Thursday 12 April 2007

Infectious Mononucleosis

Could you tell me more about Infectious Mononucleosis (“Mono”)? My 9 year-old daughter contracted Mono last year. She was sick and tired for a good 6 weeks and finally seemed to return to normal about 3 months after diagnosis. Since then she has been sick a lot! She is constantly getting viruses and then secondary infections from them. She also seems to gets rundown more easily than previously. Before the Mono she hardly ever got sick. She is generally a very healthy child with no other medical problems. Some doctors say that once the mono has gone, it is gone. But I have heard that once you have Mono, you always have Mono and relapses are likely, especially when someone does not get enough rest. Could you please tell me your opinion? I am curious if the Mono is playing the part in her getting more sick more often, and staying sick longer.

In the vast majority of cases once the virus that causes Mono has been eliminated, it does not come back. A period of fatigue after Mono is well known and usually is noticed more often in older patients – adolescent and adults. At age 9 some months of fatigue would be less common but not unknown.

It is well recognized that a small sub-group of children and adults have a very prolonged period of fatigue, fevers and predisposition to sore throats. This sounds a bit like your daughter. I don’t think that extra rest is necessary. If she feels fatigued let her rest, if she wants to exercise let her even if she feels very fatigued afterwards. The reason for some boys having this persistent problem is an impaired ability to fight infections but as your 9 year-old is s girl and previously well that is very unlikely. Medical science does not find a cause in most cases with the prolonged illness.

It would be worth having a blood test (Full Blood Examination) done to reassure everyone that the cells that fight infection are there in the right numbers and are healthy. Otherwise I would give her 12 months to recover. If she does not then more extensive evaluation by a paediatrician would be warranted.