Head and Neck Imaging

Horner's syndrome

(Johann Friedrich Horner, 1831-1886, Swiss ophthalmologist), syndrome caused by disruption of the oculosympathetic pathway. The symptoms consist of ptosis of the upper eyelid, elevation of the lower eyelid (upside-down ptosis), miosis, and loss of ipsilateral sweating of the face (anhidrosis). Based on clinical testing, the lesion can be localized to either the preganglionic (first- and second-order neurons) or postganglionic (third-order) neurons. Many postganglionic lesions appear to be idiopathic; imaging findings may include internal carotid artery dissection , a cavernous sinus lesion or an orbital tumour. Preganglionic lesions most commonly involve second-order neurons. Such a lesion may be caused by dissection of the internal carotid artery; other aetiological examples are Pancoast's neoplasm , other neoplasms involving the ventral roots C7-D1, or surgical damage to the sympathetic chain after common carotid artery endarterectomy or other neck surgery. Horner's syndrome due to a lesion at the level of the first-order neurons is rarely encountered in isolation; lesions within the hypothalamus or brain stem usually produce several neurological signs.

RH