View source for Asplenia

{{about|the medical condition|the moth genus|Asplenia (moth)|the fern genus|Asplenium}}
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'''Asplenia''' is the absence of normal [[spleen]] function and is associated with some serious infection risks. '''Hyposplenism''' is the condition of reduced ('hypo-'), but not absent, splenic functioning.

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

==Causes==

===Congenital===
* '''[[Congenital]] asplenia''' is rare. There are two distinct types of genetic disorders: [[heterotaxy syndrome]]<ref name="OMIM208530">Online Mendelian Inheritance in Man. OMIM entry 208530: Right atrial isomerism; RAI. Johns Hopkins University. [https://web.archive.org/web/20170430021822/http://www.omim.org/entry/208530]</ref> and [[isolated congenital asplenia]].<ref name="OMIM271400">Online Mendelian Inheritance in Man. Johns Hopkins University. [https://omim.org/entry/271400 OMIM entry 271400: Asplenia, isolated congenital; ICAS.] {{Webarchive|url=https://web.archive.org/web/20220122231326/https://www.omim.org/entry/271400 |date=2022-01-22 }}</ref>
* [[polysplenia]]

===Acquired===
'''[[Acquired disorder|Acquired]] asplenia''' occurs for several reasons:
* Following [[splenectomy]] due to [[splenic rupture]] from [[Physical trauma|trauma]] or because of [[tumor]]
* After splenectomy with the ''goal'' of interfering with splenic function, as a treatment for diseases (e.g. [[idiopathic thrombocytopenic purpura]], [[thalassemia]], [[spherocytosis]]), in which the spleen's usual activity exacerbates the disease
* After splenectomy with the goal of arresting the progression of cancers ([[Chronic lymphocytic leukemia]],<ref>{{cite web |last1=Leukemia & Lymphoma Society |title=Chronic Lymphocytic Leukemia |url=https://www.lls.org/sites/default/files/file_assets/PS34_CLL_Booklet_2017_9_7FINAL.pdf |access-date=18 June 2018 |archive-url=https://web.archive.org/web/20180618213647/https://www.lls.org/sites/default/files/file_assets/PS34_CLL_Booklet_2017_9_7FINAL.pdf |archive-date=18 June 2018 |pages=15 |language=en |date=2017}}</ref> [[Hodgkin's disease]] (starting in the 1970s<ref>{{cite journal |last1=Lowenbraun |first1=Stanley |title=Splenectomy in Hodgkin's disease for splenomegaly, cytopenias and intolerance to myelosuppressive chemotherapy |journal=The American Journal of Medicine |date=January 1971 |volume=50 |issue=1 |pages=49–55 |doi=10.1016/0002-9343(71)90204-X |pmid=5539576 |url=https://www.amjmed.com/article/0002-9343(71)90204-X/abstract |access-date=18 June 2018|url-access=subscription }}</ref>), [[non-Hodgkin lymphoma]]<ref>{{cite journal |last1=Xiros |first1=Nikolao |title=Splenectomy in patients with malignant non-Hodgkin's lymphoma |journal=European Journal of Haematology |date=March 2000 |volume=64 |issue=3 |pages=145–50 |doi=10.1034/j.1600-0609.2000.90079.x |pmid=10997879|s2cid=20986297 }}</ref>)
* Due to underlying diseases that destroy the spleen ([[autosplenectomy]]), e.g. [[sickle-cell disease]].
* [[Celiac disease]]: unknown physiopathology.<ref>{{cite journal|last1=Halfdanarson|first1=T. R.|last2=Litzow|first2=M. R.|last3=Murray|first3=J. A.|title=Hematologic manifestations of celiac disease|journal=Blood|date=15 January 2007|volume=109|issue=2|pages=412–421|doi=10.1182/blood-2006-07-031104|pmid=16973955|pmc=1785098}}</ref> In a 1970 study,<ref>{{cite journal|last1=Ferguson|first1=Anne|last2=Hutton|first2=MargaretM.|last3=Maxwell|first3=J.D.|last4=Murray|first4=D.|title=Adult Cœlicac Diseases in Hyposplenic Patients|journal=The Lancet|date=January 1970|volume=295|issue=7639|pages=163–164|doi=10.1016/S0140-6736(70)90405-8|pmid=4189238}}</ref> it was the second most common cause of abnormalities of red blood cells linked to hyposplenism, after surgical splenectomy.

== 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.<ref>{{Cite journal|last=Tarantino|first=Giovanni|date=2013|title=Liver-spleen axis: Intersection between immunity, infections and metabolism|journal=World Journal of Gastroenterology|volume=19|issue=23|pages=3534–42|doi=10.3748/wjg.v19.i23.3534|issn=1007-9327|pmc=3691032|pmid=23801854 |doi-access=free }}</ref>

==Partial splenectomy and preservation of splenic function==
In an effort to preserve some of the spleen's protective roles,<ref name="pmid957066">{{cite journal |vauthors=Grosfeld JL, Ranochak JE |title=Are hemisplenectomy and/or primary splenic repair feasible? |journal=J. Pediatr. Surg. |volume=11 |issue=3 |pages=419–24 |year=1976 |pmid=957066 |doi=10.1016/S0022-3468(76)80198-4}}</ref> attempts are now often made to preserve a small part of the spleen when performing either surgical subtotal (partial) splenectomy,<ref name="pmid11154215">{{cite journal |vauthors=Bader-Meunier B, Gauthier F, Archambaud F |s2cid=22741973 |title=Long-term evaluation of the beneficial effect of subtotal splenectomy for management of hereditary spherocytosis |journal=Blood |volume=97 |issue=2 |pages=399–403 |year=2001 |pmid=11154215 |doi=10.1182/blood.V97.2.399|display-authors=etal|doi-access= }}</ref> or partial splenic [[embolization]].<ref name="pmid18028435">{{cite journal |vauthors=Pratl B, Benesch M, Lackner H |title=Partial splenic embolization in children with hereditary spherocytosis |journal=European Journal of Haematology |volume=80 |issue=1 |pages=76–80|year=2007 |pmid=18028435 |doi=10.1111/j.1600-0609.2007.00979.x|s2cid=41343243 |display-authors=etal}}</ref>
This may be particularly important in poorer countries where protective measures for patients with asplenia are not available.<ref name="pmid18031639">{{cite journal |vauthors=Sheikha AK, Salih ZT, Kasnazan KH |title=Prevention of overwhelming postsplenectomy infection in thalassemia patients by partial rather than total splenectomy |journal=Canadian Journal of Surgery |volume=50 |issue=5 |pages=382–6 |year=2007 |pmid=18031639 |pmc=2386178|display-authors=etal}}</ref>
However, it has been advised that preoperative vaccination is advisable until the remnant splenic tissue can reestablish its function.<ref name="pmid9660206">{{cite journal |vauthors=Kimber C, Spitz L, Drake D |title=Elective partial splenectomy in childhood |journal=Journal of Pediatric Surgery |volume=33 |issue=6 |pages=826–9 |year=1998 |pmid=9660206 |doi=10.1016/S0022-3468(98)90651-0|display-authors=etal}}</ref>

==Risks==
Asplenia is a form of [[immunodeficiency]], increasing the risk of [[sepsis]] from [[polysaccharide encapsulated bacteria]],<ref name=Brigden2001/> 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]].<ref name=Brigden2001>{{Cite journal | last1 = Brigden | first1 = M. L. | title = Detection, education and management of the asplenic or hyposplenic patient | journal = American Family Physician | volume = 63 | issue = 3 | pages = 499–506, 508 | year = 2001 | pmid = 11272299}}</ref> The risk is elevated as much as 350–fold.<ref name="RedBook2006">[[AAP Red Book]] 2006.</ref>

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''.<ref>Kasper, D. et al (2015) Harrison's principles of internal medicine. New York, NY: McGraw-Hill Education</ref>

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.<!--
  --><ref>{{cite web |title=Splenectomy and Infection |url=http://www.ekpt.nhs.uk/pdf/PILs/EKHT_Leaflets/Splenectomy_and_Infection.pdf |date=March 2002 |publisher=Splenectomy Trust |access-date=2006-12-12 |archive-url=https://web.archive.org/web/20070928200658/http://www.ekpt.nhs.uk/pdf/PILs/EKHT_Leaflets/Splenectomy_and_Infection.pdf |archive-date=2007-09-28 }} - reprint from Kent and Medway NHS and Social Care Partnership Trust</ref> [[Thrombocytosis|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.<ref>{{cite web|url=https://www.unboundmedicine.com/5minute/view/Select-5-Minute-Pediatric-Consult/14017/all/Asplenia_Hyposplenia|title=Asplenia/Hyposplenia|website=Unbound Medicine, Inc|access-date=9 July 2021|archive-date=9 July 2021|archive-url=https://web.archive.org/web/20210709185239/https://www.unboundmedicine.com/5minute/view/Select-5-Minute-Pediatric-Consult/14017/all/Asplenia_Hyposplenia|url-status=live}}</ref>

==Management==
To minimise the risks associated with splenectomy, [[antibiotic]] and [[vaccination]] protocols have been established,<ref name="BMJ1996">{{cite journal | author=Working Party of the British Committee for Standards in Haematology Clinical Haematology Task Force | title=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 | journal=BMJ | year=1996 | pages=430–4 | volume=312 | issue=7028 | pmid=8601117 | pmc=2350106 | doi=10.1136/bmj.312.7028.430}}</ref><ref name="BMJ2001">{{cite journal | author=Davies JM | title=The prevention and treatment of infection in patients with an absent or dysfunctional spleen - British Committee for Standards in Haematology Guideline up-date | journal=BMJ | date=2001-06-02 |  url= |volume=312|issue=7028|pages=430–4|doi=10.1136/bmj.312.7028.430 | pmid=8601117 | pmc=2350106|display-authors=etal}} - published as a response by original authors</ref><ref name="pmid12448592">{{cite journal |vauthors=Davies JM, Barnes R, Milligan D, ((British Committee for Standards in Haematology - Working Party of the Haematology-Oncology Task Force)) |title=Update of guidelines for the prevention and treatment of infection in patients with an absent or dysfunctional spleen |journal=Clinical Medicine |volume=2 |issue=5 |pages=440–3 |year=2002 |pmid=12448592 |pmc=4953085 |doi=10.7861/clinmedicine.2-5-440 |url=http://www.bcshguidelines.com/pdf/SPLEEN21.pdf |access-date=2010-02-01 |archive-url=https://web.archive.org/web/20091105161025/http://www.bcshguidelines.com/pdf/SPLEEN21.pdf |archive-date=2009-11-05 }}</ref> but are often poorly adhered to by [[physician]]s and patients due to the complications resulting from antibiotic prophylaxis such as development of an overpopulation of ''[[Clostridioides difficile (bacteria)|Clostridioides difficile]]'' in the intestinal tract.<!--
  --><ref name="JCP2000">{{cite journal | author=Waghorn DJ | title=Overwhelming infection in asplenic patients: current best practice preventive measures are not being followed | journal=Journal of Clinical Pathology | year=2001 | pages=214–8 | volume=54 | issue=3 | pmid=11253134 | pmc=1731383 | doi=10.1136/jcp.54.3.214}}</ref>

===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 respiratory tract infection|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]].<ref>{{cite news |last1=Wick |first1=Jeannette |title=Asplenia Poses Management Challenges |url=https://www.pharmacytimes.com/publications/issue/2006/2006-09/2006-09-5861 |access-date=18 June 2018 |publisher=Pharmacy Times |date=September 1, 2006 |archive-url=https://web.archive.org/web/20130412113108/https://www.pharmacytimes.com/publications/issue/2006/2006-09/2006-09-5861 |archive-date=April 12, 2013}}</ref>

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.<ref>{{cite journal |last1=Huebner |first1=Mitchell |last2=Kristin |first2=Kristin |title=Asplenia and fever |journal=Baylor University Medical Center Proceedings |date=July 2015 |volume=28 |issue=3 |pages=340–1 |doi=10.1080/08998280.2015.11929267 |pmid=26130882 |pmc=4462215 }}</ref>

===Vaccinations===
It is suggested that splenectomized persons receive the following vaccinations, and ideally prior to planned splenectomy surgery:
* [[Pneumococcal polysaccharide vaccine]] (not before 2 years of age).  Children may first need one or more boosters of  [[pneumococcal conjugate vaccine]] if they did not complete the full childhood series.
* [[Haemophilus influenzae type b vaccine]], especially if not received in childhood.  For adults who have not been previously vaccinated,  two doses given two months apart was advised in the new 2006 UK vaccination guidelines (in the UK may be given as a combined Hib/MenC vaccine).<ref name="GreenBook">{{cite book |author=Joint Committee on Vaccination and Immunisation |veditors=Editors Salisbury D, Ramsay M, Noakes K |title=Immunisation Against Infectious Disease 2006 |url=http://www.dh.gov.uk/en/Policyandguidance/Healthandsocialcaretopics/Greenbook/DH_4097254 |chapter=Chapter 7 : Immunisation of individuals with underlying medical conditions |chapter-url=http://www.dh.gov.uk/prod_consum_dh/idcplg?IdcService=GET_FILE&dID=115681&Rendition=Web |format=PDF |publisher=Stationery Office |location=Edinburgh |date=21 December 2006 |isbn=978-0-11-322528-6 |access-date=22 July 2007 |archive-date=2 December 2008 |archive-url=https://web.archive.org/web/20081202224158/http://www.dh.gov.uk/en/Policyandguidance/Healthandsocialcaretopics/Greenbook/DH_4097254 }} - ''see pages 50-1 and table 7.1''</ref>
* [[Neisseria meningitidis#Vaccines|Meningococcal conjugate vaccine]], especially if not received in adolescence.  Previously vaccinated adults require a single booster and non-immunised adults advised, in UK since 2006, to have two doses given two months apart.<ref name="GreenBook"/>  Children too young for the conjugate vaccine should receive [[Neisseria meningitidis#Vaccines|meningococcal polysaccharide vaccine]] in the interim.<ref name="RedBook2006"/>
* [[Influenza vaccine]], every winter, to help prevent getting secondary bacterial infection.

===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).<ref>{{cite book |chapter=Meningococcal - Children and adults with asplenia or splenic dysfunction |title=Immunization against infectious disease - 'The Green Book' |orig-date=2006 |date=24 August 2009 |page=244 |chapter-url=http://www.dh.gov.uk/dr_consum_dh/groups/dh_digitalassets/@dh/@en/documents/digitalasset/dh_104554.pdf |format=PDF |url=http://www.dh.gov.uk/en/Publichealth/Healthprotection/Immunisation/Greenbook |access-date=7 November 2009 |archive-date=26 July 2020 |archive-url=https://web.archive.org/web/20200726101151/http://www.dh.gov.uk/en/Publichealth/Healthprotection/Immunisation/Greenbook |url-status=live }}</ref> 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.<ref>{{cite journal| author=Chief Medical Officer| title=Meningococcal immunisation for asplenic patients| journal=Professional Letter: Chief Medical Officer - Current Vaccine and Immunization Issues| volume=1| page=4| year=2001| publisher=Department of Health| url=http://www.dh.gov.uk/dr_consum_dh/groups/dh_digitalassets/@dh/@en/documents/digitalasset/dh_4013404.pdf| access-date=2009-11-07}}{{Dead link|date=October 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

Those lacking a functional spleen are at higher risk of contracting [[malaria]],<ref name="pmid7496237">{{cite journal |vauthors=Boone KE, Watters DA |title=The incidence of malaria after splenectomy in Papua New Guinea |journal=BMJ |volume=311 |issue=7015 |pages=1273 |date=November 1995 |pmid=7496237 |pmc=2551185 |doi= 10.1136/bmj.311.7015.1273}}</ref> 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.<ref name="BMJ1996"/>

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===
* ''Surgical and dental procedures'' - Antibiotic prophylaxis may be required before certain surgical or dental procedures.
* ''Animal bites'' - adequate antibiotic cover is required after even minor dog or other animal bites. Asplenic patients are particularly susceptible to infection by ''[[Capnocytophaga canimorsus]]'' and should receive a five-day course of [[amoxicillin/clavulanate]] ([[erythromycin]] in patients allergic to penicillin).<!--
  --><ref name="SHB2002-measures">{{cite web | title=Guidelines for the prevention and treatment of infection in patients with an absent or dysfunctional spleen | url=http://www.docstoc.com/docs/11102694/Guidelines-for-the-prevention-and-treatment-of-infection-in | format=PDF | date=September 2002 | publisher=Health Service Executive, Southern Area | location=Wilton, Cork, Ireland | access-date=2009-10-09 | archive-date=2012-03-04 | archive-url=https://web.archive.org/web/20120304130052/http://www.docstoc.com/docs/11102694/Guidelines-for-the-prevention-and-treatment-of-infection-in | url-status=live }}</ref>
* ''Tick bites'' - ''[[Babesiosis]]'' is a rare tickborne infection. Patients should check themselves or have themselves inspected for tick bites if they are in an at-risk situation. Presentation with fever, fatigue, and haemolytic anaemia requires diagnostic confirmation by identifying the parasites within red blood cells on blood film and by specific [[serology]]. [[Quinine]] (with or without [[clindamycin]]) is usually an effective treatment.<!--
  --><ref name="SHB2002-measures"/>
* ''Alert warning'' - People without a working spleen can carry a card, or wear a [[Medical alert jewelry|special bracelet or necklet]] which says that they do not have a working spleen. This would alert a healthcare professional to take rapid action if they become seriously ill and cannot notify them of their condition.<ref>{{cite web |author1=HSC Public Health Agency |title=Splenectomy wallet card |url=https://www.publichealth.hscni.net/publications/splenectomy-wallet-card |website=HSC Public Health Agency |access-date=1 August 2019 |archive-url=https://web.archive.org/web/20190802035458/https://www.publichealth.hscni.net/publications/splenectomy-wallet-card |archive-date=2 August 2019 |location=Belfast |url-status=live }}</ref>

==References==
{{Reflist}}

== External links ==
{{Medical resources
| DiseasesDB      =
| ICD10           = {{ICD10|D|73|0|d|70}}, {{ICD10|Q|89|0|q|80}}
| ICD9            = {{ICD9|289.59}}, {{ICD9|759.01}}
| ICDO            =
| OMIM            = 208530
| OMIM_mult       = {{OMIM|%271400||none}} {{OMIM|208540||none}}
| MedlinePlus     =
| eMedicineSubj   = ped
| eMedicineTopic  = 150
| eMedicine_mult  = {{eMedicine2|radio|58}}
| MeshID          =
| SNOMED CT       = 707147002
}}
{{Lymphatic organ disease}}

[[Category:Immune system disorders]]
[[Category:Diseases of spleen]]