Complications of glandular fever 

Most people with glandular fever will recover in two or three weeks and won't experience any further problems.

However, complications can develop in a few cases. Some of the main complications associated with the condition are described below.

Prolonged fatigue

More than 1 in every 10 people with glandular fever will experience prolonged fatigue, which lasts for six months or more after the initial infection. It is not known why fatigue lasts longer in some people.

Some experts think it may be a form of chronic fatigue syndrome (CFS). This is a poorly understood condition that causes persistent fatigue and a range of other symptoms, such as headaches and joint pain.

Adopting a gradual exercise plan to rebuild your strength and energy levels may help prevent and reduce prolonged fatigue.

Reduction in blood cells

In a few cases, glandular fever can lead to a reduction in some blood cells. It can reduce levels of:

  • red blood cells (anaemia) – this can make you feel tired and out of breath
  • white blood cells (neutropenia) – this can make you more prone to developing a secondary infection
  • platelets – this can make you bruise and bleed more easily

In most cases, the reduction in the number of blood cells is small and only causes mild symptoms. These problems should get better by themselves within a few weeks or months.

Ruptured spleen

Around half of people who develop glandular fever will have a swollen spleen. This does not present any immediate health problems, but there is a small risk of it rupturing (bursting).

The main sign of a ruptured spleen is sharp pain in the left of the tummy (abdomen).

Go to your local accident and emergency (A&E) department or dial 999 for an ambulance if you have glandular fever and you develop intense abdominal pain.

The risk of the spleen rupturing is small, occurring in just 1 in every 500 to 1,000 cases of glandular fever, but it can be life threatening because it may cause severe internal bleeding.

In some cases, emergency surgery may be required to remove an enlarged or ruptured spleen (splenectomy).

A ruptured spleen usually occurs as a result of damage caused by vigorous physical activities, such as contact sports.

It is therefore very important to avoid these activities for at least a month after the symptoms of glandular fever begin.

Be particularly careful during the second and third week of your illness, as this is when the spleen is most vulnerable.

Neurological complications

In less than 1 in every 100 cases, the Epstein-Barr virus (EBV) can affect the nervous system and trigger a range of neurological complications, including:

  • Guillain-Barré syndrome – where the nerves become inflamed, causing symptoms such as numbness, weakness and temporary paralysis
  • Bell's palsy – where the muscles on one side of the face become temporarily weak or paralysed
  • viral meningitis – an infection of the protective membranes that surround the brain and spinal cord; although unpleasant, viral meningitis is much less serious than bacterial meningitis, which is life threatening
  • encephalitis – an infection of the brain

These complications will often need specific treatment, but more than four out of every five people with them will make a full recovery.

Secondary infection

In a small number of cases, the initial infection weakens your immune system and allows bacteria to infect parts of the body. This is called a secondary bacterial infection.

Possible secondary infections that can develop during glandular fever include serious conditions such as pneumonia (infection of the lung) and pericarditis (infection of the sac that surrounds the heart).

Secondary infections usually occur in people who have a very weak immune system, such as people with HIV or AIDS, or those having chemotherapy.

If you have a weakened immune system and you develop glandular fever, as a precaution you may be referred to hospital for specialist treatment. This will allow for your health to be carefully monitored and any secondary infections to be treated.

Page last reviewed: 29/10/2014

Next review due: 29/10/2016