Saturday, February 21, 2015
Chronic obstructive pulmonary disease (COPD) exacerbations and respiratory syncitial virus--maybe a huge problem?
I have never routinely checked my patients with asthma and COPD exacerbations for respiratory syncitial virus. I thought that it was one of those tests that would take so long to come back from the lab that the patient would be well before I ever found out the result. It is possible, though, to get a result back from a rapid antigen detection test (much like a home pregnancy test) using a sample of mucus from the back of the nose, in 30 minutes.
Last week two patients with severe wheezing and uncontrollable cough who were in the hospital with worsening of their COPD tested positive for RSV. Yesterday another one did. It is RSV season. In fact, it is even more RSV season than it is flu season. We are smack dab in the middle of RSV season which stretches from January to April. RSV is best known as the virus that causes acute lung disease in infants and children. In the US alone, over 80,000 children are hospitalized each year due to this virus and worldwide it kills more children under the age of 1 than any other infectious agent with the exception of malaria. More high risk adults, such as those with lung disease or immune suppressing diseases, contract RSV than they do the flu.
RSV is, for most of us, just a cold. It causes a stuffy runny nose and a cough, sometimes a fever. In small children or people with lung disease it can cause respiratory failure. It is very contagious. It is most often contracted by directly touching an infected person or objects with infectious secretions, even when they are dry. It is very important to avoid transmitting it in the hospital, and since we don't routinely test adults for it, we are probably very efficiently spreading it from infected to uninfected patients. The time from exposure to symptoms is 2-5 days. There is no vaccine, and people who get RSV can get it again, even during the same season, though perhaps more mildly. In very susceptible babies, a monoclonal antibody, Palivizumab, can be given monthly to prevent disease, but it is terribly expensive. For a baby it might run $1000 to $3000 per dose, but since it is dosed by weight, it would probably cost around $30,000 per dose for the average size adult. Not an option.
Prevention involves good hygiene, avoiding exposure to infected people, handwashing, and avoiding cigarette smoke which can make a person more susceptible. There is an antiviral medication, ribavirin, which is active against RSV and sometimes used, primarily for immune suppressed patients like those with bone marrow transplants. Ribavirin costs about $30 a pill, would be dosed twice daily, has a black box warning for causing hemolytic anemia. It is not known if its use improves symptoms.
I think that it is likely that many of the winter adult lung disease admissions that I see are related to RSV. It is much more common than I believed. Since there are no really useful pharmaceuticals to treat it, none of the economic forces that lead to mass education are at work to raise awareness of its importance in the aging and chronically ill population that we internists see in the office or hospital. There is talk of vaccine development, but if natural infection does not give long term protection, it is unlikely that a vaccine will. It would certainly be nice if we knew whether ribavirin helped improve symptoms. Old fashioned and low tech prevention is probably the key to reducing its impact. I certainly need to be checking for it more often and thinking about taking precautions to avoid spreading it in the hospital or waiting room!