Hi Everyone,
I've had a bit of a hiatus from posts recently, in part waiting to change the feel of the website a bit but lagging behind on that.
However, unless you've been hibernating the past few weeks you know about the measles resurgence in the US, as well as the new measures being taken in New York City to get their outbreak under control. I've heard from many of you via phone and email, and I've suddenly become in demand by the news media, so I thought it might be helpful to share some measles information with you in a series of posts.
*Cases as of December 29, 2018. Case count is preliminary and subject to change.
**Cases as of April 4, 2019. Case count is preliminary and subject to change. Data are updated every Monday.
From https://www.cdc.gov/measles/cases-outbreaks.html
First I want to mention some basic clinical clues to help in diagnosing measles. I know that most practicing pediatricians in the US have never seen a case, and sometimes it takes an old-timer like me to help with some of the nuances. So, here goes.
At the onset, there is nothing very unique about a child with measles compared to any number of febrile children with upper respiratory infection. However, you should get in the habit now, if you aren't already, of verifying measles immunization history for every febrile patient you see, as well as asking about any known measles exposure. I've dusted off and updated my "Measles Clinical Pearls for Clinicians" to share with you:
1. Incubation Period: Onset of symptoms occurs about 10 days after exposure, but since measles patients are contagious up to 4 days prior to developing a rash, families may not report a measles exposure.
2. The Prodrome: This is the single most helpful finding in diagnosing measles, and it requires careful documentation of the history of present illness. Prodrome refers to the illness that occurs prior to development of the rash. The prodrome of measles consists of fever, malaise, cough, coryza (rhinorrhea), and conjunctivitis. None of these items distinguishes measles from several other viral illnesses, or from Kawasaki Disease. However, the duration of the prodrome can be very helpful. It would be most unusual for a child with measles to have a prodrome duration less than 2 days. So, if the history is that the child developed fever and rash on the same day, or the rash appeared the morning after fever onset the night before, you are unlikely to be dealing with measles.
3. Koplik Spots: These are likely pathognomonic of measles, but less helpful than the prodrome duration in practice because
a. They don’t appear in every measles patient
b. They often are gone by the time the rash appears, which is usually the time parents seek medical attention
c. They’re hard to see (and hard to photograph).
d. Ask for help from an experienced clinician (aka someone old enough to have seen a lot of this – once this person points out Koplik spots to you, you’ll never forget it!).
4. The Rash: Typically the rash progresses in a cephalocaudal and centrifugal fashion (top to bottom and centrally to peripherally). It’s not as helpful as you might think for diagnosis, possibly because parents might not notice this progression.
5. Diagnosis: We generally use measles IgM antibody for diagnosis. In the current outbreak, health authorities also are asking for collection of throat or NP specimens for measles PCR. You should contact your local health department for questions on collecting specimens. Of course, the ID service at Children's National is always available for help, 202-476-5051 or 202-476-4880 for page operator.
6. Treatment: Note that oral vitamin A treatment is recommended for children with severe (e.g. requiring hospitalization) measles in the US; dosage is based on age and available in the Red Book.
Measles is about the most contagious illness you’ll ever see; about 90% of non‐immune contacts will become ill. Your quick action can limit secondary cases.
Next Up: Measles vaccine: safety, efficacy, indications, and duration of immunity.
Stay tuned, and in the meantime please check out these helpful resources:
CDC Measles Page
CHOP Vaccine Education Center