OBJECTIVE: The goal was to characterize prospectively the course and outcome of chronic fatigue syndrome in adolescents during a 2-year period after infectious mononucleosis.
METHODS: A total of 301 adolescents (12–18 years of age) with infectious mononucleosis were identified and screened for nonrecovery 6 months after infectious mononucleosis by using a telephone screening interview. Nonrecovered adolescents underwent a medical evaluation, with follow-up screening 12 and 24 months after infectious mononucleosis. After blind review, final diagnoses of chronic fatigue syndrome at 6, 12, and 24 months were made by using established pediatric criteria.
RESULTS: Six, 12, and 24 months after infectious mononucleosis, 13%, 7%, and 4% of adolescents, respectively, met the criteria for chronic fatigue syndrome. Most individuals recovered with time; only 2 adolescents with chronic fatigue syndrome at 24 months seemed to have recovered or had an explanation for chronic fatigue at 12 months but then were reclassified as having chronic fatigue syndrome at 24 months. All 13 adolescents with chronic fatigue syndrome 24 months after infectious mononucleosis were female and, on average, they reported greater fatigue severity at 12 months. Reported use of steroid therapy during the acute phase of infectious mononucleosis did not increase the risk of developing chronic fatigue syndrome.
CONCLUSIONS: Infectious mononucleosis may be a risk factor for chronic fatigue syndrome in adolescents. Female gender and greater fatigue severity, but not reported steroid use during the acute illness, were associated with the development of chronic fatigue syndrome in adolescents. Additional research is needed to determine other predictors of persistent fatigue after infectious mononucleosis.
Comments
Figures quoted should be considered lower bounds given they have not been adjusted for refusals, etc
This is a useful contribution to the field and again shows that viruses (in this case EBV) can trigger Chronic Fatigue Syndrome (CFS).
One point which I don't think is sufficiently clear to anyone who just reads the abstract is that these figures have not been adjusted for refusals, etc. In epidemiology in particular, numbers matter. All the percentages were calculated on the basis of the initial 301 patients but we do not have information on a percentage of these. For example:
- "Six months after their IM diagnosis, 286 (95%) completed a telephone screening interview." (i.e. 5% did not)
- "On the basis of the screening interview, 70 of these adolescents (24%) were considered not fully recovered. A clinical evaluation was completed for 53 (76%) of these 70 not fully recovered adolescents; 12 refused, 3 had exclusionary diagnoses (primary depression, transverse myelitis, or anorexia), and 2 did not meet the study criteria (the fatigue predated the IM or the subject was not able to complete the 6-month evaluation in a timely manner)"
- I am not going to break down the list of others lost to follow-up as Figure 1 does it quite clearly: in total, of the 53 (of 70 who were considered not fully recovered), there was a cumulative loss of 10 at 24 months.
Figure 1 has the caption, "Follow-up summary for screened nonrecovered participants (n=70). Three-digit numbers represent unique patient identifiers that were used throughout the study.". However in fact, it only includes information on 53.
Note, this is not a criticism of patients being lost to follow-up, just demonstrating that the figures could be adjusted.
For example, if we look at the 12 who refused clinical examination at six months and also include the patient who was not able to complete the 6 -month evaluation in a timely manner, we have a total of 13 patients. If the same proportion of them had CFS (i.e. 39/53) as the group that was evaluated, then a further 9.57 on average would have CFS on average. (Of course, one can't have half a person but given we do not know the exact figure, I will use the unrounded figure). This would give a figure of (39+9.57)/301 or 16.13% at 6 months rather than the 13% quoted. Other figures would also proportionally increase on average. If one used the percentage who completed the initial telephone screening instrument, the percentage would actually be (39+9.57)/286 or 16.98% (i.e. 17%) at 6 months.
Conflict of Interest:
None declared