Doctors link polio to West Nile virus
By Stephen Smith, Globe Staff, 9/24/2002
Mosquito-borne West Nile virus is causing a medical condition rarely seen by US physicians since the 1950s: polio.
In case reports released yesterday, stunned neurologists in Mississippi and Georgia describe the conditions of four patients suffering from the hobbled limbs, impaired breathing, and fevers that are the hallmark of polio, a disease essentially eradicated in the United States.
Just like the polio patients of the first half of the 20th century, the West Nile victims seen this summer by the Southern doctors are also enduring prolonged muscle weakness and respiratory ailments that will require months of treatment and probably will disable some of the patients permanently.
”I teach this as a historical thing to the residents,” said Dr. Jonathan D. Glass, director of the neuromuscular program at Emory University in Atlanta and one of the physicians who treated the polio patients. ”We simply don’t see it today. That’s why I didn’t believe it at first.”
The strain of polio that was so widely feared in the 20th century, and now prevented by vaccines, is caused by a different virus than West Nile. In fact, West Nile comes from a different family than viruses known to cause the disease. However, the devastating effects are the same.
In polio, the virus attacks the gray matter of the patients’ spinal cord, which contains the neurons responsible for carrying information to the muscles. As the attack frays the neuron fibers, muscles turn limp, often producing uneven results – a leg gone weak on the right side, an arm on the left. It also results in bladder and bowel dysfunction, along with respiratory complications that can leave patients tethered to breathing machines.
According to the Centers for Disease Control, the West Nile virus has killed 94 people nationwide this year, including two in Massachusetts, and sickened 1,963, by far the largest outbreak since it was first reported in the United States three years ago. Although other viral illnesses kill vastly more people – the flu is blamed for 20,000 deaths annually – public-health authorities are concerned about West Nile because it has spread from coast to coast so quickly and produced unexpected symptoms, with polio being the most recent example.
”We obviously have to learn a lot more about this virus,” said Dr. Alfred DeMaria, director of communicable disease control for the Massachusetts Department of Public Health. ”This is another aspect that’s worrisome about West Nile.”
The New England Journal of Medicine released the articles on the polio link nearly a month before their scheduled publication, an unusual step reserved for reports of urgent medical importance. The doctors who wrote the articles said yesterday they believe it is vital that their findings circulate among physicians because some of the patients they treated had been misdiagnosed and prescribed treatments that could have been life-threatening.
And they suspect – strongly – that other cases of West Nile-induced polio have gone untreated and unreported. After discovering polio in their own West Nile patients, the physicians in Mississippi and Georgia decided to review previous outbreaks. In examining autopsy results from New York City in 1999, the first time West Nile was identified in the nation, the doctors uncovered symptoms that struck them as remarkably similar to the cases they had seen this summer.
Dr. A. Arturo Leis, a neurologist at Methodist Rehabilitation Center in Jackson, Miss., saw such a patient in late July or early August. He recalled walking into an exam room and witnessing a 56-year-old man who had been referred to him because of muscle weakness. In reviewing the patient’s medical chart, Leis discovered that the man had been diagnosed weeks earlier with early signs of a stroke and prescribed blood-thinning medication. The same man also was diagnosed with Guillain-Barre syndrome, a disorder in which the body’s immune system attacks part of the nervous system.
Only after running blood tests, observing symptoms similar to polio, and performing a battery of electrically activated tests that record activity in nerves and in spinal cord cells, did the Mississippi physicians reach their diagnosis: polio, caused by West Nile virus.
Previously, severe cases of West Nile had been characterized by meningitis and encephalitis, the brain swelling that is regarded as the most serious consequence of the virus. But the muscle weakness and other problems associated with polio were not evident.
”I thought, `This is extremely unusual – this can’t be,”’ Leis said. ”How can a virus, in this case West Nile, change its clinical properties to such a marked degree? It had typically not presented this way.”
The medications the man had received initially, Leis said, could have killed him. The stroke drug could have caused a hemorrhage, and the medicine initially given to treat his misdiagnosed case of Guillain-Barre had the potential to result in a stroke. That’s why the Mississippi and Georgia researchers became so determined to share their findings on the link between polio and West Nile.
Leis has now seen four cases of West Nile-related polio, one additional since he wrote his journal article. In Atlanta, Glass received a call from a suburban physician one Saturday night in July. That doctor was confounded by the symptoms of a patient he was seeing. She had muscle weakness, along with fever and meningitis. The kind of muscle fatigue she was experiencing was consistent with Guillain-Barre, but that disease does not typically produce fever and meningitis.
”The guy called me and said, `Help. I don’t know what I’m looking at,”’ Glass said. ”And I said, `I don’t know what you’re looking at either.”’
The 50-year-old woman, who lives in Louisiana, which was hard hit by West Nile and was in Georgia visiting grandchildren, was transferred to the university hospital in Atlanta. There, a neurology resident, Dr. William Hewitt, examined her and confirmed the presence of an unusual constellation of symptoms.
Glass spent the night poring over old medical textbooks and epidemiology reports on the New York cases. All evidence began pointing toward polio.
The woman treated by Glass is expected to survive but remains in a rehabilitation hospital. The four patients in Mississippi also will live, their doctor said, although three will probably have permanent disabilities.
Stephen Smith can be reached at email@example.com.
This story ran on page A1 of the Boston Globe on 9/24/2002.
© Copyright 2002 Globe Newspaper Company.