It was a typical call night in mid-January. The Children's Center was filled to capacity, and the halls of the infant floor were lined with isolation carts. The annual respiratory syncytial virus epidemic was in full swing, which meant that mask, gown, and gloves were required for almost all rooms.
Our Children's Center maintains a strict isolation policy during respiratory syncytial virus season each year. We place all children younger than 6 years who have any upper respiratory symptoms on droplet precautions until the results of nasopharyngeal viral cultures are negative for 5 days. Although seemingly effective, this policy creates nightmares for charge nurses, who must isolate and cohort patients on droplet precautions without compromising monitoring.
On this night, the charge nurse had just achieved that delicate balance of isolation and monitoring. Children requiring precautions were tucked away, whereas our higher risk patients were out of harm's way in our open 4-bed observation room. All seemed quiet, but then we received a 2 am page from the infant floor. Our 4 month old with cardiomyopathy had developed a fever. The results of the infant's physical examination and the other vital signs remained unchanged. We saw no clear source and decided to send a complete blood cell count, a blood culture, and a urine culture to the laboratory.
As we were explaining our plan to the infant's mother, she mentioned, almost in passing, that her infant had recently had a mild runny nose and cough. As hard as we tried to ignore this comment, the intern and I knew what had to be done. We requested that a nasopharyngeal aspirate be sent for respiratory syncytial virus antigen testing and viral culture.
We had upset the balance. Our patient now required isolation and droplet precautions. Additionally, we now had to move this infant with severe cardiomyopathy to a single room with less direct monitoring. The charge nurse would have to be informed. I would rather have called our department chair at 3 am to ask for a raise. We created sheer havoc.
After the dust had settled and we had escaped to the call room, I reflected on our plan. "Did we ask for antigen testing for influenza?" I asked. We did not. After some discussion, we called the nurse to add antigen testing for influenza. The results were called back as positive within 8 hours.
This case highlights several important lessons about influenza. Perhaps most important is that influenza in an infant can present just like respiratory syncytial virus or many other viral respiratory infections. It is important to consider influenza in mese situations, because we have a relatively rapid diagnostic test in the form of direct fluorescent antigen testing. Granted, in this case, the viral culture also would have given us the diagnosis, but it would have taken at least another 48 hours.
The benefits of a rapid diagnosis are twofold. First, an early diagnosis of influenza in febrile patients has been shown to limit the use of intravenous antibiotics and shorten hospital stays.1·2 Second, and more importantly, we now have access to improved therapy for influenza A and B in the form of the neuraminidase inhibitors. Although they are not currently approved for infants and young children, this will change soon. In patients with chronic illnesses, these drugs may significantly limit the morbidity of an influenza infection.3
This case also illustrates the importance of isolating patients with suspected influenza infection. Isolation places a burden on house staff, nurses, and sometimes families, but these policies have been proven effective in reducing nosocomial infection. We must resist the temptation not to isolate. Thanks to our strict isolation policy, this patient was not a source of further spread of influenza in the hospital.
Although the source of infection in our patient was not clear, it was almost certainly hospital acquired. The source could have been a parent, another patient, or a health care worker. Identifying the source is made more challenging by the fact that peak infectivity for influenza begins more than 24 hours prior to the onset of symptoms. The best thing we can do is remember to vaccinate those who have contact with high-risk patients, not just the patients themselves. That means vaccinating parents and, of course, all health care workers. Compliance with recommendations for influenza vaccine is notoriously poor among health care workers.
Influenza is often forgotten in respiratory seasons dominated by respiratory syncytial virus infection. I would strongly consider direct influenza testing any time it is deemed appropriate to test for respiratory syncytial virus. Rapid testing becomes more important because we have improved ways to treat influenza infection.
Don't forget to vaccinate your high-risk patients, as well as their close contacts. And, finally, GET YOUR FLU SHOT!
1. Noyola DE, Demmler GJ. Effect of rapid diagnosis on management of influenza A infections. Pediatr Infect Dis /. 2000;! 9:303-307.
2. Woo PC, Chiù SS, Seto WH, Peiris M. Cost-effectiveness of rapid diagnosis of viral respiratory tract infections in pediatrie patients. / Clin Microbio/. 1997;35: 1579-1581.
3. Hedrick JA, Barzilai A, Behre U, et al. Zanamivir for treatment of symptomatic influenza A and B infection in children five to twelve years of age: a randomized controlled trial. Pediatr Infect Dis J. 2000;19:410-417.