title: The diagnostic yield of neuroimaging in sixth nerve palsy--Sankara Nethralaya Abducens Palsy Study (SNAPS): Report 1.
abstract: OBJECTIVE
  The aim was to assess the etiology of sixth nerve palsy and on the basis of our data, to formulate a diagnostic algorithm for the management in sixth nerve palsy.
  
  
  METHODS
  Retrospective chart review.
  
  
  RESULTS
  Of the 104 neurologically isolated cases, 9 cases were attributable to trauma, and 95 (86.36%) cases were classified as nontraumatic, neurologically isolated cases. Of the 95 nontraumatic, isolated cases of sixth nerve palsy, 52 cases were associated with vasculopathic risk factors, namely diabetes and hypertension and were classified as vasculopathic sixth nerve palsy (54.7%), and those with a history of sixth nerve palsy from birth (6 cases) were classified as congenital sixth nerve palsy (6.3%). Of the rest, neuroimaging alone yielded a cause in 18 of the 37 cases (48.64%). Of the other 19 cases where neuroimaging did not yield a cause, 6 cases were attributed to preceding history of infection (3 upper respiratory tract infection and 3 viral illnesses), 2 cases of sixth nerve palsy were found to be a false localizing sign in idiopathic intracranial hypertension and in 11 cases, the cause was undetermined. In these idiopathic cases of isolated sixth nerve palsy, neuroimaging yielded no positive findings.
  
  
  CONCLUSIONS
  In the absence of risk factors, a suggestive history, or positive laboratory and clinical findings, neuroimaging can serve as a useful diagnostic tool in identifying the exact cause of sixth nerve palsy. Furthermore, we recommend an algorithm to assess the need for neuroimaging in sixth nerve palsy.
authors.affiliation: Department of Neuro-Ophthalmology, Sankara Nethralaya, A Unit of Medical Research Foundation, Nungambakkam, India.
authors.forename: Akshay Gopinathan
authors.initials: AG
authors.lastname: Nair
authors.forename: Selvakumar
authors.initials: S
authors.lastname: Ambika
authors.forename: Veena Olma
authors.initials: VO
authors.lastname: Noronha
authors.forename: Rashmin Anilkumar
authors.initials: RA
authors.lastname: Gandhi
mesh_terms: D020434:Abducens Nerve Diseases / Q000175:diagnosis*; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult