Don't Let Your Mono Knowledge Fatigue!

Welcome back y'all. After a reprieve from Ebola and such, I recently saw in the 3/15/15 American Family Physician journal a superb summary with actionable points on one of our most common urgent care conditions- mononucleosis. If you are an AAFP member, you can get the article online, but for the ER people, mid-levels, and others, here are the salient points:

• The article cites a 2008 Clinical Journal of Sports Medicine EBM literature review stating that all athletic participation should be curtailed in mononucleosis for the FIRST 3 WEEKS OF ILLNESS. Yes, that is news to me also, but that is why you keep reading in life. Note that is the first 3 weeks of the actual illness, not when the patient presents to you on day 7. I know that this will make many ultra competitive high school athletes happy that the "old school" 4- 6 weeks regime of rest has been countered, in a rigorous, medico-legally safe sort of way.
• As I often harp about to other providers, the article cites that the rapid "monospot" heterophile antibody test has a 25% false negative rate in the first week of illness. This fact matches the physiology, since it takes several days to get the antibody counts cranked out from the immune system. As such, for the child presenting on day 3 with the parent insisting for a mono test, you may want to write in your discharge instructions to return in a few days if symptoms (usually fatigue) continue for a recheck. In this CSI world it breaks patients' hearts that the medical religion of lab testing has limits, but this is a case where some patient education is needed. 
• For that false negative monospot, early presenting case though, you may want to co-order a CBC, since you may luck up and get a lymphocyte count LESS than 4,000. The article states, a lymphocyte count of less than 4,000 has a negative predictive value of 99%. Not too shabby. 
• Steroids only help the sore throat within the first 12 hours of illness. Beyond that, there is absolutely no benefit to steroids or antivirals either. For the patient needing the "magic of a prescription", it may be the safer alternative to alleviate the sore throat with Magic Mouthwash, as opposed to steroids. 
• While splenic rupture only occurs in 0.1%-0.5% of mono patients, the most common cause of hospitalization for mono is actually airway obstruction, more commonly in children than teens. I am sure you all have seen in the clinic firsthand that usually the "nastiest mouths" are indeed exudates from mono.

Hope this helps, but certainly the points are pertinent to our real world practices.