Sneaky Infections

by Guy McKhann, M.D.

November 27, 2012

Diseases caused by infection are like clouds on the horizon, threatening a storm at any time. We have successes in bracing for these storms, such as when we develop appropriate antibiotics or successful vaccines. However, every so often a new agent catches us by surprise.

In the 1980s and ’90s, bovine spongiform encephalopathy (BSE), commonly known as “Mad Cow Disease,” appeared, first in cattle in Great Britain and then in man. BSE spread to other counties, particularly France and Italy. Since its discovery, there have been 188,000 cases of BSE in cattle and about 280 human cases. The United States has largely been spared by this disease; there have been just four cases in cattle and three in humans.

This strange disease came to existence when young cattle were fed, as protein supplements, scraps of meat and bone (known as “renderings”) from sheep with a disease called scrapie. The brain, spinal cord, and GI tract were particularly infectious. These renderings became infective, in part, because of a change in the way they were processed. One of the reasons that the United States escaped a BSE epidemic is that protein supplements in the U.S. are derived from soy protein rather than animal protein. Recognition of this problem led to a change in the use of animal renderings in Great Britain; as a result, the disease has essentially disappeared.

The next previously unknown disease was AIDS, which appeared in the United States in the early 1980s. Progress in understanding and treating this disease has been remarkable: We identified the virus, developed a diagnostic test, and implemented therapies that changed the course of the disease. Originally an AIDS diagnosis was a death sentence; it has since been downgraded to a chronic disease.

With this background, we can turn to a current problem in the United States: a form of meningitis caused by a rare fungus (as outlined in the New York Times story, “Chasing Clues to Detect Outbreak”). This problem is iatrogenic. (Iatrogenic refers to an adverse effect resulting from an attempt at treatment). In this case the treatment is the injection of steroids close to the spinal cord or nerve roots to help neck and back pain. The idea behind this therapy is that a steroid, such as methylprednisolone, will decrease inflammation around nerve roots and relieve pain. This is a common procedure and is done thousands of times a year. The material used is often prepared in a pharmacy, which is the source of the problem in this case.

Apparently one such pharmacy, the New England Compounding Center (NECC), prepared large lots of methylprednisolone for injectable use. Certain lots of these preparations were contaminated with fungus, particularly a plant fungus, Exserohilum rostratum. This is a common fungus in the environment, but a very rare cause of human illness. It is estimated that 17,000 people received injections from contaminated lots from NECC. Very astute physicians at Vanderbilt and at the State Health Department in Tennessee should be congratulated for recognizing the index case and bringing the problem to our attention.

Fungal infections of the coverings of the spinal cord, the meninges, are rare and sneaky. They may take time to build up. Of the 460 cases found so far, the duration from injection to symptoms has been as long as 4-6 weeks. The symptoms may be what one would expect from meningitis, such as fever, headache, and stiff neck, but in other cases they are less distinct or cause a sudden loss of function, like in a stroke. Treatment can be effective if started promptly, but there have been 32 deaths.

This should be a self-limited problem. The contaminated lots of medicine from NECC have been identified and patients who received contaminated injections are being followed and their physicians are being coached on symptom recognition and therapy.  NECC has been closed down.

The discussion of how this happened has become somewhat of a political football. Margaret Hamburg, commissioner of the Food and Drug Administration, is appearing before congress as I write this. Hopefully when the political dust settles, the guidelines for regulating places like NECC will be clarified.

What to do in the meantime? I have personal experience. About one month ago, in the middle of all the uproar about injections, one of my sons, in his 40s, injured his back, causing a protruded intervertebral disc. His neurosurgeon suggested an injection of steroids to aid recovery. My son called me, and my suggestion was to be sure to find out the origin of the material being injected. He received the injection and is better. Whether he would have recovered without it is not known.

The moral of this story is clear: Be careful what you inject into vulnerable places in the body!