What Are the Causes of an Enlarged Spleen, and What Happens Next?

The main causes of an enlarged spleen are infections, liver disease, blood conditions and some cancers. The spleen itself is rarely the starting problem; it usually enlarges because of something else happening in the body. Treatment generally focuses on that underlying cause.

This guide is for adults who have been told their spleen is enlarged, often after a physical examination or a scan done for another reason. It explains common causes and what to ask. It cannot tell you which cause applies to you.

A damaged or ruptured spleen is a medical emergency. The NHS lists pain behind the left ribs with tenderness, dizziness and a racing heart as warning signs. If you think your spleen may be damaged, go to an emergency department or call local emergency services. Do not drive yourself.

MedlinePlus advises seeking help right away if belly pain is severe or gets worse when you take a deep breath. Sudden pain in the upper left abdomen while feeling unwell also needs an ambulance, according to Healthdirect. This matters most after a fall, a knock or a sports injury, and during an illness such as glandular fever.

• Sudden, sharp or severe pain in the upper left abdomen or under the left ribs.
• Pain that worsens with a deep breath.
• Dizziness, fainting or a fast pulse, especially after an injury.
• Fever, shivering or feeling suddenly very unwell if you have been told your spleen does not work properly.

Often it does not. MedlinePlus notes that splenomegaly usually causes no symptoms, and Healthdirect says it is sometimes found during a routine check or an imaging scan done for something else.

When symptoms do occur, they can include feeling full after eating only a small amount, discomfort or pain under the left ribs, and hiccups. Because the spleen helps filter blood and fight infection, an enlarged spleen can also be linked with tiredness from anaemia, more frequent infections, or bleeding and bruising easily.

A scan report that mentions an enlarged spleen is a finding to explain, not a diagnosis. Ask whether the result was expected given your other conditions, or whether it is new and needs investigating.

Yes. Infection is one of the most common causes. The CDC lists an enlarged spleen among the symptoms of Epstein-Barr virus (EBV) infection, and EBV is the most common cause of infectious mononucleosis, also called glandular fever or mono. MedlinePlus lists a swollen liver or spleen among the findings a clinician may notice during the examination.

Spleen rupture is a rare complication of glandular fever. MedlinePlus advises avoiding contact sports while the spleen is swollen, and the NHS advises against strenuous activity such as heavy lifting or sport while recovering. Neither source gives a fixed date for returning, so the decision should come from the clinician who knows your case.

If you have EBV blood test results and are unsure what they show, see the related guide on positive EBV antibodies. Other infections can also affect the spleen, so mention any recent travel, illness or animal bites.

The NHS lists cirrhosis, which is scarring of the liver, among the conditions that can enlarge the spleen. NIDDK explains that the portal vein carries blood from organs including the spleen to the liver. In cirrhosis, scarring can slow blood flow through the liver and raise pressure in this vein, a problem called portal hypertension.

If an enlarged spleen appears alongside a liver finding, such as fatty liver on ultrasound, ask how the two results fit together and whether the liver needs further assessment. The related guide on fatty liver with normal blood tests explains what follow-up can involve.

The spleen removes old or damaged blood cells. Healthdirect explains that conditions causing a rapid breakdown of blood cells can strain the spleen and make it enlarge. Diseases of the blood or lymph system and some cancers, including leukaemia, are also listed as possible causes by MedlinePlus and the NHS. The NHS also lists rheumatoid arthritis.

An enlarged spleen can sometimes hold on to more blood cells than usual. This is one reason clinicians check a full blood count, which can show low red cells, white cells or platelets. A single abnormal count does not identify the cause on its own.

MedlinePlus describes a physical examination in which the clinician feels and taps the upper left abdomen under the ribs. Imaging such as ultrasound, CT or MRI can confirm the size and look at nearby organs.

Blood tests commonly include a complete blood count and liver function tests. Depending on the history, a clinician may add tests for infections or refer to a specialist. Healthdirect notes that the condition causing the spleen problem is what gets treated. The NHS says the spleen is not usually removed if it is just enlarged; instead, the cause is treated and the spleen is monitored.

Bring the full scan report and recent blood results. These questions can help you understand the plan without assuming a cause.

• What do you think is the most likely reason my spleen is enlarged, and what has been ruled out so far?
• Do my blood count and liver tests show anything that fits with the scan finding?
• Do I need a repeat scan, and when?
• Should I avoid contact sports, heavy lifting or any other activity, and until when?
• Which symptoms mean I should go straight to emergency care?
• Am I at higher risk of infections, and do I need any vaccinations or extra precautions?

On SameCase, patients and verified doctors share de-identified cases. Reading how others with an enlarged spleen found on a scan were investigated, and which questions they asked, may help you write your own list before an appointment.

Similar cases cannot tell you why your spleen is enlarged or replace an examination and tests. Use them to prepare questions, and take those questions to the clinician responsible for your care.