-
Seminars in Ultrasound, CT, and MR Oct 2022The oculomotor nerve is the third cranial nerve, exiting the brainstem in the medial border of the cerebral peduncle, from where it crosses straight to the superior...
The oculomotor nerve is the third cranial nerve, exiting the brainstem in the medial border of the cerebral peduncle, from where it crosses straight to the superior orbital fissure. It is a purely motor nerve responsible for the innervation of all the extraocular muscles, except the superior oblique and lateral rectus muscles. It also has parasympathetic pre-ganglionic fibers, responsible for the innervation of sphincter pupillae and ciliary muscles. Magnetic resonance imaging (MRI) is the best imaging exam to evaluate patients with clinical signs of third cranial nerve palsy. The oculomotor nerve can be affected by several diseases, such as congenital malformations, trauma, inflammatory or infectious diseases, vascular disorders, and neoplasms. This article aims to review the oculomotor nerve anatomy, discuss the best MRI techniques to evaluate each nerve segment, and demonstrate the imaging aspect of the diseases that most commonly affect it.
Topics: Humans; Magnetic Resonance Imaging; Oculomotor Muscles; Oculomotor Nerve; Oculomotor Nerve Diseases; Orbit
PubMed: 36116851
DOI: 10.1053/j.sult.2022.04.009 -
Survey of Ophthalmology 2022Oculomotor nerve schwannomas are rare benign cranial nerve tumors. There are only a limited number of reports on this pathology in the literature, and there are... (Review)
Review
Oculomotor nerve schwannomas are rare benign cranial nerve tumors. There are only a limited number of reports on this pathology in the literature, and there are currently no established management guidelines that aid providers in deciding on surgical versus nonsurgical management. We assess the published literature on the topic to identify indications for treatment as well as outcome measures (e.g., local control rates, survival rates, and complication rates) that have been reported as associated with the various treatment modalities. We attempt to develop an algorithm for evaluation and treatment of oculomotor nerve schwannomas in order to establish consensus on how these tumors should be treated.
Topics: Algorithms; Cranial Nerve Neoplasms; Humans; Neurilemmoma; Oculomotor Nerve; Oculomotor Nerve Diseases
PubMed: 34813853
DOI: 10.1016/j.survophthal.2021.11.008 -
Current Problems in Diagnostic Radiology 2022The purpose of this article is to understand the complex pathologic spectrum of oculomotor nerve palsy. We review the detailed anatomy and function of the oculomotor... (Review)
Review
The purpose of this article is to understand the complex pathologic spectrum of oculomotor nerve palsy. We review the detailed anatomy and function of the oculomotor nerve and demonstrate how the location of a lesion can drive the differential diagnosis. Lastly, we review atypical presentations of oculomotor nerve palsy to include oculomotor synkinesis and oculomotor nerve hyperactivity. Radiologists must be aware of the typical and atypical presentations of CN III palsy to accurately localize lesions as well as avoid premature exclusion of CN III pathology.
Topics: Diagnosis, Differential; Humans; Oculomotor Nerve; Oculomotor Nerve Diseases
PubMed: 33495031
DOI: 10.1067/j.cpradiol.2020.12.006 -
Clinical Neurology and Neurosurgery Feb 2023This study aims to describe the clinical characteristics of patients with isolated oculomotor nerve palsy from COVID-19 infection, and provide guidance on their...
AIM
This study aims to describe the clinical characteristics of patients with isolated oculomotor nerve palsy from COVID-19 infection, and provide guidance on their treatment and management.
METHODS
We performed a systematic review and retrospective analysis on the clinical features and outcomes of patients with isolated oculomotor nerve palsy from COVID-19 reported in literature over the past three years.
RESULTS
We analyzed a total of 11 cases; 9 identified in literature from January 2020 to September 2022, together with our two patients. Their median age was 46 years (range 2-65), and three were children. More than half (6/11, 55 %) were without medical history. Oculomotor nerve palsies tended to occur early (longest interval of 16 days), but they can also occur concurrently (2/11, 18 %) or before the appearance of COVID-19 symptoms (1/11, 9 %). COVID-19 symptoms tended to be mild (8/11, 73 %). Oculomotor nerve palsies, however, displayed neither a clear gender predilection, nor consistent clinical features in terms of the severity of extraocular weakness and the involvement of pupillary light responses. Nearly two-thirds (7/11, 64 %) received no pharmacological treatment. Regardless, recovery was complete in nearly all (9/10, 90 %), with most occurring within a month (8/9, 89 %) CONCLUSION: Isolated oculomotor nerve palsies are early but uncommon complications of COVID-19. They affect patients with mild infections, and can be the first symptom. Prognosis is excellent, with recovery being often complete and early. Early discharge and outpatient clinical review, with or without short courses of oral steroids, are reasonable treatment measures.
Topics: Child; Humans; Child, Preschool; Adolescent; Young Adult; Adult; Middle Aged; Aged; Retrospective Studies; COVID-19; Oculomotor Nerve Diseases; Prognosis; Oculomotor Nerve
PubMed: 36696848
DOI: 10.1016/j.clineuro.2023.107601 -
Journal Francais D'ophtalmologie Dec 2022
Topics: Humans; Oculomotor Nerve; Edema
PubMed: 36030107
DOI: 10.1016/j.jfo.2022.04.022 -
Journal of Neuro-ophthalmology : the... Mar 2022This study identifies the diagnostic errors leading to misdiagnosis of 3rd nerve palsy and to aid clinicians in making this diagnosis. The objective of this article is...
BACKGROUND
This study identifies the diagnostic errors leading to misdiagnosis of 3rd nerve palsy and to aid clinicians in making this diagnosis. The objective of this article is to determine the incidence of misdiagnosis of 3rd cranial nerve palsy (3rd nerve palsy) among providers referring to a tertiary care neuro-ophthalmology clinic and to characterize diagnostic errors that led to an incorrect diagnosis.
METHODS
This was a retrospective clinic-based multicenter cross-sectional study of office encounters at 2 institutions from January 1, 2014, to January 1, 2017. All encounters with scheduling comments containing variations of "3rd nerve palsy" were reviewed. Patients with a documented referral diagnosis of new 3rd nerve palsy were included in the study. Examination findings, including extraocular movement examination, external lid examination, and pupil examination, were collected. The final diagnosis was determined by a neuro-ophthalmologist. The Diagnosis Error Evaluation and Research (DEER) taxonomy tool was used to categorize the causes of misdiagnosis. Seventy-eight patients referred were for a new diagnosis of 3rd nerve palsy. The main outcome measure was the type of diagnostic error that led to incorrect diagnoses using the DEER criteria as determined by 2 independent reviewers. Secondary outcomes were rates of misdiagnosis, misdiagnosis rate by referring specialty, and examination findings associated with incorrect diagnoses.
RESULTS
Of 78 patients referred with a suspected diagnosis of 3rd nerve palsy, 21.8% were determined to have an alternate diagnosis. The most common error in misdiagnosed cases was failure to correctly interpret the physical examination. Ophthalmologists were the most common referring provider for 3rd nerve palsy, and optometrists had the highest overdiagnosis rate of 3rd nerve palsy.
CONCLUSIONS
Misdiagnosis of 3rd nerve palsy was common. Performance and interpretation of the physical examination were the most common factors leading to misdiagnosis of 3rd nerve palsy.
Topics: Cross-Sectional Studies; Diagnostic Errors; Electron Spin Resonance Spectroscopy; Humans; Oculomotor Nerve Diseases; Paralysis; Retrospective Studies
PubMed: 32991390
DOI: 10.1097/WNO.0000000000001010 -
Developmental Biology Aug 2021Muscle function is dependent on innervation by the correct motor nerves. Motor nerves are composed of motor axons which extend through peripheral tissues as a compact...
Muscle function is dependent on innervation by the correct motor nerves. Motor nerves are composed of motor axons which extend through peripheral tissues as a compact bundle, then diverge to create terminal nerve branches to specific muscle targets. As motor nerves approach their targets, they undergo a transition where the fasciculated nerve halts further growth then after a pause, the nerve later initiates branching to muscles. This transition point is potentially an intermediate target or guidepost to present specific cellular and molecular signals for navigation. Here we describe the navigation of the oculomotor nerve and its association with developing muscles in mouse embryos. We found that the oculomotor nerve initially grew to the eye three days prior to the appearance of any extraocular muscles. The oculomotor axons spread to form a plexus within a mass of cells, which included precursors of extraocular muscles and other orbital tissues and expressed the transcription factor Pitx2. The nerve growth paused in the plexus for more than two days, persisting during primary extraocular myogenesis, with a subsequent phase in which the nerve branched out to specific muscles. To test the functional significance of the nerve contact with Pitx2+ cells in the plexus, we used two strategies to genetically ablate Pitx2+ cells or muscle precursors early in nerve development. The first strategy used Myf5-Cre-mediated expression of diphtheria toxin A to ablate muscle precursors, leading to loss of extraocular muscles. The oculomotor axons navigated to the eye to form the main nerve, but subsequently largely failed to initiate terminal branches. The second strategy studied Pitx2 homozygous mutants, which have early apoptosis of Pitx2-expressing precursor cells, including precursors for extraocular muscles and other orbital tissues. Oculomotor nerve fibers also grew to the eye, but failed to stop to form the plexus, instead grew long ectopic projections. These results show that neither Pitx2 function nor Myf5-expressing cells are required for oculomotor nerve navigation to the eye. However, Pitx2 function is required for oculomotor axons to pause growth in the plexus, while Myf5-expressing cells are required for terminal branch initiation.
Topics: Animals; Axons; Female; Gene Expression; Gene Expression Regulation; Homeodomain Proteins; Mice; Muscle Development; Myogenic Regulatory Factor 5; Oculomotor Muscles; Oculomotor Nerve; Pregnancy; Transcription Factors; Homeobox Protein PITX2
PubMed: 33905720
DOI: 10.1016/j.ydbio.2021.04.006