w61 A recent study involved weekly ultrasound examinations until resolution of

W61 a recent study involved weekly ultrasound

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w61 A recent study involved weekly ultrasound examinations until resolution of splenomegaly (fig 1). A mean increase in splenic length of 33.6% was observed, with a peak in enlargement on aver- age 12.3 days from the onset of clinical symptoms. Most cases of splenomegaly had resolved by 4-6 weeks and there was a predictable rate of splenic regression of approximately 1% each day after reaching peak enlargement. 17 Similar results were reported in another paper, with spleens nor- malising at one month in 84% of participants. w62 One study recommended that athletes wanting to return to contact sport at 3-4 weeks should have an ultrasound examination to ensure that the spleen had returned to normal size. w62 A systematic review published in 2014 advocated individu- alised recommendations for athletes, 18 and future work in this area may concentrate on splenic volume to allow a more accurate assessment of splenomegaly and risk. Is multiple sclerosis caused by infectious mononucleosis? There is evidence that a history of infectious mononucleosis significantly increases the risk of multiple sclerosis 19 and that this association is far stronger than with other common childhood infections or afflictions. w63 A meta-analysis con- cluded that the risk of multiple sclerosis seems to be great- est in those who were infected with Epstein-Barr virus at a later age (incidence begins to increase in adolescence, peaks around age 25 to 30 years, and declines to nearly zero by age 60) , with moderate risk for those infected with Epstein-Barr virus in early childhood, and close to zero risk in those not infected (fig 2). 19 A more recent meta-analysis showed that Epstein-Barr virus is present in 100% of cases of multiple sclerosis and therefore it has been suggested that the virus is not only a risk factor but also a prerequisite of multiple sclerosis. w64 Whether the association between multiple scle- rosis and Epstein-Barr virus demonstrates a causal relation is, however, strongly debated. w64 Although controversial, if proponents of the infectious mononucleosis-multiple sclerosis theory are correct, a Age (years) Multiple sclerosis incidence rate zero.tf five.tf one.tfzero.tf one.tffive.tf two.tfzero.tf two.tffive.tf three.tfzero.tf three.tffive.tf four.tfzero.tf four.tffive.tf five.tfzero.tf five.tffive.tf six.tfzero.tf Late Epstein-Barr virus infection with infectious mononucleosis Early Epstein-Barr virus infection without infectious mononucleosis No Epstein-Barr virus infection Fig 2 | Incidence of multiple sclerosis by Epstein-Barr virus infection. Adapted from Thacker et al 2006 19 There is evidence that a history of infectious mononucleosis significantly increases the risk of multiple sclerosis
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  • Fall '18
  • infectious mononucleosis, Herpesviridae

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