Sleeping in until noon on a lazy Saturday is the trend for many adolescents, but if a hyperactive kid is suddenly falling asleep in a pool of drool at the dinner table, it may be a sign that more is going on. Fatigue is the most common manifestation of mononucleosis facetiously termed the “kissing disease” because it can be spread through saliva. Although it is known for invading the teenage population, it is also common in toddlers, who get a kick out of licking windows and biting down on toys.
Mono is caused by EBV (the Epstein Barr virus) and is infamous for causing excessive sleepiness, an enlargement of lymph nodes, headaches, fever, and muscle soreness. The virus enters the body through epithelial cells found in the mouth. It then infects the cells of the immune system responsible for antibody production, the B-cells, causing an enormous growth in the number of these white blood cells. Hence the golf-ball sized lymph nodes.
The immune system recruits other members of the immune cell family, largely the natural killer cells and cytotoxic T-cells to fight the viral proteins. Kids can carry the virus in their body for 1-2 weeks before exhibiting symptoms, and once hit it may take up to six weeks to clear the infection. Toddlers tolerate the infection somewhat better than older kids and may appear to have cold-like symptoms that last for weeks.
Although it is easy to diagnose mono with a simple blood test, there is no pharmacologic treatment. A comforter, hydration, and some couch potato entertainment is the standard of care. One consequence of mono is an enlarged spleen (which is the largest collection of lymphoid tissue in the body that filters blood). Adolescents who normally participate in contact sports should refrain from activities like football practice or wrestling for at least 6 weeks after the infection resolves to avoid splenic rupture.