Clinical Characteristics for Predicting Recovery of Acquired Fourth Cranial Nerve Palsy

Abstract

Background:Fourth cranial nerve palsy is the most common disease diagnosed in patients with vertical diplopia. Although it is reported to present a good prognosis, there are currently no agreed on prognostic factors that anticipate the recovery of the palsy other than the etiology. The purpose of this study was to investigate the prognostic factors of acquired fourth cranial nerve palsy.Methods:The medical records of consecutive patients diagnosed with acquired unilateral fourth cranial nerve palsy from 2010 to 2020 and followed up for ≥6 months were retrospectively reviewed. The cause and degree of palsy, ocular deviation (horizontal, vertical, and cyclo), and fundus torsion were reviewed. The cause of palsy was classified as ischemic, traumatic, intracranial mass, others, or idiopathic. Patients were divided into 2 groups according to palsy recovery: complete recovery (group CR) or not CR (group NCR). The clinical characteristics of the 2 groups were compared, and the risk factors for incomplete recovery were investigated.Results:Thirty-five patients (25 men) were included in the study. The average age was 55.94 ± 16.11 years. CR was achieved in 23 patients (65.7%), and the time to recovery was 3.91 ± 4.03 months. The most common cause was traumatic (40.0%), followed by ischemia (37.1%), intracranial mass (11.4%), others (8.6%), and idiopathic (2.9%). The degree of palsy and fundus torsion was significantly higher in group NCR (P = 0.010 and P = 0.001). Severe oculomotor limitation, large fundus torsion, and intracranial mass cause rather than ischemic cause indicated a higher risk of incomplete or no recovery (P = 0.016, P = 0.009, and P = 0.043).Conclusion:Identifying whether a patient has an intracranial mass, severe oculomotor limitation, or large fundus excyclotorsion may be useful for predicting the recovery of acquired unilateral fourth cranial nerve palsy.

Torsion and clinical features in patients with acquired fourth cranial nerve palsy

“…In this study, the proportion of idiopathic cases was notably low, at 6%, compared to that in other reports 3 , 16 . However, in recent studies, the proportion of idiopathic cases has been reported to be 2.9–3.75%, similar to the results of our study 5 , 6 . This could be due to the inclusion of patients in the ischemic etiology group who had microangiopathy on MRI, and the inclusion of these patients increased the proportion of ischemic cases.…”

“…Ischemic palsy is reported to have a better outcome 5 . Recent studies reported that patients who had larger vertical angles of deviation, severe ocular limitations, intracranial masses, large fundus excyclotorsions, and more frequent head tilting did not fully recover 5 , 6 . However, the former study 5 included the decompensation of congenital palsy and the latter 6 did not include subjective torsion with the Maddox double rod test (MDRT).…”

“…Ischemic trochlear nerve palsy, advanced age, a small deviation angle at the primary position, and few cases of excyclotorsion on LRGT were characteristic of the full recovery group of acquired unilateral trochlear nerve palsy patients.Trochlear nerve (fourth cranial nerve, CN4) palsy is the most common cause of acquired vertical diplopia 1 , which causes cyclodeviation or ocular torsion, leading to the perception of image tilting 2 . Several studies have reported that decompensation of congenital CN4 palsy is the most common cause of acute vertical diplopia 3,4 , while a vascular etiology is the main cause of acquired cranial nerve palsy [5][6][7][8][9] .The recovery of diplopia caused by cranial nerve palsy is related to the etiology of the palsy. Ischemic palsy is reported to have a better outcome 5 .…”

“…Ischemic palsy is reported to have a better outcome 5 . Recent studies reported that patients who had larger vertical angles of deviation, severe ocular limitations, intracranial masses, large fundus excyclotorsions, and more frequent head tilting did not fully recover 5,6 . However, the former study 5 included the decompensation of congenital palsy and the latter 6 did not include subjective torsion with the Maddox double rod test (MDRT).We aimed to compare the objective torsion on fundus photography, the subjective torsion on MDRT, the Lancaster red-green test (LRGT), and other clinical characteristics according to the etiology and recovery state.…”

Improvement in health-related quality of life with Botulinum toxin A injection in acquired superior oblique palsy

“…We have shown that injecting BTA into the IO muscle can rapidly and safely resolve deviation in patients with acute SOP. The rate of complete recovery for SOP without treatment reportedly ranges from 50% to 65.7% at the 6-month follow-up ( 19 , 20 ). Here, we achieved complete resolution of diplopia in 85.7% (18/21) of the patients at the final follow-up.…”