By Ed Shaheen, MD.
A 16-year-old, healthy male presents with a several-day history of fever, sore throat, and malaise. He appears very tired and has a temperature of 102f. A physical examination is remarkable for diffuse pharyngeal erythema (very red throat) with moderately enlarged tonsils covered with exudate (pus) and the presence of several enlarged, tender anterior and posterior cervical lymph nodes. What do you think that this is?
Exudative tonsillitis can be a sign of many entities, both common and less common. The range would include bacterial and viral causes. On the bacterial side, there are strep infection (most common bacterial agent) and less commonly, diphtheria, gonococcal pharyngitis. As for viral causes, there are adenovirus and infectious mononucleosis, primarily.
In the case of “mono”, the above history is fairly typical. Mono is often called “the kissing disease” because it can be transmitted by enthusiastic exchanges of saliva in the heat of passion. However, I have seen many cases that do not have such a history (at least, not admittedly). Also mono may have what is called “kissing tonsils”, which refers to tonsils that are so swollen that they touch each other. Romantic? Not really. These tonsils are usually the ugliest tonsils that you will ever see.
There are several important features about mono that should be remembered. The cause is usually blamed on the EB virus (short for Epstein-Barr) even though CMV (the cytomegalic virus) can also cause a similar picture. Clinically the spleen can be enlarged and very fragile and susceptible to rupture (which can be fatal). This is why we advise that these patients avoid contact sports for at least one month. There is usually an associated period of fatigue that can last from weeks to months before subsiding. In the past, some have suggested that the EB virus is the cause of chronic fatigue syndrome. However, most authorities on the subject no longer believe this. By adulthood, 90% of individuals are positive for the EB virus and chronic EBV infections are rare.
Mono is not always a benign disease. Besides ruptured spleen, we also monitor for obstructive tonsillitis that can actually block the airway and require corticosteroids or possible intubation (placing a tube into the airway) to avoid suffocation. Patients are sometimes hospitalized for this reason and because of other less common side effects, such as hepatitis, myocarditis, kidney problems, rare neurological conditions and a few other unusual complications.
How did “mononucleosis” get its name?
An atypical lymphocyte is found on the peripheral smear of the blood of patients with infectious mononucleosis. The first discoverers of this disease thought that they were looking at monocytes instead of atypical lymphocytes. Thus the term "mononucleosis" was adopted, a case of mistaken identity.