What is mononucleosis?

Mononucleosis is also known as glandular fever or kissing disease.  It is an infection of the pharynx (located at the back of the throat) by the Epstein - Barr virus (EBV).  This virus is mainly spread via saliva which occurs from kissing, sharing food utensils or glass from someone who is infected by the virus.  Mononucleosis causes signs and symptoms such as fever, fatigue, sore throat and enlarged lymph nodes in the neck.

In the United States, mononucleosis is a common cause of viral pharyngitis (inflammation of the pharynx), especially affecting young adults.

What are the causes of mononucleosis?

Mononucleosis is caused by the virus EBV.  It is mainly spread through saliva by kissing sharing food, glass or food utensils.  This infection often resolves on its own, after which you develop antibodies against the virus, meaning that you will be immune and will not get the infection again.  On rare occasions, the virus may be spread via blood transfusion or by having direct oral contact with the female genitalia.  The infection spreads to the liver, spleen and lymph nodes.  In addition, the virus may remain in your saliva for months even after your signs and symptoms are gone.

What are the signs and symptoms of mononucleosis?

Most of the time, people having mononucleosis does not have any symptoms which may help in the spreading of the virus.  Around 90% of adults show evidence of previous EBV infection when antibodies against the virus is tested for.  In addition, the incubation period- the time taken for signs and symptoms of mononucleosis to appear- of EBV infection id 1-2 months.  The signs and symptoms of mononucleosis include:

• Fever
• Fatigue which may last for 1 month
• Malaise
• Nausea and vomiting
• Loss of appetite
• Enlarged lymph nodes of the neck
• Joint pain
• Muscle pain
• Sore throat
• Cough
• Eye pain
• Chest pain
• Light sensitivity
• Headache
• Skin rash
• Enlarged tonsils
• Jaundice- This is the yellowing of the white part of your eyes and skin.

In 50% of cases, an enlarged spleen may be detected.  The spleen is an organ located in the left upper abdomen, just below the diaphragm.  Your doctor will then advise you to avoid heavy lifting or contact sports for a few weeks.  This is because in rare cases, your spleen may rupture as a result of trauma to the abdomen or spontaneously.  The symptoms of splenic rupture include a sudden, sharp pain in the abdomen which may be life-threatening, requiring immediate medical care.

In very rare cases, mononucleosis may cause clinical manifestations such as:

• Encephalitis- Inflammation of the brain.
• Pancreatitis- Inflammation of the pancreas.
• Aseptic meningitis- This is the inflammation of the tissues surrounding your brain and spinal cord which may be caused by viruses, fungi or cancer amongst others.

• Myocarditis- This is inflammation of your heart muscles which may affect your heart rhythm and reduce your heart’s ability to pump blood effectively.
• Guillain-Barre syndrome- This is a rare syndrome which causes your immune system to attack your nerves resulting in weakness and tingling sensations in your extremities, leading ultimately to paralysis of your whole body.
• Optic neuritis: This condition occurs when inflammation damages your optic nerve- this is a bundle of nerve fibres which are responsible for the transmission of visual information from your eye to your brain.

Making a diagnosis

To make a diagnosis, your doctor will take a detailed history from you to know more about your symptoms and risk factors for acquiring the EBV virus.  After the history taking, your doctor will perform a thorough physical examination to look for signs of mononucleosis.

To confirm the diagnosis, your doctor will perform a test known as the heterophile antibody test (monospot test) which tests for the presence of EBV antibodies.  This type of antibodies levels peak 2-6 weeks after EBV infection and remains positive in low levels for up to a year.  This test may be negative during the early course of the infection.  If the initial test is negative, your doctor may order other test to rule out other infectious diseases.

A complete blood count may be done to determine whether your white blood cell count (lymphocytes) are elevated which will not confirm the diagnosis but suggests its possibility.

What are the treatments of mononucleosis?

The main goal of the treatment is to relieve your signs and symptoms while your immune system fights off the virus.  Unfortunately, there are no known antiviral medications which can be used to cure or treat mononucleosis effectively.

Fever, sore throat and muscle pain can be treated using acetaminophen or non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen.  Aspirin are contraindicated in children as when there is presence of a viral infection, using aspirin can lead to Reye’s syndrome.  This complication may cause the blood sugar level to drop while the acidity of his/her blood and the level of ammonia rise.  In addition, it may cause the liver and brain to swell leading to seizures and loss of consciousness.

As mononucleosis causes fatigue, it is important to get appropriate rest.  In addition, this condition may also cause loss of appetite which is why it is important to drink an adequate amount of fluids, even if you have no appetite.

Mononucleosis causes your spleen to enlarge which is why it is advised to avoid heavy lifting and contact sports.  This is to prevent splenic rupture which could be deadly.

What are the complications of mononucleosis?

Mononucleosis may cause the following complications:

• Enlargement of your spleen
• Splenic rupture
• Swollen tonsils
• Inflammation of your liver (hepatitis)
• Yellowing of the whites of your eyes and skin (jaundice)
• Anaemia
• Low platelet count (thrombocytopenia)
• Myocarditis
• Meningitis
• Encephalitis
• Guillain-Barre syndrome

Expectations (prognosis)

The prognosis of mononucleosis is good as most people recover completely and have no long-term problems.  However, the fatigue may persists for a few months even if other signs and symptoms are gone after 1-2 weeks.

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Cunha, B., 2018. Epstein-Barr Virus (EBV) Infectious Mononucleosis (Mono): Background, Pathophysiology, Epidemiology.

Auwaerter, P., 2021. Infectious Mononucleosis (Mono) In Adults And Adolescents