Measles in focus

Like the measles, love is most dangerous when it comes late in life - Lord Byron

The re-emergence of measles on American shores provides the opportunity for ophthalmologists to acquaint (or reacquaint) themselves with the ophthalmic manifestations of this disease. It is good that we have pediatricians and primary-care physicians who are still practicing into their 70s, as they will be the most prepared to recognize these cases. But thanks in large part to widespread immunization, most physicians in practice today were too young to contract measles themselves in childhood and have never seen a patient present with the measles.

According to news reports, the recent spike in measles cases (about 800 and rising as of the time I write this, with close to 10 cases in my state of Maryland) is largely the consequence of unvaccinated Americans traveling to other countries and returning to transmit the virus to others while they are asymptomatic or before the disease is recognized.

Diving deeper

A literature review reveals that the ophthalmic manifestations of measles are limited – in the sense that they are limited to every part of the visual pathway from the ocular surface all the way back to the cortex. A self-limited (in healthy children) conjunctivitis and keratitis may present in the front of the eye.

Deeper in, uveitis, retinitis, choroiditis, and optic neuritis may all be part of the disease, and result in permanent vision loss. The virus can gain access to the central nervous system and cause encephalitis. A particularly tragic manifestation of the disease is subacute sclerosing panencephalitis (SSPE). This disease occurs after a bout of measles followed by a latency period of six to eight years.

Death may occur quickly (within three months) in a small subset of patients, but most individuals progress more slowly and die one to three years after diagnosis. Countries with strong immunization programs have seen declines in the incidence of SSPE of 90% or greater, but it is reported to persist at relatively high levels in Eastern Europe and India.

There is no cure for SSPE, but some trials suggest that antivirals and interferon can prolong life. Of significance to ophthalmologists is that the last ophthalmologist to win the Lasker Award (not counting the posthumous award presented to the widow of the surgical innovator Charles Kelman, MD) received the prize for work related to measles. Alfred Sommer, MD, MHS, was studying the potential of vitamin A supplementation to prevent xerophthalmia and corneal ulceration and melting in nutritionally deficient children. His work focuses on xerophthalmia and vitamin A deficiency.

If one of these children suffering from chronic malnutrition were to contract measles, the manifestations of the disease were often particularly severe, including corneal melting. Dr. Sommer, professor of ophthalmology, Johns Hopkins University, Baltimore, found that the vitamin did indeed reduce the likelihood of corneal perforation and blindness in children.

But even more striking was the dramatic reduction in mortality in these children, with a vitamin A capsule costing a few pennies proving to reduce mortality by about 50%. Measles, it turns out, “often blinds and kills by its acute, dramatic interference with vitamin A metabolism.” The World Bank has concluded that giving children periodic doses of vitamin A is one of the most cost-effective treatments in the history of medicine.

Disclosures:

Peter J. McDonnell, MD
P: 443/287-1511
E: pmcdonn1@jhmi.edu
Dr. McDonnell is the director of the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, and chief medical editor of Ophthalmology Times.

References:

1. Semba RD, Bloem MW. Measles blindness. Surv Ophthalmol 2003;12:5.

2. http://www.laskerfoundation.org/awards/show/vitamin-atherapy-for-preventing-infections-and-blindness/