title: Pediatric third, fourth, and sixth nerve palsies: a population-based study.
abstract: OBJECTIVE
  To determine the population-based incidence and cause of cranial nerve palsies affecting ocular motility in children in the circumscribed population of Olmsted County, Minnesota.
  
  
  METHODS
  The Rochester Epidemiology Project medical records linkage system captures virtually all medical care provided to Olmsted County residents. By means of this database, all cases of third, fourth, and sixth cranial nerve palsy were identified among county residents less than 18 years of age from 1978 through 1992. Medical records were reviewed to confirm the diagnosis, determine the cause, and document county residency. Incidence rates were adjusted to the age and sex distribution of the 1990 white population in the United States.
  
  
  RESULTS
  Over this 15-year period, 36 incidence cases of cranial nerve palsy were identified in 35 children in this defined population. The age-adjusted and sex-adjusted annual incidence of third, fourth, and sixth nerve palsies combined was 7.6 per 100,000 (95% confidence interval, 5.1 to 10.1). The most commonly affected nerve was the fourth (36%), followed by the sixth (33%), the third (22%), and multiple nerve palsies (9%). The most common cause was congenital for third and fourth nerve palsy, undetermined for sixth, and trauma for multiple nerve palsies. Although three cases were associated with neoplasia, a cranial nerve palsy was not present at the time of diagnosis in any case.
  
  
  CONCLUSIONS
  Unlike many institutionally based referral series, our population-based study provides data on the incidence and cause of third, fourth, and sixth nerve palsies in a geographically defined population. In contrast to previous institutionally based series, nearly half the cases were congenital in origin, and in no case did intracranial neoplasia present as an isolated nerve palsy.
authors.affiliation: Department of Ophthalmology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA. holmes.jonathan@mayo.edu
authors.forename: J M
authors.initials: JM
authors.lastname: Holmes
authors.forename: S
authors.initials: S
authors.lastname: Mutyala
authors.forename: T L
authors.initials: TL
authors.lastname: Maus
authors.forename: R
authors.initials: R
authors.lastname: Grill
authors.forename: D O
authors.initials: DO
authors.lastname: Hodge
authors.forename: D T
authors.initials: DT
authors.lastname: Gray
mesh_terms: D000010:Abducens Nerve; D000293:Adolescent; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D003389:Cranial Nerve Diseases / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008910:Minnesota / Q000453:epidemiology; D009802:Oculomotor Nerve; D010243:Paralysis / Q000453:epidemiology* / Q000209:etiology; D012189:Retrospective Studies; D017678:Sex Distribution; D014321:Trochlear Nerve; D014505:Urban Population