What is mononucleosis?

Infectious mononucleosis, or glandular fever, is a common viral infection affecting primarily adolescents and young adults. It is mainly caused by the Epstein-Barr virus and is spread by saliva, which is why mononucleosis fever is also commonly known as 'the kissing disease'.

Epstein-Barr virus

A virus of the herpes family that causes mononucleosis, also known as mono or glandular fever. It is also implicated in some other medical conditions.

Fever

An increase in body temperature above the normal temperature range. Fever is often caused by the body's immune reaction to infection.

Saliva

The clear watery fluid secreted into the mouth by salivary glands, which aids chewing, swallowing and digestion.

Causes and risk factors

Infectious mononucleosis is caused by the Epstein-Barr virus. Most people will be exposed to Epstein-Barr virus at some point in their lives, many during childhood and adolescence.

Epstein-Barr virus

A virus of the herpes family that causes mononucleosis, also known as mono or glandular fever. It is also implicated in some other medical conditions.

Signs and symptoms

The signs and symptoms develop around 4-6 weeks after infection and can include:

  • Fever;
  • Malaise - a feeling of being generally unwell;
  • Body aches;
  • Lymphadenopathy - enlarged lymph nodes in the neck, armpits and groin;
  • Pharyngitis - inflammation of the back of the throat (pharynx);
  • Splenomegaly - enlargement of the spleen;
  • Hepatomegaly - enlargement of the liver;
  • Palatal petechiae - small red or purple spots on the roof of the mouth, and;
  • Jaundice - yellow discolouration of the eyes and skin (this only affects a small number of people with the disease). 

It is generally more symptomatic in adolescents and adults. Younger children can pass on the virus without experiencing any symptoms.

Fever

An increase in body temperature above the normal temperature range. Fever is often caused by the body's immune reaction to infection.

Liver

A large, internal organ of the body, located on the upper right-hand side of the abdomen. The liver has hundreds of distinct functions, including producing bile, regulating the body's metabolism and detoxifying the blood.

Lymph nodes

A small organ of the lymphatic system containing many immune cells. Lymph nodes, also known as lymph glands, are the sites where many interactions between immune cells and foreign materials occur.

Pharyngitis

Inflammation of the pharynx, or 'a sore throat'.

Spleen

An organ in the abdominal cavity that is involved in filtering out old blood cells and fighting infection.

Groin

The area where the abdomen joins the thighs.

Methods for diagnosis

Laboratory tests are not always necessary when clinical features are enough to support a diagnosis, but are sometimes done on pregnant women and people with weakened immune systems. Depending on your circumstances, your doctor may order the following tests to confirm a diagnosis:

Blood tests

Full / complete blood count

If the results of a full blood count include an elevated white blood cell count, with more than half being a type of white blood cell called a mononuclear lymphocyte (or T-cell lymphocyte), this can indicate mononucleosis.

Heterophile antibody test

Heterophile antibodies are produced in response to Epstein-Barr virus infection. However, the results can incorrectly be negative when tested early in the course of the disease. These results can also demonstrate an incorrectly positive result due to presence of other conditions such as HIV, leukaemia, rubella or lupus. The infectious mononucleosis monospot test is a heterophile antibody test that is commonly performed in Australia if mononucleosis is suspected.

Specific antibody tests

A blood sample can also be used to test for specific antibodies against the Epstein-Barr virus. These antibodies comprise: immunoglobulin M (IgM), immunoglobulin G (IgG) and antibody to the Epstein-Barr nuclear antigen (anti-EBNA). The varying levels of these antibodies can be used to assess if a person has a current or prior infection. 

Blood taken for a blood test.Blood and serum tests can be performed to confirm the presence of mononucleosis. 

Liver function tests

Liver function tests may be performed if there is concern about liver involvement. Up to 80% of people with mononucleosis will have abnormal liver function tests that will, in most cases, return to normal after the illness resolves and cause no long-term harm. [1]

Throat swab

A throat swab may be taken to rule out infection with streptococcal infection ('strep throat').

Epstein-Barr virus

A virus of the herpes family that causes mononucleosis, also known as mono or glandular fever. It is also implicated in some other medical conditions.

Full blood count

A blood test that examines the blood, either by using a microscope or an automated machine, to determine the number of red blood cells, white blood cells and platelets.

Immune systems

The organs and cells involved in protecting the body against infection.

Liver

A large, internal organ of the body, located on the upper right-hand side of the abdomen. The liver has hundreds of distinct functions, including producing bile, regulating the body's metabolism and detoxifying the blood.

White blood cell

Cells of the immune system that participate in immune and inflammatory reactions.

Immunoglobulin G

A type of antibody produced by the body in response to an infection by bacteria, viruses or fungi, to protect the body in the future from the same infection.

Heterophile antibodies

Antibodies that can recognise and bind more than one foreign substance in the body.

Infectious mononucleosis monospot test

A rapid blood test used to diagnose glandular fever, also known as infectious mononucleosis, based on detection of two specific antibodies.

Immunoglobulin M

The largest type of antibody that is produced by white blood cells, and also the first antibody that is made in response to an infection.

Epstein-Barr nuclear antigen

A protein specific to the Epstein-Barr virus (EBV). Antibodies to this protein are measured to identify a previous mononucleosis infection as they slowly appear 2-4 months after onset of symptoms and persist for the rest of a person's life. Also, the protein is present in all cancers caused by the EBV.

1. Sick and tired of being sick and tired: laboratory investigation of glandular fever. BPAC better medicine. Accessed 22 September 2014 from

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Types of treatment

There is no curative treatment for mononucleosis other than rest and maintaining proper hygiene. Unless you are have a weakened immune system, your body will clear the infection on its own and provide you with immunity that will help you to resist future infections.

Hygiene

The practice of health maintenance and the prevention of infection, disease and the spread of disease.

Immune system

The organs and cells involved in protecting the body against infection.

Immunity

The body's ability to protect against an infection or toxin, generated by immunisations or exposure to previous infection.

1. Sick and tired of being sick and tired: laboratory investigation of glandular fever. BPAC better medicine. Accessed 22 September 2014 from

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Potential complications

Treatment side effects

Amoxicillin / ampicillin

Amoxicillin and ampicillin are antibiotics that are not used to treat infectious mononucleosis. If, however, you are prescribed these during mononucleosis, you will develop a rash similar to the one that presents in cases of measles

Mononucleosis

Fatigue

Fatigue is the most common complication of mononucleosis and can persist in some cases for months after the initial symptoms resolve.

Fatigue.Fatigue is the most common complication of mononucleosis. 

Blood complications

Blood complications of mononucleosis are quite common, but are usually mild. They include elevated white cell count, low platelet count (thrombocytopenia) and anaemia (low red cell count). Potentially serious (but unusual) complications of mononucleosis include haemolytic anaemia, aplastic anaemia and a haemolytic-uraemic disorder. Red or purple spots on the skin (purpura) that do not lose their colour when pressure is applied can occur due to changes in the blood.

Brain complications

Brain complications are rare, but are serious and include facial paralysis (facial nerve palsy), meningitis and inflammation of the spinal cord (transverse myelitis) or optic nerve (optic neuritis).

Splenic rupture

Although extremely rare, rupture of the spleen is life-threatening. The risk of splenic rupture is highest a few weeks into infection and this heightened risk can last for months.

Hepatitis

Most people with mononucleosis will have mildly abnormal function of their liver, however, some may experience a more severe liver inflammation (hepatitis).  Alcohol can worsen inflammation of the liver, so should be avoided.

Dehydration

If pharyngitis is severe, making the swallowing of fluids difficult, dehydration can result. This is usually worse during the presence of a fever. People with mononucleosis sometimes need admission to hospital for rehydration. 

Anaemia

A deficiency in red blood cells or haemoglobin in the body.

Antibiotics

Chemical substances that kill or suppress the growth of bacteria.

Dehydration

The state of insufficient hydration; excessive loss of water; requiring more water in order to function normally.

Fatigue

A state of exhaustion and weakness.

Fever

An increase in body temperature above the normal temperature range. Fever is often caused by the body's immune reaction to infection.

Liver

A large, internal organ of the body, located on the upper right-hand side of the abdomen. The liver has hundreds of distinct functions, including producing bile, regulating the body's metabolism and detoxifying the blood.

Pharyngitis

Inflammation of the pharynx, or 'a sore throat'.

Platelet

Small blood cells found in the blood that are essential for clotting to occur.

Spinal cord

A bundle of nerve tissue that runs from the brain through the spinal column and connects the brain to the body, transmitting sensory and motor signals.

Spleen

An organ in the abdominal cavity that is involved in filtering out old blood cells and fighting infection.

Haemolytic anaemia

A condition marked by insufficient red blood cells due to increased destruction of the red blood cells.

Aplastic anaemia

A deficiency of all blood cell types caused by the failure of bone marrow to produce new blood cells.

Haemolytic-uraemic disorder

A rare condition triggered by certain infections, medications or unknown factors, which causes the rapid destruction of red blood cells and subsequently life-threatening kidney failure.

1. Sick and tired of being sick and tired: laboratory investigation of glandular fever. BPAC better medicine. Accessed 22 September 2014 from

External link

Prognosis

The majority of people with mononucleosis recover within a couple of weeks. However, severe fatiguethat can restrict your normal functioning can persist for up to six months. If you feel that your fatigue is debilitating, or extending beyond this time, you should speak to your doctor to rule out presence of other conditions.

Fatigue

A state of exhaustion and weakness.

1. Sick and tired of being sick and tired: laboratory investigation of glandular fever. BPAC better medicine. Accessed 22 September 2014 from

External link