title: Carotid-cavernous fistula as a mimicker of myasthenia gravis.
abstract: BACKGROUND
  A carotid-cavernous fistula (CCF) is an abnormal communication between the carotid arterial system and the cavernous sinus. Common symptoms of CCFs include proptosis and ophthalmoplegia, but fluctuating diplopia and presence of ptosis are not typical.
  
  
  METHODS
  We present an unusual case of CCF with fluctuating binocular diplopia and ptosis, mimicking myasthenia gravis. Electrodiagnostic testing, which included repetitive nerve stimulation and single-fiber electromyography, was normal. Magnetic resonance imaging of the brain and orbits was initially normal, but later magnetic resonance angiography revealed enlargement of the left superior ophthalmic vein along with a left CCF. Patient underwent a successful left cavernous sinus embolization.
  
  
  CONCLUSIONS
  Fluctuating ophthalmic symptoms are a typical presentation of myasthenia gravis; however, there may be an association of these symptoms with a CCF. Repetitive nerve stimulation and single-fiber electromyography played a key role in diagnosis of this case, as the normal result led to further investigations revealing a CCF.
authors.affiliation: Departments of Neurology and Ophthalmology, Hofstra North Shore LIJ School of Medicine, North Shore University Hospital, 300 Community Drive, Manhasset, NY 11030, USA.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Eswar
authors.affiliation: Departments of Neurology and Ophthalmology, Hofstra North Shore LIJ School of Medicine, North Shore University Hospital, 300 Community Drive, Manhasset, NY 11030, USA.
authors.forename: Howard D
authors.initials: HD
authors.lastname: Pomeranz
authors.affiliation: Departments of Neurology and Ophthalmology, Hofstra North Shore LIJ School of Medicine, North Shore University Hospital, 300 Community Drive, Manhasset, NY 11030, USA.
authors.forename: S Murthy
authors.initials: SM
authors.lastname: Vishnubhakat
authors.affiliation: Departments of Neurology and Ophthalmology, Hofstra North Shore LIJ School of Medicine, North Shore University Hospital, 300 Community Drive, Manhasset, NY 11030, USA.
authors.forename: Marissa
authors.initials: M
authors.lastname: Oller-Cramsie
keywords: Carotid-cavernous fistula; fluctuating ophthalmic symptoms; myasthenia gravis; repetitive nerve stimulation; single-fiber electromyography