CONSIDERATIONS IN SPECIFIC PATIENT POPULATIONS
Adolescents and young adults. When caring for adolescents and young adults, clinicians are advised to obtain an in-depth sexual history. In patients who are considered at high risk for sexually transmitted diseases (STDs), testing for HIV and other STDs is also recommended.26
Adults and elderly adults. Epidemiology does not support the likelihood of IM in these age-groups; this can lead to a missed diagnosis or a misdiagnosis with one of the more common adult infectious diseases, including those of a hepatic or hematologic nature.27 Adults older than 40 account for 7.5% of cases of IM.28
In these patients, manifestation of the clinical signs of IM may be altered. Rather than displaying the classic triad of symptoms, older patients may present with nonspecific complaints of fever, myalgias, malaise, and fatigue.16,28 Serologic testing should be considered to avoid misdiagnosis in this age-group.
COMPLICATIONS
Most patients with IM recover and are able to return to normal activity within two to three months.5 Several complications can develop, however (see Table 33,5,10,12,14,29,30).
Chronic fatigue is the most commonly reported sequela of IM. In one study of 12- to 18-year-olds who had had IM, chronic fatigue was reported in 13%, 7%, and 4% of patients at six, 12, and 24 months, respectively.29 The study authors concluded that IM during adolescence may be a risk factor for chronic fatigue syndrome.
A more serious but less common complication of IM is upper airway obstruction, occurring in perhaps 1% to 5% of patients.5,10 The result of IM-associated tonsillar enlargement and edema in the pharyngeal tissue, upper airway obstruction can require hospitalization. Appropriate interventions include IV corticosteroids, tonsilloadenoidectomy, and endotracheal intubation.10,14
Also less common but extremely serious is splenic rupture, which develops in 0.5% to 1% of patients with IM.5 Affected patients usually require emergency surgery.8,12
Unusual complications include central nervous system effects, such as meningitis, Guillain-Barré syndrome, encephalitis, Bell’s palsy, optic neuritis, perceptual distortions, and mental status changes. Other neurologic abnormalities, such as cerebellar ataxia and demyelinating diseases, have been reported.10,14 Ocular manifestations sometimes associated with IM are periorbital edema, dry eyes, keratitis, uveitis, and conjunctivitis.5,16
On occasion, clinicians may see patients with IM complicated by respiratory involvement, such as mediastinal lymphadenopathy, interstitial pneumonitis, myocarditis, and plural effusion. Incidences of respiratory failure and pneumonia have been documented, primarily in immunocompromised patients.3,10
Potential hematologic complications of IM include hemolytic anemia, thrombocytopenia, and mild neutropenia.10,11 Although these conditions have been reported in 25% to 50% of patients with IM, they typically present in a mild form and resolve within a few weeks.5,10
Another serious complication of IM, though rare, is chronic active EBV infection, a persistent syndrome with manifestations that may include fever, significant lymphadenopathy, persistent hepatitis, and a high viral load in the peripheral blood.3,30
If symptoms of IM persist for longer than 6 months, further evaluation should take place, including investigation for other chronic disease states, such as HIV, lupus erythematosus, or chronic fatigue syndrome.
The most common complication of IM misdiagnosed as GABHS is a rash resulting from treatment with penicillin (which is an appropriate treatment for GABHS but not IM).15 Although penicillin use is the most common cause of drug-induced rash in patients with IM, extremely rare cases have been reported in which a rash developed after treatment with a macrolide, specifically azithromycin.31
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