Anatomy of the extraneural blood supply to the intracranial oculomotor nerve

Transient ipsilateral mydriasis following carotid artery stenting

BACKGROUND AND IMPORTANCE

One of the most feared and devastating complications of carotid revascularization procedures is hyperperfusion hemorrhage. The acute onset of an ipsilateral mydriatic pupil following carotid endarterectomy (CEA) or carotid artery stenting (CAS) should prompt immediate neurosurgical evaluation to rule out hyperperfusion injury.

CLINICAL PRESENTATION

We describe a case of benign, transient ipsilateral mydriasis following CAS. After undergoing right common and internal carotid artery (ICA) angioplasty and stenting with distal embolic protection, the patient developed anisocoria with a right-sided 5 mm minimally reactive pupil. Imaging demonstrated no acute pathology, and the mydriasis resolved spontaneously within 48 hours. We hypothesise that the pathophysiologic mechanism is secondary to transient ischemia of parasympathetic structures within the petrous/cavernous ICA from arterial ostium occlusion that occurred during device placement. Alternatively, sympathetic stimulation during angioplasty is also plausible.

CONCLUSIONS

Although an ipsilateral mydriatic pupil following carotid revascularization necessitates evaluation, it may represent a self-limiting process especially in the absence of other focal neurologic deficits.

Pituitary apoplexy presenting as isolated third cranial nerve palsy: case series

Pituitary apoplexy (PA) is caused by a sudden increase in pressure in the pituitary region due to acute hemorrhage, infarction or necrosis. PA can also be caused by restricting blood supply to the nerve due to compression of the internal carotid artery. Acute third cranial nerve palsy (third CN) secondary to PA is a rare medical emergency caused by bleeding within a growing mass within the sella turcica. We presented two cases of PA with isolated third CN palsy treated with transsphenoidal pituitary decompression. PA is therefore an important differential diagnosis to consider in patients with isolated third nerve palsy. The prognosis for isolated third nerve palsy in PA appeared successful, with variable recovery from medical and surgical intervention.

Stroke risk after ocular cranial nerve palsy - A systematic review and meta-analysis

BACKGROUND

Isolated ischemic ocular cranial nerve palsies (OCNP) involving the 3rd, 4th and 6th cranial nerves (CN) are prevalent conditions in ophthalmic practice. However, it is not clearly established whether such patients are at increased risk of stroke after onset of OCNPs.

METHODS

Medline, PubMed, Embase and Cochrane Central registers were systematically searched for eligible studies comparing isolated ischemic OCNPs against matched controls on the subsequent development of stroke with at least two years of follow up. Case reports and series were excluded. Appropriate studies were entered for meta-analysis to determine hazard ratios. Search and data extraction was completed on 22 Feb 2021. Random effect models were used to generate pooled hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Three studies were suitable for meta-analysis (total n = 2,756 OCNP cases and 21,239 matched controls). The meta-analysis demonstrated a hazard ratio of 5.96 (4.20-8.46 95% CI) of subsequent stroke after isolated OCNP within the first year. The hazard ratio reduced to 3.27 (2.61-4.10 95% CI) after five years although remains raised at 2.49 (1.53-4.06 95% CI) up to 12 years. The highest risk was demonstrated with 3rd cranial nerve palsies. Two additional studies assessed the risk of stroke with newly diagnosed diabetics and compared OCNPs against lacunar stroke. These studies did not demonstrate a significant increased risk of stroke, although they may be statistically underpowered.

CONCLUSION

Ischemic OCNPs represent a significant risk factor for development of subsequent stroke in a similar magnitude to transient ischemic attack within the first year.

Isolated Third Cranial Nerve Palsy in Pituitary Apoplexy: Case Report and Systematic Review

OBJECTIVES

To report a case of isolated third nerve palsy from pituitary apoplexy and perform a systematic literature review.

MATERIALS AND METHODS

MEDLINE/EMBASE databases were searched up to September 2020.

INCLUSION CRITERIA

Age≥18, isolated third nerve palsy from pituitary apoplexy.

EXCLUSION CRITERIA

Age<18, presence of other neurological findings, no hemorrhage or infarction of pituitary.

RESULTS

Case report: A 76-year-old woman presented with headache and right-sided ptosis. Right-eye exam revealed complete ptosis, absent pupillary constriction and accommodation, depressed and abducted eye on primary gaze, and -1 impaired depression, adduction, elevation, without other neurological findings. Brain MRI was suggestive of pituitary apoplexy. Pathology after transsphenoidal resection revealed an infarcted pituitary adenoma. Third nerve palsy resolved completely in 21 days. Systematic review: Twenty-three studies reporting 35 patients were selected from 182 abstracts. Twenty-nine (83%) had complete isolated third nerve palsy. Headache was reported in 31 (97%). Thirty-one had hemorrhage and 1 had infarction of pituitary. Cavernous sinus invasion occurred in 14 (50%). Twenty-eight were managed surgically (80%) and 7 medically (20%). Nerve palsy resolved completely in 27 (82%) and partially in 4 (11%).

CONCLUSIONS

Pituitary apoplexy is an important differential diagnosis in patients with isolated third nerve palsy. Isolated third nerve palsy in apoplexy appears to have favorable prognosis.

Oculomotor nerve palsy in pituitary apoplexy associated with pituitary adenoma: a radiological analysis with fast imaging employing with steady-state acquisition

PURPOSE

Oculomotor nerve palsy (ONP) occasionally occurs in cases of pituitary apoplexy (PA) associated with pituitary adenoma, but its mechanism remains unclear. Intracranial nerves are clearly visualized by fast-imaging employing with steady-state acquisition (FIESTA). Here, we assessed the oculomotor nerve compression in patients with PA associated with pituitary adenoma using FIESTA.

METHODS

Twenty-eight cases of PA, with or without ONP, were retrospectively reviewed. All patients had undergone preoperative FIESTA. Two neuroradiologists, unaware of the patient's clinical symptoms, evaluated the presence and location of oculomotor nerve compression due to the tumor.

RESULTS

Thirteen of the twenty-eight PA cases were associated with ONP. Tumor size and degree of cavernous sinus invasion were not significantly different between the ONP and non-ONP groups. Even in the ONP group, 8/13 (62%) tumors did not show cavernous sinus invasion. Via FIESTA, the presence of oculomotor nerve compression was confirmed in 11/13 (85%) and 5/15 (33%) cases in the ONP and non-ONP groups, respectively (p = 0.008). The radiologists' diagnoses of laterality of nerve compression (right or left) were consistent with the patient's affected eye. In the ONP group, the location of the nerve compression was located at the entry point to the cavernous sinus, the so-called oculomotor triangle, in 9/11 (82%) cases and intra cavernous sinus in 2/11 (18%) cases.

CONCLUSION

Compression at the oculomotor triangle is considered the main cause of ONP with PA in pituitary adenomas.

Surgical Management of Tentorial Notch Meningioma Guided by Further Classification: A Consecutive Study of 53 Clinical Cases

Background

Management of tentorial notch meningiomas (TNM) remains a challenge for neurosurgeons. We demonstrate the clinical characteristics and surgical experiences of TNM based on our cases according to a proposed further classification.

Methods

We retrospectively analyzed clinical and follow-up data in a consecutive series of 53 TNM patients who underwent microsurgical operation from 2011 to 2019 in our institution. The operations were performed using various approaches. Clinical history, preoperative and postoperative neurofunction, imaging results, and surgical outcomes were collected for further classification of TNM.

Results

All TNM cases were divided into anterior (T1), middle (T2), and posterior notch (T3). According to the direction of tumor extension and correlation with the neurovascular structures, detailed subtypes of anterior TNMs were identified as the central (T1a), posterior (T1b), and medial type (T1c). The middle TNMs were divided into the infratentorial (T2a), supratentorial (T2b), and supra-infratentorial type (T2c). The posterior TNMs were divided into superior (T3a), inferior (T3b), lateral (T3c), and straight sinus type (T3d) in reference to Bassiouni’s classification. Total removal of the tumor was achieved in 46 cases, with five cases of subtotal and two cases of partial removal without any recorded deaths in our series. In total, five subtotal resected cases underwent gamma-knife treatment and achieved stable disease. Postoperative aggravation or new onset cranial nerve dysfunction occurred in some individual cases, with incidences ranging from 3.77 to 15.10% and improved preoperative neurological deficits ranging from 0 to 100%.

Conclusion

Further, TNM classification based on the intracranial location, extension direction, relationship with brainstem, and neurovascular structures guides preoperative evaluation, rational surgical approach selection, and surgical strategy formulation. Taking microsurgery as the main body, a satisfactory outcome of TNM treatment can be achieved for complicated tumors by combining stereotactic radiotherapy. This study demonstrates the surgical outcomes and complications in detail. Further classification might be helpful for treatment decisions in the future.

Unruptured internal carotid-posterior communicating artery aneurysm splitting the oculomotor nerve: A case report and literature review

Background:

Although it is well known that internal carotid-posterior communicating artery (ICA-PcomA) aneurysms compress the oculomotor nerve and cause nerve palsy, cases of ICA-PcomA aneurysms splitting the oculomotor nerve are extremely rare.

Case Description:

We present the rare case of an asymptomatic, growing, left-sided ICA-PcomA aneurysm that was confirmed to split the oculomotor nerve. We report the clinical course and discuss the underlying mechanism. The oculomotor nerve, which is an aggregate of multiple fibers, exhibits age-related loss of compactness in the arrangement of its nerve fibers.

Conclusion:

We speculate that injury to the nerve fibers by aneurysmal compression was avoided because of the rare phenomenon of splitting of the oculomotor nerve.

Isolated Oculomotor Nerve Palsy in Mild Traumatic Brain Injury

BACKGROUND

Isolated oculomotor nerve palsy is rarely encountered after mild traumatic brain injury. It is difficult to offer patients accurate management strategies or prognostic assessments because only a few reports have described the management of oculomotor nerve palsy.

METHODS

We performed a search for all clinical studies of isolated oculomotor nerve palsy after mild traumatic brain injury published up to July 9, 2019. We placed no restrictions on language or year of publication in our search, and we searched the following key words: traumatic brain injury, isolated oculomotor nerve palsy, mild head trauma, management, and prognosis.

RESULTS

We identified 14 cases of isolated oculomotor nerve palsy after mild traumatic brain injury. In three cases, steroids were used to manage the oculomotor nerve palsy. Five patients who had underlying brain lesions underwent surgery, and seven patients were observed and followed up. The time to partial or complete resolution was 6.0 ± 5.3 mos with a range of 0.5-18 mos.

CONCLUSIONS

This review includes a survey of surgical treatment for the management of traumatic brain injury that underlies oculomotor nerve palsies, steroid therapy to reduce related brain edema, and oculomotor rehabilitation with training eye movement behavior.

Arterial Anatomy of the Parasellar Area

The arterial anatomy of the parasellar area is complex in that it deals with extracranial-intracranial anastomosis and supply to various cranial nerves in a small area. Pathologies such as hypervascular tumors and shunts are not uncommon and require good knowledge of anatomy in planning the treatment. In this article, the basic anatomy of the arterial supply in this region is discussed, covering the origins, territories, relation to the cranial nerves, and the connections among different systems.

Ipsilateral Pupillary Dilation Following Carotid Endarterectomy: A Temporary and Benign Phenomenon

BACKGROUND AND IMPORTANCE: Cases of post carotid endarterectomy (CEA) Horner's syndrome have been reported, with symptoms attributed to manipulation of the sympathetic plexus situated along the carotid artery; however, these patients presented with the typical constricted pupil. We report the first 3 cases to our knowledge of mydriasis following CEA.

CLINICAL PRESENTATION: We present 3 cases of CEA followed by immediate postoperative development of ipsilateral mydriasis. The patients were otherwise at their neurologic baseline and the mydriasis resolved over the ensuing few days.

CONCLUSION: We suggest that these cases are secondary to an ischemic phenomenon, specifically to parasympathetic structures such as the ciliary ganglion and/or oculomotor nerve, resulting in autonomic dysfunction manifested by pupillary dilation. A similar finding of mydriasis occurring subsequent to other carotid pathology has been reported, with ischemia to parasympathetic structures also proposed as the underlying etiology. Although pupillary dilation often represents a worrisome neurosurgical sign indicating herniation, it should be recognized that after CEA this finding may be a transient, benign occurrence.

Partial oculomotor nerve palsy in a 7-year-old child

Oculomotor nerve palsy can be due to varied causes that include diabetic neuropathy, myasthenia gravis, brainstem infarction, demyelinating conditions, and cerebral aneurysms. Among the aneurysmal causes of oculomotor nerve palsy, aneurysm of the posterior communicating artery has been observed to be the most common. Pupillary dysfunction is considered to be an important feature of aneurysmal oculomotor nerve paresis. A case of a 7-year-old boy with partial oculomotor nerve palsy with pupillary sparing is being reported here, the etiology of which is tortuous and ectatic distal internal carotid artery. This is a rare cause of oculomotor nerve paresis and to the best of our knowledge has not yet been reported in children. Ischemia rather than compression seems to be the most plausible cause in this case.

Microvascular Non-Arteritic Ocular Motor Nerve Palsies-What We Know and How Should We Treat?

Patients with isolated unilateral pupil-sparing third or isolated fourth or sixth nerve palsies over 50 years are often diagnosed with "microvascular extraocular palsies". This condition and its management provoke divergent opinions. We review the literature and describe the incidence, pathology, clinical presentation, yield of imaging, and management. A retrospective diagnosis of exclusion has little practical use. We suggest a pragmatic approach to diagnosis, investigation, and management from initial presentation.

Third nerve palsy following carotid artery dissection and posterior cerebral artery thrombectomy: Case report and review of the literature

Background:

Common causes of oculomotor nerve palsy are diabetes, aneurysmal compression, and uncal herniation. A lesser-known cause of third nerve dysfunction is ischemia, often due to carotid artery dissection.

Case Description:

An 80-year-old man presented with an acute ischemic stroke with a National Institutes of Health Stroke Scale score of >20 from a high cervical internal carotid artery (ICA) dissection and a tandem ICA terminus embolic occlusion with extension of clot into the adjacent fetal posterior cerebral artery (PCA). We used a stentriever to perform selective PCA thrombectomy, with immediate postthrombectomy development of ipsilateral anisocoria. The anisocoria progressed into complete oculomotor nerve palsy over 8 h after the procedure.

Conclusions:

The clinical course described in this case is consistent with injury to the third nerve due to mechanical injury or occlusion of perforator supply to the nerve during thrombectomy. Oculomotor nerve palsy is a rare but known complication after ischemia; however, to our knowledge, this is the first case after thrombectomy for a PCA embolus.

Asymptomatic penetration of the oculomotor nerve by a de novo aneurysm associated with severe atherosclerotic stenosis of the supraclinoid internal carotid artery

A 70-year-old woman presented with headaches and recurrent stroke symptoms. During five years, the patient has been treated for cerebral infarction associated with severe atherosclerotic stenosis of the internal carotid artery. Three-year follow-up magnetic resonance angiography showed a tiny de novo aneurysm arising from the distal part of atherosclerotic internal carotid artery. And 5-year follow-up three-dimensional CT angiogram demonstrated a definite aneurysm enlargement as large as requiring treatment. During dissection of aneurysm, the oculomotor nerve was found to be penetrated with the growing de novo aneurysm. The authors report a case of a de novo aneurysm, which resulted from atherosclerotic stenosis of the internal carotid artery at the supraclinoid portion, that was found to be penetrating the oculomotor nerve with no ocular palsy.

Prevalence of ocular motor cranial nerve palsy and associations following stroke

AIM

Occurrence of ocular motor cranial nerve palsies (OMCNP), following stroke, has not been reported in relation to the type of OMCNP seen and in relation to brain area affected by stroke. The aim of this study was to identify all patients referred with suspected visual impairment to establish the presence and type of OMCNP.

METHODS

Prospective, observation study with standardised referral and assessment forms across 20 sites. Visual assessment included visual acuity measurement, visual field assessment, ocular alignment, and movement and visual inattention assessment. Multicentre ethics approval and informed patient consent was obtained.

RESULTS

In total, 915 patients were recruited with mean age of 69.18 years (SD 14.19). Altogether, 498 patients (54%) were diagnosed with ocular motility abnormalities. Of these, 89 patients (18%) had OMCNP. Unilateral third nerve palsy was present in 23 patients (26%), fourth nerve palsy in 14 patients (16%), and sixth nerve palsy in 52 patients (58%). Out of these, 44 patients had isolated OMCNP and 45 had OMCNP combined with other ocular motility abnormalities. Location of stroke was reported mainly in cerebellum, brain stem, thalamus, and internal and external capsules. Treatment was provided for each case including prisms, occlusion, typoscope, scanning exercises, and refraction.

CONCLUSIONS

OMCNP account for 18% of eye movement abnormalities in this stroke sub-population. Sixth CNP was most common, followed by third and fourth CNP. Half were isolated and half combined with other eye movement abnormality. Most were treated with prisms or occlusion. The reported brain area affected by stroke was typically the cerebellum, brain stem, and diencephalic structures.

The oculomotor nerve: anatomic relationship with the floor of the third ventricle

PURPOSE

Endoscopic third ventriculostomy (ETV) has become first-line treatment for obstructive hydrocephalus. Many complications have been described, but the literature about oculomotor palsy after ETV is scarce. Therefore we undertook an anatomical study of the relationship of the oculomotor nerve to the floor of the third ventricle.

METHODS

Distances and angles between the third nerve and the bottom of the third ventricle were studied both in two cadaver heads and in high-definition CISS images in 16 MRI scans. The angles of the trajectories putting the nerve at risk or not were compared. Finally, in a retrospective analysis of intraoperative images the appearance of the membranous portion of the floor was defined and if visible, the distance of the third nerve to the midline was estimated by comparing with the 8-mm balloon catheter.

RESULTS

The course of the third nerve is approximately 8 mm laterally and approximately 17 mm caudally distant from the midpoint of the floor of the third ventricle. The angle of the trajectory to damage the third nerve is at least 12° greater than any safe angle of ETV trajectory through a normal burr hole.

CONCLUSIONS

The third nerve is not always visible during ETV procedures, but the angular and linear measurements imply that the risk to damage the nerve should be relatively small. Confirmation of these data in hydrocephalic patients with distorted anatomy is needed.

The anatomy and physiology of the ocular motor system

Accurate diagnosis of abnormal eye movements depends upon knowledge of the purpose, properties, and neural substrate of distinct functional classes of eye movement. Here, we summarize current concepts of the anatomy of eye movement control. Our approach is bottom-up, starting with the extraocular muscles and their innervation by the cranial nerves. Second, we summarize the neural circuits in the pons underlying horizontal gaze control, and the midbrain connections that coordinate vertical and torsional movements. Third, the role of the cerebellum in governing and optimizing eye movements is presented. Fourth, each area of cerebral cortex contributing to eye movements is discussed. Last, descending projections from cerebral cortex, including basal ganglionic circuits that govern different components of gaze, and the superior colliculus, are summarized. At each stage of this review, the anatomical scheme is used to predict the effects of lesions on the control of eye movements, providing clinical-anatomical correlation.

Vasculopathic cranial ocular motor neuropathy following sudden emotional stress

We describe three patients who experienced onset of a microvascular ocular motor nerve palsy in the setting of sudden emotional stress. Such emotional states are accompanied by a marked increase in sympathetic tone in some individuals. Mechanisms by which these autonomic changes might produce an ischemic cranial nerve palsy include intra-cranial vasoconstriction and transient systemic hypotension due to alterations in cardiac function.

Ophthalmoplegia with migraine in adults: is it ophthalmoplegic migraine?

OBJECTIVE

Ophthalmoplegic migraine (OM) is a rare disorder characterized by recurrent oculomotor nerve palsy in children, following migraine headaches. We report 62 adults, seen consecutively, who developed acute ophthalmoplegia with severe attacks of migraine over a 10-year (1996-2005) period. An overwhelming majority of these patients had an antecedent worsening in severity of migraine headaches, before the ophthalmoplegic attack.

METHODS

Sixty-two patients, aged 15-68 years, with an acute attack of OM underwent detailed clinical, biochemical, and neuroradiological evaluation.

RESULTS

There were 62 patients with 86 attacks of OM. Whereas 48 patients had a single attack, 14 had 2 or more attacks, fulfilling the International Headache Society criteria for probable and definite OM, respectively. At presentation, isolated abducens, oculomotor, and trochlear nerve involvements were seen in 35 (56.5%), 21 (33.9%), and 5 (8.1%) patients, respectively. One patient had simultaneous involvement of 3rd and 6th nerves. Fifty-one (82.3%) patients exhibited an antecedent worsening in severity of migraine, before developing ophthalmoplegia during (59/95.2%) or within 24 hours (3/4.8%) of a severe migraine attack, respectively. Detailed biochemistry and cranial neuroimaging were normal. No case had any nerve enhancement. Use of steroids hastened recovery (P < .05).

CONCLUSION

We conclude: (1) OM in adults is characterized by single attacks of ophthalmoplegia in a great majority of patients; and (2) 6th nerve involvement occurs commonly. Our results indicate that moving OM to the chapter on cranial neuralgias in the second edition of the International Headache Classification may be premature, since nerve palsy occurred during a severe migraine attack in all patients.

Pituitary apoplexy presenting as isolated third cranial nerve palsy with ptosis : two case reports

Pituitary apoplexy is a clinical syndrome caused by an acute ischemic or hemorrhagic vascular accident involving a pituitary adenoma or an adjacent pituitary gland. Pituitary apoplexy may be associated with a variety of neurological and endocrinological signs and symptoms. However, isolated third cranial nerve palsy with ptosis as the presenting sign of pituitary apoplexy is very rare. We describe two cases of pituitary apoplexy presenting as sudden-onset unilateral ptosis and diplopia. In one case, brain magnetic resonance imaging (MRI) revealed a mass in the pituitary fossa with signs of hemorrhage, upward displacement of the optic chiasm, erosion of the sellar floor and invasion of the right cavernous sinus. In the other case, MRI showed a large area of insufficient enhancement in the anterior pituitary consistent with pituitary infarction or Sheehan's syndrome. We performed neurosurgical decompression via a transsphenoidal approach. Both patients showed an uneventful recovery. Both cases of isolated third cranial nerve palsy with ptosis completely resolved during the early postoperative period. We suggest that pituitary apoplexy should be included in the differential diagnosis of patients presenting with isolated third cranial nerve palsy with ptosis and that prompt neurosurgical decompression should be considered for the preservation of third cranial nerve function.

Painful vertical diplopia as a presentation of a pituitary mass

BACKGROUND

Pituitary tumours may present with a variety of neurological and endocrinological signs and symptoms. It is very rare however for them to present with sudden onset painful diplopia. The current literature and possible mechanisms for this are discussed.

CASE PRESENTATION

We describe a case of a pituitary mass which presented with sudden onset painful diplopia with an associated restricted pattern on Lees Chart testing. This led to an initial working diagnosis of orbital myositis.

CONCLUSION

Awareness of different modes of presentation of pituitary lesions is important so that appropriate imaging may be requested and delay in diagnosis prevented.

A prospective study of cavernous sinus surgery for meningiomas and resultant common ophthalmic complications (an American Ophthalmological Society thesis)

PURPOSE

Cavernous sinus surgery is considered neurosurgically feasible. A systematic review of patients undergoing cavernous sinus procedures for meningioma was undertaken to determine whether cavernous sinus surgery could be performed with an acceptable level of iatrogenic-induced dysfunction.

METHODS

Fifty-six patients undergoing 57 cavernous sinus surgical procedures performed by a single senior neurosurgeon were systematically evaluated to determine the consequences of surgery. Quantitative assessment of afferent (acuity, fields, pupil) and efferent function was stressed.

RESULTS

Five of 20 patients (25%) with preoperative optic nerve dysfunction improved, but vision worsened in 6 (30%), including 4 (20%) whose vision deteriorated to no light perception. Four (11%) of 37 patients developed newly acquired optic neuropathy. No patients with preoperative third nerve palsies (19) cleared, although one improved. All 57 patients had evidence of some cranial nerve dysfunction (III, IV, V, or VI) immediately after surgery. Eight patients with long-term follow-up had complete sixth nerve palsies (7 preoperatively), and 4 had complete third nerve dysfunction (none in patients normal preoperatively). Nine (16%) had evidence of aberrant regeneration of the third nerve, and 12 (21%) developed neurotrophic keratitis.

CONCLUSIONS

Cavernous sinus surgery results in transient worsening of third, fourth, fifth, and sixth cranial nerve function. Cavernous sinus surgery carries a high risk of worsening ocular motor disorders and producing new ones. Preexisting cranial nerve dysfunction (other than optic nerve) rarely improves. Patients and physicians should be aware of the potential for ophthalmic complications in addition to the more generalized risks of neurosurgery (eg, cerebrospinal fluid leak, infection, stroke).

Upper cranial nerve palsy resulting from spontaneous carotid dissection

INTRODUCTION

Upper cranial nerve palsy has a variety of causes such as cerebral and nerve ischemia, diabetes, infectious and non-infectious meningitis, subarachnoid hemorrhage and intracranial aneurysm. CASE 1 : A 45-year-old man suffered from holocephalic headaches and a right-sided neck pain for two weeks. He presented to our emergency department because of a sudden ptosis of the right eye. On admission neurological examination revealed a right sided Horner's syndrome and hypesthesia of the right side of the face. Magnetic resonance angiography identified a circumscribed dissection of the right extracranial internal carotid artery originating from the carotid bifurcation. Conventional angiography 2 weeks later showed a nearly recanalized artery. CASE 2 : A 55-year-old previously healthy man without cardiovascular risk factors developed right sided neck pain when loading a seeder with several sacks of crop. A few hours later he noticed a left-sided weakness. On admission a severe left sided hemiparesis and a mild neglect were present. Duplex sonography revealed a right-sided distal internal carotid artery (ICA) occlusion. The next morning the patient complained of double vision; he had a right-sided pupil-sparing oculomotor palsy. The diagnosis of ICA dissection was confirmed by conventional angiography, at that time showing a partially recanalized ICA without involvement of the cavernous region by the dissection.

CONCLUSION

ICA dissection must be included in the differential diagnosis of upper cranial nerve palsy and should be assessed by duplex ultrasound and magnetic resonance imaging. A possible explanation is nerve ischemia due to a transient or permanent interruption of the blood supply by compression of the vasa nervorum originating from the intracranial carotid artery.

Isolated oculomotor nerve palsy inspontaneous internal carotid artery dissection: case report

Partial oculosympathetic palsy followed by ischemic manifestations in brain or retina are the main symptoms of extracranial internal carotid artery (ICA) dissection. Unusually, cranial nerves may be affected. Isolated oculomotor nerve palsy is found only rarely. CASE: We present a 50-year-old nondiabetic man who experienced acute onset of right occipital headache which spread to the right retro-orbital region. Five days later he noticed diplopia and right blurred vision sensation. Neurologic examination disclosed only impaired adduction and upward gaze of right eye, slight ipsilateral pupillary dilatation, without ptosis. Brain MRI was normal. Angiography showed right internal carotid artery dissection with forward occlusion to the base of the skull. Intravenous heparin followed by warfarin was prescribed. The headache and the oculomotor nerve deficit gradually resolved in the next three weeks. DISCUSSION: Isolated oculomotor nerve palsy is underrecognized as a clinical presentation of extracranial ICA dissection. If the angiographic evaluation is incomplete without careful study of extracranial arteries, misdiagnosis may lead to failure to initiate early treatment to prevent thromboembolic complications. For this reason we draw attention to the need for careful evaluation of cervical arteries in patients with oculomotor nerve palsy. Mechanical compression or stretching of the third nerve are possible mechanisms, but the direct impairment of the blood supply to the third nerve seems to be the most plausible explanation.

Oculomotor ophthalmoplegic migraine: is it really migraine?

Oculomotor ophthalmoplegic migraine is a rare episodic childhood condition in which a unilateral oculomotor palsy is preceded by headache. I describe six new cases that had magnetic resonance imaging signal abnormalities during the acute phase, consisting of a thickened and enhancing ipsilateral oculomotor nerve at its exit from the midbrain. During the quiescent phase, when the headache had resolved, the signal abnormalities were still present but less dramatic. Seventeen similar cases have been previously reported. The pathophysiology may be a trigeminovascular migraine epiphenomenon that is dependent on the unique oculomotor nerve anatomy and porous blood-nerve barrier at the emergence of the oculomotor nerve from the brainstem and the sequelae of demyelination. Early high-dose corticosteroid treatment is recommended to rapidly resolve an acute episode and to potentially prevent permanent abnormal oculomotor nerve signs.