Infectious
MononucleosisInfectious mononucleosis or "kissing disease",
how it has sometimes been called, is a form of severe tonsillitis, but also is
a protracted systemic viral illness and can have some hidden implications in the
development of nasopharyngeal cancer in the Chinese population who have a genetic
weakness for this type of rare cancer. Epstein-Barr virus (EBV),
the cause of infectious mononucleosis, is also a triggering agent for the 20 to
30 fold higher incidence of nasopharyngeal cancer in the Chinese when compared
to the low rates of North Americans and Europeans (Ref. 4, p. 1774).
Signs
and symptoms: The symptoms of EBV infection (= infectious mononucleosis)
are as varied as the age group that gets affected by it. The most severe infections
occur in the age group of 15 to 25. It was originally among a group of college
students that the disease was investigated in the U.S. and this was where the
terminology of "kissing disease" came from as this can be a source of
transmission, although most of the time simple droplet infection like in any other
respiratory infection is the common mode of transmission. In children the symptoms
can be very mild like a cold of 1 or 2 weeks. In young adults, however,
it can be a severe infection with a high fever, extremely
sore throat with lymph gland enlargement of the neck lymph glands
and a viral tonsillitis and pharyngitis. The infected person may also suffer from
a complete loss of appetite, nausea, abdominal pain, headaches, chills and muscle
pains. In 30 % of patients there is swelling around the eyes ("periorbital
edema"). When antibodies appear in the blood in the second week there
can be sometimes a skin rash that can look quite varied. Sometimes it looks like
the measles, particularly when the person was put on amoxicillin. At other times
it looks like a rash with a multitude of pin sized red spots (petechial rash).
The spleen is enlarged in 50% of cases, the liver only in 10% . At the end of
the first week or in the second week there is a risk that the enlarged spleen
could rupture with sudden jarring motions. This is why contact sports should be
avoided for at least 3 weeks. The player would not perform well anyways because
the EBV infection is taking a lot of energy away from the person. Viral shedding
from the pharynx goes on for up to 18 months following infection with EBV! This
is the case, even when the person feels recovered after 3 or 4 weeks. The reason
why EBV is so common, is the fact that there are many asymptomatic carriers in
the population all the time, who shed the virus by droplet tansmission. Diagnostic
tests: The diagnosis is made mainly on clinical grounds, by history
and examination. The blood tests confirm some typical changes such as a moderately
elevated white blood cell count with 50% lymphocytes and 10% or more "atypical
lymphocytes" (=the "mononucleosis cells"). By the end of the 3rd
week the monospot blood test is positive in about 90% of patients (Ref. 4, p.268).
This is not too specific as chickenpox, lymphomas and influenza can lead to a
falsely positive monospot test as well. In these cases a EBV antibody level can
be ordered, which is specific for EBV infection. After 3 months the monospot test
returns to normal whereas the EBV antibody test stays positive for the rest of
the life of the individual. Treatment: Most patients
recover spontaneously from EBV infection in a course of 3 to 4 weeks. There is
no vaccination for it. In 1% or less of cases there can be neurological complications
like seizures or aseptic meningitis.
Hemolytic anemia, kidney failure, myocarditis or splenic rupture in the 2nd or
3rd week of the disease are other rare complications. If the tonsils are so large
that there is a danger of airway obstruction and in cases where the blood is thinned
too much (low platelet count) a course of corticosteroids for 1 or 2 weeks is
usually given (Ref. 4, p. 268). It is wise to do a throat swab, if there is a
change in the clinical presentation (more of a sore throat, worsening of the condition)
to rule out a bacterial uperinfection with group A beta-hemolytic streptococcus,
which would need to be treated with antibiotics.
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