Pediatric Asplenia 

Updated: Oct 19, 2016
Author: Mudra Kumar, MD, MRCP, FAAP; Chief Editor: Harumi Jyonouchi, MD 

Overview

Background

Asplenia is the absence of spleen and/or its functions. Abnormalities of the spleen may be classified on a pattern-oriented approach, based on splenic imaging.[1] These include anomalies of the following:

  • Shape (clefts, notches, lobules)

  • Location (wandering spleen)

  • Number (asplenia, polysplenia)

  • Size (splenomegaly, atrophy)

  • Solitary lesions (cysts, lymphangiomas, hemangiomas, hamartomas)

  • Multiple lesions (trauma, infections, neoplasms, storage disorders)

  • Diffuse disease (infarction, heavy metal deposition, peliosis)

Absence of splenic tissue can be total (congenital asplenia) or partial (hypoplastic) from birth.

Loss of splenic tissue due to surgical removal may occur later in life as a result of trauma that causes rupture of the organ. The spleen may be removed in other conditions (eg, hemoglobinopathies) to improve the red cell life expectancy. Removal of the spleen may be undertaken as a result of being involved in a neoplastic processor as a staging procedure in some cancers. Occasionally, the spleen may be removed to address the sheer mass effect of a massive enlargement (such as in storage disorders), which can cause mass effects.

Autosplenectomy is the process where the spleen loses its function due to multiple and repeated infarctive episodes, as in sickle hemoglobinopathies. See the image below.

Peripheral blood smear shows Howell-Jolly (HJ) bod Peripheral blood smear shows Howell-Jolly (HJ) bodies in RBCs.

Pathophysiology

Absent or defective splenic function is associated with a high risk of fulminant bacterial infections, especially with encapsulated bacteria. Although considered a nonvital organ, and once thought to serve no practical purpose, the spleen is now recognized as an important secondary lymphoid organ in immune defense and as a filter for the bloodstream.

In embryonic development, the spleen begins to form as early as 12 days' gestation, along with the splanchnic mesodermal plate; this is one of the processes involved with formation of the asymmetrical left-right axis. In mice that lack critical transcription factors (eg, BAPX1, HOX11), development of the normal left-right axis is disrupted, and no spleen is formed.

In humans, the spleen is the site for early hematopoietic development, particularly the development of erythrocytes during the first 4 months' gestation. After birth, the spleen has several important functions as a secondary lymphoid organ and as a reservoir and filter for cells and platelets.

The white pulp of the spleen contains germinal centers, with lymphocytes, plasma cells, and macrophages that help coordinate the immune response and play roles in both innate and adaptive immunity. The spleen has an active role in the production of immunoglobulin M (IgM) antibodies and complement, both of which can opsonize bacteria. Thus the spleen serves both to "tag bacteria for destruction" and plays a role in the actual destruction of the bacteria through phagocytosis. The spleen is also involved in the functional maturation of antibodies and is a significant reservoir for both B and T lymphocytes. The number of total T cells (CD3) and T-helper cells (CD4) and the lymphoproliferative responses to mitogens (concanavalin A, phytohemagglutinin, pokeweed mitogen) may decrease in patients with asplenia; however, these T-cell changes may reflect the loss of the spleen as a reservoir rather than a direct T-cell abnormality.

The spleen plays an important role in granulocyte homeostasis also by influencing the elimination of senescent cells and regulatory effects on granulocyte renewal in the bone marrow. A potentially elevated proinflammatory status of granulocytes is noted, as suggested by intensity pf CD11b,c and TREM-1 in congenital asplenia.[2, 3] Another study indicates that the T lymphocyte subset in congenital aplasia may be associated with presence of CD4(+) T cells that express the "naïve" phenotype, possible failure in CD8(+) cytotoxic effectors differentiation and tendency to the proinflammatory status of cells, low interleukin (IL) 10 expression, and suboptimal lymphocyte responses to mitogenic stimulation.[4]

The red pulp of the spleen is designed as an efficient filtering system that serves as an important scavenger. The spleen participates in the destruction of all 3 blood elements (erythrocytes, leukocytes, and platelets) when they reach senescence. In the process of removing erythrocytes, the splenic macrophages play a critical role in the body’s ability to recycle iron. The spleen also plays an important role in the selective removal of abnormal red cells (spherocytes, poikilocytes) and intracellular inclusions (Heinz bodies, Howell Jolly bodies). These functions are known as culling and pitting, respectively, and loss of these functions results in the persistence of abnormal red cells and inclusions in the peripheral smear in patients with absent splenic function.

The impaired clearance of opsonized particles, decreased IgM levels, and poor antibody production (especially in response to polysaccharide antigens) contribute to the increased susceptibility of patients with asplenia to serious and often fatal bacterial infections.

The most common and serious are rapidly progressive, overwhelming, and often fatal infections due to gram positive encapsulated organisms. Streptococcus pneumonia is most commonly reported but Haemophilus influenzae type b, and Neisseria meningitides are also common.[5, 6, 7] Other organisms include Staphylococcus aureus, Salmonella species, and Pseudomonas aeruginosa.

In infants younger than 6 months, gram-negative enteric organisms such as Klebsiella species and Escherichia coli are the most common pathogens. Multiple bacterial infections have been reported in the same patient.[6]

Unusual complications of infections may be seen in asplenic patients, especially those with congenital heart disease. Endocarditis due to Bordetella holmesii was reported in a patient with asplenia and prosthetic mitral valve. Bacteremia due to Bordetella holmesii was reported in 4 cases with asplenia.

Malaria, babesiosis, and certain viral infections may also be more severe in individuals with asplenia. The younger the patient at the time of splenic function loss, the higher the risk for serious infection.

Persistent and significant thrombocytosis associated with asplenia. This may contribute to the development of thromboembolic complications, especially in those with significant congenital cardiac abnormalities.

Isolated (congenital) absence of spleen is thought to be extremely rare, although a French report suggests that it may be more common than previously thought. An autosomal dominant mode of inheritance has been suggested. Recently the discovery of genes responsible for isolated congenital asplenia was reported.

Most cases of congenital asplenia (or polysplenia) are associated with abnormalities of other organ systems and result from interference in the establishment of normal right-left symmetry during embryogenesis (heterotaxy syndrome, laterality sequences). Congenital asplenia may be viewed as bilateral right-sidedness and is associated with dextrocardia in approximately one third of the cases. Polysplenia may be regarded as bilateral left-sidedness and may be associated with left atrial isomerism.

Both asplenia and polysplenia are associated with congenital cardiac anomalies. These anomalies are more common, severe, and generally complex in asplenia. These include endocardial cushion defects, atrioventricular canal defects pulmonary atresia or pulmonary stenosis, transposition of the great vessels, total anomalous pulmonary venous return, and a double-outlet right ventricle. Cyanotic heart diseases, tend to be more common in asplenia, whereas acyanotic defects, which usually occur with increased pulmonary blood flow, are more common in polysplenia.

In polysplenia, multiple spleens are found along the greater curvature of the stomach is on the right side. Absence of the hepatic portion of the inferior vena cava with an azygous venous connection is characteristic. Data regarding splenic competency in polysplenia is scarce, and reports vary from suboptimal to normal function.

Accessory spleens should be distinguished from polysplenia. In polysplenia, a normal spleen is absent. Accessory spleens are usually located in the hilus of the normal spleen or in the tail of the pancreas. The accessory splenules are typically small and clinically insignificant but may become hypertrophied in certain situations.

Splenosis is an unusual condition in which trauma or surgery to the spleen can result in transplantation of splenic tissue into other organs or cavities such as the thorax, kidney, or liver. Although it is generally a benign condition, it can radiographically mimic malignancy and result in extensive workup and invasive procedures.

Congenital asplenia is most often found in association with other developmental anomalies. The most common is Ivemark syndrome, also referred to as asplenia syndrome, in which visceral heterotaxy is present with bilateral right-sidedness. The right-sided organs are duplicated, and organs that are normally present on the left side are absent. Infants with Ivemark syndrome usually present during the neonatal period with cyanosis and respiratory distress, resulting from complex cardiac anomalies. Transposition of the great arteries with pulmonary stenosis (72%) or atresia (88%) and total anomalous venous drainage (72%) are common.

Accompanying malformations may involve the GI system secondary to aberrant mesenteric attachments and renal anomalies. The liver tends to be symmetrical and transverse, and the stomach may be in the midline and hypoplastic. This condition is more common in males than in females, and most patients (79%) die in their first year of life due to cardiovascular complications. A clue to the underlying problems may be obtained by carefully examining radiographs, which may reveal abnormal placement of the cardiac apex, stomach bubble, and liver.

Pearson syndrome (pancreatic insufficiency, sideroblastic anemia) is a mitochondrial disorder associated with splenic atrophy. Asplenia is also present in Stormorken syndrome (thrombocytopenia and miosis). Occasionally, asplenia may be present in Smith-Fineman-Myers syndrome (mental retardation, short stature, cryptorchidism) and ATR-X syndrome (α thalassemia and mental retardation). Asplenia may be associated with caudal deficiency or cystic disease of the liver, kidney, and pancreas. It has also been reported in association with Fanconi aplastic anemia.

Asplenia was identified in 4 family members with autoimmune polyendocrine syndrome type-1. Horseshoe adrenal glands have also been associated with Asplenia syndrome. A patient was reported with Cat eye syndrome with anatomical asplenia.

Vascular disturbances, including failure of the splenic artery to reach the developing spleen, may be a possible explanation for isolated asplenia. Familial situs abnormalities may be related to chromosome band Xq24-q27.1. Splenic hypoplasia is a poorly defined and infrequently recognized condition that is usually not associated with other anomalies and may be familial.

Functional asplenia is associated with conditions such as homozygous sickle cell disease, hemoglobin sickle cell disease, and sickle cell hemoglobin (Hb S) β thalassemia. Most children with these hemoglobinopathies start losing the splenic function in the first year of life and become anatomically asplenic (secondary to splenic infarction and splenic atrophy) by the second decade of life. The infection risks in these individuals parallel those of patients with asplenia.

Patients who undergo splenectomy because of thalassemia or Hodgkin disease have a higher risk of overwhelming infection than those patients with functional hyposplenia secondary to sickle cell disease.

Neonates may have suboptimal splenic function.

Additional conditions associated with splenic hypofunction include rheumatologic diseases (systemic lupus erythematous [SLE], rheumatoid arthritis), inflammatory bowel disease, graft versus host disease, and nephrotic syndrome.

Epidemiology

Frequency

United States

The exact incidence of these conditions is not known. Asplenia or polysplenia is present in approximately 3% of neonates with structural heart disease and in 30% of patients who die from cardiac malposition. Isolated asplenia or hyposplenia is probably an underdiagnosed condition that is most often recognized at autopsy or when relatives of an index case are investigated.

Mortality/Morbidity

Compared with mortality rates in healthy children, the rate in children with a splenectomy caused by trauma is increased 50-fold, and the rate in patients with sickle cell disease is increased 350-fold.

Neonates with congenital asplenia have high morbidity and mortality rates usually caused by related cardiovascular insufficiency.

Infants who have asplenia as part of heterotaxy syndromes, often have increased mortality and morbidity related to extrasplenic abnormalities in neonatal period. However, if they survive past age 1 month, they have a higher risk of dying from sepsis than from associated cardiac disease. Therefore, the early identification of asplenia in infants with congenital heart disease is of paramount importance.

To prevent fatal bacterial sepsis, which may be the first manifestation of asplenia in infants with sickle cell disease, routine newborn diagnosis is essential and needs to be followed by preventive measures such as prophylactic antibiotics and vaccinations (see Treatment).

Sex

There is male predominance in asplenia syndrome (ie, Ivemark syndrome) is 2:1. Polysplenia syndrome is more predominant in females, whereas asplenia may be more common in males.

Age

The risk of bacteremia is higher in younger children compared with older children.

 

Presentation

History

All patients with congenital or acquired asplenia or splenic dysfunction are at significant risk of fulminant bacteremia, especially from encapsulated bacteria.

Worldwide, most patients with asplenia or hyposplenia have an underlying hemoglobinopathy such as sickle cell disease, which causes splenic dysfunction.

  • Isolated asplenia and polysplenia are commonly associated with significant abnormalities involving other organ systems.

  • An awareness of these associations and syndromes may help in screening the patient for splenic dysfunction.

The most important clinical indication for the evaluation of splenic function is the presence of complex congenital heart disease. Patients should be evaluated for splenic dysfunction if any of the following are present:

  • Recurrent infection or sepsis, especially with encapsulated organisms

  • Family history of asplenia (may be autosomal dominant)

  • Cyanotic congenital heart disease or complex cardiac malformations

  • Evidence of visceral heterotaxy or other associated malformations

  • Bilateral trilobed or bilobed lungs on chest radiographs

In contrast, the patients with isolated congenital absence or hypoplasia of the spleen may not have any obvious clues because associated cardiovascular, pulmonary, GI, or genitourinary abnormalities may not be present to alert the physician to their underlying immunocompromised state. Children with these conditions may present to the primary caretaker with fever, overwhelming sepsis, or may even be moribund.

Features such as thrombocytosis, Howell Jolly bodies in red cells, or presence of target cells in the peripheral smear without a likely explanation should raise the suspicion of underlying splenic dysfunction.

All patients with an episode of invasive, overwhelming infections without any obvious underlying cause should be evaluated for the presence of a functional spleen. Recurrent episodes of invasive infections especially with encapsulated organisms may be helpful in identifying individuals with isolated absence or hypoplasia of the spleen. However, the absence of these features does not exclude splenic malfunction, although it may make the diagnosis more difficult.

Physical

See the list below:

  • The spleen is not usually palpable during the physical examination, except in individuals with thin abdominal musculature. Hence, lack of a palpable of spleen does not confirm asplenia.

  • Patients with sickle cell disease, particularly children, may have enlarged nonfunctional spleens, especially in their earlier years (functional asplenia).

  • In visceral heterotaxy, a right-sided liver may be mistaken for splenic enlargement.

  • The other physical findings depend on the associated anomalies.

Causes

See the list below:

  • Asplenia (and polysplenia) may be sporadic or familial (autosomal dominant).

  • Because congenital asplenia has been documented in multiple members of the same family and because it is a component of several well-defined syndromes, genetic factors may play an important role in its pathogenesis. However, no specific genetic defect has been identified.

  • Both asplenia and polysplenia have been described in the same family; this finding suggests that these defects may define a spectrum of related conditions.

  • The spleen may be surgically removed after significant splenic trauma or rupture.

  • Splenectomy may be part of clinical management in certain clinical disorders, such as idiopathic (autoimmune) thrombocytopenic purpura, hereditary spherocytosis, storage disorders or malignancy, either to prolong red cell or platelet survival, eliminate the physiological and mass effects of massive splenomegaly (pooling), or as part of cancer management, including staging procedure.

 

Workup

Laboratory Studies

Often the first clues to functional asplenia in an asymptomatic patient are abnormalities in the peripheral blood smear.

The initial evaluation should begin with a review to identify Howell Jolly bodies (see the image below).

Peripheral blood smear shows Howell-Jolly (HJ) bod Peripheral blood smear shows Howell-Jolly (HJ) bodies in RBCs.

The nuclear remnants are small, round, densely stained inclusions in RBCs. They can be seen as a normal variant in the newborn period and are occasionally seen in leukemia, steatorrhea, and a variety of anemias (megaloblastic anemia, dyserythropoietic anemia, thalassemia).

The presence of Howell Jolly bodies in the peripheral smear of an individual older than 7 days should suggest splenic dysfunction.

Other red cell abnormalities include an increased presence of target cells, Heinz bodies, Pappenheimer bodies (small basophilic inclusions that contain non-heme iron), reticulocytes, and spherocytes.

In addition, thrombocytosis and leukocytosis are observed because the elimination of senescent cells by the spleen is lost.

Another helpful means of screening the splenic function is by determining the pit (autophagic vacuoles) count (ie, counting the number of pocked erythrocytes).

  • Normally, less than 2% of red cells have these pocks or pits. A pocked erythrocyte count of more than 3.5% suggests functional hyposplenia, and a count of more than 12% is indicative of asplenia.

  • This technique involves the use of special equipment (Nomarski optics) that is not always readily accessible.

An assessment of the argyrophilic granules in the peripheral smear may be a helpful and easy method to detect splenic dysfunction, but the procedure needs further evaluation.

Howell Jolly body quantitation by flow cytometry has also been described as a way to assay for splenic function but is not currently available, except in specialized laboratories.

Imaging Studies

Various imaging modalities may be useful for splenic assessment, including CT scanning, MRI, ultrasonography, and technetium-99m scintigraphy. Although the presence of an anatomical spleen does not ensure its adequate functioning, generally an imaging modality that is noninvasive, simple, and low cost (eg, ultrasonography) may be done initially to look for the spleen.

  • Various imaging modalities may be helpful in defining splenic anomalies.

  • Certain associated anomalies, especially cardiac and visceral changes, often lead to further evaluation of the spleen.

  • Abdominal ultrasonography can be performed to document the presence of the spleen and its size, and newer ultrasonography techniques with color Doppler ultrasonography have shown promise in assessing splenic function. A small spleen with absent parenchymal vascularization on color Doppler ultrasonography has been associated with functional asplenia, but this should be confirmed with further imaging before declaring a patient functionally asplenic.

  • The absence of the spleen is best confirmed with a technetium-99m radionuclide scan. This agent is taken up by the reticuloendothelial cells and enables better assessment of splenic function. Similarly, as a result of functional asplenia, patients with sickle cell disease who still have normal-sized and even enlarged spleens demonstrate absent or decreased splenic uptake of technetium-99m sulfur colloid.

  • Absence of the intrahepatic segment of the inferior vena cava should trigger careful evaluation of abdominal masses, which could represent splenules. These masses can be confused with multiple metastatic lesions in patients, especially adults, in whom asplenia or polysplenia is undiagnosed.

  • MRI or CT scanning of the abdomen may also reveal absence or hypoplasia of the spleen. These studies have no place in the routine workup of isolated asplenia or hyposplenia but may be useful if they are obtained for other accompanying indications, such as visceral heterotaxy. Newer MRI techniques have expanded the role of MRI in the detection and characterization of splenic diseases.

  • Computerized models are available to determine the splenic volume, but this approach is mainly used to judge the increased size (eg, tumors, infiltrations) of organs. With more experience, computerized models may provide important information about conditions that decrease the size and volume of the spleen.

  • If the spleen is not visualized with radiographic imaging and if no hematologic data support the diagnosis of asplenia, the extremely rare condition of wandering spleen may be considered. In this condition, a functional spleen is present; however, because of its long pedicle, it may be in an abnormal location, such as the pelvis.

Histologic Findings

A hypoplastic spleen may exhibit a hyperemic red pulp with underdevelopment of the white pulp and a paucity of lymphoid follicles.

Peripheral blood smear shows Howell-Jolly (HJ) bod Peripheral blood smear shows Howell-Jolly (HJ) bodies in RBCs.

When hyposplenia is secondary to an underlying hemoglobinopathy such as sickle cell disease, specific histologic features may be observed because of infarction (see History).

 

Treatment

Medical Care

Once the diagnosis of anatomic or functional asplenia is confirmed, aggressive management is the key to decreasing the morbidity and mortality associated with this condition. Newborn diagnosis of sickle cell disease is essential because the first manifestation of the hemoglobinopathy in these infants may be an asplenia-related fatal bacteremia. Any episode of fever or signs of infection should be promptly and aggressively treated.

Medical care involves 4 key components: antibiotic prophylaxis, appropriate immunization, aggressive management of suspected infection, and parent education.

Antibiotic prophylaxis

Antibiotic prophylaxis should be initiated immediately upon the diagnosis of asplenia because these patients are at significant risk of pneumococcal infections. For children younger than 2 years, oral penicillin V may be given twice a day. Amoxicillin has also been recommended as an appropriate prophylactic antibiotic. Erythromycin is an alternate choice in patients who are allergic to penicillin.

In general, antimicrobial prophylaxis should be considered for all children with asplenia or splenic dysfunction until age 5 years and for at least 1 year after surgical splenectomy. Some experts recommend continuing prophylaxis into adulthood, particularly for high-risk patients.

Numerous controversies surround when to discontinue antimicrobial prophylaxis in asplenia and hyposplenia (or if it should be discontinued at all). Arguments for cessation of prophylaxis include poor patient compliance and the development of resistant bacterial strains in patients on daily antibiotics. Those in favor of lifelong prophylaxis cite case reports of overwhelming postsplenectomy sepsis that occurs years after removal of the spleen. Currently, most guidelines leave the option open to continue lifelong prophylaxis based on the clinical circumstances of the individual patient.

Immunization

All patients should receive all standard childhood and adolescent immunizations at the recommended age. Most importantly, vaccinations against encapsulated organisms, including pneumococcal conjugate and/or polysaccharide, H influenzae type b conjugate, and meningococcal conjugate and/or polysaccharide vaccines, should be administered on the standard schedule.

Most of the pediatric pneumococcal bacteremias in the United States are caused by the 13 serotypes covered in the conjugate vaccine: 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F. The conjugate vaccine has been effective in dramatically reducing the occurrence of invasive pneumococcal disease. In children younger than 2 years, the incidence of all invasive pneumococcal infections has decreased by 80% after conjugate vaccine was recommended in the routine childhood immunization schedule. Infections caused by vaccine and vaccine-related serotypes have decreased by 90% in older children and adults.

The immunization schedule for pneumococcal conjugate vaccine (PCV13) consists of a primary series of 4 doses (0.5 mL each) at age 2, 4, 6, and 12-15 months. Catch-up immunization schedules are published regarding appropriate dosing schedules for children aged 5 years or younger.

The pneumococcal polysaccharide vaccine against 23 serotypes (PPV23) should be given after age 24 months for supplemental protection. A booster dose of PPV23 is appropriate 3-5 years after the first dose. An update from the Advisory Committee on Immunization Practices (ACIP) recommends that for children aged 6-18 years with immunocompromising conditions, functional or anatomic asplenia, CSF leaks, or cochlear implants who have not previously received 13-valent pneumococcal conjugate vaccine (PCV13), PCV13 should be administered regardless of whether they received the 7-valent pneumococcal conjugate vaccine (PCV7) or the 23-valent pneumococcal polysaccharide vaccine (PPSV23).

Patients should also receive quadrivalent meningococcal vaccine. Four licensed meningococcal vaccines are available in the United States against serotypes A, C, Y, and W-135. Two of these are meningococcal conjugate vaccines (MCV4) and are recommended for infants and toddlers under the age of 2 years who are at an increased risk of invasive meningococcal disease. MCV4 is indicated routinely for all children aged 11-12 years, with a booster given 5 years after the initial vaccine. The availability of a serogroup B vaccine would improve impact and cost-effectiveness of a routine infant meningococcal vaccine program. Patients who were previously vaccinated at age 7 years or older should be revaccinated 5 years after their previous meningococcal vaccine. Patients who were previously vaccinated at age 2-6 years should be revaccinated 3 years after their previous meningococcal vaccine. Although no specific guidelines exist, patients with asplenia should continue to be re-evaluated andrevaccinatedat5-yearintervals.

The ACIP and the American Academy of Pediatrics updated the recommendations for the use of quadrivalent (serogroups A, C, W-135, and Y) meningococcal conjugate vaccines (Menactra [Sanofi Pasteur, Swiftwater, PA] and Menveo [Novartis, Basel, Switzerland]) in adolescents and in people at persistent high risk of meningococcal disease.

A 2-dose primary series should be administered 2 months apart for those who are at increased risk of invasive meningococcal disease because of persistent complement component (eg, C5-C9, properdin, factor H, or factor D) deficiency (age 9 mo to 54 y) or functional or anatomic asplenia (age 2-54 y) and for adolescents with HIV infection. A booster dose should be given 3 years after the primary series, if the primary 2-dose series was given from age 2-6 years and every 5 years for persons whose 2-dose primary series or booster dose was given at age 7 years or older who are at risk of invasive meningococcal disease because of persistent component (eg, C5-C9, properdin, factor H, or factor D) deficiency or functional or anatomic asplenia.[8]

The recommended vaccination schedule for H influenzae type b is a primary series of 3 doses given at age 2, 4, and 6 months or 2 doses given at age 2 and 4 months, depending on the particular conjugate vaccine product administered. A booster dose at age 12 months is recommended for all vaccine products. Children who are undergoing scheduled splenectomy after completion of their primary series and booster dose may benefit from an additional dose of conjugate vaccine at least 7-10 days before surgery. Catch-up immunization schedules regarding H influenzae type b vaccine are published. Patients 5 years or older who never received Hib immunization should receive 1 dose. H influenza type b conjugate vaccine may provide long-term protection to asplenic individuals and should be administered regardless of previous vaccinations and time from splenectomy, even if antibody evaluation is not available.[2, 3]

Yearly influenza vaccine is also recommended to minimize the likelihood of secondary bacterial infections.

Children 2 years of age or older undergoing elective splenectomy should receive 1 or both pneumococcal vaccines and the meningococcal vaccine at least 2 weeks prior to surgery. Children younger than 2 years should receive PCV13 prior to elective splenectomy. Ensure the Hib vaccination series is completed.

Management of suspected infection

The risk of serious bacterial infection is always present in these patients. Many patients have trivial symptoms yet rapidly develop fulminant sepsis and death within hours.

All patients with impaired splenic function with suspected infection must be urgently and promptly evaluated. Obtain blood, urine, and, if indicated, cerebrospinal fluid (CSF) cultures. Initiate broad-spectrum intravenous antibiotics effective against S pneumoniae, H influenzae type b, and N meningitidis. Because of the fulminant nature of infections with these agents, intravenous antibiotics need to be initiated before bacteriological results are available. Second-generation or third-generation cephalosporins may be the initial choices. If multiple-drug resistance is a concern, vancomycin should be added to the regimen. In addition, many patients require supportive care with intravenous fluids, volume expanders, and pressor support.

Because of the potential rapid progression of a serious bacterial infection, some experts recommend that asplenic patients have access to "stand-by" antibiotics, which can be initiated at the first sign of infection (fever, chills, or malaise). That the initiation of "stand-by" antibiotics is not a substitute for seeking immediate medical attention at the onset of an illness cannot be overemphasized.

Patients with asplenia are at an increased risk of sepsis, shock, and meningitis secondary to Capnocytophaga canimorsus resulting from dog, cat, or rodent bites. The diagnosis may be made by means of Gram staining of the buffy coat, blood, and CSF cultures. Early treatment with penicillin is the therapy of choice, but cephalosporins, clindamycin, and erythromycin may also be used.

Parent education

The most important component in the treatment of these patients is parent education. Risks must be explained to all caretakers because they are an integral part of the management team. Seeking medical advice at the first sign of illness is crucial.

Ongoing education must become a part of each physician-parent encounter so that the parents remain vigilant, which allows potentially serious infections to be identified early and managed aggressively. The child should wear a Medic Alert bracelet that reads "Asplenia" or "No Spleen." Written instructions should be given to the parents in a form that they can keep with them. For example, they can be given a wallet-sized card with the child's diagnosis and concise guidelines for early treatment and intervention.

Surgical Care

See the list below:

  • Elective splenectomy for conditions such as hemolytic anemia are strongly discouraged before age 6 years and should be delayed as long as possible.

  • Options to splenectomy should be considered when appropriate. These include partial splenectomy or embolization, conservative management of splenic trauma, and autotransplantation.

  • To the author's knowledge, no data support the routine use of prophylactic antibiotics in the perioperative period.

  • When surgical splenectomy is imminent, administration of pneumococcal, H influenzae type b, and meningococcal vaccines at least 2 weeks before splenectomy, if possible, is appropriate. If the immunizations are not received prior to surgery, some recommend immunization 14-21 days postsurgery because of enhanced immune response, compared with immediately postsurgery.

  • Surgical splenectomy in patients with immunodeficiency should be avoided because of increased risk of invasive bacterial infections.

Activity

See the list below:

  • No restrictions on activities are usually advised.

  • Infections with H influenzae type b and pneumococcal and meningococcal bacteria are known to be increased among immunologically competent children and adults in daycare centers, college dormitories, military barracks, and other crowded facilities. Therefore, the risks of these situations should be explained to patients and their families.

 

Medication

Medication Summary

The aim of medical therapy is to prevent invasive disease secondary to polysaccharide-encapsulated organisms, especially pneumococci. Penicillin and amoxicillin are currently the drugs of choice.

Antibiotics, prophylactic

Class Summary

These agents are used to prevent invasive bacterial disease. Antibiotic prophylaxis is given to patients before they undergo procedures that may cause bacteremia.

Penicillin V (V-Cillin K, Veetids)

Bactericidal β -lactam antibacterial antibiotic. Main activity is against gram-positive organisms such as streptococci, some gram-negative organisms, and anaerobes. Approximately 60% of PO dose is absorbed. Best taken on empty stomach. Some prefer amoxicillin because it is more bioavailable and less expensive. Preferred for children < 2 y. PO susp (125 or 250 mg/mL) available.

Erythromycin base (EES, E-Mycin, Eryc)

Used for those with penicillin hypersensitivity. Limited activity against H influenzae. Bacteriostatic antibiotic that acts mainly by inhibiting protein synthesis. Administer >1-2 h pc. PO susp, chewable tab, and enteric-coated tab available.

Amoxicillin (Amoxil, Trimox)

Superior bioavailability and stability to gastric acid and has broader spectrum of activity than penicillin. Somewhat less active than that of penicillin against Streptococcus pneumococcus. Penicillin-resistant strains also resistant to amoxicillin, but higher doses may be effective. More effective against gram-negative organisms (eg, N meningitidis, H influenzae) than penicillin, thus, may provide better prophylaxis in children < 2 y.

Susp (125, 200, 250, or 400 mg/5 mL) and pediatric drops (50 mg/mL) available.

Vaccines

Class Summary

Active immunization increases resistance to infection. Vaccines consist of microorganisms or cellular components that act as antigens. The administration of the vaccine stimulates the production of antibodies with specific protective properties.

Because of the increased problem of penicillin resistance in S pneumoniae, prevention with PCV7/PCV13 in children or PPV23 in children and adults is mandatory. Similarly, immunizations with the conjugated H influenzae type b vaccine and the meningococcal conjugated or polysaccharide vaccine are essential.

Pneumococcal 7-valent conjugate vaccine (Prevnar)

Sterile solution of saccharides of capsular antigens of S pneumoniae serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F individually conjugated to diphtheria CRM197 protein. These 7 serotypes responsible for >80% of invasive pneumococcal disease in children < 6 y in the United States. Accounts for 74% of penicillin-nonsusceptible S pneumoniae (PNSP) and 100% of pneumococci with high-level penicillin resistance. First dose recommended at age 2 mo but can be given in patient as young as 6 wk. Preferred sites of IM injection include the anterolateral aspect of the thigh in infants or the deltoid muscle of the upper arm in toddlers and young children. Do not inject in gluteal area or areas where a major nerve trunk or blood vessel may be present.

Three 0.5-mL doses for infants aged 7-11 mo (4 wk apart; third dose after first birthday), 2 doses for 12-23 mo (2 mo apart), 1 dose for >24 mo through 9 y. Minor illnesses such as a mild upper respiratory tract infection with or without low-grade fever are generally not contraindications.

Pneumococcal vaccine 13-valent (Prevnar 13)

Indicated for active immunization to prevent invasive disease caused by Streptococcus pneumoniae serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F. Also indicated for prevention of otitis media caused by S pneumoniae serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F.

Pneumococcal vaccine polyvalent (Pneumovax-23, Pnu-Imune 23)

Polyvalent vaccine used for prophylaxis against infection with S pneumoniae. Used in populations with increased risk for pneumococcal pneumonia (eg, >55 y, chronic infection, asplenia, immunocompromise).

Haemophilus influenza type b vaccine (HibTITER, ActHIB, PedvaxHIB)

For routine immunization of children against invasive diseases caused by H influenzae type b. Decreases nasopharyngeal colonization. The CDC Advisory Committee on Immunization Practices (ACIP) recommends that all children routinely receive one of the conjugate vaccines licensed for use in infants beginning at age 2 mo.

Meningitis group A C Y and W-135 vaccine (Menomune)

Capsular polysaccharide antigens (groups A, C, Y, and W-135) of N meningitidis. Used for active immunization against invasive meningococcal disease caused by inclusive serogroups. May be used to prevent and control outbreaks of serogroup C meningococcal disease according to CDC guidelines. Routine vaccination is recommended for high-risk groups (eg, deficiencies in late complement components [C3, C5-C-9], functional or actual asplenia, laboratory or industrial exposure to N meningitidis aerosols, travelers or residents of hyperendemic areas). The vaccine induces antibody response for serogroup A in individuals as young as 3 mo, but it is poorly immunogenic for serogroup C in recipients who are younger than 18-24 mo.

For information concerning geographic areas in which vaccination is recommended, contact the CDC at (404)-332-4559.

Meningococcal conjugate vaccine (Menactra)

Capsular polysaccharide antigens (groups A, C, Y, and W-135) of N meningitidis individually conjugated to diphtheria toxoid proteins. Used for active immunization in individuals aged 2-55 years for the prevention of invasive meningococcal disease caused by inclusive serogroups. Routine vaccination also recommended for high-risk groups (eg, those with deficiencies in late complement components [C3, C5-C-9], functional or anatomic asplenia, properdin deficiencies, and travelers or residents of hyperendemic areas).

Influenza virus vaccine

Indicated for active immunization to prevent influenza a and b viruses. Induces antibodies following administration specific to virus strains contained in vaccine. Influenza vaccine contents are determined annually by the US Public Health Service. Typically, 3 live, attenuated virus strains are included in the formulation each year, which antigenically represent the influenza strains likely to circulate the next flu season.

 

Follow-up

Further Inpatient Care

See the list below:

  • The most difficult and crucial aspect of asplenia is establishing the diagnosis.

    • Although this task is relatively simple in patients with accompanying anomalies, especially complex cyanotic cardiac problems, and in those with a family history of the condition, the patient with isolated asplenia or hyposplenia may not be easily identified.

    • The diagnosis is often made at autopsy.

  • Patients require regular monitoring with an established provider.

  • All immunizations, including routine childhood vaccinations and additional immunizations, are recommended (see Medical Care).

    • These vaccinations should be administered at the earliest opportunity.

    • Close observation and monitoring is mandatory, especially in the first few years of childhood, to educate the family and to ensure compliance with antibiotic prophylaxis.

Prognosis

See the list below:

  • With early diagnosis and aggressive treatment, the long-term prognosis of a child with isolated congenital asplenia is good.

    • The risk of overwhelming sepsis, although it does not end, significantly decreases in individuals older than 5 years.

    • The primary care physician plays an integral role in the identification and long-term treatment of patients with asplenia.

  • Congenital asplenia, polysplenia, and hypoplasia may be underdiagnosed. An increased awareness of their existence may be crucial and life-saving in immunocompromised individuals with these conditions.