Imaging of intracranial aneurysms causing isolated third cranial nerve palsy

Impact of Diplopia and Ptosis From Lingering Third Nerve Palsy After Treatment of Cerebral Aneurysms

BACKGROUND

Third nerve palsies (TNPs) may not resolve after intervention for intracranial aneurysms that have compressed the nerve. The disability related to this lingering condition has not been assessed with the support of patient self-report.

METHODS

A single-institutional retrospective study of patients with TNP who had undergone interventions for intracranial aneurysms. We used residual primary-position diplopia, a narrow zone of single binocular vision, and vision-obscuring ptosis to divide TNP recovery into complete, incomplete nondisabling, and incomplete disabling outcomes based on medical record documentation and patient self-report derived from telephonic interviews.

RESULTS

In a cohort of 33 patients, 13 (39%) had complete TNP recovery. There were 11 patients (33%) with lingering visual disability from diplopia or ptosis present before ophthalmic interventions. Of the 6 patients who underwent ophthalmic interventions, visual disability was relieved in only 2 patients, leaving 9 patients (27%) with lingering impairment in instrumental activities of daily living. Telephonic interviews of 23 patients (70% of the cohort) confirmed that the outcome criteria we applied were accurate in assessing visual disability in 17 patients (74%). Univariate analysis using the Fisher exact test showed that aneurysmal clipping as a treatment modality was the only clinical feature associated with a favorable TNP outcome.

CONCLUSIONS

In applying a novel method of assessing disability, this study showed that more than one-quarter of patients undergoing procedures for brain aneurysms had lingering disability from third nerve palsy-associated diplopia or ptosis, despite later ophthalmic interventions. Patient self-report gleaned from telephonic interviews was valuable in largely validating the assessment method derived from medical records and in revealing differences between physician and patient estimation of disability.

Contained Rupture of a Posterior Communicating Artery Aneurysm in a Patient With a Third Nerve Palsy

ABSTRACT

It is recommended that every patient with a new third nerve palsy undergo urgent neuroimaging (computed tomography angiography or magnetic resonance angiography) to exclude a posterior communicating artery aneurysm. Because of the novel coronavirus (COVID-19) pandemic, our institution noted a significant decline in the number of patients with aneurysmal subarachnoid hemorrhage presenting to the hospital. We report one such example of a patient who developed new-onset severe headache and vomiting and did not seek medical attention because of COVID-19. Two months later, she was noted to have ptosis during a routine follow-up and was found to have a complete, pupil-involving third nerve palsy. Computed tomography angiography was performed and revealed an irregular bilobed saccular aneurysm (7 × 9 × 5 mm) of the right posterior communicating (PComm) artery, but no acute hemorrhage was visible on CT. On MRI, immediately adjacent to the aneurysm, there was a small subacute hematoma in the right medial temporal lobe with surrounding vasogenic edema. This case had a fortunate and unique outcome as she had a contained hematoma adjacent to the ruptured PComm aneurysm and did not experience severe morbidity from the subarachnoid hemorrhage nor did she rebleed in the interval in which she did not seek care. This case highlights the importance of providing neuro-ophthalmic care even during a pandemic.

Delayed oculomotor nerve palsy associated with a ruptured anterior communicating aneurysm: Case report

BACKGROUND AND IMPORTANCE

Oculomotor nerve palsy (ONP) is usually associated with posterior communicating (PCOM) aneurysms. ONP in patients with anterior circulation aneurysms are extremely rare, with only a handful of such published cases to date. There is currently no accepted mechanism to explain this clinical finding.

CLINICAL PRESENTATION

We describe a case of a 60-year-old female that benefitted from endovascular coiling of a ruptured anterior communicating (ACOM) aneurysm. In the following days, she clinically deteriorated and benefitted from another digital subtraction angiography (DSA) with intravascular verapamil for suspected vasospasm, and subsequently developed a right ONP.

CONCLUSION

Although classically related to PCOM aneurysm, ONP may be associated with ACOM aneurysms. The causative mechanism is unclear, but vasospasm may alter the microvascularisation of the oculomotor nerve, leading to ischemia.

Intracranial Aneurysms of Neuro-Ophthalmologic Relevance

BACKGROUND

Intracranial saccular aneurysms are acquired lesions that often present with neuro-ophthalmologic symptoms and signs. Recent advances in neurosurgical techniques, endovascular treatments, and neurocritical care have improved the optimal management of symptomatic unruptured aneurysms, but whether the chosen treatment has an impact on neuro-ophthalmologic outcomes remains debated.

EVIDENCE ACQUISITION

A review of the literature focused on neuro-ophthalmic manifestations and treatment of intracranial aneurysms with specific relevance to neuro-ophthalmologic outcomes was conducted using Ovid MEDLINE and EMBASE databases. Cavernous sinus aneurysms were not included in this review.

RESULTS

Surgical clipping vs endovascular coiling for aneurysms causing third nerve palsies was compared in 13 retrospective studies representing 447 patients. Complete recovery was achieved in 78% of surgical patients compared with 44% of patients treated with endovascular coiling. However, the complication rate, hospital costs, and days spent in intensive care were reported as higher in surgically treated patients. Retrospective reviews of surgical clipping and endovascular coiling for all ocular motor nerve palsies (third, fourth, or sixth cranial nerves) revealed similar results of complete resolution in 76% and 49%, respectively. Improvement in visual deficits related to aneurysmal compression of the anterior visual pathways was also better among patients treated with clipping than with coiling. The time to treatment from onset of visual symptoms was a predictive factor of visual recovery in several studies. Few reports have specifically assessed the improvement of visual deficits after treatment with flow diverters.

CONCLUSIONS

Decisions regarding the choice of therapy for intracranial aneurysms causing neuro-ophthalmologic signs ideally should be made at high-volume centers with access to both surgical and endovascular treatments. The status of the patient, location of the aneurysm, and experience of the treating physicians are important factors to consider. Although a higher rate of visual recovery was reported with neurosurgical clipping, this must be weighed against the potentially longer intensive care stays and increased early morbidity.

Clinical Evaluation of Blepharoptosis: Distinguishing Age-Related Ptosis from Masquerade Conditions

Aponeurotic ptosis accounts for the majority of acquired ptosis encountered in clinical practice. Other types of ptosis include traumatic, mechanical, neurogenic, and myogenic. In addition to true ptosis, some patients present with pseudoptosis caused by globe dystopia, globe asymmetry, ocular misalignment, or retraction of the contralateral lid. It is particularly important for the clinician to rule out neurologic causes of ptosis such as dysfunction of the third cranial nerve, Horner's syndrome, and myasthenia gravis, as these conditions can be associated with significant systemic morbidity and mortality. A thorough history and physical examination is necessary to evaluate each patient presenting with a complaint of ptosis. Correctly identifying the cause of the patient's complaint allows the ptosis surgeon to plan for appropriate surgical repair when indicated and to defer surgery when observation or additional clinical evaluation is warranted.

Imaging of Oculomotor (Third) Cranial Nerve Palsy

When evaluating a patient with an oculomotor cranial nerve palsy it may be unclear which neuroimaging modality is optimal; MRI, MR angiography, computed tomography, computed tomography angiography, or intraarterial digital subtraction angiography. We discuss the clinical guidelines in the evaluation of such patients and review neuroimaging techniques, outlining the advantages and disadvantages of each.

Infrared pupillometry, the Neurological Pupil index and unilateral pupillary dilation after traumatic brain injury: implications for treatment paradigms

Pupillary dysfunction, a concerning finding in the neurologic examination of the patient with an acute traumatic brain injury often dictates the subsequent treatment paradigm. Patients were monitored closely with an infrared pupillometer, with NPi technology, for acute changes in pupillary function. NPi technology applies a scalar value to pupillary function. A retrospective chart review was performed of traumatic brain injury patients with acute unilateral pupillary dilation, admitted to Legacy Emanuel Medical Center’s NeuroTrauma Unit, Portland, OR, and followed as outpatients, between January 2012 and December 2013. Clinical exam findings of pupillary size, NPi scores, and brain Magnetic Resonance Imaging and Computed Tomography images were analyzed. Five traumatic brain injury patients were identified with unilateral pupillary dysfunction with long-term follow-up after the initial injury. Each patient was monitored closely in the trauma bay for neurological deterioration with a pupillometer and the clinical exam. Two patients underwent subsequent intracranial pressure monitoring based on a deteriorating clinical scenario, including consistent abnormal unilateral NPi scores. One patient with consistent abnormal NPi scores and an improved clinical exam did not undergo invasive interventions. Two patients showed early improvement in NPi scores correlating with the normalization of their pupillary reactivity. Anisocoria improved in all patients despite concurrent abnormal NPi scores. Magnetic Resonance Imaging and Computed Tomography imaging studies, with a focus on the third nerve, revealed focal abnormalities consistent with the clinical findings. A unilateral blown pupil and abnormal NPi score in a traumatic brain injury patient are not necessarily indicative of intracranial pressure issues, and must be correlated with the entire clinical scenario, to determine the etiology of the third nerve injury and direct potential therapeutic interventions. Early NPi score normalization suggests pupillary function may improve. We found that NPi scores, as a component of the clinical exam, provide a sensitive, noninvasive and quantitative means of following pupillary function acutely and chronically after a traumatic brain injury.

Managing the patient with oculomotor nerve palsy

PURPOSE OF REVIEW

To provide clinically relevant information regarding the evaluation and current treatment options for oculomotor nerve palsies. We survey recent literature and provide some insights into these studies.

RECENT FINDINGS

Recent case reports highlight emerging new causes of oculomotor cranial nerve palsies, including sellar chordoma, odontogenic abscess, nonaneurysmal subarachnoid hemorrhage, polycythemia, sphenoiditis, neurobrucellosis, interpeduncular fossa lipoma, metastatic pancreatic cancer, leukemia, and lymphoma. Surgical studies have focused on modifications and innovations regarding strabismus surgery for this condition. New globe fixation procedures may include fixation to the medial orbital wall by precaruncular and retrocaruncular approaches, apically based orbital bone periosteal flap fixation and the suture/T-plate anchoring platform system.

SUMMARY

Management of oculomotor nerve palsy depends in part upon the underlying cause and anatomical location of the lesion. Careful clinical evaluation and appropriate imaging can identify a definitive cause in most cases. Surgical options depend on the number, extent, and severity of the muscles involved as well as the presence or absence of signs of aberrant regeneration. The clinician should also address issues that arise due to involvement of the pupil and accommodation. Strabismus surgery can be challenging but also rewarding with appropriate selection and staging of procedures.

Neuro-imaging: a review for the general ophthalmologist

The diagnosis of many neuro-ophthalmic conditions is facilitated with neuro-imaging. The two main modalities are Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). Clinicians who refer patients for either of these techniques must not only know which of them to choose, but also where the imaging should be performed (e.g. brain, orbit), whether or not contrast is indicated, and if angiography should be supplemented. These complexities often result in imaging studies that are either unneeded or unhelpful. The goal of this manuscript is to provide a practical set of guidelines for the general ophthalmologist of how to choose the correct parameters for neuro-imaging studies.

Neuroimaging in patients referred to a neuro-ophthalmology service: the rates of appropriateness and concordance in interpretation

OBJECTIVE

Neuroimaging studies frequently are ordered to investigate neuro-ophthalmic symptoms. When misused, these studies are expensive and time consuming. This study describes the type and frequency of neuroimaging errors in patients referred to an academic neuro-ophthalmology service and measures how frequently these neuroimaging studies were reinterpreted.

DESIGN

Prospective cohort study.

PARTICIPANTS

Eighty-four consecutive patients referred to an academic neuro-ophthalmology practice.

METHODS

From November 2009 through July 2010, 84 consecutive new patients who had undergone a neuroimaging study in the last 12 months specifically to evaluate their presenting neuro-ophthalmic symptoms were enrolled prospectively. Participants then underwent a complete neuro-ophthalmic evaluation, followed by a review of prior neuroimaging. Questions regarding appropriateness of the most recent imaging, concordance of radiologic interpretation, and re-evaluation of referring diagnoses were answered by the attending physician.

MAIN OUTCOME MEASURES

The frequency and types of errors committed in the use of neuroimaging and the frequency of reinterpretation of prereferral neuroimaging studies after neuro-ophthalmic history and examination.

RESULTS

Most study participants (84.5%; 71/84) underwent magnetic resonance imaging before referral; 15.5% (13/84) underwent only computed tomography. The rate of suboptimal neuroimaging studies was 38.1% (32/84). The 3 most common reasons for suboptimal studies were incomplete area of imaging (34.4%; 11/32), wrong study type (28.1%; 9/32), and poor image quality (21.9%; 7/32). Twenty-four of 84 subjects (28.6%) required additional neuroimaging. The authors agreed with the radiology interpretation of the prior neuroimaging studies in most patients (77.4%; 65/84). The most common anatomic locations for discordance in interpretation were the intraorbital optic nerve (35%; 7/20) and the brainstem (20%; 4/20).

CONCLUSIONS

There was a high rate of suboptimal neuroimaging studies performed in patients referred for neuro-ophthalmology examination. These findings have significant implications given the increasing attention to resource use currently and in the near future.

Underdiagnosis of posterior communicating artery aneurysm in noninvasive brain vascular studies

BACKGROUND

Expert interpretation of modern noninvasive neuroimaging such as computed tomographic angiography (CTA) or MRA should detect nearly all aneurysms responsible for an isolated third nerve palsy. Whether a catheter angiogram should still be obtained in cases with negative CTA or MRA remains debated and mostly relies on whether the noninvasive study was correctly performed and interpreted. The aim of our study was to review the diagnostic strategies used to evaluate patients with isolated aneurysmal third nerve palsy at a large academic center.

METHODS

Retrospective review of all cases with posterior communicating artery (PCom A) aneurysmal third nerve palsies seen at our institution since 2001.

RESULTS

We identified 417 cases with third nerve palsy, aneurysm, or subarachnoid hemorrhage, among which 17 presented with an acute isolated painful third nerve palsy related to an ipsilateral PCom A aneurysm (mean age: 52 years; range: 33-83 years). Patients were classified into 3 groups based on the results of the noninvasive imaging obtained at initial presentation. Group I included 4 cases with subarachnoid hemorrhage on initial noncontrast head CT initially obtained in an emergency department for evaluation of their isolated third nerve palsy. Group II included 5 cases with isolated third nerve palsy and normal noncontrast head CT at presentation, immediately correctly diagnosed with a PCom A aneurysm at the referring institution. Group III included the 8 remaining cases who all had aneurysms that were missed on noninvasive studies at outside institutions. Review of these outside studies at our institution showed a PCom A aneurysm, confirming misinterpretation of these tests by the outside radiologists, rather than inadequate technique. Absence of specific training in neuroradiology and inaccurate clinical information provided to the interpreting radiologist were associated with test misinterpretation at the outside institutions. The average size of PCom A aneurysms causing an isolated third nerve palsy across all 3 groups was 7.3 mm and was similar in each group.

CONCLUSION

Our study suggests that aside from an accurate history, the training and experience of the interpreting radiologist is probably the most important factor in determining the reliability of a noninvasive scan in patients with isolated third nerve palsies.