Complications

These include:

• persistent fatigue – appears to be present in 9% to 22% of cases at six months after illness onset compared with 0% to 6% following an ordinary upper respiratory infection (1). One prospective study of patients with EBV-IM found that patients required nearly 2 months to achieve pre-illness functional status (2)
• hepatitis - probably occurs in all cases and abnormal liver function tests are usual (3)
• splenic rupture - in 0.1 to 0.5 % of cases with mortality rates up to 30%. The majority of patients are male with an average age of 22 years. The average time between onset of symptoms and rupture is 14 days (4)
• thrombocytopaenia
• haemolytic anaemia
• cardiac involvement - 10% of patients develop minor T-wave changes
• meningitis - benign
• encephalitis - 33% mortality of an 11 case series
• single nerve palsies
• Guillain-Barre syndrome
• depression and malaise
• airway blocked by pharyngeal oedema - rare
• nephritis - extremely rare and excellent prognosis
• pneumonitis
• acute interstitial nephritis (3)
• myocarditis and cardiac conduction abnormalities (3)
• neurologic abnormalities
• cranial nerve palsies(3)
• retrobulbar neuritis (3)

Infection may be fatal in males with the rare Duncan's syndrome.

Very rarely, patients develop chronic active disease, which carries a poor prognosis with high mortality. Diagnosis should be considered in patients with persistent symptoms of IM for >3 months (5). Death usually is a result of lymphoma, haemophagocytic syndrome, or fulminant hepatitis (6)

Reference:

1. Candy B et al. Recovery from infectious mononucleosis: a case for more than symptomatic therapy? A systematic review. Br J Gen Pract. 2002;52(483):844-51
2. Rea TD, Russo JE, Katon W, et al. Prospective study of the natural history of infectious mononucleosis caused by Epstein-Barr virus. J Am Board Fam Pract. 2001 Jul-Aug;14(4):234-42.
3. Mark H. Ebell. Epstein-Barr Virus Infectious Mononucleosis. Am Fam Physician 2004;70:1279-87,1289-90.
4. Bartlett A, Williams R, Hilton M. Splenic rupture in infectious mononucleosis: a systematic review of published case reports. Injury. 2016 Mar;47(3):531-8.
5. Fugl A, Andersen CL. Epstein-Barr virus and its association with disease - a review of relevance to general practice. BMC Fam Pract. 2019 May 14;20(1):62.
6. Kimura H, Hoshino Y, Kanegane H, et al. Clinical and virologic characteristics of chronic active Epstein-Barr virus infection. Blood. 2001 Jul 15;98(2):280-6.