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FeedExplaining Encephalitis
Its global scope makes it a disorder of our modern times.
Illustration by Dàv Bordeleau Published November 19, 2009 at 01:39 PM
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Years from now, when we consider all the stresses of the season—affordable healthcare, swine flu, global strife, etc.—we’ll have a good reason to call it our winter of discontent. With all this uncertainty afoot, it may be smart to take a hard look at viral encephalitis, a serious medical condition that has the potential to become more widespread, especially when one considers its history and connection to global epidemics. Its link to viruses transmitted by mosquitoes and ticks makes it a downright scary symptom of a modern world where no one is immune to global disease, pestilence and man-made threats.
Doctors know surprisingly little about the exact cause of encephalitis. What they do know is that the brain swells when too many white cells overreact to a bacteria or a virus that has invaded the body. Several thousand cases of encephalitis are reported in the U.S. each year. But those numbers actually may be higher, since swelling of the brain may go unnoticed in persons recovering from a viral illness.
A majority of cases in this country are thought to be secondary encephalitis or post-infectious encephalomyelitis (swelling of the brain, optic nerves and spinal cord). But they’re no less dangerous than primary encephalitis, where an infection from a tick or mosquito bite goes directly to the brain.
In adults, secondary encephalitis can be a complication of mononucleosis, the flu, cold sores, shingles, cancer or AIDS. Bacteria-related causes can be as diverse as Lyme disease and tuberculosis. In kids, it can follow a bout of measles, mumps or chickenpox—all the more reason for parents to be vigilant about immunizations.
Just knowing the symptoms of encephalitis could save your child’s life. Andro Zangaladze, a neurologist with Thomas Jefferson University Hospital, estimates that 5-10 percent of the young patients he sees have seizures due to encephalitis—particularly the type known as secondary encephalitis. It affects a disproportionate number of school-aged children who’ve either just recovered from one of the viruses mentioned or, in rare cases, are suffering from bacterial meningitis or other infection. A third scenario—even more rare, but worth a mention—is encephalitis due to an allergic reaction to an immunization.
Secondary encephalitis is labeled as such because it’s the result of an earlier viral infection that might mask symptoms. By way of an example, 90 percent of those with secondary encephalitis or post-infectious encephalomyelitis have flu-like symptoms such as fever, sore throat, coughing and malaise. “The bottom line is that, if your child is experiencing these [flu-like] symptoms but also has a fever, stiff neck, headaches, light sensitivity and confusion, you should take them to the emergency room right away—without question,” says Zangaladze.
By the time patients start experiencing confusion or disorientation—two important warning signs that it’s not just the flu—brain tissue may have become so inflamed that they’re in danger of a hemorrhage, an aneurysm, or convulsions and epileptic-like seizures. Potential internal bleeding and damage to the central nervous system are two reasons why patients with even mild forms of encephalitis are carefully monitored for changes in blood pressure, heart rate and breathing.
