Cranial nerve palsies in childhood

Abstract

We review ocular motor cranial nerve palsies in childhood and highlight many of the features that differentiate these from their occurrence in adulthood. The clinical characteristics of cranial nerve palsies in childhood are affected by the child's impressive ability to repair and regenerate after injury. Thus, aberrant regeneration is very common after congenital III palsy; Duane syndrome, the result of early repair after congenital VI palsy, is invariably associated with retraction of the globe in adduction related to the innervation of the lateral rectus by the III nerve causing co-contraction in adduction. Clinical features that may be of concern in adulthood may not be relevant in childhood; whereas the presence of mydriasis in III palsy suggests a compressive aetiology in adults, this is not the case in children. However, the frequency of associated CNS abnormalities in III palsy and the risk of tumour in VI palsy can be indications for early neuroimaging depending on presenting features elicited through a careful history and clinical examination. The latter should include the neighbouring cranial nerves. We discuss the impact of our evolving knowledge of congenital cranial dysinnervation syndromes on this field.

Figure 1

(a) This 3-year-old boy does not have any facial features of craniofacial synostosis. (b) He presents with a V-pattern exotropia with marked elevation of each eye in adduction, suggesting a diagnosis of bilateral superior oblique palsy. (c) Coronal T2-weighted MRI shows excyclorotation of the orbital contents. Lines are drawn through the centre of the vertical recti on each side emphasizing the muscle displacement. There is un-pairing of the horizontal yoke muscles, leading to elevation of the adducting eye and depression of the abducting eye on each side. A full colour version of this figure is available at the Eye journal online.

Figure 2

(a) This 3-year-old boy was involved in a severe motor vehicle accident; after a week in intensive care, he was transferred to the ward. At that time he was noted to develop a red left eye, prompting referral to ophthalmology. At 3 h after referral, the redness had resolved but a left VIth nerve palsy was evident. The ipsilateral corneal sensation was decreased, indicating likely cavernous sinus compression of V and VI. Neuroimaging and angiography (b) revealed a dissecting carotid aneurysm causing Vth and VIth nerve compression within the cavernous sinus. A full colour version of this figure is available at the Eye journal online.

Figure 3

A 17-year-old girl presented with a left VIth nerve palsy (a). Ipsilateral VIIth nerve function was decreased (b). MRI showing a pontine glioma (c). A full colour version of this figure is available at the Eye journal online.