Acute abducens nerve palsy with acute disseminated encephalomyelitis-like presentation following COVID-19 vaccination

We report two adult cases of abducens nerve palsy presenting immediately (within weeks) after they received the first dose of Covishield vaccination. Magnetic resonance imaging (MRI) of the brain obtained after the onset of diplopia demonstrated demyelinating changes. The patients had associated systemic symptoms. Post-vaccination demyelination typically known as acute disseminated encephalomyelitis (ADEM) associated with several vaccines is more common in children. Although the mechanism of the nerve palsy remains unclear, it is suspected to be related to the post-vaccine neuroinflammatory syndrome. Cranial nerve palsies and ADEM-like presentations may represent part of the neurologic spectrum following COVID-vaccination in adults, and ophthalmologists should be aware of these sequelae. Although cases of sixth nerve palsy following COVID vaccination are already reported, associated MRI changes have not been reported from India.

Síndrome de Moebius y ortotropía en posición primaria: ¿es infrecuente esta asociación? (Colombia) / Moebius syndrome and orthotropia in primary position: is this association uncommon? (Colombia) / Síndrome de Moebius e ortotropia em posição primária: é uma associação incomum? (Colômbia)

El síndrome de Moebius es una enfermedad congénita poco común que se caracteriza por el compromiso unilateral o bilateral del VI y VII par craneal, lo que compromete los músculos que controlan la oculomotricidad, produciendo una parálisis en la abducción del globo ocular y los músculos involucrados en la expresión facial. Su presentación clínica y grados de severidad son variables, puede presentar compromiso simétrico o asimétrico. Adicionalmente, gran parte de los casos se relacionan con trastornos del lenguaje, anomalías musculoesqueléticas y orofaciales. En el presente artículo se presenta el caso de una paciente femenina de 3 años producto de un embarazo trigemelar con diagnóstico clínico de síndrome de Moebius al nacer, confirmado por neuroimagen en la que se evidencia la ausencia bilateral del nervio facial en ángulos pontocerebelosos, adicionalmente con un defecto completo en los movimientos oculares de abducción y aducción lo que impide el estrabismo convergente común en estos pacientes.

Moebius syndrome is a rare congenital disease characterized by unilateral or bilateral involvement of the VI and VII cranial nerves, which compromises the muscles that control ocular motricity with paralysis in the abduction of the eyeball and the muscles involved in the facial expression. Its clinical presentation and degrees of severity are variable, and it can be symmetric or asymmetric. Additionally, most of the cases are related to language disorders, musculoskeletal and orofacial anomalies. This paper presents the case of a 3-year-old female patient, product of a trigemellar pregnancy with a clinical diagnosis of Moebius syndrome at birth, confirmed by neuroimaging, which shows the bilateral absence of the facial nerve in point-lateral angles. Additionally she has a complete defect in abduction and adduction eye movements, which prevents the common convergent strabismus in these patients.

A síndrome de Moebius é uma doença congênita rara caracterizada pelo envolvimento unilateral ou bilateral dos nervos cranianos VI e VII, que compromete os músculos que controlam a oculomotricidade com paralisia na abdução do globo ocular e dos músculos envolvidos na expressão facial. Sua apresentação clínica e graus de gravidade são variáveis, podendo ser um comprometimento simétrico ou assimétrico. Além disso, a maioria dos casos está relacionada a distúrbios de linguagem, anomalias musculoesqueléticas e orofaciais. Este paper apresenta o caso de uma paciente de 3 anos de idade, fruto de uma gravidez trigêmea com diagnóstico clínico de Síndrome de Moebius ao nascimento, confirmado por neuroimagem em que é evidente a ausência bilateral do nervo facial nos ângulos ponto-cerebelares. Além disso, ela tem um defeito completo nos movimentos oculares de abdução e adução, o que impede o estrabismo convergente comum nesses pacientes.

Isolated abducens nerve palsy associated with coronavirus disease: an 8-month follow-up / Paresia isolada do nervo abducente associada ao COVID-19: 8 meses de seguimento

ABSTRACT We report the case of a previously healthy 48-year-old man who developed an isolated abducens nerve palsy 18 days after presenting with coronavirus disease (COVID-19) confirmed by reverse transcriptase polymerase chain reaction. His main complaint at arrival was double vision. Ocular examination revealed a sixth cranial nerve palsy in the left eye. The incomitant esotropia at arrival was 30 prism diopters. Abduction was markedly limited, while adduction was normal in the left eye. The patient underwent complete clinical, neurological, and neuroimaging investigations, including cerebrospinal fluid sample analysis to rule out infectious causes. A conservative approach with orthoptic therapy and Fresnel prism was opted. Eight months after the onset of COVID-19, regression of the strabismus was observed, and the patient reported complete recovery of the diplopia. This case suggests that isolated abducens nerve palsy caused by severe acute respiratory syndrome coronavirus 2 infection may improve with a conservative approach.

RESUMO Reportamos o caso de homem previamente hígido, 48 anos, com paralisia isolada do nervo abducente 18 dias após infecção pelo novo coronavírus (COVID-19) confirmada por reação cadeia polimerase de transcriptase reversa. A principal queixa do paciente na admissão era diplopia. O exame ocular revelou paralisia do sexto nervo craniano do olho esquerdo. Esotropia incomitante no exame inicial media 30 dioptrias prismáticas. Abdução estava limitada com adução completa no olho esquerdo. O paciente foi submetido a investigação clínica e neurológica com exame de neuroimagem, incluindo análise de amostra do líquido cefalorraquidiano para descartar causas infecciosas. Optou-se por abordagem conservadora com terapia ortóptica e prisma de Fresnel. Oito meses após a infecção pelo COVID-19, o paciente evoluiu com regressão do estrabismo e informou recuperação completa do quadro. Este relato sugere que paralisia isolada do nervo abducente causada por SARS-CoV-2 pode melhorar com abordagem conservadora.

Papilledema and abducens nerve palsy associated with vitamin B12 deficiency

Papilledema is defined as optic disc swelling that is secondary to elevated intracranial pressure. Vision is usually well preserved with this condition. The optic discs appear blurred in papilledema. Elevation in intracranial pressure is due to variety of reasons of which intracranial hemorrhageis the most common. We present a case in which our patient developed papilledema due to vitamin B12 deficiency. Lateral rectus muscle palsy occurs due to abducens nerve palsy. The lateral rectus muscle is responsible for lateral movement of the eyeball, specificallyabduction. Its palsy results in sudden onset of horizontal double vision, which is worse when the patient looks to the affected side. There is also limited outward movement of the affected eye. Abducens nerve palsy can occur due to ischemia injury, stroke, infection, brain tumour, elevated intracranial pressure, or inflammation of the nerve. In our patient the abducens nerve palsy was due to homocysteinemia secondary to dietary vitamin B12 deficiency. Homocysteine is a potent atherosclerotic risk factor and can cause ischemic nerve palsy, as seen in our patient.

Síndrome de pseudo-Duane secundario a Schwannoma de nervio abducens: Reporte de caso y revisión / Pseudo-Duane syndrome secondary to abducens nerve schwannoma: Case report and review

Reporte de caso de síndrome de pseudo-Duane asociado a schwannoma de nervio abducens y neurofibromatosis tipo 2 (NF2). Este síndrome es raro, caracterizado por limitación en abducción, retracción ocular, disminución de hendidura palpebral en abducción y restricción del recto medial ipsilateral en test de ducción forzada. La NF2 es también una enfermedad infrecuente caracterizada por tumores de sistema nervioso central y periférico. Los schwannomas de nervio abducens son también poco frecuentes, y se presentan comúnmente con diplopia. Se revisan brevemente estas enfermedades. Es el primer caso reportado de pseudo-Duane secundario a schwannoma de nervio abducens y NF2 según nuestro conocimiento.

A pseudo-Duane syndrome case associated with abducens nerve schwannoma and neurofibromatosis type 2 (NF2) is presented. This syndrome is a rare disease characterised by abduction limitation, ocular retraction, narrowing of the palpebral fissure in abduction, and ipsilateral medial rectus restriction on forced duction test. NF2 is also an uncommon disease which is characterised by peripheral and central nervous system tumours. Abducens nerve schwannomas are also uncommon and presents usually as diplopia. A short review of these diseases is given. This is the first case of pseudo-Duane secondary to abducens nerve schwannoma, to our knowledge.

Parálisis del nervio motor ocular externo luego de anestesia neuroaxial combinada epidural-espinal / Paralysis of the external oculomotor nerve after combined epidural-spinal neuroaxial anesthesia

Introducción: El abordaje del espacio subaracnoideo fue descrito por Quincke en el 1891. En la actualidad es práctica común para la realización de la anestesia neuroaxial subaracnoidea en las pacientes obstétricas. Las complicaciones descritas, asociadas a esto, son varias. Dentro de estas, la parálisis del nervio abducens o VI par no es frecuente y en ocasiones, no está relacionada a la punción ya que se produce días después del evento. Objetivo: Revisar la información relacionada con la complicación de parálisis del VI par. Presentación del caso: Paciente de 33 años de edad, femenina, de profesión médico, con antecedentes personales de migraña, historia de anestesia neuroaxial epidural sin complicaciones, que para la realización de una cesárea de segmento arciforme y salpinguectomia parcial bilateral, recibió una anestesia combinada peridural-espinal. El transoperatorio transcurre con estabilidad hemodinámica, hizo cefalea al tercer día del posoperatorio, que la atribuyó al antecedente de migraña y fue tratada sin evaluación por anestesiología con dipirona. A los 10 días de operada hace desviación de la mirada y diplopia, se diagnostica parálisis del VI par. Fue tratada por Neurología y se plantean varios diagnósticos diferenciales. Los estudios imagenológicos resultan negativos, se trató con vitaminas y se produjo remisión a las 6 semanas. Conclusiones: El diagnóstico de esta complicación es necesario ya que puede pasar inadvertida la relación con la anestesia y, por tanto, ser mal conducido su tratamiento(AU)

Introduction: The approach to the subarachnoid space was described by Quincke in 1891. It is now a common practice to perform subarachnoid neuroaxial anesthesia in obstetric patients. The complications described, associated with this, are several. Within these, the paralysis of the abducens nerve or sixth pair is not frequent and sometimes is not related to the puncture, since it occurs days after the event. Objective: To review the information related to the complication of paralysis of the sixth pair. Case presentation: A 33-year-old female patient, a physician, with a personal history of migraine, a history of epidural neuroaxial anesthesia without complications, who underwent combined epidural-spinal anesthesia for performing a cranial segment cesarean section and bilateral partial salpingectomy. The transoperative period runs with hemodynamic stability. There was headache three days after surgery, which was attributed to the migraine history and the patient was treated, without evaluation by anesthesiology, with dipyrone. At 10 days after surgery, the eyes are diverted and diplopia is manifested, paralysis of the sixth pair is diagnosed. She was treated by neurology and several differential diagnoses were proposed. Imaging studies are negative. She was treated with vitamins and remission occurred at six weeks. Conclusions: The diagnosis of this complication is necessary, since the relationship with anesthesia may go unnoticed and, therefore, its treatment may be poorly conducted(AU)

Abducens Nerve Palsy as Initial Manifestation of Chronic Subdural Hematoma: Case Report

Chronic subdural hematoma (CSDH) is a form of progressive intracranial hemorrhage, typically associated with cases of trauma. The manifestation of this comorbidity with abducens palsy is a rare finding. The present work aims to describe the case of an adult patient with abducens nerve palsy as a manifestation of CSDH. Chronic subdural hematoma is most commonly found in elderly patients, with systemic hypertension as amanifestation. The relation with the sixth cranial nerve is unusual and draws attention to the case reported. In addition, the prognosis is positive, since trepanation and drainage surgery was performed, as it is recommended in the literature.

Benign abducens nerve palsy: diagnosis by exclusion

Of all the cranial nerves, the abducens nerve has the longest intracranial course hence is most common cranial nerve to be affected secondary to any potentially devastating intracranial cause. It can indicate significant underlying pathology. Abducens or sixth cranial nerve innervates lateral rectus muscle and pathology of this nerve results in abduction deficiency of ipsilateral eye. Most of the time it will be unilateral but bilateral involvement is also well known. It can recurrent without any underlying identifiable pathology. The 6th nerve palsy is considered as benign after ruling out all possible causes. Benign causes account for just 9 to 14% of all 6th nerve palsies in children. Most of the time benign 6th nerve palsy occurs after viral infection or vaccination as an immunological reaction. In our case patient had history of pentavalent vaccination 1 month back. After thorough investigation and ruling out all possible causes it was attributed to post vaccination immunological reaction. which resolved spontaneously over 4months.

Síndrome de Pierre Robin associada à Síndrome de Duane familiar do tipo III / Pierre Robin Syndrome associated with type III familial Duane Retraction Syndrome

Resumo A síndrome de Pierre Robin (PRS) consiste em uma tríade de anomalias caracterizada por micrognatia, glossoptose e fissura de palato, comumente associada com outras síndromes e ocasionalmente com alterações oculares. Na Síndrome de Duane (DRS), há uma falha na inervação do reto lateral pelo VI nervo, com inervação anômala do reto lateral por fibras do III nervo. Ainda que a PRS já tenha sido associada com mais de 50 outras síndromes, não existe na literatura relato de casos de associação com a DRS familiar. Dessa forma, esse trabalho tem por objetivo relatar um caso dessa associação em um paciente de 29 anos com recorrência das síndromes na família.

Abstract The Pierre Robin Syndrome (PRS) consists of a triad of anomalies characterized by micrognathia, glossoptosis and fissure of the palate, usually associated with other syndromes e occasionally associated with ocular variations. In Duane Retraction Syndrome (DRS), there is a failure in the lateral rectus innervation by the VI cranial nerve, with anomalous innervation of the lateral rectus by fibers of the III nerve. Even though PRS has already been associated with more than 50 other syndromes, there is not any report in literature of association with familial DRS. Thus, this work aims to report a case of this association in a 29 years old patient with recurrence of the syndromes in the family.

Ossification of the roof of the porus trigeminus with duplicated abducens nerve / 대한해부학회지

Ossification of parts of the intracranial dura mater is common and is generally accepted as an age-related finding. Additionally, duplication of the abducens nerve along its course to the lateral rectus muscle is a known, although uncommon anatomical variant. During routine cadaveric dissection, an ossified portion of dura mater traveling over the trigeminal nerve's entrance (porus trigeminus) into the middle cranial fossa was observed unilaterally. Ipsilaterally, a duplicated abducens nerve was also observed, with a unique foramen superolateral to the entrance of Dorello's canal. To our knowledge, there has been no existing report of a simultaneous ossified roof of the porus trigeminus with an ipsilateral duplicated abducens nerve. Herein, we discuss this case and the potential clinical and surgical applications. We believe this case report will be informative for the skull base surgeon in the diagnosis of neuralgic pain in the frontomaxillary, andibular, orbital, and external and middle ear regions.

Delayed Onset Abducens Nerve Palsy and Horner Syndrome after Treatment of a Traumatic Carotid-cavernous Fistula

PURPOSE: We report a patient with delayed-onset abducens nerve palsy and Horner syndrome after endovascular treatment of traumatic carotid-cavernous fistula (CCF). CASE SUMMARY: A 68-year-female visited our ophthalmic department complaining of gradual-onset ptosis of the left eye and horizontal diplopia. She had undergone endovascular treatment to treat left-sided traumatic CCF after a car accident 10 years before; she had been told at that time that the treatment outcome was favorable. The left-sided ptosis gradually developed 6 years after the procedure, accompanied by diplopia. The left eye exhibited miosis and the extent of anisocoria increased in dim light. An extraocular examination revealed 30 prism diopters of left esotropia in the primary gaze and a −4 abduction limitation of the left eye. CCF recurrence was suspected; however, magnetic resonance imaging with magnetic resonance angiography of brain did not support this. The esotropia did not improve during the 6-month follow-up and strabismus surgery was performed. CONCLUSIONS: Delayed-onset abducens nerve palsy and Horner syndrome can develop even after successful endovascular treatment of CCF. Strabismus surgery should be considered in patients whose diplopia does not spontaneously improve.

Palsy of the Contralateral Abducens Nerve after Aneurysm Surgery and Temporal Meningioma in the Presence of Petroclival Meningioma: A Case Report

The sixth abducens nerve is subject to injury after rare complications of intracranial hypotension caused by procedures such as dural punctures and spinal surgeries. The purpose of this case report is to discuss the mechanism of nerve palsy in these situations. Therefore, we describe a case of onset of contralateral sixth cranial nerve palsy after intracranial aneurysm and temporal meningioma surgery. Moreover, in this case there is a singularity due to the presence of the petroclival meningioma that amplified the unfolding of the lesion.

O sexto nervo abducente está sujeito a lesões após raros eventos de hipotensão intracraniana gerada por procedimentos como punções de dura-máter e cirurgias de coluna. O propósito deste relato de caso é discutir o mecanismo da paralisia deste nervo nestas situações. Para isso, descrevemos um caso de aparecimento de paresia do sexto nervo craniano contralateral após cirurgia de aneurisma intracraniano e de meningioma temporal. Além do mais, neste caso há uma singularidade em razão da presença do meningioma petroclival contralateral, que amplificou o desdobramento da lesão.

Epidural blood patch treatment of diplopia that developed after headache resolution in a patient with spontaneous intracranial hypotension

Sudden headache onset may rarely be caused by spontaneous intracranial hypotension (SIH). Other associated symptoms in patients with SIH are nausea, vomiting, vertigo, hearing alteration, and visual disturbance. This case report describes a 43-year-old female diagnosed with SIH who developed diplopia after resolution of an abrupt-onset headache, which was managed with conservative treatments, including bed rest and hydration. She was also diagnosed with secondary right sixth cranial nerve palsy. Although conservative management relieved her headache, the diplopia was not fully relieved. Application of an autologous epidural blood patch successfully relieved her diplopia, even after 14 days from the onset of visual impairment.

Ramsay Hunt syndrome presenting with abducens nerve palsy followed by V, VII, VIII, IX, and X nerve palsies

@#Ramsay Hunt syndrome, associated with varicella zoster virus infection is characterized by herpes zoster oticus, facial nerve palsy, and cochleovestibular symptoms. Ramsay Hunt syndrome associated cranial polyneuropathy occasionally occurs with involvement beyond VII and VIII. We represent a patient of Ramsay Hunt syndrome who presented with only VI involvement at the first visit followed by cranial polyneuropathy. Varicella zoster virus infection was confirmed by the detection of varicella zoster virus-DNA in cerebrospinal fluid.

Abducens Nerve Palsy Associated with Ramsay-Hunt Syndrome / 대한평형의학회지

Ramsay-Hunt syndrome is an infectious disease caused by the varicella zoster virus. It is usually associated with facial and vestibulocochlear nerve palsy, but other cranial nerve dysfunction can be accompanied. We present a 68-year-old woman with abducens nerve palsy associated with Ramsay-Hunt syndrome. She showed abduction limitation of left eye with peripheral facial palsy and vestibulopathy of the left side. Varicella zoster virus polymerase chain reaction of cerebrospinal fluid was positive and internal auditory canal magnetic resonance imaging was revealed enhancement of labyrinthine segment of left facial nerve. Although abducens nerve palsy is uncommon feature of Ramsay-Hunt syndrome, but it can be developed by several different mechanisms.

Therapeutic Observation of Acupuncture plus Medication for Diabetic Abducens Nerve Palsy / 上海针灸杂志

Objective To observe the clinical efficacy of acupuncture plus medication in treating diabetic abducens nerve palsy.Method Twenty-three cases of diabetic abducens nerve palsy were randomized into a treatment group of 12 cases and a control group of 11 cases. The two groups both were intervened by Compound anisodine hydrobromide via para-temporal-superficial-artery injection, based on which, the treatment group received acupuncture at extraocular muscles and body acupoints, while the control group received subconjunctival injection of Dexamethasone beside the endpoint of rectus lateralis. The fasting blood glucose, eye movement and diplopia were observed before and after the intervention for the two groups to evaluate the therapeutic efficacy.Result After the intervention, the two groups didn't show significant intra-group or inter-group differences in fasting blood glucose (P>0.05). The total effective rate was 91.7％ in the treatment group versus 54.5％ in the control group, and the between-group difference was statistically significant (P<0.05).Conclusion Acupuncture plus medication is an effective method in treating diabetic abducens nerve palsy.

Abducens Nerve Palsy and Optic Perineuritis Caused by Fungal Sphenoidal Sinusitis

PURPOSE: To report a case of abducens nerve palsy and optic perineuritis caused by fungal sphenoidal sinusitis. CASE SUMMARY: A 48-year-old male visited emergency department for retrobulbar pain, decreased vision, and horizontal diplopia for 3 days. He reported that previous medical history was non-specific, however, blood glucose level was 328 mg/dL (70–110). He had experienced severe headache for 7 days. The best corrected visual acuity was 20/20 at right eye and 20/25 at left eye. The pupil of left eye did not have relative afferent pupillary defect. Left mild proptosis was noted. The extraocular examination showed 30 prism diopters left esotropia at primary gaze and −4 abduction limitation of left eye. The left eye showed mild optic disc swelling and inferior field defect by field test. Brain magnetic resonance imaging showed enhancement of sphenoidal sinus, ethmoidal sinus, and around optic nerve at left eye. Three days after antibiotics treatment, the vision of left eye deteriorated to 20/40 and periorbital pain developed. The drainage and biopsy of sphenoidal sinus were performed. The histopathologic examination showed hyphae consistent with aspergillosis. The ocular symptoms were improved with anti-fungal treatment. Follow-up magnetic resonance imaging performed 1 month after treatment showed improvement of lesion at left orbit. Five months after surgery, the visual acuity of left eye was improved to 20/25. The patient showed orthotropia at primary gaze without limitation. CONCLUSIONS: The abducens nerve palsy and optic perineuritis can be caused by fungal sphenoidal sinusitis. The early diagnosis and appropriate treatment can lead to favorable outcome.

Abducens Nerve Palsy Caused by the Ophthalmic Segment of an Internal Carotid Artery Aneurysm

PURPOSE: To report a case of isolated abducens nerve palsy caused by the ophthalmic segment of an internal carotid artery (ICA) aneurysm which improved after endovascular coil trapping. CASE SUMMARY: A 59-year-old female visited the ophthalmology department for a sudden onset of horizontal diplopia for 10 days. The best corrected visual acuity was 20/20 in both eyes. The pupils showed normal response to light and near stimulation in both eyes. The extraocular examination showed 35 prism diopters left esotropia at primary gaze and −4 abduction limitation of the left eye. The patient suffered intermittent headaches in the left temporal area and left retrobulbar pain for 1 month. Magnetic resonance imaging with magnetic resonance angiography of the brain was performed. A focal protruding lesion of the left ICA suggested an aneurysm. The patient consulted with the neurosurgery department. The left ophthalmic segment of the ICA aneurysm was confirmed by transfemoral cerebral angiography and treated with coil placement and the patient showed gradual improvement after the procedure. Three months after the procedure there was no diplopia. The patient showed orthotropia at primary gaze without abduction limitation. CONCLUSIONS: Isolated abducens nerve palsy can be caused by the ophthalmic segment of an ICA aneurysm, which should be considered in the differential diagnosis of ocular motility disorders. The disorder improved with coil replacement treatment. Differential diagnosis as a cause of abducens nerve palsy is important for prompt and appropriate treatment. Neuroimaging should be considered in patients with isolated abducens nerve palsy with a non-ischemic origin.

Dorello´s canal or abducens nerve canal: constancy or inconstancy? / El canal de Dorello o canal para el nervio abducente: ¿constancia o inconstancia?

Dorello´s canal is an eponym term referring to a small fibro osseous landmark, by way of arc, located at the apex of the petrous temporal region and for which the nerve abducens passes before reaching the cavernous sinus. This landmark is not referenced in Terminologia Anatomica, even as a variable structure. We selected 74 adult dry skulls and six heads fixed in formalin 10 % without classifying them by ethnicity or gender. As inclusion criteria, we selected those where the middle cranial fossa and the apex of the petrous temporal region were in good condition. Fifty seven (57) skulls (83, 82 %) showed the presence of canal bilaterally; 4 (5.89 %) showed it unilaterally to the right; 4 (5,89 %) were unilaterally at the left and 3 (4,41 %) had no canal. The results of this study indicate that this bone landmark is present in most of the skulls, even bilaterally. Since it is not referenced in the Terminologia Anatomica, we propose the term canal abducens nerve to avoid using the eponymous term Dorello´s canal.

El "canal de Dorello" es un epónimo que hace referencia a un pequeño relieve osteofibroso, a manera de arco, ubicado a nivel del ápex de la región petrosa del temporal y por el cual pasa recostado el nervio abducente antes de llegar al seno cavernoso. Dicho relieve no se encuentra referenciado en Terminologia Anatomica, ni siquiera como estructura inconstante. Se seleccionaron 74 cráneos secos y completos de adultos y seis cabezas fijadas con formalina al 10 %, sin clasificarlos por grupos étnicos ni por sexo. Como criterio de inclusión, se escogieron aquellos que tuvieran en buen estado la fosa craneal media y el ápex de la región petrosa del temporal. 57 cráneos (83,82 %) mostraron presencia del canal en forma bilateral; 4 (5,89 %) lo mostraron unilateralmente a la derecha; 4 (5,89 %) lo tenían unilateralmente a la izquierda y 3 (4,41 %) no presentaban el canal. Los resultados de este estudio señalan que este relieve óseo se presenta en la mayoría de los cráneos, incluso en forma bilateral. Puesto que no aparece referenciado en Terminologia Anatomica, proponemos el término "canal para el nervio abducente", con el fin de evitar el uso del término epónimo "canal de Dorello".

A Case of Idiopathic Unilateral Abducens Nerve Palsy in an Adolescent Patient

PURPOSE: To report a case of idiopathic unilateral abducens nerve palsy in an adolescent patient. CASE SUMMARY: A healthy 14-year-old boy presented with binocular horizontal diplopia that started that same day. He did not have any history of trauma, vaccination or infectious disease and showed no other neurological signs. The best corrected visual acuity of both eyes was 20/20. Slit lamp and fundus examinations revealed no other abnormalities. On the alternative prism cover test, he had 6 prism diopter (PD) esotropia with −1 degree abduction limitation in the left eye. After 1 week, the abduction limitation in the left eye was progressed to −3.5 degrees, so we performed brain imaging. The brain magnetic resonance imaging (MRI) and systemic evaluation (serologic test, cerebrospinal fluid examination) were normal therefore, we suspected idiopathic unilateral abducens nerve palsy. Thus, intravenous steroid injection was started, and the patient was partially recovered after 5 days of treatment. At 5 weeks after presentation, diplopia and abduction limitation in the left eye were completely resolved, and recurrence was not found during the 1 year of follow-up. CONCLUSIONS: We report a case of progressive idiopathic unilateral abducens nerve palsy in an adolescent which has resolved completely after intravenous steroid treatment in a short period.