NEURO-OPHTHALMOLOGIC EVALUATION OF OCULOMOTOR NERVE PARALYSIS

Etiological distribution of isolated oculomotor nerve palsy: analysis of 633 patients and literature review

BACKGROUND AND PURPOSE

The etiological distribution of oculomotor nerve palsy has varied amongst the studies. This study aimed to define the clinical features and underlying etiologies of isolated oculomotor nerve palsy by recruiting patients from all departments in a referral-based university hospital.

METHODS

The medical records of 672 patients who had a confirmed diagnosis of isolated oculomotor nerve palsy at all departments of Seoul National University Bundang Hospital, Seongnam, South Korea, from 2003 to 2020 were reviewed. A proportion of the etiology of isolated oculomotor nerve palsy was also compared with that of patients pooled from the previous studies that were searched on PubMed in May 2022.

RESULTS

The most common etiology was microvascular (n = 168, 26.5%), followed by vascular anomalies (n = 110, 17.4%), neoplastic (n = 86, 13.6%), inflammatory (n = 79, 12.5%), idiopathic (n = 60, 9.5%) and traumatic (n = 53, 8.4%). Neurologists were mainly involved in the management of microvascular and inflammatory oculomotor nerve palsies whilst ophthalmologists mainly participated in the care of idiopathic, neoplastic and traumatic palsies. Neurosurgeons mostly took care of oculomotor nerve palsy due to vascular anomalies.

CONCLUSIONS

The proportion of etiologies of isolated oculomotor nerve palsy may differ according to the specialties involved in the management. The results of previous studies on the etiological distribution of isolated oculomotor nerve palsy should be interpreted with this consideration.

Aberrant regeneration in an international registry of patients with 3rd-nerve palsy

BACKGROUND/AIMS

To describe the patterns of pre-operative aberrant regeneration and motility outcomes reported in an international registry of patients with 3rd-nerve palsy treated with nasal transposition of the split lateral rectus muscle (NTSLR).

METHODS

This cross-sectional study used data from an international, multicentre registry of patients with 3rd-nerve palsy treated with NTSLR. Patients with aberrant regeneration were identified, and patterns of innervation described. Demographics and postoperative success defined as horizontal alignment ≤15 PD were compared based on the presence, and type, of aberrant regeneration using Wilcoxon rank sum and Fisher's exact tests.

RESULTS

Aberrant regeneration was reported in 16% (21/129) of patients. Age at diagnosis, sex, and aetiology of palsy were not significantly associated with aberrant regeneration. Abnormal movements were triggered by adduction in 52% (11/21), infraduction in 23% (5/21), and supraduction in 23% (5/21) of cases. Presentation patterns involved rectus muscle innervation in 29% (6/21) and levator muscle innervation in 71% (15/21) of cases. Although patients with aberrant regeneration had similar probability of success in comparison to those without following NTLSR (76% vs. 69%, p = 0.5), those with abnormal innervation of a rectus muscle had a lower success rate than those with abnormal innervation of the levator palpebrae superioris muscle (17% vs. 93%; p = 0.002).

CONCLUSION

Successful treatment of a 3rd nerve palsy with NTSLR was not influenced by aberrant regeneration involving the levator muscle. Alternative surgical interventions should be considered when aberrant regeneration alters rectus muscle function given its adverse impact on motor outcomes with NTSLR.

Internal carotid artery aneurysm with incomplete isolated oculomotor nerve palsy: a case report

BACKGROUND

Oculomotor nerve palsy is a common and well-described disease with diverse etiologies. Clinicians should quickly and correctly diagnose and treat oculomotor nerve palsy according to its characteristics and the accompanying symptoms and signs. Intracranial aneurysm is an important and frequent cause of oculomotor nerve palsy. Considering the catastrophic consequences of rupture, the possibility of an urgent, life-threatening disease should always be considered.

CASE PRESENTATION

A 63-year-old Chinese woman presented with intermittent left ptosis and diplopia and painless incomplete oculomotor nerve palsy without pupil involvement. She manifested no mydriasis or extraocular muscle weakness, and the light reflex was normal. Other cranial nerves and somatosensory and somatomotor examinations were normal. The neostigmine experiment and electromyography were normal, so the diagnosis of myasthenia gravis was excluded. Brain magnetic resonance angiography showed a 4-mm aneurysm located at the cavernous segment of the left internal carotid artery. Unfortunately, the patient refused digital subtraction angiography and was discharged home without further treatment.

CONCLUSION

Neuroimaging must be performed to exclude intracranial aneurysms in oculomotor nerve palsy regardless of whether the pupils are involved, as aneurysm rupture carries substantial morbidity and mortality.

Diabetic Mononeuropathies and Diabetic Amyotrophy

This brief review describes the etiology, pathophysiology, clinical features, therapy and prognosis of the diabetic mononeuropathies and diabetic amyotrophy and neuropathic cachexia. Mononeuropathies include cranial neuropathies, of which the oculomotor nerve is most commonly affected, and are thought to be due to microvascular occlusion. Peripherally, entrapment neuropathies occur in both the upper and lower limbs and are due to compression of an already damaged nerve in anatomically restricted channels. Diabetic radiculopathies occur in the dermatones of the thorax and abdomen, mimicking intraabdominal or intrathoracic pathology. I also describe the features of the rare but very distinctive diabetic amyotrophy and neuropathic cachexia. Overall, the prognosis from these conditions is excellent with residual pain or muscle weakness being rare with the exception of diabetic amyotrophy where the prognosis is dependent upon cooperation with intensive rehabilitation. Therapies include "watchful waiting," physical therapy and rarely surgical intervention, which may be urgently needed for nerve decompression and reversal of motor defects.

The spectrum and differential diagnosis of acquired ocular motor nerve palsies: a clinical study of 502 patients

Background

Ocular motor nerve palsies (OMNP) frequently cause patients to present in an emergency room. In the following study, we report the differential diagnosis of OMNP by use of magnetic resonance imaging (MRI) and CSF examination as a standard.

Method

We performed a data analysis of N = 502 patients who presented with oculomotor, trochlear, and/or abducens nerve palsy in the emergency room of the Department of Neurology, University of Ulm, between January 2006 and December 2019. We report clinical and MRI scan findings in all patients; furthermore, the CSF of 398 patients has been analysed.

Results

Abducens nerve palsies were most common (45%), followed by palsies of the oculomotor (31%) (CNP III) and trochlear nerve (15%). Multiple OMNPs were seen in 9% of our cohort. The most common causes included inflammations (32.7%), space-occupying lesions, such as aneurysms or neoplasms (17.3%), diabetes mellitus (13.3%), and brainstem infarctions (11%). Still 23.4% of the patients could not be assigned to any specific cause after differential diagnostic procedures and were described as idiopathic. One of three patients with an inflammation and 39% of the patients with space-occupying lesions showed additional cranial nerve deficits.

Conclusion

Inflammation and space-occupying processes were the most frequent causes of OMNP, although brainstem infarctions also play a significant role, in particular in CNP III. The presence of additional CNPs increases the probability of an inflammatory or space-occupying cause.

Characteristics of pupil palsy in miller-fisher syndrome: case reports and review of the literature

Pupil palsy has been a frequent finding in Miller Fisher syndrome (MFS), but its clinical characteristics have not been clearly defined. The basis for differential diagnosis with other diseases with pupil palsy has also remained vague. We report cases of four MFS patients with bilateral pupil palsy and specify pupil characteristics of light-near dissociation (LND), cholinergic super-sensitivity, vermiform movements, and prognosis. We conducted a literature review to compare with our cases and investigate common findings of pupil palsy in MFS patients. We suggest that the acute generalized pupil palsy without vermiform movements can serve as a key finding for the diagnosis of pupil palsy associated with MFS. However, the presence of LND and cholinergic super-sensitivity was not distinctive clinical findings in MFS patients who had pupil palsy and did not prove useful for differential diagnosis. The prognosis of pupil palsy in MFS patients was good in our 4 cases and the literature review.

The Incidence and Etiologies of Third Cranial Nerve Palsy in Koreans: A 10-year Nationwide Cohort Study

PURPOSE

This study aimed to determine the incidence, prevalence, and etiologies of third cranial nerve (CN3) palsy in Koreans.

METHODS

Data were collected from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) database of South Korea and analyzed. Incident CN3 palsy subjects in the cohort population were defined as cases occurring after the initial 4-year or longer washout period. The incidence and prevalence were analyzed by sex, age group, and year. The etiologies of CN3 palsy were evaluated using comorbidities.

RESULTS

Of 1,108,253 subjects, 387 patients were newly diagnosed with CN3 palsy between 2006 and 2015. The incidence of CN3 palsy was 3.71 per 100,000 person-years (95% confidence interval, 3.35-4.09). The incidence of CN3 palsy increased with age and accelerated after the age of 60 years. The mean male-to-female incidence ratio was 1.16. The main cause was presumed to be vascular disease (52.7%), followed by idiopathic causes (25.8%), intracranial neoplasm (7.8%), unruptured cerebral aneurysm (5.4%), and trauma (5.2%).

CONCLUSIONS

The incidence of CN3 palsy in Koreans increased with age and peaked between 75 and 79 years. The main cause of CN3 palsy was vascular disease.

Quantitative analysis of pupillometry in isolated third nerve palsy

OBJECTIVES

To objectively assess pupillary involvement according to various etiologies of acquired isolated third nerve palsy using automated pupillometry, and evaluate the efficacy of digital pupillometry in discriminating compressive lesions from microvascular ischemic third nerve palsy.

DESIGN

Retrospective, observational case series.

METHODS

A total of 171 subjects were included in this study, consisting of 60 subjects with presumed microvascular ischemic third nerve palsy, 51 with non-ischemic third nerve palsy, and 60 controls whose pupillary light responses were measured using a dynamic automated pupillometer. Subjects with non-ischemic third nerve palsy were divided into subgroups according to their etiology; inflammatory and compressive groups including tumor and aneurysm. Pupillometry parameters including minimum and maximum pupil diameters, constriction latency and ratio, maximum and average constriction velocities and dilation velocity were noted. The diagnostic ability of pupillometry parameters for discriminating compressive vs microvascular ischemic third nerve palsy was evaluated. The inter-eye difference of the involved eye and the uninvolved fellow eye was calculated to adjust for individual variability.

RESULTS

Among all parameters, reduced pupillary constriction ratio was the most specific parameter for detecting non-ischemic third nerve palsy, as a large inter-eye difference beyond the normative range of controls was found in 0% of ischemic, 20% of inflammatory and 60% of compressive third nerve palsy. With the diagnostic criteria using inter-eye differences of 1) minimum pupil diameter > 0.45 mm, or 2) pupillary constriction ratio < -7.5% compared to the fellow eye, the sensitivity and specificity for diagnosing compressive third nerve palsy were 95% and 88%, respectively. In the compressive group, positive correlations were found between the degree of external ophthalmoplegia and constriction ratio (r = 0.615, p<0.001), average constriction velocity (r = 0.591, p = 0.001) and maximum constriction velocity (r = 0.582, p = 0.001).

CONCLUSIONS

Abnormal pupillary constriction ratio was highly specific for detecting compressive third nerve palsy, although the sensitivity was not high. Digital pupillometry demonstrated relatively good performance for discriminating compressive lesions from microvascular ischemic third nerve palsy.

Oculomotor palsy in diabetics

INTRODUCTION

Oculomotor palsy is one of the most frequent neuro-ophthalmologic complications of diabetic patients. It generates less interest in the literature than the other ocular manifestations. Our goal was to study the clinical, epidemiological, therapeutic and prognostic characteristics of oculomotor palsy in the diabetic.

METHODS

This is a retrospective study of 24 diabetic patients with oculomotor palsy. The ophthalmological examination emphasized ocular motility. We performed an orthoptic assessment and a Hess-Lancaster test. Neuro-imaging was ordered in case of IIIrd and IVth nerve involvement, bilateral involvement, multiple ocular cranial nerve palsy or associated optic neuropathy. Treatment consisted of glucose management and alternating monocular occlusion or prisms for the diplopia. Data were entered and analyzed on SPSS 11.5 software.

RESULTS

The mean age of the patients was 58.5±11.9 years. Binocular diplopia was the main symptom. The oculomotor palsy involved the VIth nerve in 50% of cases and was bilateral in two cases. Three patients also had an optic neuropathy. The mean duration of diabetes was 11.7±11 years; poorly controlled diabetes was found in 75% of cases and an association with diabetic retinopathy was noted in 56% of cases.

CONCLUSIONS

Long-standing uncontrolled type 2 diabetes, hypertension, coronary artery disease, left ventricular hypertrophy, and elevated hematocrit are the most common risk factors. The VIth nerve is commonly involved. Certain characteristics of the pupillary light reflex can help to differentiate an ischemic insult from an aneurysmal injury to the IIIrd nerve.

Stroke risk among adult patients with third, fourth or sixth cranial nerve palsy: a Nationwide Cohort Study

PURPOSE

This study sought to determine whether isolated third, fourth and sixth cranial nerve palsies (NPs) are associated with increased short- and long-term risk of a subsequent stroke.

METHODS

This was a nationwide retrospective propensity score-matched cohort study. A cohort of patients with NP (n = 466) and a randomly selected, propensity-matched control cohort (n = 2281) were extracted from the Korean national insurance claim database. Subjects were tracked for 5 years total, subdivided into periods of 0-1 years, 1-3 years and 3-5 years. We assessed the risk of stroke using hazard ratios (HRs) and confidence intervals (CIs) after adjustments using Cox regression at different time intervals.

RESULTS

The median follow-up was 3.1 years. Stroke developed in 18.9% of the NP cohort and 7.5% of the control cohort. Stroke risk after NP was highest in the first year [14.7 per 100 person-year at 0-1 years (HR = 6.6), 3.1 per 100 person-year at 1-3 years (HR = 1.6) and 4.3 per 100 person-year at 3-5 years (HR = 2.8)]. Each type of NP was also associated with stroke risk: within 0-1 years, stroke risk was increased in third (HR = 7.6), fourth (HR = 6.0) and sixth (HR = 5. 84) NPs. In the 3- to 5-year period, risk was increased in sixth (HR = 4.7) and fourth (HR = 3.3) NPs, but not third (HR = 0.6) NPs.

CONCLUSION

Patients in the NP cohort were more likely to have a stroke than those in the matched control cohort; the increased risk was both time- and cranial nerve-dependent.

Incidence and Etiologies of Acquired Third Nerve Palsy Using a Population-Based Method

Importance

Among cranial nerve palsies, a third nerve palsy is important because a subset is caused by life-threatening aneurysms. However, there is significant disagreement regarding its incidence and the reported etiologies.

Objective

To determine the incidence and etiologies of acquired third nerve palsy using a population-based method.

Design, Setting, and Participants

All newly diagnosed cases of acquired third nerve palsy from January 1, 1978, through December 31, 2014, in Olmsted County, Minnesota, were identified using the Rochester Epidemiology Project, a record-linkage system of medical records for all patient-physician encounters among Olmsted County residents. All medical records were reviewed to confirm a diagnosis of acquired third nerve palsy and determine the etiologies, presenting signs, and symptoms. Incidence rates were adjusted to the age and sex distribution of the 2010 US white population.

Main Outcomes and Measures

Incidence and etiologies of acquired third nerve palsies. The secondary outcome was incidence of pupil involvement in acquired third nerve palsies.

Results

We identified 145 newly diagnosed cases of acquired third nerve palsy in Olmsted County, Minnesota, over the 37-year period. The age- and sex-adjusted annual incidence of acquired third nerve palsy was 4.0 per 100 000 (95% CI, 3.3-4.7 per 100 000). The annual incidence in patients older than 60 was greater than patients younger than 60 (12.5 vs 1.7 per 100 000; difference, 10.8 per 100 000; 95% CI, 4.7-16.9; P < .001). The most common causes of acquired third nerve palsy were presumed microvascular (42%), trauma (12%), compression from neoplasm (11%), postneurosurgery (10%), and compression from aneurysm (6%). Ten patients (17%) with microvascular third nerve palsies had pupil involvement, while pupil involvement was seen in 16 patients (64%) with compressive third nerve palsies.

Conclusions and Relevance

This population-based cohort demonstrates a higher incidence of presumed microvascular third nerve palsies and a lower incidence of aneurysmal compression than previously reported in non-population-based studies. While compressive lesions had a higher likelihood of pupil involvement, pupil involvement did not exclude microvascular third nerve palsy and lack of pupil involvement did not rule out compressive third nerve palsy.

Isolated oculomotor nerve palsy after lumbar epidural steroid injection in a diabetic patient

Background:

In patients with diabetes mellitus, epidural steroid injections (ESI) have been noted to cause significant elevation of blood glucose levels, typically lasting 1–3 days. Here, we describe a previously unreported complication of a diabetic third nerve palsy associated with an ESI.

Case Description:

A 66-year-old man with a history of coronary artery disease, hypertension, and insulin-dependent diabetes mellitus presented with low back pain and left lower extremity radiculopathy. The lumbar magnetic resonance imaging (MRI) revealed mild spondylosis, most severe at the L4-5 level, accompanied by a broad based disc protrusion resulting in mild central and moderate biforaminal stenosis. The patient underwent a left-sided L4-L5 transforaminal ESI resulting in transient elevation of his blood glucose levels. On post-procedure day 2, he developed a frontal headache and a complete right third nerve palsy with partial pupillary involvement. The MRI and MR angiography (MRA) of the brain revealed no compressive lesions or oculomotor abnormalities. Ophthalmoplegia and pupillary dysfunction resolved spontaneously over 4 months.

Conclusions:

Although rare, a history of a recent ESI should be considered as the etiology of an isolated oculomotor palsy in diabetic patients.

Surgical management of third nerve palsy

Third nerve paralysis has been known to be associated with a wide spectrum of presentation and other associated factors such as the presence of ptosis, pupillary involvement, amblyopia, aberrant regeneration, poor bell's phenomenon, superior oblique (SO) overaction, and lateral rectus (LR) contracture. Correction of strabismus due to third nerve palsy can be complex as four out of the six extraocular muscles are involved and therefore should be approached differently. Third nerve palsy can be congenital or acquired. The common causes of isolated third nerve palsy in children are congenital (43%), trauma (20%), inflammation (13%), aneurysm (7%), and ophthalmoplegic migraine. Whereas, in adult population, common etiologies are vasculopathic disorders (diabetes mellitus, hypertension), aneurysm, and trauma. Treatment can be both nonsurgical and surgical. As nonsurgical modalities are not of much help, surgery remains the main-stay of treatment. Surgical strategies are different for complete and partial third nerve palsy. Surgery for complete third nerve palsy may involve supra-maximal recession - resection of the recti. This may be combined with SO transposition and augmented by surgery on the other eye. For partial third nerve, palsy surgery is determined according to nature and extent of involvement of extraocular muscles.

Prevalence and clinical characteristics of blepharoptosis in patients with diabetes in the Korea National Health and Nutrition Examination Survey (KNHANES) 2009-2010

We investigated the prevalence and clinical characteristics of ptosis in patients with diabetes in the general Korean population. This cross-sectional study is based on data from the fourth and fifth Korea National Health and Nutrition Examination Surveys , conducted in 2009 and 2010 among members of the Korean population. Participants included 5,811 males and 7,650 females 20 years of age or older. Ptosis was defined as the marginal reflex distance 1 of <2 mm. Homeostatic model assessment of insulin resistance was calculated in participants without diabetes. HbA1c was measured and diabetic retinopathy was defined in participants with diabetes by ophthalmologic examination. The prevalence of ptosis was 20.8 and 9.4 % among participants with diabetes (n = 1,379) and those without diabetes (n = 12,082), respectively. Results of multiple regression analyses of the correlation between ptosis and the study variables showed that diabetes was a significant determinant in the general population. Patients with diabetes and ptosis had longer duration of diabetes (7.49 ± 0.51 vs. 6.19 ± 0.23 years, P = 0.012), higher serum creatinine level (80.4 ± 1.76 vs. 76.9 ± 0.88 mmol/l, P = 0.009), and higher prevalence of hypertension (60.3 vs. 47.9 %, P < 0.001), and were older (67.0 ± 0.6 vs. 60.5 ± 0.4 years, P < 0.001) compared to those without ptosis. Prevalence of ptosis was found to be remarkably higher in subjects with diabetes compared to those without diabetes. Diabetes is an independent risk factor for ptosis in the general Korean population. Screening for ptosis is warranted for patients with diabetes and longer duration, higher serum creatinine, hypertension, and old age.

Third Nerve Palsy: Analysis of 1400 Personally-examined Inpatients

Background:

Most studies of third nerve palsy (TNP) antedate computerized imaging and focus primarily on chart review of referral outpatients.

Methods:

To compare a large contrasting population, I reviewed 1400 personally-examined municipal hospital inpatients with TNPs seen over 37 years.

Results:

TNPs were bilateral in 11%, complete in 33%, without other neurological signs (isolated) in 36%, and associated with recurrent cranial neuropathies in 7%. Third nerve damage occurred in the subarachnoid space in 32%, the cavernous sinus in 23%, the brainstem in 14%, as a nonlocalized peripheral neuropathy in 18% and at an uncertain location in 13%. Causes were trauma (26%), tumor (12%), diabetes (11%), aneurysm (10%), surgery (10%), stroke (8%), infection (5%), Guillain-Barre and Fisher syndromes (5%), idiopathic cavernous sinusitis (3%), benign self-limited (2%), miscellaneous (4%), and unknown (3%). Local causes, besides an abundance of trauma, included six cases involving cysticercosis, four with wound botulism, and one with coccidiomycotic meningitis. Of 234 patients with diabetes, microvascular ischemia was the cause of TNP in only two-thirds (five had aneurysms) and 53% of those with diabetic microvascular ischemia had pupillary involvement—often bilateral, suggesting concomitant autonomic neuropathy. Only 2% of aneurysms spared the pupil. Apainful onset occurred with 94% of aneurysm and 69% of diabetic cases.

Conclusions:

Bilateral TNPs, multiple cranial neuropathies, and accompanying neurological signs were common among our inpatients, as were causes rare in outpatient settings such as severe trauma, transtentorial herniation, midbrain strokes, and the Guillain-Barre syndrome. Few cases remained undiagnosed and nondiabetic ischemia was rare.

A Case of the Internal Carotid Artery-Posterior Communicating Artery Aneurysm Mimicking Tolosa-Hunt Syndrome

A 53-year-old woman experienced a right retrobulbar pain followed by ipsilateral extraocular palsies in all directions without dilated pupils or ptosis. Because a plain head computed tomography (CT) scan obtained on her initial visit showed no abnormal findings, such as subarachnoid hemorrhage or a giant cavernous aneurysm, her condition was provisionally diagnosed as Tolosa–Hunt syndrome and elective magnetic resonance (MR) imaging was scheduled. The day after her initial visit, however, she suddenly developed complete ptosis and a dilated pupil on the right side. Emergency MR imaging and angiography revealed a clover leaf-shaped aneurysm projecting to the cavernous sinus at the junction of the internal carotid artery and the posterior communicating artery. Her condition was diagnosed as impending rupture of the aneurysm, and she underwent emergency open surgery. Her symptoms completely resolved within the following 2 weeks. Our case demonstrated that a medium-sized internal carotid artery–posterior communicating artery aneurysm can cause simultaneous oculomotor and abducens nerve palsies with retrobulbar pain if the shape of the aneurysm is complicated. Although these symptoms are very similar to those of Tolosa–Hunt syndrome, we believe that prompt radiological examinations such as MR or 3D CT angiography should be performed to prevent subsequent rupture of the aneurysm.

Three common ophthalmic emergencies

Vision changes and ophthalmic complaints may represent potentially serious, sometimes fatal, systemic illnesses. This article summarizes the presenting signs and symptoms of retinal artery occlusion, giant cell arteritis, and oculomotor nerve palsy.

Pupil-sparing oculomotor nerve palsy caused by upward compression of a large posterior communicating artery aneurysm. Case report

A 69-year-old woman without diabetes or hypertension presented with a large posterior communicating artery aneurysm projecting beneath the oculomotor nerve manifesting as a 2-week history of progressive diplopia. Neurological examination revealed external ophthalmoplegia and blepharoptosis without pupil involvement. Neuroimaging showed a large aneurysm in the left internal carotid artery projecting postero-inferiorly. Craniotomy and neck clipping of the aneurysm revealed the origin at the junction of the internal carotid artery and posterior communicating artery, and elevation of the oculomotor nerve. Pupil-sparing oculomotor nerve palsy is often assumed to be caused by ischemic injury such as hypertension and diabetes mellitus. Sometimes compressive lesion can cause pupil-sparing oculomotor nerve palsy with a short interval from the onset of symptoms to diagnosis. Despite the 2-week interval from the onset of symptoms, this patient presented with pupil-sparing oculomotor nerve palsy caused by compressive lesion. Involvement or sparing of the pupil is often considered to be the most important criterion in the diagnosis of isolated oculomotor nerve palsy. This unique case demonstrated that unusual compressive lesions must be taken into consideration in the diagnosis of pupil-sparing oculomotor nerve palsy.

Incidence of pupillary involvement, course of anisocoria and ophthalmoplegia in diabetic oculomotor nerve palsy

AIMS

To derive a reliable estimate of the frequency of pupillary involvement and to study the patterns and course of anisocoria in conjunction with ophthalmoplegia in diabetes-associated oculomotor nerve palsy.

MATERIALS AND METHODS

In this prospective analytical study, standardized enrolment criteria were employed to identify 35 consecutive patients with diabetes-associated oculomotor nerve palsy who were subjected to a comprehensive ocular examination. Standardized methods were used to evaluate pupil size, shape, and reflexes. The degree of anisocoria, if present and the degree of ophthalmoplegia was recorded at each visit.

RESULTS

Pupillary involvement was found to be present in 25.7% of the total number of subjects with diabetic oculomotor nerve palsy. The measure of anisocoria was < 2 mm, and pupil was variably reactive at least to some extent in all cases with pupillary involvement. Majority of patients in both the pupil-involved and pupil-spared group showed a regressive pattern of ophthalmoplegia. Ophthalmoplegia reversed much earlier and more significantly when compared to anisocoria.

CONCLUSIONS

Pupillary involvement in diabetes-associated oculomotor nerve palsy occurs in about 1/4 th of all cases. Certain characteristics of the pupil help us to differentiate an ischemic insult from an aneurysmal injury to the 3 rd nerve. Ophthalmoplegia resolves much earlier than anisocoria in diabetic oculomotor nerve palsies.

Diabetic neuropathy

Diabetes is the most common cause of peripheral neuropathy in the world. Both type 1 (insulin-dependent) and type 2 diabetes are commonly complicated by peripheral nerve disorders. Two main types of neuropathy are observed: the most common is a nerve fiber length-dependent, distal symmetrical sensory polyneuropathy with little motor involvement but frequent, and potentially life threatening, autonomic dysfunction. Alteration of temperature and pain sensations in the feet is an early manifestation of diabetic polyneuropathy. The second pattern is a focal neuropathy, which more commonly complicates or reveals type 2 diabetes. Poor diabetic control increases the risk of neuropathy with subsequent neuropathic pains and trophic changes in the feet, which can be prevented by education of patients.

Infranuclear ocular motor disorders

This chapter covers the very large number of possible disorders that can affect the three ocular motor nerves, the neuromuscular junction, or the extraocular muscles. Conditions affecting the nerves are discussed under two major headings: those in which the site of damage can be anatomically localized (e.g., fascicular lesions and lesions occurring in the subarachnoid space, the cavernous sinus, the superior orbital fissure, or the orbit) and those in which the site of the lesion is either nonspecific or variable (e.g., vascular lesions, tumors, "ophthalmoplegic migraine," and congenital disorders). Specific comments on the diagnosis and management of disorders of each of the three nerves follow. Ocular motor synkineses (including Duane's retraction syndrome and aberrant regeneration) and disorders resulting in paroxysms of excess activity (e.g., neuromyotonia) are then covered, followed by myasthenia gravis and other disorders that affect the neuromuscular junction. A final section discusses disorders of the extraocular muscles themselves, including thyroid disease, orbital myositis, mitochondrial disease, and the muscular dystrophies.

Pupil-involving third nerve palsy as a manifestation of anti-myelin-associated glycoprotein neuropathy

A 56-year-old man developed a pupil-involving left third nerve palsy. Imaging studies of the brain and intracranial vessels were normal. Neurological examination demonstrated a sensory polyneuropathy and mild distal weakness. Nerve conduction studies showed prolonged distal motor latencies. An enzyme-linked immunosorbent assay test detected high titers of anti-myelin-associated glycoprotein (MAG) antibodies. The patient improved with prednisone and rituximab treatment. Anti-MAG neuropathy should be considered when evaluating a patient with an undiagnosed cranial neuropathy, especially in the setting of a sensory neuropathy.

Focal and multifocal diabetic neuropathies

Diabetic neuropathy is the most common neuropathy in industrialized countries, with a remarkable range of clinical manifestations. The vast majority of the patients with clinical diabetic neuropathy have a distal symmetrical form that progress following a fiber-length dependent pattern, with predominant sensory and autonomic manifestations. This pattern of neuropathy is associated with a progressive distal axonopathy. Patients are exposed to trophic changes in the feet, pains and autonomic disturbances. Less often, diabetic patients may develop focal and multifocal neuropathy that includes cranial nerve involvement, limb and truncal neuropathies. This neuropathic pattern tends to occur after 50 years of age, mostly in patients with longstanding diabetes mellitus. The LDDP does not show any trend to improvement and either relentlessly progresses or remain relatively stable over years. Conversely the focal diabetic neuropathies, which are often associated with inflammatory vasculopathy on nerve biopsies, remain self limited, sometimes after a relapsing course.

Pupil sparing incomplete third nerve palsy secondary to a cavernous sinus meningioma: challenges in management

BACKGROUND

The diagnosis of incomplete third nerve palsy can be clinically challenging because the aetiologies, as well as presentations, can be variable and subtle. The optometric clinician should be familiar with the association of third nerve palsy with compressive lesions, including the clinical presentations and management of these patients.

CASE REPORT

We present a 68-year-old hypertensive male complaining of intermittent diplopia for the previous six months. Neurological examination revealed a mild deficit in adduction, reduced range of vertical motility and questionable ptosis, all limited to the OD. No pupillary involvement was noted. MRI revealed a cavernous sinus meningioma. The patient elected against surgery, choosing MRI every six months.

CONCLUSION

Due to the subtle clinical presentation of incomplete pupil sparing third nerve palsy, this ophthalmoplegia may be easily overlooked. The associated aetiologies of palsy of cranial nerve three (CN3) carry increased risk of morbidity and mortality. Management should include evaluation for mass lesions and/or vascular aetiologies, regardless of pupillary involvement.

High-resolution magnetic resonance imaging of the extraocular muscles and nerves demonstrates various etiologies of third nerve palsy

PURPOSE

The etiology of third nerve palsy is usually diagnosed by history, motility examination, and presence of lid and pupil involvement, as well as cranial and vascular imaging. We used high-resolution magnetic resonance imaging (hrMRI) of the oculomotor nerve and affected extraocular muscles (EOMs) to investigate oculomotor palsy.

DESIGN

Prospective, noncomparative, observational case series in an academic referral setting.

METHODS

Twelve patients with nonaneurysmal oculomotor palsy of 0.75 to 252 months' duration were studied. In the orbit and along the intracranial oculomotor nerve, hrMRI at 1- to 2-mm thickness was performed. Coronal plane images of each orbit were obtained in multiple, controlled gaze positions. Structural abnormalities of the oculomotor nerve and associated changes in EOM volume and contractility were evaluated.

RESULTS

Cases were categorized as tumor related, congenital, diabetic, traumatic, and idiopathic according to clinical characteristics and hrMRI findings. Reduction of volume and contractility of affected EOMs were noted in six patients; however, there was no marked EOMs atrophy in two cases of diabetic oculomotor palsy, and there were four cases of aberrant regeneration. hrMRI demonstrated the oculomotor nerve at the midbrain and at EOMs in all cases, and in two cases with previous normal neuroimaging elsewhere that demonstrated contrast-enhancing tumors on the oculomotor nerve. One patient with apparently unilateral congenital inferior division oculomotor palsy had no detectable ipsilateral and a hypoplastic contralateral oculomotor nerve exiting the midbrain.

CONCLUSIONS

hrMRI provides valuable information in patients with oculomotor palsy, such as structural abnormalities of the orbit and oculomotor nerve, and atrophy and diminished contractility of innervated EOMs. This information could be helpful in diagnosis and management of oculomotor palsy.

"Mirror-image" bilateral giants: intracavernous carotid artery aneurysms

SUMMARY

The literature on the incidence of "mirror image" bilateral giant intracavernous aneurysms, their symptoms and their association with other entities is reviewed, with a brief comment on their evolution and treatment. A case of "mirror image" bilateral giant intracavernous aneurysms in a 76-year-old man who presented a sudden diplopia with pupillary sparing is reported. A CT scan showed parasellar images and dolichomega circle of Willis arteries that enhanced with endovenous contrast. MRI and angiography disclose bilateral aneurysms in detail, associated with an anomalous origin of the left common carotid artery and bilateral renal artery stenosis.

Magnetic resonance angiography and clinical evaluation of third nerve palsies and posterior communicating artery aneurysms

Object

The authors conducted a study to determine the utility of the clinical profile and magnetic resonance (MR) angiography in evaluating patients with isolated third cranial nerve palsies or posterior communicating artery (PCoA) aneurysms.

Methods

Three-dimensional time-of-flight MR angiography was performed in a consecutive series of patients with isolated acute third cranial nerve palsy not due to a ruptured aneurysm and in patients with unruptured PCoA aneurysms. A neuroradiologist, masked to the identities of the patients, interpreted reformatted maximum intensity projection (MIP) and source images of the PCoAs and aneurysms. The investigators assessed clinical features of oculomotor nerve dysfunction and focal head pain. Cases involving cranial third nerve palsy without aneurysms were classified as Group 1 (no case entailed catheter-based angiography), and cases involving PCoA aneurysms seen on MR angiography (42 cases confirmed by catheter-based angiography) were classified as Group 2.

The mean age of the 73 patients in Group 1 was 60.1 years and that of the 45 patients in Group 2 was 59.1 years (p = 0.37). The pattern and severity of oculomotor (p = 0.61) and lid (p = 0.83) dysfunction and pain frequency (p = 0.2) were similar for the 73 patients with vasculopathy in Group 1 and the 15 symptomatic patients in Group 2. Abnormal pupils were observed in 38% of the patients in Group 1 and 80% of those in Group 2 (p = 0.016). In cases of complete external third nerve palsy, nine of 22 in Group 1 and none of four in Group 2 had normal pupil function. For all patients, source imaging showed 206 PCoAs (85%) and MIP imaging demonstrated 120 PCoAs (49%). Of 48 aneurysms (three bilateral), MIP imaging showed 44 (92%) and source imaging showed 47 (98%). Only a 2-mm aneurysm seen on catheter-based angiography was missed by MR angiography. Symptomatic aneurysms were equal or greater than 4 mm in size.

Conclusions

Only the presence of complete external third nerve palsy and normal pupil function allowed ischemia to be clinically distinguished from a PCoA aneurysm in a patient with isolated third nerve palsy and no subarachnoid hemorrhage. When source image MR angiography demonstrates normal findings, catheter-based angiography need not be performed in these patients, even if pupil function is abnormal.

Third, fourth, and sixth cranial nerve palsies following closed head injury

BACKGROUND

The relationship between the circumstances and severity of closed head injury (CHI) and the clinical and imaging features of cranial nerve 3, 4, and 6 palsies has not been rigorously addressed in a large study.

METHODS

Retrospective chart review of 210 consecutive patients with CHI examined at a single tertiary care center from 1987 to 2002. Patients were located by searching the ophthalmology inpatient consultation and neuro-ophthalmology outpatient databases and hospital emergency room billing codes for a diagnosis of traumatic 3, 4, or 6 cranial nerve palsy (Cranial Nerve Injury Group) and a diagnosis of CHI without traumatic 3, 4, or 6 nerve palsy (Control Group). The Cranial Nerve Injury Group was then subdivided into two groups: those with injuries to an individual cranial nerve and those with multiple (including bilateral) cranial nerve injuries. Comparisons between groups were based on age, gender, type of accident, Glasgow Coma Scale (GCS), documented loss of consciousness (LOC), type of ocular injury, presence of systemic injury, need for rehabilitation, physical therapy and cognitive scores, and imaging features.

RESULTS

The Cranial Nerve Injury Group had a significantly higher severity of head injury, more CT abnormalities, and worse short-term neurologic outcomes as compared with the Control Group. These trends were also found when each cranial nerve injury subgroup was compared with the Control Group. Those with cranial nerve 3 palsy had the most severe head injury; those with cranial nerve 4 palsy had an intermediate level of head injury; and those with cranial nerve 6 palsy had the lowest level of head injury. There were no consistent associations between the location of the imaging abnormalities and which cranial nerve was damaged.

CONCLUSIONS

CHI with palsy of an ocular motor nerve was more severe than CHI without ocular motor nerve palsy, as measured by the GCS, intracranial and skull imaging abnormalities, and a greater frequency of inpatient rehabilitation. Palsy of cranial nerve 3 was associated with relatively more severe CHI than was palsy of cranial nerves 4 or 6. The location of the imaging abnormalities did not correlate with a particular cranial nerve injury.

Unusual ocular motor findings in multiple sclerosis

In multiple sclerosis (MS), nystagmus or internuclear ophthalmoplegia (INO) are the usual ocular motor dysfunctions. However, in patients with focal brainstem lesions, other rare manifestations may be observed, such as an isolated ocular motor nerve palsy or complex ocular motor disturbances. We report five MS patients with unusual ocular motor disturbances (bilateral third nerve palsy [n = 2], opsoclonus, Horner's syndrome and one-and-a-half syndrome). We discuss possible correlations between clinical disturbances and MRI abnormalities. Patients were seen in two MS centres. They had a confirmed diagnosis of MS and underwent a brain MRI and a complete neuro-ophthalmological work-up. In one case (opsoclonus), ocular motor manifestations were the first manifestation of MS. In the other four cases they occurred 3 months (Horner syndrome), 6 years and 12 years (bilateral third nerve palsy) and 2 years (one-and-a-half syndrome) after the disease onset, respectively. Four out of five patients were still in a relapsing-remitting form of MS. In the opsoclonus case, there was no evidence of a brainstem lesion. A gadolinium-enhanced lesion (2 cases) or a new T2-weighted lesion located in the brainstem correlated with the clinical presentation. All patients completely or partially recovered after corticosteroid infusions. Our study shows some rare or previously undescribed complex ocular motor symptoms in MS.

Ophtalmoplégie extrinsèque pure douloureuse du nerf moteur oculaire commun révélant un anévrysme de la carotide

INTRODUCTION

In third cranial nerve palsy, the lack of mydriasis evokes a noncompressive mechanism. Case report. We report a case of a slightly painful, pure extrinsic third-nerve palsy, complete except for the partial ptosis secondary to the compression by an intracavernous carotid aneurysm. Percutaneous endovascular embolization was followed by complete regression of the palsy within 4 weeks. The pupil may have been spared by the mechanism of compression after the separation of the pupillomotor and extrinsic fibers or the ischemia of the third nerve by its arterial trunk lesion.

CONCLUSION

This case report underlines that brain radiological explorations are necessary in some third-nerve pupil-sparing palsies.

[Bilateral third cranial nerve palsy triggered by an acute relapse of multiple sclerosis]

INTRODUCTION

We report a case of bilateral third cranial nerve palsy in a patient with a secondary progressive multiple sclerosis.

OBSERVATION

MRI revealed a large hyperintense lesion in T2-weighted images in the mesencephalic area. The clinical and radiological outcome was good after intravenous methylprednisolone. The oculomotor signs were probably caused by this mesencephalic lesion.

CONCLUSION

This case of bilateral third cranial nerve palsy is, to our knowledge, the first one occurring in a patient with multiple sclerosis.

Literature review regarding the methodology of assessing third nerve paresis associated with non-ruptured posterior communicating artery aneurysms

The association of third cranial nerve palsy subsequent to an enlarging posterior communicating artery (P-Com A) aneurysm has been well described. In our current communication, we review the relevant literature and propose a classification system for the severity of the third cranial nerve palsy, correlating it to the postoperative recovery. Our four grade scale (I-IV) included the degree of the levator palpebrae muscle paresis, the presence of pupillary reaction and the impairment of the third nerve mediated extraocular muscle movement. We evaluated five patients with third nerve palsy secondary to non-ruptured, P-Com A aneurysm. Patients were re-evaluated at 2, 4, 8, 24 weeks postoperatively. Four of the five patients had complete recovery within 4-8 weeks after surgery. One patient had grade II third nerve paresis and complete resolution of the third nerve symptoms within 4 weeks, whereas three patients with grade III and IV had complete resolution 4-8 weeks after surgery. The fifth patient, with grade IV paresis, had minimal (grade III) improvement 6 weeks after surgery, and incomplete recovery (grade I) 6 months postoperatively. Our simple grading system of third nerve palsy associated with P-Com A aneurysms, can be a helpful tool for the initial evaluation and for the monitoring of recovery in these patients.

Pupil-sparing third nerve palsy with preoperative improvement from a posterior communicating artery aneurysm

BACKGROUND

Despite the plenitude of reports concerning partial or complete third nerve palsies, especially as presenting symptoms with posterior communicating artery (PCoA) aneurysms, we present a patient with an unusual variation.

CASE DESCRIPTION

A 66-year-old woman presented with progressive right-sided headaches and diplopia and was found to have a partial, pupil-sparing third nerve palsy. A small right-sided PCoA aneurysm, nearly indistinguishable from an infundibulum, was identified on magnetic resonance angiography and subsequent digital subtraction angiography. The third nerve palsy improved before surgical repair of the aneurysm.

RESULTS

Microsurgical exploration revealed a small PCoA aneurysm, which was tethered to the third nerve by arachnoid adhesions. Adhesions were lysed and the aneurysm was repaired sparing the PCoA and its branches. The patient's third nerve function recovered completely postoperatively.

CONCLUSIONS

Even a very small PCoA aneurysm may present with an improving, pupil-sparing partial third nerve palsy. Selection of patients for imaging studies should take this unusual variant into consideration. We describe the anatomy and potential mechanisms of this pupil-sparing third nerve palsy.

The evaluation of isolated third nerve palsy revisited: an update on the evolving role of magnetic resonance, computed tomography, and catheter angiography

The evaluation and management of the neurologically isolated third nerve palsy continues to evolve. The major concern for the clinician confronted with a patient with a third nerve palsy has been the exclusion of an intracranial aneurysm. The evolution of new imaging techniques, such as computed tomography angiography and magnetic resonance angiography, have provided new imaging options for clinicians. This article reviews the pertinent recent literature on the use of these imaging studies in evaluating the patient with a third nerve palsy.