(DRG) Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, Emergency Medicine, and Medicine, The Johns Hopkins School of Medicine, Baltimore, Maryland
Subject
Myasthenia Gravis
Description
This is a 20-yo-woman who presented with generalized weakness, ptosis and ophthalmoplegia. She had severe ptosis OU at baseline, but when one eyelid was manually elevated, there was marked enhanced ptosis of the opposite eyelid. This was in accordance with Hering's law of equal innervation of the levator muscles - i.e., manual elevation of a ptotic eyelid decreases the muscle strength necessary to keep the lid elevated, causing contralateral levator relaxation and enhanced ptosis. In MG-related unilateral ptosis, lifting the normal-appearing eyelid commonly leads to ‘enhanced ptosis of the already ptotic eyelid. Alternatively, lifting the ptotic eyelid may cause the normal-appearing eyelid to become ptotic, which is referred to as ‘curtaining'. The baseline equal innervation of the levator muscles due to Hering's law explains both enhanced ptosis and curtaining in MG.
Date
2016
Language
eng
Format
video/mp4
Type
Image/MovingImage
Collection
Neuro-Ophthalmology Virtual Education Library: Dan Gold Neuro-Ophthalmology Collection: https://novel.utah.edu/Gold/
Publisher
North American Neuro-Ophthalmology Society
Holding Institution
Spencer S. Eccles Health Sciences Library, University of Utah, 10 N 1900 E SLC, UT 84112-5890