Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Brief Report Isolated Benign Unilateral Abducent Nerve Palsies in Young Children - A Case Series Sanitha Sathyan DNB, Meena C.K DNB, Elizabeth Joseph K MS ABSTRACT Aim: To report a case series of benign isolated abducent nerve palsies, in 6 children, diagnosed in 2 months at a tertiary care centre from within an area of 30 square km. Methods: This retrospective case series includes 6 patients < 18 months of age with acute onset abducent nerve palsy, who presented during a period of 2 months. There was no history of prior trauma/ neurological disease. The mean deviation was 40 prism diopters and there was -3 to -4 limitation of abduction in the involved eyes. All underwent MRI brain, which was normal. Results: All the patients had partial recovery within 2-5 days and total recovery in 10-14 days after treatment with oral steroids. Conclusion: This case series supports the entity of benign idiopathic sixth nerve palsy and emphasizes on the importance of supportive treatment in otherwise asymptomatic young children. Key words: Abducent palsy, children, isolated Introduction Acute onset sixth nerve palsy in a child raises suspicion of serious neurological disease like raised intracranial pressure, pontine glioma and meningitis. However, benign self resolving sixth nerve palsies are also reported. In 1967, Knox, Clark, and Schuster1 reported a series of 10 children with spontaneous sixth cranial nerve paralysis that occurred about 7 to 21 days after a nonspecific illness. Symonds2 , Bixenman and Von Noorden et al3 also have reported isolated self resolving abducent nerve palsies. Acquired sixth nerve palsies following immunisation have also been reported.4,5 Clustering of the cases of acute abducent nerve palsies have not been reported in literature so far. Materials and Methods We report a retrospective case series of 6 patients < 18 months of age, who presented within a period of 2 months, with acute onset of sixth nerve palsy, which resolved with supportive therapy. All the patients presented to us with acute onset deviation of eyes and associated face turn to the same side, within 2 days of onset of symptoms. Mean age was 13.83 months (10 – 18 months). There was no history of trauma, documented fever, previous ocular deviations or neurological disease. The mean deviation by the Modified Krimsky test was 40 prism diopters (30-60 prism diopters) and there was -3 to -4 limitation of abduction in the involved eyes. Cycloplegic refraction, anterior segment and fundus examinations were otherwise normal. All the patients had normal neurological evaluation including MRI brain and were started on oral prednisolone (1 mg/ kg body weight), which was tapered over 4 weeks, with a presumed etiology of transient neuritis of the abducent nerve. Results All the patients had partial recovery within 2-5 days and total recovery with a mean of 13.66 days (10-14 days). (ref: Table:1) Table:1 Clinical profile of patients: Age Case (months) Partial Esotropia recov(prism ery diopters) (days) Total Recovery (days) 10 1 10 60 2 (recurrence 2 months later) 2 11 40 5 14 3 12 30 3 10 4 18 40 3 14 5 14 40 2 10 6 18 30 3 14 Kerala Journal of Ophthalmology | 83 | Address for Correspondance: Little Flower Hospital, Angamaly - 683 572. Email: [email protected] Vol. XXVI, No.1, March 2014 One child had a second episode of acute onset sixth nerve palsy in the same eye 2 months after the steroids were weaned off. MRI brain was normal in this episode also and the patient was restarted on oral steroids. Partially recovery was seen in 3 days and total recovery in 7 days. Discussion Benign self resolving unilateral sixth nerve palsy in young children is a relatively rare diagnosis. The etiology of benign, self resolving, unilateral sixth nerve palsies remain uncertain and none of the published literature points to a definitive cause. The major predisposing conditions listed in the series by Knox et al1 included viral infection, otitis media and thrombosis of the inferior petrosal sinus. Symonds et al2 postulated that since the sixth nerve and the inferior petrosal sinus pass through a tightly fitting dural sheath of Dorello’s canal, the compression of the nerve could readily occur if the sinus becomes thrombosed. Functional recovery of the sixth nerve may occur with organization and canalization of the clot . A case of recurrent sixth nerve palsy in a child of 5 episodes was reported by Bixenman and Von Noorden et al3, indicating a viral neuritis. They postulated that benign sixth nerve palsy of childhood may have the same immunological basis similar to post-infectious processes like Guillian-Barre syndrome. With recovery from the initial episode, the abducens nerve may have become predisposed to recurrent inflammatory episodes, triggered by febrile illnesses. Acquired sixth nerve palsies after immunisation have also been reported.4,5 All these cases reported in our series in children less than 18 | 84 | Kerala Journal of Ophthalmology months of age were seen in a period of 2 months and 4 of the cases were reported from an area of 30 square kilometres, which points toward a probable infective etiology. Though there was no definite history of viral infection or trauma, the relatively benign course with recovery within 2 weeks suggest a transient neuritis of the sixth nerve, probably triggered by an insignificant viral infection. Also the one recurrent case of sixth nerve palsy suggests a possible immunological basis as proposed by Bixenman and Von Noorden et al.5 Though we could not suggest a definitive etiological diagnosis, all the patients in our series were empirically treated with systemic steroids with full recovery within 2 weeks. This report is in favour of the entity called benign idiopathic sixth nerve palsy and emphasizes on the importance of avoiding invasive procedures like lumbar puncture in otherwise asymptomatic infants. References 1. Knox DL, Clark DB, Shuster FF. Benign VI nerve palsies in children. Pediatrics. 1967;40:560–564 2. Symonds, C. P. Annals of Royal College of Surgeons England 1952: 10- 347 3. Bixenman WW, von Noorden G. Benign recurrent VI nerve palsy in childhood. J Pediatr Ophthalmol Strabismus. 1981 18(3):29–34. 4. Werner DB, Savino PJ, Schatz NJ. Benign recurrent sixth nerve palsies in childhood secondary to immunization or viral illness. Arch Ophthalmol 1983; 101:607-8 5. A McCormick, S Dinakaran. Recurrent sixth nerve palsy following Measles Mumps Rubella vaccination. Eye 2001: 15: 356–357