Spleen

The spleen sits on the left side of the abdomen and weighs around 200g in the average healthy adult. It can be thought of as two organs in one: it filters the blood and removes abnormal cells (such as old and defective red blood cells), and it makes disease-fighting components of the immune system (including antibodies and lymphocytes).

Because the spleen is involved in so many bodily functions, it is vulnerable to a wide range of disorders. The body adapts well to life without this organ, however, so a diseased or damaged spleen can be surgically removed without causing serious harm.

Spleen structure#

The body of the spleen appears red and pulpy and is surrounded by a tough capsule. The red pulp consists of blood vessels (splenic sinusoids) interwoven with connective tissue (splenic cords), and it filters the blood and removes old and defective blood cells. Inside the red pulp is the white pulp, which consists of small lumps of lymphoid tissue where antibodies are made.

As with other organs of the lymphatic system, particular immune cells (B lymphocytes and T lymphocytes) and blood cells are either made or matured inside the spleen. Blood enters through the splenic artery, which subdivides into many tiny branches. Each branch is encased in a clump of lymphocytes, so every drop of blood is filtered for foreign particles as it enters the spleen.

Disorders of the spleen#

Some of the disorders that can affect the spleen include enlargement (splenomegaly), overactivity (hypersplenism), splenic rupture, blood disorders, cancers, cysts and tumours, and conditions where the spleen is absent or not working.

Splenomegaly (enlarged spleen)#

A variety of disorders can cause the spleen to enlarge, sometimes to 2kg or more. Any condition that causes a rapid breakdown of blood cells, such as haemolytic anaemias, can place great strain on the spleen and make it enlarge. Other causes include infections (such as glandular fever), liver disease and some cancers (such as Hodgkin’s disease, leukaemia and lymphoma).

Hypersplenism#

An enlarged spleen is sometimes overactive and destroys more blood cells than necessary, leading to a deficiency of one or more blood components. The two characteristic features of hypersplenism are an enlarged spleen and a low blood count. Symptoms depend on which blood component is lacking; for example, if red blood cells are deficient, anaemia results, with symptoms including fatigue and pallor. Most cases are caused by disorders elsewhere in the body, such as cirrhosis of the liver. A very enlarged spleen can occasionally become delicate enough to rupture spontaneously.

Splenic rupture#

A sudden blow to the left side of the abdomen can split the outer capsule of the spleen and cause bleeding into the abdominal cavity. There are various degrees of splenic rupture. When bleeding is life threatening, surgery to remove the spleen (splenectomy) is needed. Sometimes the spleen can be saved by placing a synthetic clot into the splenic artery, a procedure called splenic artery embolisation.

Absent or non-functioning spleen#

Hyposplenism (a non-functioning spleen) is usually diagnosed by a haematologist or other specialist. Some people are born without a spleen, a condition known as congenital asplenia, which may be found at birth or incidentally later in life on a scan.

It is important to note that when the pancreas, or part of it, is removed, the spleen is also removed in most cases. The spleen and pancreas sit so close together that they touch and share some vascular tissue, which is why the spleen may need to come out. Removing the spleen along with the pancreas helps avoid risky post-operative bleeding.

Diagnosis of spleen disorders#

Depending on the condition being investigated, disorders of the spleen can be diagnosed using a number of tests, including:

• physical examination
• blood tests
• ultrasound
• computed tomography (CT) scan
• MRI or PET scan
• bone marrow biopsy

Treatment for spleen disorders#

Treatment depends on the disorder and its specific cause. For example, if splenomegaly is caused by certain cancers (including Hodgkin’s disease, leukaemia or lymphoma), treatment focuses on eliminating or controlling the primary disease. Hypersplenism triggered by cirrhosis of the liver can be treated with abstinence from alcohol and special dietary changes. A severely ruptured spleen is usually surgically removed.

The surgical removal of the spleen is called a splenectomy. The body can cope without the spleen, although the person may be more susceptible to infections afterwards, and their blood may contain odd-shaped red blood cells. In some cases it is possible to remove only the diseased or damaged parts of the spleen, allowing the remaining healthy portions to keep functioning normally.

Infection, immunisation and splenectomy#

People who have had their spleen removed or who have a spleen disorder are at increased risk of infection, most commonly pneumococcal and meningococcal infections. Although rare, these can develop into severe infections (sepsis) without prompt treatment.

Vaccines#

Vaccines are recommended for people without a working spleen and should be discussed with a doctor. These typically include the pneumococcal, meningococcal and haemophilus influenzae type b vaccines.

People without a spleen are not at increased risk of catching viral infections such as influenza and COVID-19. However, if you do get a virus, the chance of a secondary bacterial infection increases, so annual influenza and COVID-19 vaccines are encouraged as recommended for your age.

Antibiotics#

Low-dose preventive antibiotics are usually prescribed after a splenectomy, generally a penicillin-based antibiotic unless allergies have been recorded. These may be prescribed for several years or lifelong, depending on your medical history, and help protect against some bacterial infections. People who are otherwise immunocompromised (for example, having chemotherapy or taking steroids) may be advised by their specialist to take them for a longer period. Penicillin is one of the most important antibiotics for treating infections in people without a spleen. If you have a penicillin allergy, it is recommended you see a specialist immunologist so this can be reviewed under supervised conditions.

Emergency antibiotics are also prescribed in case you feel unwell and cannot be assessed by a doctor within 4 to 6 hours. If you take your emergency antibiotics, always follow up with an assessment by a medical professional.

Warning signs after splenectomy#

Be alert, not alarmed. The most important thing to watch for is any sign of infection, including:

• fevers
• vomiting or diarrhoea
• shivers, sweats or shakes
• confusion
• severe headaches
• generally feeling very unwell

If you experience these symptoms, seek medical attention immediately (a doctor or hospital emergency department). If you know medical attention will be delayed, take your prescribed emergency antibiotics, then seek help as soon as possible. People without a spleen can become very sick very quickly if these symptoms are ignored. Early antibiotic treatment can prevent an unnecessary hospital stay.

Always tell your doctor that your spleen is absent or not working, and use a medical alert card or an emergency alert on your phone.

Animal bites and scratches#

Dogs and cats carry a bacterium in their mouths, Capnocytophaga canimorsus, that people without a spleen are very susceptible to, and it can be harmful in those without a functioning spleen. If you are bitten or scratched, immediately wash the area with an antiseptic or soap and watch for signs of infection (redness, swelling). Seek medical attention if you suspect an infection.

Travel advice#

See a travel doctor before going overseas. In some areas malaria is common. It is spread by mosquitoes, so use mosquito repellent and barrier clothing, and preventive anti-malarial medication is warranted. Always travel with your daily antibiotics (if you take them) and, very importantly, a supply of emergency antibiotics. Seek immediate medical attention if you become unwell.

Key points#

• A variety of disorders can cause the spleen to enlarge, sometimes to 2kg or more.
• An overactive spleen can destroy too many blood cells, leading to a deficiency with symptoms such as fatigue and pallor.
• Removal of the spleen along with the pancreas avoids risky post-operative bleeding.
• Treatment depends on the disorder and its specific cause.
• Removing only the diseased part of the spleen allows the remaining healthy portions to keep functioning normally.

Where to get help#