Mono is more than fatigue

Mono. We’ve all heard of it and almost everyone knows that the illness is associated with tremendous fatigue. What many don’t understand is that the fatigue is virtually never the only symptom. Sometimes parents of groggy teenagers who lack the energy to do their school work or chores and who sleep until noon on the weekends worry that their seemingly exhausted teenager has mono. Most of the time these teenagers are merely sleep-deprived, since most teens need a minimum of eight hours of sleep each night but seem to only get six. Also,  some are fatigued because of depression while others are exhausted when it comes time to do things they don’t enjoy, but still have the energy to be on Facebook or stay out late with friends.

Mono is different. Mono is a viral illness caused by the Ebstein Barr Virus (EBV). Infection with this virus typically causes severe sore throat with huge tonsils, swollen lymph nodes in the neck, a classic sound to the voice like you’ve got marbles in your throat, prolonged fever and significant loss of appetite. Many kids will also have an enlarged spleen that the doctor can feel on exam and a few will even be jaundiced. The virus is usually transmitted through exposure to saliva (hence the name “kissing disease”) but not everyone exposed will get symptoms.

Mono has a long incubation period of 4-6 weeks, so if your teenager’s significant other is diagnosed with mono, you may not see symptoms of infection for a long time. One of the tricky things about mono is that it is most contagious before you exhibit symptoms and as such it is easily spread. The contagious period begins during the incubation time and for most people ends once the fever has resolved. A few will continue to shed the virus in their saliva for a while after that, but are much less contagious by that point.

The good news is that many teenagers have already developed immunity to the virus so exposure doesn’t mean that they are going to get sick. Most adults and even most teens have already been exposed to mono when younger and are immune. Since the younger you are, the milder the illness — and because so many people get exposed and develop immunity without ever having visible signs of illness — you can’t assume that just because you’ve never been told you have mono that you are susceptible if exposed. Indeed, over 90 percent of all adults have antibodies to the virus even though many will not remember being sick.

Young children who have mono may not look any sicker than they would with any other fever-causing virus and since younger kids seem to have less severe illness, they recover quickly and testing for mono isn’t ever done. Older children and teenagers who get sick will often have significant fever, which can last up to 10 days, and will also usually have a very sore throat, enlarged lymph nodes and will be disinterested in eating. It is often the prolonged fever (beyond five days) or extremely swollen tonsils that are getting worse and not caused by strep that leads us to test for mono. Testing for mono is done with a blood test. A rapid test called a monospot may be done in a physician’s office and if positive, gives a definitive answer. If it is negative, though, a second blood test sent to the lab can more definitively answer the question as to whether or not this is mono. Often too white blood cell counts are very high and large numbers of monocytes or atypical lymphocytes are seen.

Testing for mono is only necessary when symptoms have extended beyond the typical time frame of a viral illness. Since there is no treatment for mono, knowing that is the cause of fever is only needed when you worry that other things like cancer or occult (hidden) bacterial infections may be the cause. By testing for mono and getting a positive result, you can stop looking for other causes of fever.

Once the fever phase of the illness is over, the recovery can take as little as a week or two or as long as a couple of months. Usually teenagers are quite fatigued during this time and slowly improve over time. The spleen enlargement and other lymph node enlargement may be a sign of severity of illness and predict duration of fatigue. In other words, the longer the duration of fever and the more swollen your spleen and lymph nodes are, the longer your recovery will take. Often kids with mono are restricted from sports, phys ed and other physical activity during the recovery phase to protect the swollen spleen from blunt abdominal trauma and to allow the body to recover without getting increasingly worn out by significant exertion.

Occasionally mono will present more mildly without as much fever, sore throat, and swollen glands but then the fatigue during recovery is much less too. During the months following mono infection when other illnesses occur the fatigue and severity of those new symptoms may be greater than expected because the body is still recovering. Some call these episodes mono relapses but really they are more likely a new illness on top of an already stressed body and as such the symptoms are more pronounced.

Mono can indeed cause fatigue but if your teenager didn’t have a real illness prior to the onset of the fatigue, chances are mono isn’t the cause.