Poster Presentations, BIOS Annual Scientific Conference, Birmingham, June 2006

摘要

Aim: To report a case of acute-onset esotropia (horizontal skew deviation) that was probably the result of the toxic effects of two epilepsy-mediating drugs, sodium valproate (epilim) and lamotrogine (lamictal). Sodium valproate and lamotrogine are both anticonvul-sants whose mode of action is to reduce electrical discharges within the brain, Acute-onset esotropia is a relatively rare neurological disorder in which a concomitant horizontal deviation occurs as a result of lesions within the posterior fossa. This results in a disturbance of the otolithic input pathways to the horizontal vergence centre.Methods: Details are reported of an 18-year-old epileptic taking sodium valproate and lamotrogine who suffered acute-onset esotropia within 2 weeks of commencing fasting for Ramadan Orthoptic, ophthal-mological and radiological findings are presented and considered in relation to the patient's medication and fasting at the time of onset.Results: The patient presented with a sudden-onset esotropia with diplopia, At this time the patient was in the process of fasting for Ramadan. Orthoptic assessment revealed a concomitant esotropia with no limitation of ocular motility. Following full orthoptic, ophthalmo-logical and radiological investigations the patient was diagnosed with acute-onset esotropia (horizontal skew deviation). The horizontal skew deviation resolved completely within 6 weeks of ceasing fasting for Ramadan. The patient regained binocular single vision and there was no need for further management.Conclusion: High doses of epilepsy medication may cause significant brainstem damage, and in this case are the most probable cause of the acute-onset esotropia. Sodium valproate and lamotrogine are known to have significant dose-related side-effects, including diplopia. The dosage of these drugs is calculated on an individual basis and is dependent on age and weight. The patient should be advised to take anticonvulsants after food. This advice was not adhered to whilst fasting for Ramadan. A case of acute-onset esotropia has also been reported in a young boy after taking carbamazepine,another anticonvulsant,1 Patients and clinicians should consider adjusting the dose of highly toxic drugs such as anticonvulsants prior to patients undertaking a significant change in diet.