Infectious nucleosis/Glandular fever

Today I was involved in a case on infectious mononucleosis, also known as the Kissing Disease. I found this case very interesting so am going to write about it here. Sources used for this post include direct experience and eMedicine.

Infectious mononucleosis is a syndrome comprising fever, pharyngitis and lymphadenopathy. It is caused by infection by Epstein-Barr Virus (EBV). It is transmitted via intimate contact with body secretions, primarily oropharyngeal secretion (ie. kissing). In a host, EBV will affect the reticular endothelial system (liver, spleen, peripheral lymph nodes). Pharyngitis is due to proliferation of EBV-infected B lymphocytes in the lymphatic tissue of the orophrynx.



Other symptoms include fatigue (resolving gradually but sometimes lasting up to 3 months), spontaneous splenic rupture (so avoid contact sports while ill), hepatic necrosis, fever, chills, arthralgias, myalgias, nausea, vomitting, anorexia, cough, photophobia, chest pain, jaundice.

EBV infection also increases the risk of developing both Hodgkin and non-Hodgkin lymphoma, oral hairy leukoplakia (in those with HIV coinfection), Burkitt lymphoma and nasopharyngeal carcinoma.

Pressure Points (ie. where you could go wrong)

• Exudative pharyngitis is commonly confused with group A streptococcal pharyngitis, and this is further complicated by the fact that approximately 30% of patients with EBV infectious mononucleosis have group A strep carriage of the oropharynx.

Rashes

• Earlier in the course patients may present with a maculopapular rash (faint, evanescent, rapidly disappears, non-pruritic).
• If patients are administered ampicillin or amoxicillin (if their doctor mistakes the pharyngitis for strep throat) then the patient could develop a maculopapular rasj as a drug reaction. This rash is pruritic and prolonged. These patients are not allergic to these medications. Administration of beta-lactams after resolution of the infection will not result in drug fevers or rashes.

Investigations include heterophile antibody tests:

• Paul-Bunnell test: Sheep blood agglutinates in the presence of heterophile antibodies.
• Monospot test (less sensitive): Horse blood agglutinates in presence of heterophile antibodies.

Can also look for anti-EBV antibodies. IgM (acute), IgG (chronic). FBC will show increased lymphocytes. ESR will help differentiate between strep throat and EBV (ESR raised in EBV but not in strep throat).

Patients suspected to have infectious mono dont need to have throat swabs because 30% will be colonised by Strep anyway and the result of this test will not change management.

Management is symptomatic and includes monitoring for tonsillar enlargement (could cause airway obstruction). Impending or established airway obstruction can be treated with steroids. Advise to rest and refrain from active physical activity for 3 weeks. Dont need to treat the throat even with positive throat cultures because that represents colonisation rather than infection. Patients should avoid exposing other people to their bodily fluids as EBV remains viable in patients for months after initial infection.

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