Kissing Disease is a disease spread through saliva by sharing a glass or utensils.
Infectious mononucleosis, commonly known as glandular fever, is a viral infection that causes fever, lymphadenopathy and fatigue. The highest incidence is seen in patients aged 15 to 24 and is caused by the Epstein-Barr virus (EBV), also known as human herpes virus 4.
Epidemiology
EBV is a type of herpes virus that is one of the most prevalent human viruses in the world and is estimated that more than 90% of the world’s population is seropositive. The age of infection is largely dependent on cultural and socioeconomic factors. Infection in early life usually results in milder symptoms. Childhood infection is generally asymptomatic but the presentation in adulthood results in infectious mononucleosis symptoms.
Mechanism of Disease
EBV infects antibody-producing B cells in the throat (oropharyngeal) area. These infected B cells disseminate throughout the lymphatic system and can last in the body for decades before being reactivated in later life.
Transmission
EBV can be transmitted via bodily secretions and primarily via infected saliva or oropharyngeal secretions. Infectious mononucleosis is also dubbed the ‘kissing disease and is prevalent among young adults. The virus can be shed in the saliva of patients with infectious mononucleosis for a general period of up to 32 weeks and can go on for even longer in some patients. It is rarely spread through sexual contact and less commonly by sharing utensils.
Signs and Symptoms
Children who are infected are usually asymptomatic, but adults are more likely to develop symptoms. The classic symptomatic triad includes fever, pharyngitis and lymphadenopathy.
Other symptoms can include:
- Sore throat (Pharyngitis)
- Headache
- Fever
- Lymph nodes that are abnormal in size (Lymphadenopathy)
- Fatigue – moderate to severe
- Early maculopapular rash
Patients with more serious forms of the disease may present with
- Enlarged liver (Hepatomegaly)
- Yellowing of the skin (Jaundice) develops in 10% of young adults and 30% of elderly
- Splenomegaly
- Swelling of glands (Adenopathy)
- Tonsillar enlargement
Splenomegaly is the enlargement of the spleen, usually found in the late stages of the disease. The spleen usually returns to its normal size 3 weeks after treatment.
In the elderly, infectious mononucleosis rarely develops symptoms and is usually diagnosed as an incidental finding during viral hepatitis testing.
Diagnosis of Infectious Mononucleosis
Fever and lymphadenopathy are usually enough to diagnose infectious mononucleosis clinically. In a laboratory setting, blood tests that indicate laboratory abnormalities include:
- Positive heterophile antibody test (Monospot Test)
- Presence of atypical lymphocytes (type of white blood cells) on blood smears
- Low white blood cell count (Leukopenia)
- Elevated IgM EBV capsid antigen
Imaging studies should also be conducted in cases of nervous system complications to rule out other causes.
Complications
Infectious mononucleosis usually clears well with recovery. However, complications can occur in patients who are immunocompromised and are especially problematic in those with haematological complications. Females are also more prone to developing chronic fatigue syndrome.
In rare cases, infectious mononucleosis can cause serious central nervous and neurologic disorders such as encephalitis, optic neuritis, transverse myelitis and cranial nerve disorders.
EBV-induced cancer
EBV is associated with multiple human cancers of lymphoid and epithelial cell origin such as Burkitt’s lymphoma, Hodgkin’s lymphoma, nasopharyngeal carcinoma, gastric carcinoma, post-transplant lymphoproliferative disease (PTLD) and T-cell lymphomas. Cancer can occur in patients with latent EBV infections when EBV triggers B lymphocytes to replicate uncontrollably.
Hodgkin Lymphoma
In Hodgkin lymphoma, EBV-infected tumour cells express genetically altered genes that express EBV genes that allow these cells to be undetected by the immune system and to also avoid natural cell death.
Nasopharyngeal Cancer
Nasopharyngeal cancer in Southern China is highly associated with EBV latency. Markers that are indicative of patients high at risk for EBV-nasopharyngeal cancer include IgA antibodies produced by the body against EBV antigens.
Diffuse large B-cell Carcinoma
EBV-positive diffuse large B-cell carcinoma accounts for up to 15% of diffuse large B-cell lymphomas in the Asian population. Patients with this type of cancer have a very poor prognosis and a survival rate of fewer than two years.
Post-transplant lymphoproliferative disorders (PTLD)
EBV-PTLD usually occurs between the first 6 months to a year after transplantation. EBV is the most common cause of PTLD where EBV-negative recipients develop a primary EBV infection from a graft of an infected donor.
Since EBV can establish lifelong infection in host B lymphocytes, the virus can be reactivated in immunocompromised hosts after transplant. This is especially apparent in patients who undergo haematopoietic stem cell transplantations, drastically decreasing their survival rates by hijacking their immune systems.
Treatment for Infectious Mononucleosis
Symptomatic ailments such as fever are usually treated with nonsteroidal anti-inflammatory drugs (NSAIDs). Lozenges that contain benzocaine, a local anaesthetic, and prescription lidocaine are commonly prescribed to soothe a sore throat.
Corticosteroids such as prednisone (also known as prednisolone) can help to decrease pharyngeal inflammation and help with airway constriction or obstruction in severe cases. Patients with extreme tonsillar enlargement will require extra care.
Surgery must also be done on patients that present with splenic rupture to ensure a good prognosis.
Patients are highly encouraged to stay hydrated to avoid complications involving the kidneys and are advised to take adequate rest and refrain from physical activity for at least 3 weeks.
Conclusion
Infectious mononucleosis is a self-limiting disease that can progress to severe complications in immunocompromised individuals. Patients should refrain from spreading bodily fluids to those around them as the virus remains viable in the body from initial infection for up to 32 weeks or more.
