Frequency and Etiology of Paralytic Strabismus

Research Article

Austin J Clin Ophthalmol. 2015;2(1): 1038.

Frequency and Etiology of Paralytic Strabismus

Niyaz L*, Gul A and Ariturk N

Department of Ophthalmology, Ondokuz Mayis University, Samsun, Turkey

*Corresponding author: Niyaz L, Department of Ophthalmology, Ondokuz Mayis University, Samsun, Turkey, 55000

Received: October 28, 2014; Accepted: January 12, 2015; Published: January 19, 2015

Abstract

Aim: To describe demographics and etiologic factors of patients with paralytic strabismus.

Materials and Methods: A retrospective review of strabismus patient charts was performed and paralytic strabismus was isolated and evaluated for age, sex, etiology, type of strabismus and lateralization.

Results: Out of 800 charts of strabismus patients, 38 (4.75%) patients were found to have paralytic strabismus. Mean age of patients was 25.6 (3- 63) years. Fifteen were female and 23 were male. The most common affected nerve was the fourth (52.6%). Sixth cranial nerve was affected in 26.3% and third nerve in 5.3% of patients. Four patients (10.5%) had vertical or horizontal gaze palsy and two (5.3%) had double elevator palsy. Regarding the etiology of strabismus, most were congenital (34.2%) and others developed secondary to trauma (26.3%), intracranial lesion (18.35%), infection (7.9%) and some were undetermined (13.15%).

Conclusion: The most commonly affected nerve in our study is the fourth and the most frequent cause is congenital. Sixth and third CN palsies developed mostly after trauma. In gaze palsies intracranial pathology should be considered.

Keywords: Cranial nerve; Paralytic strabismus, Etiology

Introduction

Paralytic strabismus is an ocular pathology where one or more of the Cranial Nerves (CN) innervating the extraocular muscles are affected. In a study of Stidwill D. the prevalence of paralytic strabismus among 3075 cases with binocular vision anomaly was found to be 10% [1]. Martinez-Thompson et al evaluated the incidence and types of adult onset strabismus in a population-based cohort and found that paralytic strabismus is the most common subtype of new-onset adult strabismus [2]. Etiology varies in different types of paralytic strabismus. The most commonly affected CN varies between previous reports on paralytic strabismus. Fourth CN is commonly involved in studies on pediatric population and sixth nerve is more frequently affected in adults. In a review of only acquired pediatric cranial nerve palsies, Kodsi and Younge noted that sixth nerve palsies were the most common [3-6]. In pediatric population paralysis is mostly congenital whereas in elderly, trauma or underlying pathology should be suspected [4,6,7].

Data on the incidence and etiology of different types of paralytic strabismus may be helpful for ophthalmologists or other physicians in guiding diagnosis and evaluation, and may be useful for proper intervention. The aim of this study is to describe demographics and etiologic factors of patients with paralytic strabismus.

Materials and Methods

A retrospective chart review of all patients with strabismus who presented to Samsun Ondokuz Mayis University Ophthalmology clinics from March 2012 to August 2014 was performed. From approximately 800 cases, patients with paralytic strabismus of all ages were identified. Entire medical record of these patients was reviewed for data collection. Age, sex, type of strabismus, etiology and treatment strategies were analyzed. Fourth, third, sixth cranial nerve palsy, Double Elevator Palsy (DEP) and gaze palsies were included in this study. The diagnosis of nerve palsy was mainly based on the presenting symptoms and signs. Neurology consultation and imaging was performed in selected cases. Etiology was classified as congenital, traumatic, idiopathic (undetermined cause), postinfectious, or secondary to intracranial lesion or dural sinus thrombosis. The study followed the tenets of the Declaration of Helsinki.

Results

A total of 38 patients with paralytic strabismus were identified. Age at presentation ranged from 3 to 63 years, with a mean age of 25.6 years. There were 15 (39.5%) female and 23 (60.5%) male patients. The most commonly affected nerve was the fourth (20 patients, 52.6%). Sixth cranial nerve was affected in 10 (26.3%) and third nerve in 2 (5.3%) of patients. Four patients (10.5%) had vertical or horizontal gaze palsy and two (5.3%) had double elevator palsy. Age, sex and affected eye of patients according to the type of palsy are shown in Table 1. Regarding the etiology of strabismus, most were congenital (34.2%) and others were associated with trauma (26.3%), intracranial lesion (18.35%), infection (7.9%), or were idiopathic (13.15%). Fourth nerve palsy was congenital in 11, due to trauma in 4, postinfectious in 1 and idiopathic in 4. All patients had strabismus surgery. Sixth nerve palsy developed secondary to trauma in 4, intracranial tumor in 1, infection in 2 and dural sinus thrombosis in 2 patients, while etiology was not determined in 1 case. Only 3 patients had strabismus surgery and four were managed with botulinum toxin injection. Patients with dural sinus thrombosis were treated with anticoagulation therapy. Both cases with third nerve palsy were traumatic and had botulinum toxin injection to alleviate the symptoms. One patient with DEP was treated surgically and the other patient had no intervention. Three patients with gaze palsies were associated with intracranial tumors in the brainstem region. One patient had internuclear ophthalmoplegia secondary to multiple thrombi in the pons region after the cardiac angiography which resolved with anticoagulation treatment.

Citation: Niyaz L, Gul A and Ariturk N. Frequency and Etiology of Paralytic Strabismus. Austin J Clin Ophthalmol. 2015;2(1): 1038. ISSN : 2381-9162