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Abstract This case presents the diagnosis and management of a patient with congenital superior oblique palsy (CSOP) with possible hereditery etiology. First Author: Tamara Petrosyan, OD Northport VAMC Northport, NY 11768 Second Author: Theresa Lonsky, OD Northport VAMC Northport, NY 11768 Third Author: Adam C. Deutscher, OD University Optometric Center New York, NY 10036 Introduction Congenital superior oblique muscle palsy (CSOP) is a common cause of vertical strabismus with torticollis and accounts for a large percentage of all patients with isolated cranial nerve weakness1. The clinical features of CSOP include hypertropia in primary gaze which increases with adduction and downgaze, head tilt toward the non paralyzed side, a positive ParksBielschowsky three-step, and large vertical fusional amplitudes2. Congenital palsies can be differentiated from the acquired form by patient history and clinical presentation3. The etiology of congenital superior oblique muscle palsy remains speculative. Possible causes include hypoplasia of the trochlear nucleus or fascicle, nerve injury, and anatomic defects of the superior oblique tendon or the trochlea4. On rare occasions, reports of familial CSOP with autosomal dominant transmission patterns have been made5. Recent studies indicate that CSOP could be attributed to a genetic abnormality in the ARIX gene involved in the development of the oculomotor and trochlear nerve in mice and zebrafish6. This case presents a possible discovery of a family with familial superior oblique muscle palsy and discusses the diagnosis and management of a patient. 1 2 3 4 5 6 Botelho PJ and Giangiacomo JG: Autosomal-dominant inheritance of congenital superior oblique palsy. Opthalomology (1996) 103: 1508-1511 Imai S, Matsuo T, Itoshima E and Ohtsuki H: Clinical features, ARIX and PHOX2B nucleotide changes in three families with congenital superior oblique muscle palsy. Acta Med Okayama (2008) 62: 45-53 Astle WF and Rosenbaum AL: Familial congenital fourth cranial nerve palsy. Arch Opthalmol (1985) 103: 532-535 Botelho PJ and Giangiacomo JG: Autosomal-dominant inheritance of congenital superior oblique palsy. Opthalomology (1996) 103: 1508-1511 Astle WF and Rosenbaum AL: Familial congenital fourth cranial nerve palsy. Arch Opthalmol (1985) 103: 532-535 Jiang Y, Matsuo T, Fujiwara H, Hasebe S, Ohtsuki H and Yasuda T: ARIX and PHOX2B polymorphisms in patients with congenital superior oblique muscle palsy. Acta Med Okayama (2005) 59: 55-62 Case Presentation A 24 yo WF (K.Y.) was referred for an evaluation of her binocular diagonal diplopia in all gazes. She had been getting fusion training for a left inferior oblique overaction beginning two years prior for a total of 23 office visits, scheduled twice a week for one hour per visit, with no alleviation of symptoms. The diplopia was first noticed eight to ten years ago with symptoms progressively worsening. She reported increasing headaches when reading and inability to do computer work which is required for her occupation. Regarding her diplopia, the patient describes the upper image as “real” and the lower image as “appearing to float.” The patient presented with a right head tilt and stated that the diplopia is dampened in inferior and near gaze and worse on right upgaze and distance. She felt that her right eye was becoming dominant and was very conscious about her cosmetic appearance. K.Y. reported that both her father and younger sister suffered from similar symptoms. The patient reported a recent unremarkable physical and denied trauma, any medications, or allergies Her fusional therapy included working on unfused activities, various anaglyph and fixation activities, and Brock string. Rx Posture / Alignment Report from first consulting doctor SCL: -5.25 OD, -5.00 OS +1.25 OU over CLs for prolonged NV Convergent strabismus with a vertical component Distance 7 LHyper 10 Eso Near 15 LHyper 10 Eso Report from a second consulting doctor Our results performed over several visits Habitual spectacle Rx: OD -5.25sph (20/20) OS -4.50 sph (20/20) ADD +1.00 (20/20) Pupils PERRL - APD EOM / Pursuits Noncomitant EOMs (OS moves up on right gaze) No restrictions OD or OS Diplopia lessens in inferior gaze Poor tracking Suppression OD dominant OS suppression with increased viewing distance Posture Distance CT 10LHT, 6EP Phoria 7 LH, Iso ParksBielschowsky Three-Step Left Hypertropia → worse on RIGHT gaze → worse on LEFT head tilt Modified Thorington DV: Concomitant LHyper with Eso NV: Non-concomitant LHyper with Eso, diplopia worse in down and right gaze Near CT 19LHT, 10 EP Phoria 9LH, 6 Eso *OS suppression during range testing* Result: Left Superior Oblique palsy 6 Eso 12LH Distance 6 Eso 12LH Near 6 Eso 12LH 20 Eso 30 LH 6 Eso 35 LH 15 Eso 30 LH 6 Eso 12LH 6 Eso 12LH 6 Eso 12LH 26 Eso 35 LH 16 Eso 30 LH 20 Eso 18 LH 6 Eso 12LH 6 Eso 12LH 6 Eso 12LH 30 Eso 35 LH 24 Eso 16 LH 18 Eso 19 LH Extensive prism trial framing showed that she was most comfortable at distance and near with 6^BU OD and 6^BD OS K.Y. was given12^ BD Fresnel prism to try for several weeks After 6^BU OD and 6^BD OS ground into her spectacle Rx Diagnosis of congenital left superior oblique palsy (not inferior oblique overaction) was based on the history and the results of cover test, versions, vertical fusional ranges, Parks-Bielschowsky three-step and Modified Thorington. Discussion http://commons.wikimedia.org/wiki/Image:Eyemuscles.jpg Oblique Muscle Review Superior Oblique Inferior Oblique Depresses on Adduction Intorts Abducts Elevates on Adduction Extorts Abducts Overview of Superior Oblique Muscle Palsy7 Binocular diplopia with vertical or diagonal separation of objects, worse on downgaze and gaze away from side of affected muscle. Hypertropia, especially on adduction with intortion of elevated eye and head tilted away from the eye with the palsy. Most common cause is congenital. The etiology of congenital superior oblique muscle palsy remains speculative. Congenital palsies can be differentiated from the acquired form by patient history, clinical presentation, and lack of other inciting factors8. The clinical features of CSOP include hypertropia on primary gaze which increases with adduction and downgaze, head tilt toward the non-paralyzed side, a positive ParksBielschowsky three-step, and large vertical fusional amplitudes9. 7 Prieto-Diaz, Julio and Souza-Dias, Carlos. Strabismus. Massachusetts: Butterworth-Heinemann, 2000 8 9 Astle WF and Rosenbaum AL: Familial congenital fourth cranial nerve palsy. Arch Opthalmol (1985) 103: 532-535 Imai S, Matsuo T, Itoshima E and Ohtsuki H: Clinical features, ARIX and PHOX2B nucleotide changes in three families with congenital Possible causes include hypoplasia of the trochlear nucleus, trochlear fascicle, or nerve injury and anatomic defects of the superior oblique tendon or the trochlea10. Many congenital cases are first seen as adults who have compensated for many years; these patients usually have large vertical fusional ranges. Second most common cause is severe head trauma. Microvasculopathy secondary to diabetes, atherosclerosis, or hypertension may also cause isolated fourth nerve palsy. Both of these are important factors to rule out before making a diagnosis of congenital superior oblique palsy. Familial Connection In 1926 Franceschetti was the first to report a hereditary pattern of CSOP and recent research on this familial occurrence shows that it follows an autosomal dominant mode of inheritance 11. CFEOM2 is a subtype of congenital fibrosis of the extraocular muscles in which patients have bilateral ptosis and opthalmoplegia with their eyes partially or completely fixed in an exotropic, hypertropic or hypotropic position. It is hypothesized that CSOP is a clinically milder variant of CFEOM type 212. ARIX is a homeobox-containing gene expressed in the brainstem and encodes a homeodomain transcription factor protein required for oculomotor and trochlear nerve development in mice and zebrafish. ARIX mutations have been identified as the cause of CFEOM213. ARIX gene polymorphism has been identified as one of the genetic risk factors for development of congenital superior oblique muscle palsy14. Treatment If the superior oblique palsy is acquired and the cause has been treated, it is usual to wait 6 months for the palsy to resolve by itself before surgery is considered. When the palsy is congenital or the acquired palsy does not resolve completely after 6 months the superior oblique muscle palsy is treated by one of several ways. Patients with small deviations lacking a torsional component are usually relieved with vertical prism and fusional therapy, although the efficacy of prism is limited due to noncomitant deviations. Many cases of superior oblique palsy require surgery15. The surgery should be directed to those muscles whose greatest action is in the field where the vertical deviation is the largest. Deviations < 15 PD require simple muscle surgery while those >15 PD require 2-3 muscle surgeries. superior oblique muscle palsy. Acta Med Okayama (2008) 62: 45-53 10 Botelho PJ and Giangiacomo JG: Autosomal-dominant inheritance of congenital superior oblique palsy. Opthalomology (1996) 103: 1508-1511 11 Bhola RM, Horne GV, Squirrell DM, Chan TK and Kumar D: Autosomal dominant congenital superior oblique palsy. Eye (2001) 15: 479-484 12 Imai S, Matsuo T, Itoshima E and Ohtsuki H: Clinical features, ARIX and PHOX2B nucleotide changes in three families with congenital superior oblique muscle palsy. Acta Med Okayama (2008) 62: 45-53 13 Jiang Y, Matsuo T, Fujiwara H, Hasebe S, Ohtsuki H and Yasuda T: ARIC gene polymorphisms in patients with conenital superior oblique muscle palsy. Br J Opthalmol (2004) 88:263-267 14 Jiang Y, Matsuo T, Fujiwara H, Hasebe S, Ohtsuki H and Yasuda T: ARIX and PHOX2B polymorphisms in patients with congenital superior oblique muscle palsy. Acta Med Okayama (2005) 59: 55-62 15 Americal Association for Pediatric Opthalmology and Strabismus. 2005. Superior Oblique Palsy. <http://www.aapos.org/displaycommon.cfm?an=1&subarticlenbr=226> (accessed 7.19.2008) If an inferior oblique overaction is present then an inferior oblique myectomy or recession is performed. For a superior oblique laxity (often in congenital cases) a superior oblique tendon tuck is done. If the deviation is greatest in downgaze (and there is no evidence of superior rectus restriction or superior oblique laxity), then the contralateral inferior rectus is recessed. Botulinum neurotoxin can be used to temporarily delay or avoid further surgery or to correct a residual deviation after surgery, it is not recommended as a primary therapy. In cases of diplopia, it is critical to isolate the affected muscle before any treatment can be initiated, the process of which has been reviewed. Although it was shown that therapy alone was not sufficient to relieve the symptoms of the CSOP, in the case of K.Y., a successful course of prism and fusion therapy relieved her symptoms without the need for surgery. K.Y. is currently finishing a very successful course of fusional therapy; 12^ BD OS split between the eyes allowed an increase in ease of fusion and single vision in all gazes and relief in her head turn of which she was very conscious. Due to the likely genetic etiology of this palsy, as per family history, we educated the patient about ARIX mutations and she will be considering genetic testing in the future before starting a family.