INTRODUCTION Lesions in either the central or peripheral sympathetic pathways to the eye and face lead to the triad of symptoms known as Horner's syndrome. Loss of sympathetic tone to Muller's accessory eyelid muscle results in upper eyelid ptosis, loss to the dilator muscle of the iris causes pupillary miosis, and absence of sympathetic innervation to facial sweat glands produces anhidrosis. In addition, parasympathetic innervation is unopposed resulting in overaction of parasympathetic stimulation to the iris constrictor muscle, the ciliary muscle, the lacrimal gland, and the salivary glands.
The course of the sympathetic fibers from the cervical sympathetic trunk and cervical ganglia divide to follow two separate routes; those to the eye course along the internal carotid artery, while those destined for the sweat glands of the face follow the external carotid system. Thus, the constellation of symptoms may vary depending upon the level of the sympathetic injury. The neurologic deficit may result from ischemia, thoracic trauma, mediastinal neoplasms, enlargement of the thyroid gland, internal carotid dissection, or iatrogenic surgical insults. In children Horner's syndrome may the initial manifestation of neuroblastoma. Horner's syndrome has been reported fairly commonly following lumbar epidural anesthesia. It has also been seen with carotid dissection, Pancoast tumor, and thyroid tumors. The condition can be bilateral in diabetic autonomic neuropathy, amyloidosis, and pure autonomic failure.
Horner's Syndrome (Contd.)
CLINICAL SYMPTOMS Muller's sympathetic eyelid muscles contribute to retraction of both the upper and lower eyelids. In Horner's syndrome there is a minimal ptosis of the upper lid of about 1 to 2 mm, associated with elevation of the lower eyelid. Thus, the interpalpebral fissure is narrowed. The pupil is mildly constricted and there may be loss of sweating on the ipsilateral face and dryness of the mouth. In congenital Horner's syndrome the affected iris is lighter in color resulting in heterochromia. Diagnosis is facilitated by pharmacologic testing with 4% cocaine where the affected pupil does not dilate but he normal pupil does. If the denervation involves the third order neurons between the superior cervical ganglion and the eye, the pupil is supersensitive to epinephrine and will dilate with 1:1000 dilution of epinephrine, a concentration that does not affect the normal pupil.
TREATMENT In children with congenital Horner's syndrome a history of forceful manipulation of the infant during birth reduces the need for medical work up. In 90% of affected children either trauma or no clearly identifiable cause will be found. However, in 10% an underlying pathology may be uncovered. All cases of acquired Horner's syndrome without a known etiology require extensive evaluation since a high percentage of cases may be associated with a serious underlying condition. In acute cases the eyelid ptosis should be observed. When the ptosis is persistent and visually significant or is of cosmetic concern, surgical correction may be indicated. Since levator function is usually excellent, a conjunctival-Muller's muscle resection or levator aponeurosis advancement procedure will give good results.
Was this article helpful?
This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.