Pediatric Asplenia - Causes, Symptoms, Diagnosis, and Treatment

Introduction:

Asplenia refers to a medical condition where the spleen is absent. The spleen is an extramedullary lymphoid organ that helps the body in defense mechanisms battling against bacterial infections. The spleen may be absent right from birth (congenital asplenia) or surgically removed following trauma or infection (functional asplenia) or a very small spleen. This article explains asplenia, its symptoms, and treatment in detail.

The Spleen: What Is It?

The spleen is an important extramedullary lymphoid organ present in the left upper abdomen. The size of this organ varies in each individual, race, and gender. The spleen is generally larger in males, especially in the white population, than the Africans. This organ is generally not palpable; if it is palpable, it may be due to an underlying medical condition. Functionally the spleen has two types of tissues called the “red pulp” and the “white pulp.”

What Are the Functions of the Spleen?

• The spleen is one of the vital organs in the body’s defense/immune mechanism and a part of the lymphatic system.

• The white pulp of the spleen is a large network of lymphoid tissues where it produces antibodies against the infection, and the red pulp has a tight network of sinusoids or tissues called the” cord of Billroth.” Its chief function is the filtration of the blood cells, where the old red blood cells (RBCs), blood-borne microorganisms, or antigens are removed from the body.

• Its main function is to produce the immune cells for battling infection and transport them throughout the body.

• They also protect the body in response to pathogenic infections and various encapsulated microorganisms.

• They are involved in the filtration process of the blood cells, and the old or aged cells are eradicated. They are referred to as “the graveyard of red blood cells (RBCs).”

What Are The Causes of Asplenia?

• The main cause of congenital asplenia may be due to the mutation of the ribosomal protein SA gene (RPSA). The ribosome has two units: the large subunit and the small subunit. These ribosomal proteins SA (RPSA) belong to the small subunit of the ribosomes. These RPSA mutations are thought to affect the development of the spleen.

• Congenital asplenia is associated with syndromes such as Ivemark syndrome. It is characterized by asplenia or hyposplenism, along with heart malformations and derangements of the organs in the chest and abdomen.

• Trauma or infection of the spleen results in the need for splenectomy.

• Benign and malignant disorders contribute to the surgical removal of the spleen. They are

1. Spherocytosis: The red blood cells are spherical in nature rather than biconcave in shape.
2. Sickle Cell Anemia: In the case of sickle cell anemia, the red blood cells are sickle in shape affecting the oxygen-carrying capacity.
3. Thalassemia: It is a condition where hemoglobin levels in the body are reduced than normal.
4. Refractory Immune Thrombocytopenia: The immune system affects the platelets resulting in bleeding conditions.
5. Myeloproliferative Disorders: Abnormality in the blood cells (platelets, red blood cells, and white blood cells).
6. Autoimmune Hemolytic Anemia: Autoantibodies are created, resulting in the destruction of red blood cells.

• Gastrointestinal disorders are associated with the function of the spleen. Celiac diseases, Whipple disease, and inflammatory bowel diseases.

• HIV, rheumatological disorders such as systemic lupus erythematosus.

What Are the Symptoms in Asplenic Patients?

These patients are often asymptomatic. However, they may present the following.

• Fever, malaise, and fatigue.

• In the case of fever, nuchal rigidity (stiffness of the neck) is seen.

• Encephalopathy: A disease affecting the brain.

• These patients are more vulnerable to severe infection with Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitides.

• On normal examination, the spleen is not palpable. Only in the case of enlargement or infection the spleen gets palpable. During asplenia, the spleen cannot be palpated due to atrophy of the organ (a decrease in the size of the tissues or organs).

• Pneumococcal meningitis is four times highly fatal in asplenic individuals.

What Is Splenectomy?

Splenectomy is a medical procedure or surgical removal of the spleen. It may be due to problems such as trauma, infection, or spleen enlargement in the cases of thalassemia (a condition where there is less hemoglobin than normal) or spherocytosis (the red blood cells are spherical rather than disc-shaped). This enlarged spleen may cause discomfort to the patient. This may sometimes rupture due to the accumulation of the blood cells within the spleen, where surgical removal of the spleen is mandatory either completely or partially.

What Are the Complications in Asplenic Individuals?

• Patients with asplenia or hypo functional spleen are highly prone to serious infections with encapsulated organisms such as Streptococcus and Neisseria.

• Meningitis (inflammation of the brain and spinal cord) is more likely to occur.

• In the absence of a spleen, especially in children less than two years of age, they are more prone to life-threatening infections such as overwhelming post-splenectomy infection (OPSI).

• Sepsis after splenectomy or overwhelming post-splenectomy infection. The incidence is more during the first one to three years after the surgery.

• Parasitic infections such as malaria and babesia are very common.

• Purpura fulminans (it is an acute purpuric rash due to coagulation of the microvasculature leading to skin necrosis.)

How Can We Diagnose Asplenia?

Diagnosis is the difficult part of asplenia. It can be easily diagnosed in patients with associated syndromes and developmental anomalies. In hyposplenism (decreased function of the spleen), diagnosis is made only during autopsy. However, a blood examination can be used to rule out spleen dysfunction.

• The peripheral smear of the blood shows the presence of “Howell Jolly's bodies.” They are the remnants of the red blood cell nuclei. Their presence in the blood over seven days may be suggestive of the dysfunction of the spleen.

• Other diagnostic modalities are abdominal ultrasound (USG), computed tomography scan (CT), and magnetic resonance imaging (MRI).

• Spleen scintigraphy (uses the 99Tc radio colloid specific to the spleen tissue. If the tissue does not take up the radiocolloid, it is suggestive of asplenia.)

How to Prevent the Child From Infection?

As we know, children with the absence of a spleen are more susceptible to bacterial infection, and proper measures can prevent serious infection. They are:

1. Immunization.

2. Antibiotics prophylaxis.

Immunization:

• Vaccination against bacterial infections such as pneumococcus, meningococcus, and Haemophilus influenzae type B.

• In the case of splenectomy, vaccination against pneumococcus, meningococcus, and Haemophilus influenza B should be done 14 days prior to surgery or at least 14 days after surgery.

• The influenza vaccine is recommended once a year.

Antibiotic Prophylaxis:

Antibiotics are prescribed for the prevention of fever and infection if your child has undergone splenectomy or, in the case of congenital asplenia.

What Is the Management of Asplenic Individuals?

The most common condition in asplenia is fever. They are also susceptible to infection from encapsulated organisms. So vaccinations are recommended before and after splenectomy. The medical management of asplenia involves four main components. They are:

• Antibiotic Prophylaxis.

• Immunization Therapy.

• Management of Suspected Infections: If any known infection is suspected, then appropriate treatment is started immediately.

• Parent Education: It is always advisable to explain to their parents about the child’s condition and explain the immunization protocols to be followed.

• Antibiotics Prophylaxis:

1. In children < three months of age: Amoxicillin/Clavulanate 10 mg/ kg two times daily.

2. From three months to five years: Amoxicillin 10mg/ kg twice daily OR

3. Penicillin VK 125 mg/ dose. Two doses daily. In children > five years: Amoxycillin 250 mg/dose twice daily OR

4. Penicillin V 250 or 300 mg /dose twice daily.

• Immunization Therapy:

1. Pneumococcal Vaccine: Pneumococcal Conjugate Vaccine (Prevenar).
2. Single-dose Pneumococcal 23 Valent Polysaccharide vaccine.
3. Pneumovax 23 0.5ml intramuscularly or deep subcutaneously.
4. Repeat Pneumovax 23 booster dose every five years. 0.5ml intramuscularly or deep subcutaneous injection.
5. Haemophilus Influenzae Vaccine: To be followed according to the childhood schedule.
6. Influenza Vaccine: It is recommended in infants annually younger than six months of age.
7. Meningococcal Vaccine: Meningococcal Type C Conjugate Vaccine.
8. Single-dose of Meningococcal Quadrivalent Polysaccharide vaccine.
9. 0.5 ml deep subcutaneous at two years of age.
10. Repeat booster dose every five years (0.5ml deep subcutaneous).

Conclusion:

The spleen is recognized as the vital organ and the defense system. So patients with asplenia and the parents of the pediatric patients should understand the possible complications and take proper preventive measures to avoid serious infections etc. It is always important to strictly follow the health care professional’s instructions regarding immunization and antibiotic therapy. Special care should be taken while traveling to avoid the risk of parasitic infections. Though it is a complicated lifelong condition, preventive measures can be helpful.