Ocular tilt reaction due to a mesencephalic lesion in juvenile polyarteritis nodosa

: PurposeTo describe a case of ocular tilt reaction caused by vasculitic lesions in the midbrain in a child with polyarteritis nodosa.: DesignObservational case report.: MethodsA 5-year-old girl with a chronic illness developed diplopia associated with a left head tilt, right hypertropia, torsional nystagmus, slowed vertical saccades and poor convergence. Fundoscopic examination demonstrated conjugate leftward torsion of the eyes consistent with a sustained ocular tilt reaction.: ResultsRenal angiography confirmed polyarteritis nodosa and cerebral magnetic resonance imaging demonstrated mesencephalic pathology.: ConclusionsPolyarteritis nodosa is a difficult condition to diagnose in a child and can cause brainstem lesions. This rare case of ocular tilt reaction of midbrain origin highlights that a sustained head tilt in a child can be due to brainstem pathology, rather than a fourth nerve palsy. [Copyright &y& Elsevier]