In at least half of mono cases, a person is found to have an enlarged spleen. While an enlarged spleen itself isn’t a problem, the potential for the spleen to rupture is cause for concern as a ruptured spleen is a life-threatening situation.

Anatomy of the Spleen

Your spleen is located under your ribcage, on the upper left side of your abdomen. It is filled with blood and works to filter out old, damaged red blood cells as well as produce lymphocytes, white blood cells that make antibodies.

Because this sensitive organ is normally tucked away underneath the ribcage, it is protected from potential dangers that could cause it to tear, which would lead to serious internal hemorrhaging (bleeding).

Getting Bigger

At least half of people infected with mono develop an enlarged spleen. When a spleen becomes enlarged, it tends to hang down further in your body, below the ribcage and into the abdomen.

As a result, your spleen is at risk of rupturing if trauma occurs to your abdomen. This is why it is important to have a thorough examination when you start developing mono symptoms.

Symptoms of an Enlarged Spleen

Most of the time, knowing that your spleen has enlarged is not obvious. While there are symptoms, they are not always obvious or may be attributed to some other cause.

Possible signs of having an enlarged spleen include:

• Feeling full despite eating very little or nothing
• Abdominal or back pain around the spleen
• Radiating pain from abdomen to left shoulder

Even if you don’t notice these signs, your doctor will likely check your spleen when you are diagnosed with mononucleosis. An enlarged spleen can be diagnosed by palpating the area.

However, your doctor may choose to x-ray the area to confirm that your spleen has enlarged. She may also choose to perform an ultrasound or a CT scan in order to determine the size of your spleen and see just how far into your abdomen your spleen has extended.

Protecting Against Rupture

Although only 0.1% to 0.2% of mono patients experience a ruptured spleen, it is necessary to take precautions. Because the spleen is filled with blood, if it is torn, blood will begin spilling into the abdominal cavity.

Only with medical intervention can this bleeding be stopped. While it is possible for a spleen to rupture spontaneously, the majority of the time it occurs as a result of trauma to the stomach, such as a punch to the abdomen.

To reduce your risk of a ruptured spleen, your doctor may advise you to avoid the following activities:

• Contact sports
• Heavy lifting
• Roughhousing
• Vigorous exercise
• Any other activity that could potentially cause a direct blow to the stomach

These activities should be avoided until your spleen returns to its normal size, about four weeks after infection. Your doctor will advise you as to when it is safe to resume these activities.

Symptoms of Ruptured Spleen

If the unthinkable happens and your spleen does rupture, here are the signs to watch out for:

• Pain on left side of upper abdomen
• Pain radiating to left shoulder
• Pain worsens when you breath
• Troubles breathing

In some cases, a spleen may have a small tear resulting in a much slower loss of blood. However, this can lead to low blood pressure and an insufficient supply of oxygen to the brain and heart, which may become apparent through these symptoms:

• Lightheadedness
• Confusion
• Blurred vision
• Fainting

If you have been told you have an enlarged spleen and notice any of these symptoms, seek medical attention right away.

Treating a Ruptured Spleen

Because you begin to hemorrhage heavily when your spleen ruptures, it is necessary to have emergency surgery in order to prevent the life-threatening blood loss associated with a ruptured spleen. This surgery is known as a splenectomy and results in the complete removal of your spleen.

In some instances, it may be possible to leave your spleen intact and just repair the tear. However, this can only be done if the tear is a small one.