Asplenia

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Asplenia
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Asplenia refers to the absence of normal spleen function and is associated with some serious infection risks. Hyposplenism is used to describe reduced ('hypo-') splenic functioning, but not as severely affected as with asplenism.

Contents

Functional asplenia occurs when splenic tissue is present but does not work well (e.g. sickle-cell disease, polysplenia) – such patients are managed as if asplenic – while in anatomic asplenia, the spleen itself is absent.

Causes

Congenital

Acquired

Acquired asplenia occurs for several reasons:

Functional asplenia

Functional asplenia can occur when patients with metabolic or haematological disorders have their splenic tissue organisation altered. This can lead to results similar to those seen in patients who have undergone a splenectomy e.g. becoming infected with encapsulated bacteria such as Haemophilus influenzae, Streptococcus pneumoniae and Neisseria meningitidis. Patients who have some form of asplenia have an increased susceptibility to these encapsulated bacterial infections mainly because they lack IgM memory B cells and their non-adherence to polysaccharide vaccines. Furthermore, there is a deficiency of other splenic cells e.g. splenic macrophages. This combined with the lack of B cells can provide an environment favourable for the development of bacterial infections. [8]

Partial splenectomy and preservation of splenic function

In an effort to preserve some of the spleen's protective roles, [9] attempts are now often made to preserve a small part of the spleen when performing either surgical subtotal (partial) splenectomy, [10] or partial splenic embolization. [11] This may be particularly important in poorer countries where protective measures for patients with asplenia are not available. [12] However, it has been advised that preoperative vaccination is advisable until the remnant splenic tissue can reestablish its function. [13]

Risks

Asplenia is a form of immunodeficiency, increasing the risk of sepsis from polysaccharide encapsulated bacteria, [14] and can result in overwhelming post splenectomy infection (OPSI), often fatal within a few hours. In particular, patients are at risk from Streptococcus pneumoniae , Haemophilus influenzae , and meningococcus. [14] The risk is elevated as much as 350–fold. [15]

The increased risk of infection is due to inability to clear opsonised bacteria from circulating blood. There is also a deficiency of T-cell independent antibodies, such as those reactive to the polysaccharide capsule of Streptococcus pneumoniae. [16]

The risk to asplenic patients has been expressed as equivalent to an adult dying in a road traffic accident (1 to 5 percent of people without spleens would develop a severe infection per decade) (reference UK Splenectomy Trust Advice)—hence sensible precautions are advisable. [17] Increased platelet counts can be seen in individuals without a functioning spleen.

Diagnosis

Diagnosis is confirmed by abdominal ultrasonography and detection of Howell-Jolly bodies in red blood cells. [18]

Management

To minimise the risks associated with splenectomy, antibiotic and vaccination protocols have been established, [19] [20] [21] but are often poorly adhered to by physicians and patients due to the complications resulting from antibiotic prophylaxis such as development of an overpopulation of Clostridioides difficile in the intestinal tract. [22]

Antibiotic prophylaxis

Because of the increased risk of infection, physicians administer oral antibiotics as prophylaxis after a surgical splenectomy, or starting at birth for congenital or functional asplenia.

Those with asplenia are also cautioned to start a full-dose course of antibiotics at the first onset of an upper or lower respiratory tract infection (for example, sore throat or cough), or at the onset of any fever. Even with a course of antibiotics and even with a history of relevant vaccination, persons without a functional spleen are at risk for Overwhelming post-splenectomy infection. [23]

In an emergency room or hospital setting, appropriate evaluation and treatment for an asplenic febrile patient should include a complete blood count with differential, blood culture with Gram stain, arterial blood gas analysis, chest x-ray, and consideration for lumbar puncture with CSF studies. None of these evaluations should delay the initiation of appropriate broad-spectrum intravenous antibiotics. The Surviving Sepsis Campaign guidelines state that antibiotics should be administered to a patient suspected of sepsis within 1 hour of presentation. Delay in starting antibiotics for any reason is associated with a poor outcome. [24]

Vaccinations

It is suggested that splenectomized persons receive the following vaccinations, and ideally prior to planned splenectomy surgery:

Travel measures

In addition to the normal immunizations advised for the countries to be visited, Group A meningococcus should be included if visiting countries of particular risk (e.g. sub-saharan Africa). [26] The non-conjugated Meningitis A and C vaccines usually used for this purpose give only 3 years coverage and provide less-effective long-term cover for Meningitis C than the conjugated form already mentioned. [27]

Those lacking a functional spleen are at higher risk of contracting malaria, [28] and succumbing to its effects. Travel to malarial areas will carry greater risks and is best avoided. Travellers should take the most appropriate anti-malarial prophylaxis medication and be extra vigilant over measures to prevent mosquito bites. [19]

The pneumococcal vaccinations may not cover some of the other strains of pneumococcal bacteria present in other countries. Likewise, their antibiotic resistance may also vary, requiring a different choice of stand-by antibiotic.

Additional measures

Related Research Articles

<span class="mw-page-title-main">Spleen</span> Organ recycling old red blood cells and also housing lymphocytes

The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes from Ancient Greek σπλήν (splḗn).

<span class="mw-page-title-main">Waterhouse–Friderichsen syndrome</span> Adrenal gland failure from internal bleeding, often due to infection

Waterhouse–Friderichsen syndrome (WFS) is defined as adrenal gland failure due to bleeding into the adrenal glands, commonly caused by severe bacterial infection. Typically, it is caused by Neisseria meningitidis.

<span class="mw-page-title-main">Splenectomy</span> Surgical removal of the spleen

A splenectomy is the surgical procedure that partially or completely removes the spleen. The spleen is an important organ in regard to immunological function due to its ability to efficiently destroy encapsulated bacteria. Therefore, removal of the spleen runs the risk of overwhelming post-splenectomy infection, a medical emergency and rapidly fatal disease caused by the inability of the body's immune system to properly fight infection following splenectomy or asplenia.

<span class="mw-page-title-main">Hereditary spherocytosis</span> Genetic disorder causing red blood cells to be spherical

Hereditary spherocytosis (HS) is a congenital hemolytic disorder wherein a genetic mutation coding for a structural membrane protein phenotype causes the red blood cells to be sphere-shaped (spherocytosis), rather than the normal biconcave disk shape. This abnormal shape interferes with the cells' ability to flex during blood circulation, and also makes them more prone to rupture under osmotic stress, mechanical stress, or both. Cells with the dysfunctional proteins are degraded in the spleen, which leads to a shortage of erythrocytes and results in hemolytic anemia.

<i>Streptococcus pneumoniae</i> Species of bacterium

Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, spherical bacteria, alpha-hemolytic member of the genus Streptococcus. S. pneumoniae cells are usually found in pairs (diplococci) and do not form spores and are non motile. As a significant human pathogenic bacterium S. pneumoniae was recognized as a major cause of pneumonia in the late 19th century, and is the subject of many humoral immunity studies.

An overwhelming post-splenectomy infection (OPSI) is a rare but rapidly fatal infection occurring in individuals following removal of the spleen. The infections are typically characterized by either meningitis or sepsis, and are caused by encapsulated organisms including Streptococcus pneumoniae. It is a medical emergency and requires immediate treatment. Death has been reported to occur within 12 hours.

<span class="mw-page-title-main">Splenomegaly</span> Enlargement of the spleen

Splenomegaly is an enlargement of the spleen. The spleen usually lies in the left upper quadrant (LUQ) of the human abdomen. Splenomegaly is one of the four cardinal signs of hypersplenism which include: some reduction in number of circulating blood cells affecting granulocytes, erythrocytes or platelets in any combination; a compensatory proliferative response in the bone marrow; and the potential for correction of these abnormalities by splenectomy. Splenomegaly is usually associated with increased workload, which suggests that it is a response to hyperfunction. It is therefore not surprising that splenomegaly is associated with any disease process that involves abnormal red blood cells being destroyed in the spleen. Other common causes include congestion due to portal hypertension and infiltration by leukemias and lymphomas. Thus, the finding of an enlarged spleen, along with caput medusae, is an important sign of portal hypertension.

An autosplenectomy is a negative outcome of disease and occurs when a disease damages the spleen to such an extent that it becomes shrunken and non-functional. The spleen is an important immunological organ that acts as a filter for red blood cells, triggers phagocytosis of invaders, and mounts an immunological response when necessary. Lack of a spleen, called asplenia, can occur by autosplenectomy or the surgical counterpart, splenectomy. Asplenia can increase susceptibility to infection. Autosplenectomy can occur in cases of sickle-cell disease where the misshapen cells block blood flow to the spleen, causing scarring and eventual atrophy of the organ. Autosplenectomy is a rare condition that is linked to certain diseases but is not a common occurrence. It is also seen in systemic lupus erythematosus (SLE).

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Pneumococcal polysaccharide vaccine, sold under the brand name Pneumovax 23, is a pneumococcal vaccine that is used for the prevention of pneumococcal disease caused by the 23 serotypes of Streptococcus pneumoniae contained in the vaccine as capsular polysaccharides. It is given by intramuscular or subcutaneous injection.

<i>Neisseria meningitidis</i> Species of bacterium that can cause meningitis

Neisseria meningitidis, often referred to as the meningococcus, is a Gram-negative bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life-threatening sepsis. The bacterium is referred to as a coccus because it is round, and more specifically a diplococcus because of its tendency to form pairs.

<span class="mw-page-title-main">Meningococcal disease</span> Often life-threatening bacterial infection

Meningococcal disease describes infections caused by the bacterium Neisseria meningitidis. It has a high mortality rate if untreated but is vaccine-preventable. While best known as a cause of meningitis, it can also result in sepsis, which is an even more damaging and dangerous condition. Meningitis and meningococcemia are major causes of illness, death, and disability in both developed and under-developed countries.

Artificial induction of immunity is immunization achieved by human efforts in preventive healthcare, as opposed to natural immunity as produced by organisms' immune systems. It makes people immune to specific diseases by means other than waiting for them to catch the disease. The purpose is to reduce the risk of death and suffering, that is, the disease burden, even when eradication of the disease is not possible. Vaccination is the chief type of such immunization, greatly reducing the burden of vaccine-preventable diseases.

<span class="mw-page-title-main">Splenic infarction</span> Medical condition

Splenic infarction is a condition in which blood flow supply to the spleen is compromised, leading to partial or complete infarction in the organ. Splenic infarction occurs when the splenic artery or one of its branches are occluded, for example by a blood clot.

<span class="mw-page-title-main">Pneumococcal conjugate vaccine</span> Vaccine against Strep pneumoniae

Pneumococcal conjugate vaccine is a pneumococcal vaccine made with the conjugate vaccine method and used to protect infants, young children, and adults against disease caused by the bacterium Streptococcus pneumoniae (pneumococcus). It contains purified capsular polysaccharide of pneumococcal serotypes conjugated to a carrier protein to improve antibody response compared to the pneumococcal polysaccharide vaccine. The World Health Organization (WHO) recommends the use of the conjugate vaccine in routine immunizations given to children.

<span class="mw-page-title-main">Pneumococcal vaccine</span> Vaccine to prevent infection by the bacteria Stretococcus pneumoniae

Pneumococcal vaccines are vaccines against the bacterium Streptococcus pneumoniae. Their use can prevent some cases of pneumonia, meningitis, and sepsis. There are two types of pneumococcal vaccines: conjugate vaccines and polysaccharide vaccines. They are given by injection either into a muscle or just under the skin.

<span class="mw-page-title-main">Hib vaccine</span> Haemophilus influenzae type B vaccine

The Haemophilus influenzae type B vaccine, also known as Hib vaccine, is a vaccine used to prevent Haemophilus influenzae type b (Hib) infection. In countries that include it as a routine vaccine, rates of severe Hib infections have decreased more than 90%. It has therefore resulted in a decrease in the rate of meningitis, pneumonia, and epiglottitis.

Pneumococcal infection is an infection caused by the bacterium Streptococcus pneumoniae.

NmVac4-A/C/Y/W-135 is the commercial name for a polysaccharide vaccine that protects against meningococcal meningitis caused by Neisseria meningitidis, specifically the serotypes A, C, Y, and W-135. This vaccine is part of a broader group of meningococcal vaccines. It is especially formulated for use in developing countries, aimed at protecting populations during meningitis outbreaks, particularly in high-risk regions like the African meningitis belt.

<span class="mw-page-title-main">Meningitis</span> Inflammation of the membranes around the brain and spinal cord

Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, intense headache, vomiting and neck stiffness and occasionally photophobia.

Meningococcal vaccine refers to any vaccine used to prevent infection by Neisseria meningitidis. Different versions are effective against some or all of the following types of meningococcus: A, B, C, W-135, and Y. The vaccines are between 85 and 100% effective for at least two years. They result in a decrease in meningitis and sepsis among populations where they are widely used. They are given either by injection into a muscle or just under the skin.

References

  1. ↑ Online Mendelian Inheritance in Man. OMIM entry 208530: Right atrial isomerism; RAI. Johns Hopkins University.
  2. ↑ Online Mendelian Inheritance in Man. Johns Hopkins University. OMIM entry 271400: Asplenia, isolated congenital; ICAS. Archived 2022-01-22 at the Wayback Machine
  3. ↑ Leukemia & Lymphoma Society (2017). "Chronic Lymphocytic Leukemia" (PDF). p. 15. Archived from the original (PDF) on 18 June 2018. Retrieved 18 June 2018.
  4. ↑ Lowenbraun, Stanley (January 1971). "Splenectomy in Hodgkin's disease for splenomegaly, cytopenias and intolerance to myelosuppressive chemotherapy". The American Journal of Medicine. 50 (1): 49–55. doi:10.1016/0002-9343(71)90204-X. PMID   5539576 . Retrieved 18 June 2018.
  5. ↑ Xiros, Nikolao (March 2000). "Splenectomy in patients with malignant non-Hodgkin's lymphoma". European Journal of Haematology. 64 (3): 145–50. doi:10.1034/j.1600-0609.2000.90079.x. PMID   10997879. S2CID   20986297.
  6. ↑ Halfdanarson, T. R.; Litzow, M. R.; Murray, J. A. (15 January 2007). "Hematologic manifestations of celiac disease". Blood. 109 (2): 412–421. doi:10.1182/blood-2006-07-031104. PMC   1785098 . PMID   16973955.
  7. ↑ Ferguson, Anne; Hutton, MargaretM.; Maxwell, J.D.; Murray, D. (January 1970). "Adult Cœlicac Diseases in Hyposplenic Patients". The Lancet. 295 (7639): 163–164. doi:10.1016/S0140-6736(70)90405-8. PMID   4189238.
  8. ↑ Tarantino, Giovanni (2013). "Liver-spleen axis: Intersection between immunity, infections and metabolism". World Journal of Gastroenterology. 19 (23): 3534–42. doi: 10.3748/wjg.v19.i23.3534 . ISSN   1007-9327. PMC   3691032 . PMID   23801854.
  9. ↑ Grosfeld JL, Ranochak JE (1976). "Are hemisplenectomy and/or primary splenic repair feasible?". J. Pediatr. Surg. 11 (3): 419–24. doi:10.1016/S0022-3468(76)80198-4. PMID   957066.
  10. ↑ Bader-Meunier B, Gauthier F, Archambaud F, et al. (2001). "Long-term evaluation of the beneficial effect of subtotal splenectomy for management of hereditary spherocytosis". Blood. 97 (2): 399–403. doi:10.1182/blood.V97.2.399. PMID   11154215. S2CID   22741973.
  11. ↑ Pratl B, Benesch M, Lackner H, et al. (2007). "Partial splenic embolization in children with hereditary spherocytosis". European Journal of Haematology. 80 (1): 76–80. doi:10.1111/j.1600-0609.2007.00979.x. PMID   18028435. S2CID   41343243.
  12. ↑ Sheikha AK, Salih ZT, Kasnazan KH, et al. (2007). "Prevention of overwhelming postsplenectomy infection in thalassemia patients by partial rather than total splenectomy". Canadian Journal of Surgery. 50 (5): 382–6. PMC   2386178 . PMID   18031639.
  13. ↑ Kimber C, Spitz L, Drake D, et al. (1998). "Elective partial splenectomy in childhood". Journal of Pediatric Surgery. 33 (6): 826–9. doi:10.1016/S0022-3468(98)90651-0. PMID   9660206.
  14. 1 2 Brigden, M. L. (2001). "Detection, education and management of the asplenic or hyposplenic patient". American Family Physician. 63 (3): 499–506, 508. PMID   11272299.
  15. 1 2 AAP Red Book 2006.
  16. ↑ Kasper, D. et al (2015) Harrison's principles of internal medicine. New York, NY: McGraw-Hill Education
  17. ↑ "Splenectomy and Infection" (PDF). Splenectomy Trust. March 2002. Archived from the original (PDF) on 2007-09-28. Retrieved 2006-12-12. - reprint from Kent and Medway NHS and Social Care Partnership Trust
  18. ↑ "Asplenia/Hyposplenia". Unbound Medicine, Inc. Archived from the original on 9 July 2021. Retrieved 9 July 2021.
  19. 1 2 Working Party of the British Committee for Standards in Haematology Clinical Haematology Task Force (1996). "Guidelines for the prevention and treatment of infection in patients with an absent or dysfunctional spleen. Working Party of the British Committee for Standards in Haematology Clinical Haematology Task Force". BMJ. 312 (7028): 430–4. doi:10.1136/bmj.312.7028.430. PMC   2350106 . PMID   8601117.
  20. ↑ Davies JM; et al. (2001-06-02). "The prevention and treatment of infection in patients with an absent or dysfunctional spleen - British Committee for Standards in Haematology Guideline up-date". BMJ. 312 (7028): 430–4. doi:10.1136/bmj.312.7028.430. PMC   2350106 . PMID   8601117. - published as a response by original authors
  21. ↑ Davies JM, Barnes R, Milligan D, British Committee for Standards in Haematology - Working Party of the Haematology-Oncology Task Force (2002). "Update of guidelines for the prevention and treatment of infection in patients with an absent or dysfunctional spleen" (PDF). Clinical Medicine. 2 (5): 440–3. doi:10.7861/clinmedicine.2-5-440. PMC   4953085 . PMID   12448592. Archived from the original (PDF) on 2009-11-05. Retrieved 2010-02-01.
  22. ↑ Waghorn DJ (2001). "Overwhelming infection in asplenic patients: current best practice preventive measures are not being followed". Journal of Clinical Pathology. 54 (3): 214–8. doi:10.1136/jcp.54.3.214. PMC   1731383 . PMID   11253134.
  23. ↑ Wick, Jeannette (September 1, 2006). "Asplenia Poses Management Challenges". Pharmacy Times. Archived from the original on April 12, 2013. Retrieved 18 June 2018.
  24. ↑ Huebner, Mitchell; Kristin, Kristin (July 2015). "Asplenia and fever". Baylor University Medical Center Proceedings. 28 (3): 340–1. doi:10.1080/08998280.2015.11929267. PMC   4462215 . PMID   26130882.
  25. 1 2 Joint Committee on Vaccination and Immunisation (21 December 2006). "Chapter 7 : Immunisation of individuals with underlying medical conditions". In Editors Salisbury D, Ramsay M, Noakes K (eds.). Immunisation Against Infectious Disease 2006 (PDF). Edinburgh: Stationery Office. ISBN   978-0-11-322528-6. Archived from the original on 2 December 2008. Retrieved 22 July 2007. - see pages 50-1 and table 7.1
  26. ↑ "Meningococcal - Children and adults with asplenia or splenic dysfunction" (PDF). Immunization against infectious disease - 'The Green Book' (PDF). 24 August 2009 [2006]. p. 244. Archived from the original on 26 July 2020. Retrieved 7 November 2009.
  27. ↑ Chief Medical Officer (2001). "Meningococcal immunisation for asplenic patients" (PDF). Professional Letter: Chief Medical Officer - Current Vaccine and Immunization Issues. 1. Department of Health: 4. Retrieved 2009-11-07.[ permanent dead link ]
  28. ↑ Boone KE, Watters DA (November 1995). "The incidence of malaria after splenectomy in Papua New Guinea". BMJ. 311 (7015): 1273. doi:10.1136/bmj.311.7015.1273. PMC   2551185 . PMID   7496237.
  29. 1 2 "Guidelines for the prevention and treatment of infection in patients with an absent or dysfunctional spleen" (PDF). Wilton, Cork, Ireland: Health Service Executive, Southern Area. September 2002. Archived from the original on 2012-03-04. Retrieved 2009-10-09.
  30. ↑ HSC Public Health Agency. "Splenectomy wallet card". HSC Public Health Agency. Belfast. Archived from the original on 2 August 2019. Retrieved 1 August 2019.
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