For a therapy rooted in ancient ayurvedic medicine, it is perhaps not surprising that there have not been many startling developments regarding nasal irrigation for chronic rhinosinusitis. A slow but steady increase in popularity, a few seminal studies and a Cochrane review documenting its safety and efficacy were about all one could point to in the way of newsworthy trends.
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November 2012That all changed in February, when the Centers for Disease Control and Prevention in Atlanta announced that two patients had died from primary amebic meningoencephalitis (PAM) that had likely been caused by sinus irrigation with contaminated tap water. The culprit? Naegleria fowleri, a rare and usually lethal thermophilic amoeba that had colonized both patients’ household plumbing, according to the CDC and other infectious disease specialists, noted in a full report on the cases published online in August (Clin Infect Dis. DOI:10.1093/cid/cis626).
As a result of these cases, both the CDC and the FDA warned that only distilled, boiled or properly filtered water should be used when preparing saline solutions for nasal washes.
That caution gained even more traction in October, when a study linked eight cases of treatment-resistant chronic rhinosinusitis to tap water contaminated with another potentially dangerous organism—Mycobacterium. As in the CDC report, the patients had been regular users of nasal irrigation; the bacteria was traced to household plumbing; and the researchers concluded that patients should avoid sinus rinses with tap water and use sterile water instead (Emerg Infect Dis. 2012;18(10):1612-1617; doi: 10.3201/eid1810.120164).
Jonathan S. Yoder, coordinator for the waterborne disease outbreak surveillance system at the CDC, helped put the risks posed by the N. fowleri infections, which have so far garnered the most attention, in perspective. “These are very rare and tragic infections,” he told ENT Today. “And although the risk to people using tap water for nasal irrigation is extremely low—remember, these are the first two cases of PAM associated with nasal irrigation ever reported in the United States—we still think it prudent to use water that is distilled, filtered or previously boiled.”
Yoder said he understands that following the recommendation will add an extra layer of logistics to the nasal irrigation process. But given the rapidly progressing nature of the rare N. fowleri infections—both patients died within a week of exhibiting symptoms and after repeated courses of treatment, including liposomal amphotericin B and rifampin—avoiding untreated tap water “is the prudent thing to do,” he said.
In fact, choosing appropriate water for preparing nasal irrigation solutions is the most effective means for preventing PAM because, according to the study, the salinity of nasal irrigation solutions does not begin to kill off N. fowleri for at least four to eight hours. And since the municipal water supply was found to be negative for the organism, all efforts to eradicate N. fowleri should be done at home at the source of the infection, said Yoder. (In the two cases reported, raising the heat of the water in the pipes killed off the N. Fowleri colonization.)