What is Functional Asplenism?
The spleen is the body’s largest organ specifically involved in defending against illness and disease by aiding the growth and development of certain necessary components. These components include a type of protein used by the immune system to fight disease (immunoglobulin M), a specific kind of white blood cell (B lymphocytes), and substances that enhance the body’s immune response (opsonins). It plays a key role in the body’s protection against infections caused by certain types of bacteria such as Streptococcus pneumoniae and other similar species.
In addition to this, the spleen also functions as the main storage place for platelets (essential for blood clotting) and acts as a filter for red blood cells, removing those that are damaged or deformed. Furthermore, the spleen supports the production of blood cells outside of the bone marrow, a process vital for maintaining healthy blood cell levels.
Functional asplenism, or “functional hyposplenism” or “splenic hypofunction,” is a condition where the spleen, although physically intact, isn’t working properly. This term was first used by Pearson and others in 1969 during their studies on patients with a blood disorder known as sickle cell anemia.
What Causes Functional Asplenism?
Functional asplenism is a condition where the spleen is present but not working properly. The spleen is crucial because it helps the body fight infections by removing harmful bacteria and damaged blood cells. In people with functional asplenism, the spleen doesn’t do a great job of removing these bacteria and blood cells.
This condition can occur due to various reasons, including:
* Certain autoimmune conditions, where the body’s immune system mistakenly attacks its own cells. These include lupus, Hashimoto thyroiditis (a type of thyroid disease), antiphospholipid syndrome (a disorder that can cause blood clots), rheumatoid arthritis, or a syndrome where multiple glands in the body are affected, known as autoimmune polyglandular syndrome type 1.
* Inflammation-related conditions like multiple sclerosis (a nervous system condition), celiac disease (a reaction to gluten), inflammatory bowel disease, liver disease (known as hepatic cirrhosis), or blood disorders like sickle cell disease and beta thalassemia. Other causes can be conditions where the body rejects a transplant (chronic graft-versus-host disease), and a kidney condition called nephrotic syndrome.
* Advanced stages of HIV infection.
Other causes can be related to blood and cancer disorders like acute leukemias, non-Hodgkin lymphoma, and advanced stages of breast cancer. Certain treatments like bone marrow transplants, high-dose corticosteroids (a type of medication), radiation therapy on the spleen, or receiving all nutrition through a vein (a treatment called total parenteral nutrition) can also cause this condition.
Lastly, conditions like amyloidosis (where abnormal proteins build up in tissues and organs), primary biliary cirrhosis (a chronic liver condition), and primary pulmonary hypertension (high blood pressure in the lungs) can also lead to functional asplenism.
Risk Factors and Frequency for Functional Asplenism
Functional asplenism, or a non-working spleen, can vary in occurrence based on the frequency and prevalence of the disease causing it. This has been shown in various research studies. Here are some of their findings:
- In some cases of alcoholic liver disease, an effect known as hyposplenism can occur where the spleen isn’t working as well as it should. An examination of 82 patients dealing with alcoholic liver disease found that over two years, 16% of these patients died and 6% showed signs similar to patients who had their spleens removed. However, it was noted that cutting out alcohol for 2 months significantly decreased the count of abnormal red blood cells in most patients.
- Functional asplenism is somewhat common in those with sickle cell disease, affecting 20% to 30% of children and up to 50% of adults. In the United States, it is estimated that around a million people have a non-functioning or missing spleen, with about 100,000 of these cases due to sickle cell disease.
- The incidence of non-functioning spleen in patients with thalassemia, another blood disorder, can depend on the specific type and seriousness of the disease as well as the age of the patient. According to a 2013 study, functional asplenism was found in about 50% to 75% of patients diagnosed with beta-thalassemia major, the most serious form of the disease.
Signs and Symptoms of Functional Asplenism
When consulting with a patient suspected of having functional asplenism, a condition where the spleen does not work properly, a healthcare provider will usually start by asking about the patient’s medical history. This includes any existing health conditions like sickle cell disease that might impact how the spleen functions. They may also inquire about past infections or fever episodes as these could be more prevalent in individuals with functional asplenism.
During the physical check-up, the healthcare provider will look for signs of a swollen spleen, such as discomfort or a discernible lump in the top left section of the abdomen. They might also check for signs of infection, like fever or a high count of white blood cells. Additional physical symptoms the healthcare provider may note include jaundice (a yellow tint to the skin and eyes), anemia (a lower number of red blood cells), and a decreased number of platelets.
It’s important for patients with asplenia (no spleen function) or hyposplenism (reduced spleen function) to get immediate medical attention if they are bitten by an animal, especially a dog. They have a higher chance of experiencing a swift and severe body-wide infection, caused by Capnocytophaga canimorsus, which could be deadly. There is also an increased risk of infections caused by parasites that live inside red blood cells, such as Malaria and Babesia. A rare, serious condition called Waterhouse-Friderichsen syndrome, caused by Capnocytophaga canimorsus, has also occurred in a patient without a functioning spleen.
Testing for Functional Asplenism
To diagnose functional hyposplenism, or abnormal spleen function, your doctor may order a variety of tests. These could include blood tests, special scans, ultrasounds, or certain tests related to your immune system.
One essential test in diagnosing functional hyposplenism is peripheral blood smear. This test looks at a sample of your blood under a microscope to identify different types of cells – a useful indicator of spleen function. In particular, the test looks for Howell-Jolly bodies, which are remnants of old red blood cells that the spleen usually removes.
While normally these bodies are identified using a peripheral blood smear, researchers are now exploring whether flow cytometry – a technique that quickly measures the properties of individual cells in a fluid sample – can also be used. Unusually high levels of platelets (thrombocytosis), white blood cells (lymphocytosis), and a type of white blood cell called monocytes (monocytosis) can also point to functional hyposplenism. Your doctor may also look for, acanthocytes, giant platelets, Heinz bodies, and iron granules in the blood smear. Checking for these abnormalities may need special dyes and microscopy techniques.
Additionally, looking at the number of “pitted” red blood cells – cells that have tiny dents or depressions in them – can provide information about how well any remaining spleen tissue is working.
Another tool your doctor might use is a specialized scan called a technetium-99m-labeled radiocolloid scan. This scan gauges spleen function by measuring how much of a certain type of radio-labeled particle the spleen absorbs in relation to the liver. But this method can be invasive and time-consuming for patients.
Doctors also use newer techniques, such as assessing your immune response after vaccination or analyzing specific subsets of your B-cells (a type of white blood cell). They might also use Doppler sonography, a type of imaging that uses sound waves to create pictures of the spleen, which can show smaller, non-vascular spleens associated with functional hyposplenism.
Evaluating spleen phagocytic function, which is the spleen’s ability to destroy unwanted particles in the blood, via methods like measuring levels of an immune response mediator, tuftsin, have not proven to be of significant clinical value, however.
Treatment Options for Functional Asplenism
Living with a non-functional spleen poses certain infection risks and complications that must be guarded against. One can do this by following these essential steps:
Vaccinations: Getting specific vaccinations is vital if you have a non-working spleen. You should get protection against specific bacteria that are known to cause infections in people who have spleens that aren’t functioning properly. These include vaccinations for S pneumoniae, H influenzae type b, and N meningitidis. An annual flu shot is also recommended. Studies show that vaccines specifically targeting pneumonia bacteria have significantly reduced severe infections in patients with non-functional spleens. Certain types of pneumonia vaccines work better in such cases, and thus, are preferred. Also, if you’re scheduled for spleen removal surgery, it’s best to have your vaccines two weeks in advance because they work better when the spleen is intact. In the light of the current pandemic, those with a non-working spleen should receive three doses of the COVID-19 vaccine because they have the same immune-compromising conditions as others.
Antibiotics: If you have a spleen that isn’t working, you may need to take antibiotics long-term to prevent infections. Usually, penicillin or amoxicillin is prescribed, but it depends on whether local bacteria are resistant to these antibiotics or not. Also, if you’re planning to travel to areas where malaria is prevalent, taking anti-malaria drugs as prevention is a good idea.
Procedure-specific antibiotics: This specifically applies to those with non-working spleens who are set for procedures like endoscopic sinus surgery or bronchoscopy. In these cases, particular bacteria that cause severe infections can develop or increase in numbers in certain areas of your body. So, some form of antibiotics are given before the procedure to prevent this. Alternatives can include different types of antibiotics such as cephalosporins, macrolides, or fluoroquinolones.
Handling animal bites: If you have a non-working spleen and you get bitten by an animal, you must promptly clean the wound and take specific antibiotics. The first line of treatment generally taken along with an antibiotic to combat the bacteria types found in animal bites. Other medicines may be preferred if meningitis is suspected because they can reach the fluids around the brain and spinal cord more effectively.
Educate yourself and spread awareness: If you live with a non-working spleen, it’s crucial to know the signs and symptoms of an infection and when to seek medical help. Wearing a medical alert bracelet or carrying a card can also be beneficial in emergency situations.
Regular medical checks: Regular visits to the doctor help monitor for complications and adjust your treatment as the need arises.
Remember, handling a non-working spleen is a personalised task and may depend on the reasons causing it. Always consult a healthcare professional who specializes in managing this condition to get the best advice.
What else can Functional Asplenism be?
When doctors try to diagnose functional asplenism, a condition where the spleen doesn’t work properly, they need to consider many possible causes. Here are a few of them:
- Chronic lymphocytic leukemia
- Different types of lymphomas
- Amyloidosis, a condition where abnormal proteins called amyloids accumulate in tissues and organs
- Having had a bone marrow transplant
- Celiac disease, which is an autoimmune disorder affecting the small intestine
- Glomerulonephritis, a condition that damages the kidney’s filtering units
- Graves’ disease, an autoimmune disorder that results in an overactive thyroid
- Hereditary hemoglobinopathies, genetic defects that result in abnormal structure of one of the globin chains of the hemoglobin molecule
- Inflammatory bowel disease, which causes long-lasting inflammation in parts of the digestive tract
- Congenital asplenia, a condition where a person is born without a spleen
- Having had surgery to remove the spleen (post splenectomy)
- Rheumatoid arthritis, a long-term autoimmune disorder that primarily affects the joints
- Sarcoidosis, which presents in lumps, known as granulomas, in different parts of the body
- Undergoing splenic irradiation, a type of radiation therapy
- Splenic vein thrombosis, a condition where a blood clot forms in the splenic vein
- Tumors such as lymphoma
- B-Thalassemia, a blood disorder that reduces the production of hemoglobin
The exact cause of functional asplenism can vary greatly from person to person. It’s important for the doctor to thoroughly consider these possibilities and conduct appropriate tests to reach an accurate diagnosis.
What to expect with Functional Asplenism
With the correct care, including vaccinations and preventative treatments, people with functional asplenism – a condition where the spleen isn’t working properly – can enjoy a long and relatively healthy life, even though their immune system is compromised. The risk of death for these patients can greatly vary. This depends on what type of infection they contract, any additional health issues they may have, and their access to vaccinations and preventative antibiotics, among other factors.
Recognizing the early signs of sepsis, a potentially life-threatening condition caused by the body’s response to an infection, and treating it appropriately can substantially lower the overall risk of death. Therefore, early sepsis detection is crucial for those with functional asplenism.
Possible Complications When Diagnosed with Functional Asplenism
Overwhelming post-splenectomy infection, or OPSI, is a dangerous condition that can occur in patients without a properly working spleen. This syndrome is characterized by bloodstream infection, most often caused by a specific bacteria called Streptococcus pneumoniae. OPSI could appear suddenly, without clear signs of infection and typically presents with symptoms like septic shock, widespread clotting disorders, and bleeding into both adrenal glands. It is an urgent medical situation that requires swift antibiotic treatment and supportive care.
Patients without a functional spleen might already be on preventive antibiotics, so bacterial cultures might show no growth. However, it’s important to note that antibiotic treatment should still continue. Immediate antibiotic therapy typically includes vancomycin and either cefotaxime or ceftriaxone. Intravenous special proteins to fight infections, while not proven effective in this condition, are still recommended by some experts. OPSI is a deadly condition with a mortality rate of 50% to 70% and can potentially cause death within 24 to 48 hours.
This syndrome can occur from 10 up to 30 years post-diagnosis. Some research suggests the risk of OPSI decreases over time following the medical procedure that removed the spleen, while other studies report no significant reduction in risk.
Patients with non-working spleens usually have a higher than normal count of blood platelets because the spleen is the primary site where platelets are destroyed. This increased count, which is known as thrombocytosis, is not seen in patients with liver cirrhosis and high blood pressure in the liver; these patients usually have low platelet count due to impaired liver function. High platelet counts could increase the risk of clot formation.
Blood clots in the veins are associated with very high platelet counts and happen in around 5% of patients. High platelet counts can also cause arterial clots, which can lead to heart attack and stroke. To reduce the risk of clots, some patients might take aspirin or a medication to lower their blood platelet counts.
Acute infectious purpura fulminans is a rapidly worsening condition that causes skin to bruise and die because of acute infection usually due to encapsulated bacteria such as Streptococcus pneumoniae. This condition leads to widespread clotting disorders and is often seen in patients with non-functional spleens.
Preventing Functional Asplenism
Patients should carry a special card, known as an asplenic alert card. This card lets doctors and other healthcare professionals know that the patient’s spleen isn’t working properly. It’s also important for these patients to keep their vaccinations up to date and always have preventative antibiotics on hand.
As part of staying safe, patients are advised to avoid situations where they might get bitten by a dog or tick. When they travel to places where malaria is common, they need to be extra careful about bug bites and other risks.