequent anatomic structures they innervate.

OBJECTIVE

The purpose of this article is to review radiographic imaging findings of end-organ aberrations secondary to cranial neuropathies.

METHOD

All articles related to cranial neuropathies were retrieved through the PubMed MEDLINE NCBI database from January 1, 1991 to August 31, 2014. These manuscripts were analyzed for their relation to cranial nerve end-organ disease pathogenesis and radiographic imaging.

RESULTS

The present review reveals detectable end-organ changes on CT and/or MRI for the following cranial nerves: olfactory nerve, optic nerve, oculomotor nerve, trochlear nerve, trigeminal nerve, abducens nerve, facial nerve, vestibulocochlear nerve, glossopharyngeal nerve, vagus nerve, accessory nerve, and hypoglossal nerve.

CONCLUSION

Radiographic imaging can assist in the detailed evaluation of end-organ involvement, often revealing a corresponding cranial nerve injury with high sensitivity and diagnostic accuracy. A thorough understanding of the distal manifestations of cranial nerve disease can optimize early pathologic detection as well as dictate further clinical management.

Neurofibromatosis Type 2 Presenting with Oculomotor Ophthalmoplegia and Distal Myopathy

Neurofibromatosis type 2 usually presents with bilateral acoustic schwannomas. We highlight the rare presentation of neurofibromatosis initially involving third nerve. A 23-year-old Malay female presented with left eye drooping of the upper lid and limitation of upward movement for 8 years. It was associated with right-sided body weakness, change in voice, and hearing disturbance in the right ear for the past 2 years. On examination, there was mild ptosis and limitation of movement superiorly in the left eye. Both eyes had posterior subcapsular cataract. Fundoscopy showed generalised optic disc swelling in both eyes. She also had palsy of the right vocal cord, as well as the third and eighth nerve. There was wasting of the distal muscles of her right hand, with right-sided decreased muscle power. Pedunculated cutaneous lesions were noted over her body and scalp. MRI revealed bilateral acoustic and trigeminal schwannomas with multiple extra-axial lesions and intradural extramedullary nodules. Patient was diagnosed with neurofibromatosis type 2 and planned for craniotomy and tumour debulking, but she declined treatment. Neurofibromatosis type 2 may uncommonly present with isolated ophthalmoplegia, so a thorough physical examination and a high index of suspicion are required to avoid missing this condition.

Headache in the Emergency Department: Avoiding Misdiagnosis of Dangerous Secondary Causes

There are a number of dangerous secondary causes of headaches that are life, limb, brain, or vision threatening that emergency physicians must consider in patients presenting with acute headache. Careful history and physical examination targeted at these important secondary causes of headache will help to avoid misdiagnosis in these patients. Patients with acute thunderclap headache have a differential diagnosis beyond subarachnoid hemorrhage. Considering the "context" of headache "PLUS" some other symptom or sign is one strategy to help focus the differential diagnosis.

Assessment of the prevalence and risk factors of ophthalmoplegia among diabetic patients in a large national diabetes registry cohort

BACKGROUND

There are limited data on the epidemiology and risk factors of ophthalmoplegia among diabetic patients. This study aims to determine the prevalence and important risk factors related to ophthalmoplegia among diabetic patients.

METHODS

This is an observational registry-based study using the Saudi National Diabetes Registry (SNDR) database to select diabetic patients regardless of their diabetes type. A total of 64,351 Saudi diabetic patients aged more than 18 years and registered in SNDR between January 2000 and December 2010 were analyzed to identify ophthalmoplegic cases. Demographic, clinical, and biochemical parameters were studied and STROBE guidelines were used to design and report the results of this study.

RESULTS

The overall prevalence of ophthalmoplegia cases was 0.32 %, further distributed into: 53.11 %, 36.36 %, and 2.8 % for cranial nerves VI, III, IV palsies respectively. Ophthalmoplegic cases were predominantly type 2 diabetic males with older age and longer diabetes duration. The most important and significant risk factors were age ≥ 45 years, diabetes duration ≥ 10 years, male gender and presence of retinopathy and nephropathy.

CONCLUSIONS

Ophthalmoplegia is a rare entity associated mainly with type 2 diabetes. Clinicians have to consider its risk factors when screening or planning for prevention of this condition.

Facial asymmetry in ocular torticollis

Torticollis can arise from nonocular (usually musculoskeletal) and ocular conditions. Some facial asymmetries are correlated with a history of early onset ocular torticollis supported by the presence of torticollis on reviewing childhood photographs. When present in an adult, this type of facial asymmetry with an origin of ocular torticollis should help to confirm the chronicity of the defect and prevent unnecessary neurologic evaluation in patients with an uncertain history. Assessment of facial asymmetry consists of a patient history, physical examination, and medical imaging. Medical imaging and facial morphometry are helpful for objective diagnosis and measurement of the facial asymmetry, as well as for treatment planning. The facial asymmetry in congenital superior oblique palsy is typically manifested by midfacial hemihypoplasia on the side opposite the palsied muscle, with deviation of the nose and mouth toward the hypoplastic side. Correcting torticollis through strabismus surgery before a critical developmental age may prevent the development of irreversible facial asymmetry. Mild facial asymmetry associated with congenital torticollis has been reported to resolve with continued growth after early surgery, but if asymmetry is severe or is not treated in the appropriate time, it might remain even with continued growth after surgery.

Sixth cranial nerve palsy due to arachnoid cyst

Sixth cranial nerve palsy is an extremely rare complication of an arachnoid cyst. A 4-year-old boy who presented with left abducens palsy and a subdural hygroma complicating arachnoid cyst is discussed. Comprehensive review of the world literature revealed only 12 additional cases.

Infrared pupillometry, the Neurological Pupil index and unilateral pupillary dilation after traumatic brain injury: implications for treatment paradigms

Pupillary dysfunction, a concerning finding in the neurologic examination of the patient with an acute traumatic brain injury often dictates the subsequent treatment paradigm. Patients were monitored closely with an infrared pupillometer, with NPi technology, for acute changes in pupillary function. NPi technology applies a scalar value to pupillary function. A retrospective chart review was performed of traumatic brain injury patients with acute unilateral pupillary dilation, admitted to Legacy Emanuel Medical Center’s NeuroTrauma Unit, Portland, OR, and followed as outpatients, between January 2012 and December 2013. Clinical exam findings of pupillary size, NPi scores, and brain Magnetic Resonance Imaging and Computed Tomography images were analyzed. Five traumatic brain injury patients were identified with unilateral pupillary dysfunction with long-term follow-up after the initial injury. Each patient was monitored closely in the trauma bay for neurological deterioration with a pupillometer and the clinical exam. Two patients underwent subsequent intracranial pressure monitoring based on a deteriorating clinical scenario, including consistent abnormal unilateral NPi scores. One patient with consistent abnormal NPi scores and an improved clinical exam did not undergo invasive interventions. Two patients showed early improvement in NPi scores correlating with the normalization of their pupillary reactivity. Anisocoria improved in all patients despite concurrent abnormal NPi scores. Magnetic Resonance Imaging and Computed Tomography imaging studies, with a focus on the third nerve, revealed focal abnormalities consistent with the clinical findings. A unilateral blown pupil and abnormal NPi score in a traumatic brain injury patient are not necessarily indicative of intracranial pressure issues, and must be correlated with the entire clinical scenario, to determine the etiology of the third nerve injury and direct potential therapeutic interventions. Early NPi score normalization suggests pupillary function may improve. We found that NPi scores, as a component of the clinical exam, provide a sensitive, noninvasive and quantitative means of following pupillary function acutely and chronically after a traumatic brain injury.

Understanding the Neuro-ophthalmology of Head Trauma: A Review of the Current Literature

Head trauma is a major medical, social, economic, national, and public health priority issue in the United States. In severe head trauma, the overwhelming clinical manifestations are so compelling that damage to the visual system is most likely to be ignored. Both the afferent and efferent visual systems are susceptible to injury after head trauma, and physicians should be aware of the visual system and perform a thorough neuro-ophthalmic evaluation in patients presenting with head trauma.Most of the data available on neuro-ophthalmic complications of head trauma including cortical blindness, Horner's syndrome, traumatic internuclear ophthalmoplegia, and ocular motor palsy, comes from case reports highlighting the need for future studies to better understand these complications.This review summarizes some of the most important neuro-ophthalmic complications of head trauma including cortical blindness, Horner's syndrome, traumatic internuclear ophthalmoplegia, and ocular motor palsy. Search of the peer-reviewed literature was conducted using MEDLINE, Cumulative Index to Nursing and Allied Health Literature, Cochrane Library, Global Health, and MD Consult.

A prospective study on 132 cases of ocular palsy

OBJECTIVES

In this prospective study, we used one diagnostic protocol to establish an early diagnosis in patients with ocular palsies in absence of other neurological findings.

MATERIALS AND METHODS

The study was performed on a consecutive series of 132 patients who visited our Neurological Department for ptosis and/or diplopia in absence of other neurological signs, using the same diagnostic protocol.

RESULTS

An etiological diagnosis was made in 74% of cases during a mean time of 17 ± 23 months from symptom onset. Myasthenia gravis was the most common diagnosis (n = 60, 45.5%). Thirty-four cases (26%) remained undiagnosed in spite of a follow-up lasting 32 ± 33 months on average.

CONCLUSIONS

Identifying the cause of an isolated ocular palsy can be difficult, and an extended follow-up time does not aid in further establishment of the diagnosis.