Saturday, September 19, 2009

Flu tests- Fact and Fiction

How do you know if your flu is the H1N1 strain? Is there a quick test in the doctor's office?
Well, yes and no. Most primary care offices now have rapid flu tests in their offices that can tell you if you test positive for type A or type B influenza. If indeed you test positive for type A, at this point in the United States, you most likely have H1N1. 99% of samples of known positive type A flu that have been sent to the CDC are testing positive for H1N1. The difficulty is that the rapid flu tests are very specific (meaning if it is positive, you definitely have the flu) but not too sensitive (meaning if you do have the flu, there is a good chance - up to 30%- that the test will not show it.)
So, please understand that flu is primarily a clinical diagnosis. This means if you have high fever, intense headache, sore throat, cough, and body aches, and your doctor doesn't find evidence of any other disease (like strep throat or pneumonia), your doctor will likely conclude that you have influenza- whether or not she has the "proof" of a positive rapid test. It is also no longer necessary to send every positive type A flu test on to the CDC for confirmation that it is H1N1.
The good news is that H1N1 is proving to be primarily more mild than initially feared, and now treatment (meaning antiviral medicines) are only recommended for high risk groups (pregnant women, patients with poor immune systems as in cancer or HIV disease, young children under 5 or adults over 65, people with chronic diseases or people who are hospitalized.)
BOTTOM LINE: See your doctor and get tested if you think you have the flu, but understand the limitations of our current testing. Most importantly, remember GOOD HAND WASHING and STAY HOME if you have a fever!

Is that the FLU??

Picture your child miserably sick, teeth chattering, shaking chills, complaining of a sore throat, body aches, cough and headache. When you touch her forehead, she is burning up- sure enough, her temperature is 104.8*! As your brain is trying to process all this, she suddenly tries to jump out of bed and push past you but starts vomiting before she ever leaves her room. What is this? What should you do??
Well, this is no imaginary scene, but one I simply can recall from a few nights ago in our house, when our 12 year old daughter's flu symptoms first showed 2am (of course ;0) What did I do? Well, with a fever that high, the first thing I did was to give her some liquid ibuprofen. (I picked liquid so it would be absorbed more quickly, and because she was more likely to gag and vomit again if she tried to swallow a pill. And yes, I got the ibuprofen in her before I cleaned up the mess.) We put a cold, wet washcloth on her forehead and I read to her (as a distraction) for the next half hour while the medicine was kicking in. By 3am, her temperature was out of the scary range, and "just" 102*.
What I want to emphasize, though, is not the care of a high fever. I want to make it clear the difference between a common cold and the flu. A cold can cause headache, stuffy/runny nose, and sore throat, but generally does not cause intense body aches and high fevers. The flu is not so subtle! It often comes on suddenly, and the flu victim typically feels (and looks) like they've been hit by a Mack truck, with serious aches and pains in their muscles, bad headache, intense sore throat worse with swallowing, high fever, and often a cough.
So, what did she have? The flu. What type? Presumably H1N1 as 99% of type A influenza being tested right now is H1N1, and she had repeated exposure to friends & classmates with confirmed type A. She became ill on Saturday, missed 3 days of school, and is now 7 days later she is feeling back to normal, although easily fatigued.
BOTTOM LINE: Recognize that a stuffy nose, low grade temperature (99*) and sore throat are uncomfortable but very unlikely to be the flu. High fever, chills, headache, cough, sore throat and body ache at this time is most likely influenza- see your doctor and try to limit your exposure to others to slow the spread of this year's flu!