aCase 4 Answers

by Dr. Chua

This 62-year-old man developed a left red eye with lacrimation the day after his coronary artery bypass graft. He was referred to the eye clinic where he was treated for infective conjunctivitis with topical chlormaphenicol. Despite treatment, his red eye and lacrimation persisted. Culture and sensitivity of the conjunctival swab was negative for bacteria and virus. At the 3 months review, his red eye had improved but he still complained of lacrimation and problem in opening his eye. Syringing of the left punctum was patent.

 

a. What is the diagnosis?

A left Horner's syndrome. The man has a left partial ptosis and miosis. The temporal relation suggests that the sympathetic pathway (see diagram below) was damaged during insertion of a central venous pressure line or during thoracotomy.

Other features¹ of Horner's syndrome include:

• apparent enophthalmos (less eye is seen because of the ptosis and the updrawing of the lower lid),

• ocular hypotony (the IOP of the affected eye typically has an IOP 5mmHg less than the fellow eye),

• increase in accommodation (due to changes in the tone of the ciliary muscle and may amount to 0.5 to 1.5 dioptres),

• anhidrosis (ipsilateral loss of sweating is seen in lesion of the first and second order neurones) and

• heterochromia (this occurs in congenital Horner's syndrome with the affected eye being lighter in colour and this occurs because sympathetic innervation is involved in melanocytes migration).

 

From the Atlas of Ophthalmology by the Bascoe Palmer Institute.

 b. How can you confirm the diagnosis?

Horner's syndrome can be confirmed with the cocaine test and damage to the second order neuron is supported with the hydroxyamphetamine test.

In the cocaine test, 4% (not 10% as some advocated) cocaine is instilled into both eyes. Horner's pupil dilates little or none at all. Reuptake of the norepinephrine occurs normally in the synaptic cleft. Cocaine blocks the reuptake, causing rapid accumulation within the synaptic cleft resulting in dilation of a normal pupil. The presynaptic nerve endings in Horner's syndrome have impaired sympathetic tone and therefore respond poorly or none at all to the effect of cocaine.

Hydroxyamphetamine stimulates the release of norepinephrine from the presynaptic nerve endings resulting in dilatation of the pupil. If the nerve is damage, the nerve will not release norepinephrine as is the case with third order neurone lesion. In the case of first and second order neurone lesion, the pupil will dilate as the third order neurones are intact.
 
 

c. How do you explain the initial presentation?

The conjunctival vessels and the lacrimal glands are innervated by the sympathetic nerves. Reduced sympathetic input results in dilatation of the conjunctival vessels and increased lacrimation. This may be mistaken for conjunctivitis if the possibility of Horner's syndrome is not considered.

Romano et al studied the ocular manifestations after upper dorsal sympathectomy for palmar hyperhidrosis in 50 patients. Postoperative examination was done during the first week, at 3 to 4 weeks and at 6 to 12 months after the operation. Immediately after surgery there were 18 patients with ptosis (6 severe) and 23 with miosis (12 severe). There were 19 patients with excessive lacrimation and some degree of congestion of conjunctival blood vessels was present in almost all patients. Uniocular decrease in tears was present in 2 patients. Most of these manifestations decreased with passage of time.

Reference:

1.  Walsh TJ. Chapter 3: Pupillary abnormalities. Neuro-ophthalmology: Signs and symptoms. Third Edition. 1992 Lea and Febiger.

2. Romano A, Kurchin A, Rudich R, Adar R. Ocular manifestations after upper dorsal sympathectomy. Ann Ophthalmol. 1979 Jul;11(7):1083-6.
 

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