Asplenia
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2008-06-23T11:50:16Z
Thijs!bot
1392310
robot Adding: [[pl:Asplenia]]
:''This article is about the medical condition. For the [[moth]] [[genus]], see [[Armadini]]. For spleenwort [[fern]]s, see ''[[Asplenium]].
{{Infobox_Disease
| Name = Asplenia
| Image =
| Caption =
| 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 = {{OMIM2|%271400}} {{OMIM2|208540}}
| MedlinePlus =
| eMedicineSubj = ped
| eMedicineTopic = 150
| eMedicine_mult = {{eMedicine2|radio|58}}
| MeshID =
}}
'''Asplenia''' refers to the absence ('a-') 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.
==Causes==
* '''[[Congenital]] asplenia''' (rare) may be due to genetic disorders, [[heterotaxy syndrome]], or exposure to environmental factors during gestation.<ref>{{cite journal |author= |title=A 3-Month-Old With Sepsis |work=New Orleans Citywide Rounds |journal=Infect Med |year=1999 |volume=16 |issue=5 |pages=311–316 |url=http://www.medscape.com/viewarticle/417489_4 |format=Final Diagnosis and Discussion}}</ref>
* '''[[Acquired disorder|Acquired]] asplenia''' occurs for several reasons:
**After [[splenectomy]] (surgical removal) e.g. after [[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. [[ITP]], [[thalessemia]], [[spherocytosis]]) where the spleen's usual activity exacerbates the disease
**Due to underlying diseases that destroy the spleen ([[autosplenectomy]]), e.g. [[sickle-cell disease]].
* '''''Functional'' asplenia''' occurs when splenic tissue is present but does not work well, e.g. [[sickle-cell disease]], [[polysplenia]]; these patients are managed as if asplenic.
===Partial splenectomy and preservation of splenic function===
In an effort to preserve some of the spleen's protective roles,<ref name="pmid957066">{{cite journal |author=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 |author=Bader-Meunier B, Gauthier F, Archambaud F, ''et al'' |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}}</ref> or partial splenic [[embolization]].<ref name="pmid18028435">{{cite journal |author=Pratl B, Benesch M, Lackner H, ''et al'' |title=Partial splenic embolization in children with hereditary spherocytosis |journal=Eur J Haematol |volume= 0|issue= |pages=071119202650002|year=2007 |pmid=18028435 |doi=10.1111/j.1600-0609.2007.00979.x}}</ref>
This may be particularly important in poorer countries where protective measures for patients with asplenia are not available.<ref name="pmid18031639">{{cite journal |author=Sheikha AK, Salih ZT, Kasnazan KH, ''et al'' |title=Prevention of overwhelming postsplenectomy infection in thalassemia patients by partial rather than total splenectomy |journal=Can J Surg |volume=50 |issue=5 |pages=382–6 |year=2007 |pmid=18031639 |doi=}}</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 |author=Kimber C, Spitz L, Drake D, ''et al'' |title=Elective partial splenectomy in childhood |journal=J. Pediatr. Surg. |volume=33 |issue=6 |pages=826–9 |year=1998 |pmid=9660206 |doi=10.1016/S0022-3468(98)90651-0}}</ref>
==Risks==
Asplenia increases the risk of [[septicaemia]] from encapsulated bacteria, and can result in a syndrome known as [[overwhelming post splenectomy infection]] (OPSI) which can kill within a few hours. In particular, patients are at risk from [[Pneumococcus]], ''[[Haemophilus influenzae]]'', and [[meningococcus]]. The risk is elevated as much as 350-fold.<ref name="RedBook2006">[[AAP Red Book]] 2006.</ref>
The risk to asplenic patients has been expressed as equivalent for a child to die in home accident, and for adults dying in a road traffic accident (reference UK Splenectomy Trust Advice) - so sensible precautions are needed, but no panic.<!--
--><ref>{{cite web | title=Splenectomy and Infection | url=http://www.ekpt.nhs.uk/pdf/PILs/EKHT_Leaflets/Splenectomy_and_Infection.pdf | format=PDF | date=March 2002 | publisher=Splenectomy Trust | accessdate=2006-12-12}} - reprint from Kent and Medway NHS and Social Care Partnership Trust</ref>
==Management==
To minimise the risks, antibiotic & vaccination protocols have been established,<!--
--><ref name="BMJ1996">{{cite journal | author= | 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 | url=http://bmj.bmjjournals.com/cgi/content/full/312/7028/430}}</ref><!--
--><ref name="BMJ2001">{{cite journal | author=J M Davies et al | 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 | year=2001-06-02 | url=http://bmj.bmjjournals.com/cgi/eletters/312/7028/430#12088}}</ref> <!--
-->but are often poorly adhered to by doctors and patients.<!--
--><ref name="JCP2000">{{cite journal | author=Waghorn DJ | title=Overwhelming infection in asplenic patients: current best practice preventive measures are not being followed | journal=J Clin Pathol | year=2001 | pages=214–8 | volume=54 | issue=3 | pmid=11253134 | url=http://jcp.bmjjournals.com/cgi/content/full/54/3/214 | doi=10.1136/jcp.54.3.214}}</ref>
===Antibiotic prophylaxis===
Because of the increased risk of infection, physicians administer oral antibiotics as a [[prophylaxis]] after a surgical splenectomy (or starting at birth, for congenital asplenia or functional asplenia). The duration suggested varies: one suggestion is that antibiotics be taken for two years or until the age of sixteen years old is reached, whichever is longer.
Patients 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.
===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 those adults who have not been previously vaccinated, two doses given two months apart were 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 |editor=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 |chapterurl=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 |pages= |isbn=0113225288 |oclc= |doi= }} - ''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 immunisations advised for the countries to be visited, Group A meningococcus should be included if visiting counties of particular risk (e.g. sub-saharan Africa). The non-conjugated Meningitis A&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.
Those lacking a functional spleen are at higher risk of catching [[malaria]] and dying from this. Travel to malarial areas will carry greater risks and may be best avoided. Travellers should take the most appropriate anti-malarial prophylaxis medication and be extra vigilant over measures to prevent mosquito bites.
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 ''C. canimorsus'' and should receive a five day course of [[co-amoxiclav]] ([[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.shb.ie/Nonworddocs/hp/asplenia.pdf | format=PDF | year=2002 September | publisher=UK Southern Health Board}}</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'' - Consider carrying a card, or wearing a [[Medical alert jewelry|special bracelet or necklet]] which says that you do not have a working spleen. This would alert a doctor to take rapid action if you are seriously ill and cannot tell them yourself.
==Footnotes==
{{Reflist|2}}
==External links==
* {{cite web | title=Septicaemia Risks In Patients with Non-functioning Spleens | year=2004 | url=http://www.medik.info/MI_Asplenia_OPSI.doc | format=DOC | publisher=Medik.Info}} - patient factsheet, expanded from the original (UK) Splenectomy Trust 1993 factsheet.
{{Hematology}}
{{Phakomatoses and other congenital malformations not elsewhere classified}}
[[Category:Immune system disorders]]
[[Category:Hematology]]
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