At the 2017 Annual EIS Conference, researchers presented findings from a prospective case-control study on acute Zika infection at 9 hospitals in Puerto Rico, as well as on a patient who was paralyzed due to Guillain-Barre Syndrome, unrelated to Zika infection.
Patients who contract Zika virus could find themselves at risk for developing Guillain-Barré syndrome (GBS), an autoimmune disorder that can lead to bilateral weakness, sensory abnormalities, and even temporary paralysis. Emilio Dirlikov, PhD, reported on a case of GBS in a woman who was not diagnosed with Zika during a media briefing at the 2017 Annual EIS Conference in Atlanta, Georgia, on April 24, 2016.
Although the young woman in question does not appear to have contracted GBS as a result of a Zika infection, the account of her GBS progress proved valuable to the researchers. They believe that studying this case assisted them in documenting early signs of GBS that practitioners and patients alike should watch for in the presence of a Zika infection.
Dr. Dirlikov noted that in addition to conducting a prospective case-control study at 9 hospitals in Puerto Rico between April and December 2016, he and his team were able to conduct a series of interviews with a patient who had been paralyzed due to GBS, and on a ventilator for nearly a year, to gain insight into her relatively rapid decline prior to her paralysis. “GBS generally happens after an infection, so hearing her symptoms firsthand gave us a lot of insight,” he explained, adding that his team in Puerto Rico had become concerned by an apparent association between Zika infections and GBS diagnoses.
“Puerto Rico reported its first Zika infection in December 2013, and among the first 30 patients, one was also diagnosed with GBS,” Dr. Dirlikov said. He also said that by February 2015, Puerto Rico had implemented a surveillance system to monitor the two conditions. “At first, we were not really sure what association there might be between Zika and GBS. We would interview patients at the hospital, then go into their communities to recruit willing, healthy participants who might have also been exposed to certain factors. We did ultimately find that Zika is a risk factor toward developing GBS,” he said. The researchers had to make allowances for the unique nature of GBS that causes most patients to develop it after another infection. “We asked providers to report any [Zika] case that had a suspicion of GBS,” Dr. Dirlikov explained, adding that they identified a total of 120 Zika-and-GBS cases during the study and that 102 of those cases were reported to the team by healthcare providers. “To put this in context, we expected about 60 GBS patients. Having 120 doubled baseline expectations,” he said.
Dr. Dirlikov noted that the ability to interview the GBS patient, who had recently begun a recovery from near-total paralysis that forced her to use a ventilator for about a year, provided valuable insight into the progress of a severe GBS condition. “The young woman had recently returned to her grandmother’s house [from college] and noticed that she had a mild rash that self-resolved in a few days.” This was likely the infection that instigated the GBS in this instance. He continued, “A few days later, she noticed that she was losing coordination and then found while driving that she was unable to step on the gas. Shortly thereafter, her legs were too weak to support her weight. When she visited the emergency room, she was turned away by local physicians, who said she was likely just experiencing symptoms of stress and overwork. As the condition progressed and she had difficulty breathing, however, she eventually was hospitalized and put on a ventilator,” he said.
For the prospective study conducted in Puerto Rico, researchers defined acute Zika virus infection as positive using “reverse transcription-polymerase chain reaction (RT-PCR) in any specimen,” while “evidence of [Zika virus] infection was defined as positive by RT-PCR or immunoglobulin M (igM) enzyme-linked immunosorbent assay (ELISA).” Once the infection statuses were confirmed, the group was able to enroll 42 case-patients and 84 controls in the original study, with case-patients having suspected GBS but not necessarily Zika. As indicated in the media briefing, there were more cases discovered after the initial abstract’s publication. In the initial study, however, 24% of acute Zika cases were followed by GBS; 58% of cases showing evidence of Zika infection were followed by GBS; and 88% of cases self-reporting acute Zika within the previous two months were followed by GBS.
This study “provided the first identification of acute [Zika virus] infection as a risk factor for GBS,” the researchers concluded. They recommended that healthcare providers should “elevate clinical suspicion of GBS in order to improve patient prognosis through prompt diagnosis and treatment.”
When asked if he felt that his team had captured all related cases of GBS and Zika in Puerto Rico during the study period, Dr. Dirlikov was skeptical. “It is important to remember that GBS is a post-infectious autoimmune disorder that can be caused by Zika and other viruses,” he cautioned, noting that the study was based largely on provider-reported data and, as such, might be limited in scope.