Asplenia

Asplenia means the absence of a functioning spleen, an organ that plays a crucial role in fighting infections. People living without a spleen or with a spleen that doesn’t work properly face a lifelong increased risk of serious bacterial infections that can become life-threatening within hours, but with proper vaccination, preventive antibiotics, and education, they can lead healthy, normal lives.

Table of contents

• What is asplenia?
• Where is the spleen and what does it do?
• Types of asplenia
• What causes asplenia?
• Symptoms and warning signs
• How is asplenia diagnosed?
• Complications and infections
• Management and prevention
• Living with asplenia

What is asplenia?

Asplenia means the absence of a spleen or the absence of normal spleen function^[1]. This condition can occur in various ways: some people are born without a spleen, others have had it surgically removed, and some have a spleen that is present but doesn’t work properly^[2].

Although you can live a normal, healthy life without a spleen, this organ plays an important role in protecting your body from certain types of infections^[5]. When the spleen is absent or not functioning, other organs like the liver and bone marrow take over most of its functions, but the increased risk of infection remains lifelong^[2].

Where is the spleen and what does it do?

The spleen is a fist-sized organ located in the upper left side of your abdomen, just under your rib cage^[1]. Normally, the spleen cannot be felt during a physical examination and measures on average 10.65 by 5.16 cm^[1]. Normal spleen size can vary by sex and race—men typically have larger spleens than women, and White individuals tend to have larger spleens compared to African American individuals^[1].

The spleen is one of the primary extramedullary lymphoid organs (organs outside the bone marrow that are part of the immune system)^[1]. It has two functionally and structurally distinct tissues: the white pulp and the red pulp. The white pulp contains a large mass of lymphoid tissue that produces antibodies against recognized antigens, whereas the red pulp has a tight network of channels that helps filter blood^[1].

The spleen’s primary roles include filtering and processing old blood cells (predominantly red blood cells) and helping protect against encapsulated microorganisms (bacteria with protective outer coverings)^[1]. As the body’s largest blood filter, it removes old red blood cells from circulation and aids in the removal of blood-borne microorganisms^[1]. The spleen also produces white blood cells that make antibodies to fight infections^[5].

• Abdomen
• Lymphatic system
• Immune system

Types of asplenia

There are two main types of asplenia^[2]:

Anatomic asplenia is when you don’t have a spleen at all. This occurs most commonly due to surgical removal (called splenectomy) following trauma or injury, such as a car accident that causes a ruptured spleen^[2]. Less commonly, some people are born without a spleen, a condition called congenital asplenia^[2].

Functional asplenia means you have a spleen, but it doesn’t work properly. This is often due to health conditions that damage the spleen over time^[2]. The spleen may be present but has lost its function due to underlying diseases that destroy the spleen tissue^[3].

What causes asplenia?

Causes of anatomic asplenia

The most common reason for not having a spleen is surgical removal^[3]. A healthcare provider may need to remove your spleen due to trauma or injury—for example, a direct hit to your upper left abdomen during a car accident or contact sport can rupture your spleen, causing life-threatening internal bleeding^[2].

Splenectomy may also be performed to treat certain medical conditions, including^[3]:

• Blood disorders such as idiopathic thrombocytopenic purpura, thalassemia, and spherocytosis
• Cancers including chronic lymphocytic leukemia, Hodgkin’s disease, and non-Hodgkin lymphoma
• Severe enlargement of the spleen causing mass effects

Congenital asplenia, meaning you were born without a spleen, is rare. A genetic change in the RPSA gene (responsible for creating proteins) may lead to this condition^[2]. There are two distinct types of genetic disorders: heterotaxy syndrome and isolated congenital asplenia^[3]. Sometimes congenital asplenia occurs as part of a rare syndrome, while in other cases only the spleen is missing and other organs function normally^[5].

Causes of functional asplenia

Certain medical conditions can damage your spleen or cause it to stop working properly. The most common cause is sickle cell disease, where abnormally shaped red blood cells block blood flow to the spleen, causing irreparable damage through a process called autosplenectomy (the spleen loses its function due to multiple and repeated episodes of tissue death)^[3][5].

Other conditions that can cause functional asplenia include^[2][3]:

• Celiac disease
• Lupus
• Advanced HIV infection
• Liver disease
• Tumor infiltration
• Splenic infarction (blood clot in the splenic artery)

In a 1970 study, celiac disease was the second most common cause of abnormalities of red blood cells linked to reduced spleen function, after surgical splenectomy^[3].

Symptoms and warning signs

Asplenia itself usually doesn’t cause any noticeable symptoms^[2]. The condition is often discovered during evaluation for other medical problems or when a person develops a serious infection.

The most important symptoms to watch for are signs of infection, which can be extremely dangerous if you have asplenia^[2]. If you develop any of the following symptoms, you should reach out to your healthcare provider or go to the nearest emergency room right away^[2]:

• Fever (temperature of 100.5°F or 38°C or higher)
• Chills or sweating
• Rapid heart rate
• Fatigue
• Confusion or irritability
• Dizziness or passing out
• Vomiting, diarrhea, or belly pain
• Cough or trouble breathing
• Severe headache or neck pain

Initial symptoms are often mild, with a flu-like presentation that includes fever, malaise, muscle aches, headache, vomiting, diarrhea, and abdominal pain^[12]. However, the infection can then rapidly progress within hours to full-blown shock^[12]. Fever may be the only symptom of infection in some cases^[14].

How is asplenia diagnosed?

The most difficult and crucial aspect of asplenia is establishing the diagnosis^[4]. Although this task is relatively simple in patients with accompanying abnormalities, especially complex heart disease, and in those with a family history of the condition, the patient with isolated asplenia may not be easily identified^[4]. The diagnosis is sometimes made only at autopsy^[4].

Your healthcare provider will ask about any symptoms you have and your medical history. They’ll want to know if you have a biological family history of asplenia^[2]. Your provider will also perform a physical exam, although the exam might not reveal signs of asplenia itself^[2].

Often the first clues to functional asplenia in an asymptomatic patient are abnormalities in the peripheral blood smear^[4]. The initial evaluation should begin with a review to identify Howell-Jolly bodies—small round fragments of DNA that appear as dark spots inside red blood cells^[4]. The presence of Howell-Jolly bodies in the peripheral smear of an individual older than 7 days should suggest splenic dysfunction^[4]. The identification of Howell-Jolly bodies on peripheral blood film is an important clue to the diagnosis of asplenia or reduced spleen function^[12].

Asplenic patients typically have Howell-Jolly bodies on peripheral blood smears as well as neutrophilia (increased white blood cells) and thrombocytosis (increased platelets)^[6]. Other blood changes may include target cells and lymphocytosis^[6]. The lack of Howell-Jolly bodies in asplenic patients is suggestive of the presence of an accessory spleen^[6].

Complications and infections

Risk of serious infections

Asplenia increases your risk of developing serious bacterial infections^[2]. All patients with congenital or acquired asplenia or splenic dysfunction are at significant risk of fulminant bacterial infection, especially from encapsulated bacteria^[4]. Worldwide, most patients with asplenia or reduced spleen function have an underlying blood disorder such as sickle cell disease, which causes splenic dysfunction^[4].

If you don’t have a spleen, your body has trouble fighting certain bacteria. These bacteria have outer protective coverings that make them resistant to many of the body’s defenses^[2]. They include^[2]:

• Streptococcus pneumoniae
• Haemophilus influenzae
• Neisseria meningitidis

These bacteria can cause serious infections including^[2]:

• Pneumococcal disease
• Haemophilus influenzae type b infection
• Meningococcal disease

The risk of developing a life-threatening bacterial infection is higher in children with asplenia than in adults^[2]. However, patients have had serious infections more than 40 years after a splenectomy, indicating that the increased risk is lifelong^[12]. The majority (50 to 70 percent) of serious infections occur within the first two years following splenectomy^[12].

A splenectomized person also has an increased susceptibility to infections with blood parasites such as Plasmodium falciparum (which causes malaria) and Babesia microti^[12]. More rarely involved organisms include group B streptococci and various other bacteria^[1].

Overwhelming post-splenectomy infection

The most dreaded infectious complication is overwhelming post-splenectomy infection (OPSI) or asplenic sepsis^[6][12]. This is a bacterial infection that rapidly progresses to fulminant, overwhelming sepsis (a life-threatening response to infection) in the setting of anatomic or functional asplenia^[6].

Initial symptoms are often mild and flu-like, followed by rapid deterioration within hours with fever, severe illness, signs of sepsis, and sometimes meningitis^[6]. The infection may rapidly progress to full-blown shock, accompanied by low blood pressure, kidney failure, blood clotting problems, and low blood sugar^[12]. Bacterial growth in OPSI is often so extreme that bacteria are noted in blood preparations or even in the white blood cells present on a peripheral blood film^[12].

Despite appropriate antibiotic therapy and other intensive intervention, the reported mortality ranges from 50 to 80 percent without early treatment^[12][6]. Mortality can be reduced to approximately 10 to 40 percent with early treatment^[6]. More than one half of the patients who die do so within 48 hours of admission to the hospital^[12].

Other complications

Other complications of asplenia may include^[2]:

Increased bleeding risk: Your spleen plays a role in storing platelets, which you need for blood clotting. Without a spleen, you have a slightly higher risk of bleeding.

Autoimmune issues: Asplenia can upset the balance of your immune system, which can lead to autoimmune disorders—conditions where your body attacks its own tissues.

Thrombosis: Asplenia can sometimes cause blood clots to form in your veins or arteries.

Management and prevention

Once the diagnosis of anatomic or functional asplenia is confirmed, aggressive management is the key to decreasing the illness and death associated with this condition^[4]. Medical care involves four key components: antibiotic prevention, appropriate vaccination, aggressive management of suspected infection, and patient education^[4][10].

Vaccinations

Vaccines significantly decrease the risk of infections and are available against the most common types of encapsulated bacteria^[15]. You can protect yourself and your loved ones by getting vaccinated^[2].

If you did not get all the vaccinations you need before surgery, be sure to get all the vaccines your doctor recommends in the weeks after surgery^[19]. Vaccination should ideally be performed 14 days prior to elective surgery^[6]. If emergency splenectomy is performed, vaccination should start 2 weeks after surgery^[6].

Important vaccinations for people with asplenia include^[6][10]:

• Pneumococcal vaccines: 15-valent pneumococcal conjugate vaccine (PCV15) followed 8 weeks later by 23-valent pneumococcal polysaccharide vaccine (PPSV23). Revaccination with PPSV23 is needed 5 years later and at 65 years of age.
• Meningococcal vaccines: Meningococcal quadrivalent vaccine once 2 weeks after surgery and then every 5 years, plus meningococcal B vaccine
• Haemophilus influenzae type b (Hib) vaccine: Once 2 weeks after surgery
• Annual influenza vaccination: Inactivated flu vaccine every year
• COVID-19 vaccine

Stay up to date with all age-appropriate vaccines^[14]. Most of the pediatric pneumococcal bacterial infections in the United States are caused by the serotypes covered in the conjugate vaccine^[10]. The conjugate vaccine has been effective in dramatically reducing the occurrence of invasive pneumococcal disease^[10].

Antibiotic prophylaxis

Antibiotic prevention should be initiated immediately upon the diagnosis of asplenia because these patients are at significant risk of pneumococcal infections^[10]. You may need to take antibiotics for a while^[19]. You may also need to take them each time you have a fever, as this could be a sign of a serious infection^[19].

Daily antibiotic prevention with oral penicillin or amoxicillin should be considered in the following groups^[6]:

• Asplenic children: until at least 5 years of age
• Following splenectomy: children over 5 years of age and adults for at least 1 year
• Patients with weakened immune systems or a history of previous invasive pneumococcal disease

For children younger than 2 years, oral penicillin V may be given twice a day. Amoxicillin has also been recommended as an appropriate preventive antibiotic. Erythromycin is an alternate choice in patients who are allergic to penicillin^[10].

Some experts recommend continuing prevention into adulthood, particularly for high-risk patients^[10]. Currently, most guidelines leave the option open to continue lifelong prevention based on the clinical circumstances of the individual patient^[10].

Alternatively, you may be given a course of antibiotics to keep at home in case you become ill and there is a delay in seeing your doctor^[21].

Immediate treatment of fever and suspected infection

An asplenic patient with fever requires immediate antibiotic treatment^[6]. Asplenic infection and sepsis are a medical emergency^[6]. Any episode of fever or signs of infection should be promptly and aggressively treated^[10].

If you or your child develops a fever, contact your health care team right away. This is a medical emergency, and you need to be seen within 1 hour^[14]. These infections may progress very quickly and cause organ failure^[14].

Immediate intravenous antibiotic therapy with vancomycin plus ceftriaxone or cefotaxime should be given^[6]. Early blood cultures prior to antibiotic administration, urgent blood tests, and fast detection tests should be utilized in these patients^[18]. Prompt management and aggressive treatment can alter the course of disease in the at-risk splenectomized patient^[18].

Patient education and general measures

Patient education is essential. Patients or their caregivers should be taught to watch for early signs of illness and should seek any needed medical attention sooner rather than later^[5].

General measures include^[6][21]:

• Carry a patient identification card or wear a MedicAlert bracelet/necklace to alert other people in an emergency
• Remind your doctor and dentist that you do not have a spleen
• Take precautions to avoid dog and tick bites
• Caution is recommended when traveling to malaria-endemic areas
• Do not travel to areas where you could get serious infections such as malaria

Living with asplenia

The absence of a spleen is manageable, but caution and education are required to prevent potential life-threatening complications^[5]. You can live without a spleen and continue to live a normal, healthy life with a regular lifespan^[2][5].

Adults who lose their spleen do better than children born without one, but in either case, patients or their caregivers should be taught to watch for early signs of illness^[5]. With proper management, individuals can lead healthy lives^[5].

After a splenectomy, you are likely to have pain for several days. You may also feel like you have influenza. You may have a low fever and feel tired and nauseated. This is common. You should feel better after a few days and will probably feel much better in about a week^[19].

You will probably need to take 4 to 6 weeks off from work, depending on the type of work you do and how you feel^[19]. Avoid strenuous activities, such as biking, jogging, weight lifting, or aerobic exercise, until your doctor says it is okay^[19].

Although the risk for fulminant infection is low (probably in the range of 1 per 500 person-years of observation), in one large study the overall cumulative risk of infection severe enough to require hospitalization was 33 percent at the end of a 10-year follow-up period^[12]. The risk is elevated as much as 350-fold compared to people with a functioning spleen^[3].

Patients with asplenia have a lifelong risk of fulminant, life-threatening infections and sepsis for up to 30 years or longer after splenectomy^[6]. Early recognition of reduced spleen function and proper management of asplenia are warranted to prevent overwhelming post-splenectomy infections through vaccination and antibiotic prevention^[8].