Organ transplant recipients who become infected with West Nile virus develop more severe neurological illness caused by the virus, according to an article in the August issue of The Archives of Neurology, one of the JAMA/Archives journals.
West Nile virus (WNV) is a potentially lethal virus that can infect mosquitoes, birds, horses, humans, and other mammals. WNV affects the nervous system and can cause encephalitis -- an inflammation of the brain, or meningitis -- an inflammation of the membrane surrounding the brain and spinal cord. WNV is also associated with fever, headaches, fatigue and neurologic symptoms. According to the article, naturally acquired WNV first appeared in North America in 1999.
Between July 2003 and October 2003, there were 2,947 confirmed cases of WNV and 63 deaths in Colorado. The article states that approximately 25,000 patients receive organ transplants in the United States each year. Transplant recipients are treated with long-term immune system-suppressing drugs that put them at greater risk for infections, including WNV.
B.K. Kleinschmidt-DeMasters, MD, of the University of Colorado Health Sciences Center, Denver, and colleagues describe eleven transplant recipients (four kidney, two stem cell, two liver, one lung, and two kidney/pancreas) hospitalized with WNV encephalitis. All cases of WNV occurred between July 2003 and October 2003 and patients were seen in Colorado hospitals. All 11 patients received their organ five months to 15 years before being infected with WNV.
The researchers found that all but one patient had the usual early symptoms of WNV as documented in non-immunosuppressed patients. Ten patients developed meningoencephalitis (inflammation of the brain and membrane surrounding the brain and spinal cord), and three of the 10 also developed acute flaccid paralysis (paralysis associated with loss of muscle tone). One patient developed acute flaccid paralysis without encephalitis. Six patients had significant movement disorders, including tremor.
Magnetic resonance imaging (MRI) of the brain revealed abnormalities in seven of eight tested patients. Nine of the 11 patients studied survived their infections, but three of them had significant problems caused by their infections and two patients died of complications of WNV.
"Naturally acquired WNV encephalitis in transplant recipients shows diagnostic, clinical, and laboratory features similar to those reported in nonimmunocompromised individuals, but neuroimaging, electroencephalography, and autopsy results verify that these patients develop neurological damage at the severe end of the spectrum," the authors write.
In an accompanying editorial, Roger N. Rosenberg, MD, of the University of Texas Southwestern Medical Center, Dallas, and editor, The Archives of Neurology, writes, "The report of Kleinschmidt-DeMasters and colleagues is significant because it documents the lethality of WNV encephalomyelitis in immunosuppressed patients and alerts the neurological community to be vigilant about the occurrence of severe disease consequences in this population."