Carotid-cavernous fistula: A potential treatable cause of bilateral abducens palsy and conjunctival hyperemia.

OBJECTIVE: Carotid cavernous fistulas (CCFs) represent uncommon and anomalous communications between the carotid artery and the cavernous sinus. MATERIALS AND METHODS: Case report RESULTS: We present the clinical details and successful management of a previously healthy 44-year-old patient who presented with one-month worsening headache, bilateral abducens palsy and conjunctival injection. Imaging modalities including magnetic resonance imaging (MRI) with contrast and digital subtraction angiography (DSA) facilitated the diagnosis of CCF. The patient underwent endovascular coiling of the CCF, leading to neurological recovery and symptom remission. CONCLUSION: This case highlights the importance of promptly CCF diagnosis in patients with multiple cranial nerve palsies and conjunctival hyperemia. Moreover, it emphasizes the efficacy of endovascular coiling in achieving symptom remission.

Computed tomography scan to diagnose abducens nerve palsy cases with superior-compartment atrophy.

PURPOSE: To use orbital computed tomography (CT) to explore the proportion of superior-compartment lateral rectus muscle atrophy in abducens nerve palsy and its relationship with clinical findings. METHODS: Twenty-two patients with isolated unilateral abducens nerve palsy were enrolled. Orbital CT scans of all patients were acquired. All measurements were performed in two ways for normal and paretic lateral rectus muscles: posterior volume (mm3) and maximal cross-section area (mm2). These variables were also measured separately in the superior and inferior 40% of the muscle. Primary position esotropia and amount of abduction limitation was also recorded. RESULTS: The mean deviation was 23.4Δ ± 12.1Δ (range, 0Δ-50Δ); the mean limitation of abduction, -2.7 ± 1.3 (range, -1 to -5). Seven cases (31.8%) showed the gross morphologic characteristics of superior-compartment atrophy. In these 7 cases, the mean percentage of atrophy in posterior volume and in maximal cross-section was significantly greater in the superior compartment than the inferior compartment (P = 0.02 for both). The mean limitation of abduction in these 7 cases (-1.7 ± 0.9; range, -1 to -3) was significantly lower than in other cases (-3.1 ± 1.3, range, -1 to -5 [P = 0.02]). CONCLUSIONS: In our study cohort, a subgroup of abducens nerve palsy cases demonstrated evidence of superior portion lateral rectus atrophy on orbital CT. The superior-compartment-atrophy group had both a smaller primary gaze esotropia and a smaller abduction deficit, providing evidence that compartmental atrophy should be considered in patients with partially retained lateral rectus function.

Isolated abducens nerve palsy in a patient with asymptomatic SARS-CoV-2 infection.

The neuro-ophthalmological complications of SARS-CoV-2 infection are emerging but the spectrum of presentations and pathophysiological mechanism underpinning the association remains to be fully determined. We describe the case of a 44-year-old female who presented with a 12-hour history of diplopia preceded by a mild headache and found to have an isolated right abducens nerve palsy. Initial vital signs were normal but she developed a fever and nasopharyngeal swab confirmed SARS-CoV-2 infection by RT-PCR. All other investigations returned normal including blood tests, chest X-ray, MRI brain and cerebrospinal fluid analysis. She remained systemically well, and there was complete resolution of the abducens palsy and diplopia at two week follow up. In the absence of an alternative underlying cause or risk factors identified, the aetiology was presumed to be microvascular and potentially related to the viral infection. We add to the evolving literature of neuro-ophthalmological associations of SARS-CoV-2, discuss possible causal mechanisms and suggest considering asymptomatic SARS-CoV-2 infection in cases of isolated abducens palsy without clear risk factors.

Acute-onset binocular diplopia in neurological unit: Aetiological factors and diagnostic assessment.

OBJECTIVES: To investigate the aetiology of acute-onset binocular diplopia (AOBD) in neurological units and identify the key diagnostic procedures in this setting. MATERIALS AND METHODS: Clinico-demographic data from patients hospitalized for AOBD from 2008 to 2019 were retrospectively reviewed. AOBD due to an underlying neurological disorder known to cause diplopia was addressed as secondary diplopia. Ophthalmoparesis plus was defined when subtle neurological signs/symptoms other than ophthalmoparesis were detected during neurological examination. RESULTS: A total of 171 patients (mean age 57.6 years) were included in the study. A total of 89 subjects (52%) had an oculomotor disturbance consistent with sixth nerve palsy, and 42 (24.6%) showed multiple oculomotor nerve involvement. The most common cause of AOBD was presumed to be microvascular in 56 patients (32.7%), while a secondary aetiology was identified in 102 (59.6%). Ophthalmoparesis plus and multiple oculomotor nerve involvement significantly predicted a secondary aetiology in multivariable logistic regression analysis. Brain CT was never diagnostic in isolated ophthalmoparesis. A combination of neuroimaging examinations established AOBD diagnosis in 54.9% of subjects, whereas rachicentesis and neurophysiological examinations were found to be performant in the remaining cases. CONCLUSIONS: AOBD may herald insidious neurological disease, and an extensive diagnostic workup is often needed to establish a diagnosis. Neurological examination was pivotal in identifying patients at higher risk of secondary aetiology. Even in cases of apparently benign presentation, a serious underlying disease cannot be excluded. Brain MRI was found to perform well in all clinical scenarios, and it should be always considered when managing AOBD.

Isolated Abducens Nerve Palsy as Manifestation of Diffuse Intracranial Dolichoectasia.

An 83-year-old man presented with a 1-year history of abducens palsy. Brain MRA revealed arterial dolichoectasia of most cerebral vessels, including the basilar, internal carotid, and middle cerebral arteries. Abducens nerve palsy as a sole manifestation of diffuse intracranial dolichoectasia is unusual but may occur in diffuse intracranial dolichoectasia.

Unilateral Lateral Rectus Paralysis Showing Incomplete "V" Sign' on 18F-FDG PET/CT.

Extraocular muscles show physiologic radiotracer uptake on F-FDG PET/CT as is encountered in most routine scans. Certain pathologies can cause palsy of one or more of the extraocular muscles, leading to hypometabolism on F-FDG PET/CT. We present a case with a classical finding of unilateral hypometabolism of the lateral rectus muscle, disrupting the "V" sign formed due to physiologic uptake. The patient had presented with the complaint of diplopia and was being evaluated further to rule out the possibility of inflammatory/granulomatous infectious etiopathogenesis leading to compression of the abducens nerve resulting in lateral rectus palsy.

Cause of acquired onset of diplopia due to isolated third, fourth, and sixth cranial nerve palsies in patients aged 20 to 50 years in Korea: A high resolution magnetic resonance imaging study.

AIMS: This study aimed to describe the etiologies of acquired onset of diplopia due to isolated third, fourth, and sixth cranial nerve palsies in young adults in Korea. METHODS: This retrospective study included 127 patients aged 20 to 50 years with acquired onset isolated third, fourth, and sixth cranial nerve palsies who received care at the Strabismus and Neuro-ophthalmology Department of Samsung Medical Center from 2013 to 2017. The etiologies of the palsies determined by clinical assessment, high-resolution magnetic resonance imaging (MRI) with three-dimensional constructive interference in steady state, and laboratory testing were analyzed. RESULTS: Fifty-nine patients manifested sixth cranial nerve palsy. Forty-six patients had fourth cranial nerve palsy and 22 patients had third cranial nerve palsy. The most common etiologies of the ocular motor nerve palsies were presumed inflammatory lesions (21.3%), followed by presumed microvascular causes (17.3%), and neoplasms involving the central nervous system (15.7%). Neoplasms were the most common cause of sixth cranial nerve palsy (25.4%). The most common cause of fourth cranial nerve palsy was presumed microvascular ischemia (28.3%), and presumed inflammatory lesions was the most common cause of third cranial nerve palsy (36.4%). Other non-traumatic causes included vascular lesions, ischemic brainstem stroke, intracranial hemorrhage, non-aneurysmal neuro-vascular contact, multiple sclerosis, and infection. CONCLUSION: A substantial proportion of young adult patients with ocular motor nerve palsies manifested pathologies other than presumed microvascular ischemia or idiopathic causes. Neuroimaging and laboratory tests have important roles in the evaluation of patients aged 20-50 years with acquired ocular motor nerve palsies.

Nasopharyngeal carcinoma presenting as a sixth nerve palsy and Horner's syndrome.

The combination of a sixth nerve palsy and ipsilateral Horner's syndrome localises the disease process to the posterior cavernous sinus and can be a result of various pathologies in this region. A 74-year-old Chinese woman presented with a 9-month history of binocular horizontal diplopia worse when looking left. She was found to have a left sixth nerve palsy and Horner's syndrome and MRI revealed an enhancing soft tissue mass in the nasopharynx with involvement of the bones of the skull base and invasion of the left cavernous sinus. Endoscopic biopsy of the mass confirmed the diagnosis of non-keratinising squamous cell carcinoma, which was Epstein-Barr virus positive. She was treated with radiation therapy. Patients with a sixth nerve palsy and ipsilateral Horner's syndrome should have urgent neuroimaging with careful attention to the cavernous sinus since sympathetic fibres join the sixth nerve for a short distance in this location.

Diplopia: a unique presentation of recurrence of a salivary gland carcinoma.

A 79-year-old man with a history of radical excision of a left submandibular gland carcinoma ex-pleomorphic adenoma presented with a new 2 cm lump in his left submandibular region which proved to be recurrence on surgical excision. During work up for revision surgery he developed a right VI cranial nerve palsy, which was attributed to his microvascular status having had a history of three previous transient ischemic attacks (TIAs). 6 months later, his palsy had not resolved. MRI revealed new soft tissue by the cavernous segment of the internal carotid artery. The exact source of this was unclear as there was no evidence of local recurrence or nodal disease. A repeat MRI scan 16 months later revealed further growth of abnormal tissue in the cavernous sinus and the primary submandibular location, now involving multiple nerves including branches of cranial nerves IV, V, VI, VII and XII making surgical excision impossible.

Recurrent abducens nerve palsy and hypophosphatasia syndrome.

A 47-year-old woman presented with six episodes of horizontal binocular double vision over a 2-year period. CT imaging was significant for extensive dural calcification in the spine and calcification of the skull base, likely involving Dorello's canal. Biochemical testing revealed a persistently low alkaline phosphatase level. Recurrent nerve palsy may possibly be induced by mechanical compression of the sixth cranial nerve in Dorello's canal from calcification due to hypophosphatasia syndrome.

Abducens Nerve Schwannoma: A Case Report and Literature Review.

BACKGROUND: Abducens nerve function seldom shows complete recovery after removal of abducens nerve schwannoma. No cases with unclear course of the abducens nerve during surgery have been reported to achieve complete recovery of nerve function. CASE DESCRIPTION: We report the case of a 44-year-old woman who presented with occasional dysgeusia without abducens nerve paresis. Magnetic resonance imaging showed a solid tumor about 2 cm in diameter at the left cerebellopontine cistern. Cranial nerves except the abducens nerve appeared intact. The tumor was removed via suboccipital craniotomy. The abducens nerve was totally invisible on the surface of the tumor throughout the procedure. Only short segments of abducens nerve were identifiable at around Dorello's canal and the root exit zone. The tumor was resected by subcapsular dissection, and part of the tumor capsule was preserved as a scaffold for nerve generation, although whether any abducens nerve was included remained uncertain. Histopathologic examination confirmed World Health Organization grade I schwannoma. Postoperatively, the patient presented with complete left abducens nerve paresis and diplopia, but abducens nerve function began to improve 3 months later and had completely recovered within 16 months after surgery. CONCLUSIONS: This represents the first description of abducens nerve schwannoma in which the course of the abducens nerve was intraoperatively unclear but complete recovery was achieved. In such cases, intentional subcapsular dissection may potentiate functional recovery.

Petroclival Meningioma Presenting With an Ipsilateral Sixth Nerve Palsy and a Contralateral Homonymous Quadrantanopia: A Unique and Topographically Localizing Syndrome.

An 84-year-old woman reported onset of headaches, diplopia, and blurred vision. On examination, she was found to have a left sixth nerve palsy and an incongruous right homonymous hemianopia. Brain MRI demonstrated a left petroclival meningioma, causing this unusual combination of clinical findings. The patient was treated with radiation therapy and has remained stable over 4 years of follow-up.