Meningitis
37639
225340610
2008-07-13T04:44:44Z
Xris0
2448220
trying to keep consistent with the acronyms
{{DiseaseDisorder infobox
| Name = Meningitis
| Image = Illu_meninges.jpg
| Caption = Meninges of the central nervous system: dura mater, arachnoid, and pia mater.
| DiseasesDB = 22543
| ICD10 = {{ICD10|G|00||g|00}}-{{ICD10|G|03||g|00}}
| ICD9 = {{ICD9|320}}-{{ICD9|322}}
| MedlinePlus = 000680
| eMedicineSubj = med
| eMedicineTopic = 2613
| eMedicine_mult = {{eMedicine2|emerg|309}} {{eMedicine2|emerg|390}}
| MeshID = D008581
}}
'''Meningitis''' is [[inflammation]] of the protective membranes covering the [[brain]] and [[spinal cord]], known collectively as the [[meninges]]. Meningitis may develop in response to a number of causes, usually [[bacteria]], [[virus]]es and other [[pathogen]]s, but also physical injury, [[cancer]] or certain drugs. While some forms of meningitis are mild and resolve on their own, meningitis is a potentially life-threatening condition due to the proximity of the inflammation to the brain and spinal cord. The potential for serious neurological damage or even death necessitates prompt medical attention and evaluation. Infectious meningitis, the most common form, is typically treated with [[antibiotic]]s and requires close observation. Some forms of meningitis (such as those associated with [[meningococcus]], [[mumps virus]] or [[pneumococcus]] infections) may be prevented with [[immunization]].
==Signs and symptoms==
Severe headache is the most common symptom of meningitis (87 percent) followed by [[nuchal rigidity]] ("neck stiffness", found in 83%). The classic triad of diagnostic signs consists of nuchal rigidity (being unable to flex the neck forward), sudden [[Fever#Types|high fever]]<ref>[http://www.webmd.com/solutions/meningitis-teen-risk/symptoms Meningitis Symptoms & Warning Signs<!-- Bot generated title -->]</ref> and altered mental status. All three features are present in only 44% of all cases of infectious meningitis.<ref>{{cite journal |author=van de Beek D, de Gans J, Spanjaard L, Weisfelt M, Reitsma JB, Vermeulen M |title=Clinical features and prognostic factors in adults with bacterial meningitis |journal=N. Engl. J. Med. |volume=351 |issue=18 |pages=1849–59 |year=2004 |pmid=15509818 |doi=10.1056/NEJMoa040845}}</ref> Other signs commonly associated with meningitis are [[photophobia]] (inability to tolerate bright light), [[phonophobia]] (inability to tolerate loud noises), [[irritability]] and [[delirium]] (in small children) and [[seizure]]s (in 20-40% of cases). In infants (0-6 months), swelling of the [[fontanelle]] (soft spot) may be present.
Nuchal rigidity is typically assessed with the patient lying [[Supine position|supine]], and both hips and knees flexed. If pain is elicited when the knees are passively extended ([[Woldemar Kernig|Kernig's sign]]), this indicates nuchal rigidity and meningitis. In infants, forward flexion of the neck may cause involuntary knee and hip flexion ([[Brudzinski's sign]]). Although commonly tested, the sensitivity and specificity of Kernig's and Brudzinski's tests are uncertain.<ref name=Thomas_2002>{{cite journal |author=Thomas KE, Hasbun R, Jekel J, Quagliarello VJ |title=The diagnostic accuracy of Kernig's sign, Brudzinski's sign, and nuchal rigidity in adults with suspected meningitis |journal=Clin. Infect. Dis. |volume=35 |issue=1 |pages=46–52 |year=2002 |pmid=12060874| doi = 10.1086/340979 <!--Retrieved from CrossRef by DOI bot-->}}</ref>
In "meningococcal" meningitis (i.e. meningitis caused by the bacteria ''[[Neisseria meningitidis]]''), a rapidly-spreading [[petechial rash]] is typical, and may precede other symptoms. The rash consists of numerous small, irregular purple or red spots on the trunk, lower extremities, mucous membranes, conjunctiva, and occasionally on the palms of hands and soles of feet. Other clues to the nature of the cause may be the skin signs of [[hand, foot and mouth disease]] and [[genital herpes]], both of which may be associated with viral meningitis.<ref name=LoganMacMahon>{{cite journal |author=Logan SA, MacMahon E |title=Viral meningitis |journal=BMJ |volume=336 |issue=7634 |pages=36–40 |year=2008 |pmid=18174598 |doi=10.1136/bmj.39409.673657.AE}}</ref>
Meninigitis can be diagnosed after death has occurred. The findings from a [[post mortum]] are usually a diffuse (widespread) inflammation of the pia-arachnoid area. [[Neutrophil]] [[leucocytes]] tend to have migrated to the [[cerebrospinal fluid]] and the base of the brain, along with [[cranial nerve]]s and the [[spinal cord]], may be surrounded with pus—as may the [[Meningeal arteries|meningeal vessel]]s.<ref name="OTM1">{{cite book |title=Oxford Textbook of Medicine Volume One |last=Warrell |first=David A |coauthors=''et al'' |year=2003 |publisher=Oxford |isbn=0-19852787-X |pages=1115-1129}}</ref>
==Diagnosis==
===Investigations===
Investigations include [[blood test]]s (electrolytes, liver and kidney function, inflammatory markers and a [[complete blood count]]) and usually [[X-ray]] examination of the chest. The most important test in identifying or ruling out meningitis is analysis of the cerebrospinal fluid (fluid that envelops the brain and the spinal cord) through [[lumbar puncture]] (LP). However, if the patient is at risk for a cerebral mass lesion or elevated [[intracranial pressure]] (recent head injury, a known immune system problem, localizing neurological signs, or evidence on examination of a raised ICP), a lumbar puncture may be contraindicated because of the possibility of fatal [[brain herniation]]. In such cases a [[Computed tomography|CT]] or [[Magnetic resonance imaging|MRI]] scan is generally performed prior to the lumbar puncture to exclude this possibility. Otherwise, the CT or MRI should be performed after the LP, with MRI preferred over CT due to its superiority in demonstrating areas of cerebral edema, ischemia, and meningeal inflammation.
During the lumbar puncture procedure, the opening pressure is measured. A pressure of over 180 mm H<sub>2</sub>O is indicative of bacterial meningitis.
The cerebrospinal fluid (CSF) sample is examined for [[white blood cell]]s (and which subtypes), [[red blood cell]]s, [[protein]] content and [[glucose]] level. [[Gram staining]] of the sample may demonstrate bacteria in bacterial meningitis, but absence of bacteria does not exclude bacterial meningitis; [[microbiological culture]] of the sample may still yield a causative organism. The type of white blood cell predominantly present predicts whether meningitis is due to bacterial or [[virus|viral]] infection. Other tests performed on the CSF sample include [[latex agglutination test]], [[limulus lysate]]s, or [[polymerase chain reaction]] (PCR) for bacterial or viral DNA. If the patient is [[immunodeficiency|immunocompromised]], testing the CSF for [[toxoplasmosis]], [[Epstein-Barr virus]], [[cytomegalovirus]], [[JC virus]] and [[fungi|fungal infection]] may be performed.
{| style="background:#FDF5E6;padding:0.3em; margin-left:5px; border:1px solid #996666"
|+ style="color:#996666"|'''CSF finding in different conditions'''<ref>{{cite book |last=Provan |first= Drew|authorlink= |coauthors=Andrew Krentz |title= Oxford Handbook of clinical and laboratory investigation|year=2005 |publisher=Oxford university press |location=Oxford |isbn=0198566638 }}</ref>
!bgcolor="#FFEFD5"|Condition !! bgcolor="#FFEFD5"|Glucose !! bgcolor="#FFEFD5"|Protein!!bgcolor="#FFEFD5"|Cells
|-
! bgcolor="#FFEFD5"|Acute bacterial meningitis
| Low|| high||high, often > 300/mm³
|-
! bgcolor="#FFEFD5"|Acute viral meningitis
|Normal ||normal or high|| [[Lymphocyte|mononuclear]], < 300/mm³
|-
! bgcolor="#FFEFD5"|Tuberculous meningitis
|Low ||high||[[pleocytosis]], mixed < 300/mm³
|-
! bgcolor="#FFEFD5"|Fungal meningitis
|Low||high||< 300/mm³
|-
! bgcolor="#FFEFD5"|Malignant meningitis
|Low ||high||usually mononuclear
|-
! bgcolor="#FFEFD5"|Subarachnoid hemorrhage
|Normal ||normal, or high ||[[Erythrocytes]]
|}
[[Image:Streptococcus pneumoniae meningitis, gross pathology 33 lores.jpg|thumb|200px|right|An [[autopsy]] demonstrating signs of [[pneumococcus|pneumococcal]] '''meningitis'''. The [[forceps]] (center) are retracting the [[dura mater]] (white). Underneath the dura mater are the [[leptomeninges]], which are [[edema]]tous and have multiple small [[hemorrhage|hemorrhagic]] foci (red).]]
In bacterial meningitis, the CSF glucose to serum glucose ratio is < 0.4. The Gram stain is positive in >60% of cases, and culture in >80%. Latex agglutination may be positive in meningitis due to ''[[Streptococcus pneumoniae]]'', ''[[Neisseria meningitidis]]'', ''[[Haemophilus influenzae]]'', ''[[Escherichia coli]]'', Group B Streptococci. Limulus lysates may be positive in Gram-negative meningitis.
Cultures are often negative if CSF is taken after the administration of antibiotics. In these patients, [[polymerase chain reaction|PCR]] can be helpful in arriving at a diagnosis. It has been suggested that CSF [[cortisol]] measurement may be helpful.<ref>{{cite journal | title=Cortisol levels in cerebrospinal fluid correlate with severity and bacterial origin of meningitis | author=Holub M, Beran O, Dzupova O, ''et al.'' | journal=Critical Care | year=2007 | volume=11 | pages=R41 | doi=10.1186/cc5729 }}</ref>
Aseptic meningitis refers to non-bacterial causes of meningitis and includes infective etiologies such as [[viruses]] and [[fungi]], neoplastic etiologies such as carcinomatous and lymphomatous meningitis, inflammatory causes such as [[sarcoidosis]] ([[neurosarcoidosis]])) and chemical causes such as meningitis secondary to the intrathecal introduction of [[radiocontrast|contrast media]].
Although the term "viral meningitis" is often used in any patient with a mild meningeal illness with appropriate CSF findings, certain patients will present with clinical and CSF features of viral meningitis, yet ultimately be diagnosed with one of the other conditions categorized as "aseptic meningitis". This may be prevented by performing [[polymerase chain reaction|PCR]] or [[serology]] on CSF or blood for common viral causes of meningitis ([[enterovirus]], [[herpes simplex virus|herpes simplex virus 2]] and [[mumps]] in those not vaccinated for this).<ref name=LoganMacMahon/>
A related diagnostic and therapeutic conundrum is the "partially treated meningitis", i.e. meningitis symptoms in patients who have already been receiving antibiotics (such as for presumptive [[sinusitis]]). In these patients, CSF findings may resemble those of viral meningitis, but antibiotic treatment may need to be continued until there is definitive positive evidence of a viral cause (e.g. a positive [[enterovirus]] PCR).<ref name=LoganMacMahon/>
===Prediction rules===
The Bacterial Meningitis Score predicts reliably whether a child (older than two months) may have infectious meningitis. In children with at least 1 risk factor (positive CSF Gram stain, CSF absolute neutrophil count ≥ 1000 cell/µL, CSF protein ≥ 80 mg/dL, peripheral blood absolute neutrophil count ≥ 10,000 cell/µL, history of seizure before or at presentation time) it had a [[sensitivity (tests)|sensitivity]] of 100%, [[specificity (tests)|specificity]] of 63.5%, and negative predictive value of 100%.<ref>{{cite journal |author=Nigrovic LE, Kuppermann N, Macias CG, ''et al'' |title=Clinical prediction rule for identifying children with cerebrospinal fluid pleocytosis at very low risk of bacterial meningitis |journal=JAMA |volume=297 |issue=1 |pages=52–60 |year=2007 |pmid=17200475 |doi=10.1001/jama.297.1.52}}</ref>
==Causes==
Most cases of meningitis are caused by [[microorganisms]], such as [[viruses]], [[bacteria]], [[fungi]], or [[parasite]]s, that spread into the blood and into the cerebrospinal fluid (CSF).<ref name=Sherris>{{cite book | author = Ryan KJ, Ray CG (editors) | title = Sherris Medical Microbiology | pages = 876–9 |edition = 4th ed. | publisher = McGraw Hill | year = 2004 | isbn = 0838585299 }}</ref> Non-infectious causes include [[cancer]]s, [[systemic lupus erythematosus]] and certain [[drugs]]. The most common cause of meningitis is viral, and often runs its course within a few days. Bacterial meningitis is the second most frequent type and can be serious and life-threatening. Numerous microorganisms may cause bacterial meningitis, but ''[[Neisseria meningitidis]]'' ("meningococcus") and ''[[Streptococcus pneumoniae]]'' ("pneumococcus") are the most common pathogens in patients without immune deficiency, with meningococcal disease being more common in children. ''[[Staphylococcus aureus]]'' may complicate neurosurgical operations, and ''[[Listeria monocytogenes]]'' is associated with poor nutritional state and alcoholism. ''[[Haemophilus influenzae]]'' (type B) incidence has been much reduced by immunization in many countries. ''[[Mycobacterium tuberculosis]]'' (the causative agent of [[tuberculosis]]) rarely causes meningitis in Western countries but is common and feared in countries where tuberculosis is endemic.
==Treatment==
===Initial treatment===
Meningitis is a life-threatening condition and treatment should not be delayed for confirmation if suspected.<ref name="oxford">{{cite book | last = Longmore | first = Murray | coauthors = Ian Wilkinson, Tom Turmezei, Chee Kay Cheung | title = Oxford Handbook of Clinicial Medicine | publisher = Oxford | date = 2007 | pages = 806-807 | isbn = 0-19-856837-1 }}</ref> If a physician is present on scene then treatment should begin immediately with [[benzylpenicillin]]. High-flow [[oxygen]] should be administered as soon as possible, along with an [[intravenous]] fluids if [[hypotension|hypotensive]] or in [[shock (medical)|shock]].<ref name="oxford"/>
===Bacterial meningitis===
Bacterial meningitis is a [[medical emergency]] and has a high mortality rate if untreated.<ref name=Beckham_2006>{{cite journal |author=Beckham J, Tyler K |title=Initial Management of Acute Bacterial Meningitis in Adults: Summary of IDSA Guidelines |journal=Rev Neurol Dis |volume=3 |issue=2 |pages=57–60 |year=2006 |pmid=16819421}}</ref> All suspected cases, however mild, need emergency medical attention. [[Empiric antibiotics]] must be started immediately, even before the results of the [[lumbar puncture]] and [[Cerebrospinal fluid|CSF]] analysis are known. Antibiotics started within 4 hours of lumbar puncture will not significantly affect lab results. Adjuvant treatment with [[corticosteroids]] reduces rates of mortality, severe hearing loss and neurological sequelae in adults, specifically when the causative agent is ''Pneumococcus''.<ref>{{cite journal |author=van de Beek D, de Gans J, McIntyre P, Prasad K |title=Corticosteroids for acute bacterial meningitis |journal=Cochrane database of systematic reviews (Online) |volume= |issue=1 |pages=CD004405 |year=2007 |pmid=17253505 |doi=10.1002/14651858.CD004405.pub2}}</ref>
{| class = "prettytable" style = "float:right; font-size:85%; margin-left:15px"
|-
! Age group
! Causes
|-
| [[Neonate]]s
| Group B Streptococci, ''[[Escherichia coli]]'', ''[[Listeria monocytogenes]]''
|-
| Infants
| ''[[Neisseria meningitidis]]'', ''[[Haemophilus influenzae]]'', ''[[Streptococcus pneumoniae]]''
|-
| Children
|''N. meningitidis'', ''S. pneumoniae''
|-
| Adults
| ''S. pneumoniae'', ''N. meningitidis'', [[Mycobacteria]], [[Cryptococcus|Cryptococci]]
|}
The choice of antibiotic depends on local advice. In most of the developed world, the most common organisms involved are ''[[Streptococcus pneumoniae]]'' and ''[[Neisseria meningitidis]]'': first line treatment in the UK is a third-generation [[cephalosporin]] (such as [[ceftriaxone]] or [[cefotaxime]]). In those under 3 years of age, over 50 years of age, or immunocompromised, [[ampicillin]] should be added to cover ''[[Listeria monocytogenes]]''.<ref name="oxford">{{cite book | last = Longmore | first = Murray | coauthors = Ian Wilkinson, Tom Turmezei, Chee Kay Cheung | title = Oxford Handbook of Clinicial Medicine | publisher = Oxford | date = 2007 | pages = 841 | isbn = 0-19-856837-1 }}</ref> In the U.S. and other countries with high levels of penicillin resistance, the first line choice of antibiotics is [[vancomycin]] and a [[carbapenem]] (such as [[meropenem]]). In [[sub-Saharan Africa]], oily [[chloramphenicol]] or [[ceftriaxone]] are often used because only a single dose is needed in most cases.
Staphylococci and gram-negative bacilli are common infective agents in patients who have just had a neurosurgical procedure. Again, the choice of antibiotic depends on local patterns of infection: [[cefotaxime]] and [[ceftriaxone]] remain good choices in many situations, but [[ceftazidime]] is used when ''[[Pseudomonas aeruginosa]]'' is a problem, and intraventricular [[vancomycin]] is used for those patients with intraventricular shunts because of high rates of [[Staphylococcus|staphylococcal]] infection. In patients with intracerebral prosthetic material (metal plates, electrodes or implants, etc.) then sometimes [[chloramphenicol]] is the only antibiotic that will adequately cover infection by ''[[Staphylococcus aureus]]'' (cephalosporins and carbapenems are inadequate under these circumstances).
Once the results of the CSF analysis are known along with the Gram-stain and culture, empiric therapy may be switched to therapy targeted to the specific causative organism and its sensitivities. {{Fact|date=September 2007}}
*''[[Neisseria meningitidis]]'' (Meningococcus) can usually be treated with a 7-day course of IV antibiotics:
**Penicillin-sensitive -- [[penicillin]] G or [[ampicillin]]
**Penicillin-resistant -- [[ceftriaxone]] or [[cefotaxime]]
**Prophylaxis for close contacts (contact with oral secretions) -- [[rifampin]] 600 mg bid for 2 days ''(adults)'' or 10 mg/kg bid ''(children)''. Rifampin is not recommended in pregnancy and as such, these patients should be treated with single doses of [[ciprofloxacin]], [[azithromycin]], or [[ceftriaxone]]
*''[[Streptococcus pneumoniae]]'' (Pneumococcus) can usually be treated with a 2-week course of IV antibiotics:
**Penicillin-sensitive -- [[penicillin]] G
**Penicillin-intermediate -- [[ceftriaxone]] or [[cefotaxime]]
**Penicillin-resistant -- [[ceftriaxone]] or [[cefotaxime]] + [[vancomycin]]
*''[[Listeria monocytogenes]]'' is treated with a 3-week course of IV [[ampicillin]] + [[gentamicin]].
*Gram negative bacilli -- [[ceftriaxone]] or [[cefotaxime]]
*''[[Pseudomonas aeruginosa]]'' -- [[ceftazidime]]''
*''[[Staphylococcus aureus]]''
**Methicillin-sensitive -- [[nafcillin]]
**Methicillin-resistant -- [[vancomycin]]
*''[[Streptococcus agalactiae]]'' -- [[penicillin]] G or [[ampicillin]]
*''[[Haemophilus influenzae]]'' -- [[ceftriaxone]] or [[cefotaxime]]
===Viral meningitis===
Patients diagnosed with mild viral meningitis may improve quickly enough to not require admission to a hospital, while others may be hospitalized for many more days for observation and supportive care. Overall, the illness is usually much less severe than bacterial meningitis.
Unlike bacteria, viruses cannot be killed by antibiotics. Drugs such as [[acyclovir]] may be employed if herpes virus infection is either suspected or demonstrated.<ref name=LoganMacMahon/>
===Fungal meningitis===
This form of meningitis is rare in otherwise healthy people but is a higher risk in those who have [[AIDS]], other forms of [[immunodeficiency]] (an immune system that does not respond adequately to infections) and [[immunosuppression]] (immune system malfunction as a result of medical treatment). In AIDS, ''[[Cryptococcus neoformans]]'' is the most common cause of fungal meningitis; it requires [[Indian ink]] staining of the CSF sample for identification of this capsulated yeast. Fungal meningitis is treated with long courses of highly dosed [[Antifungal drug|antifungals]].<ref>{{cite journal |author=Gottfredsson M, Perfect JR |title=Fungal meningitis |journal=Seminars in neurology |volume=20 |issue=3 |pages=307–22 |year=2000 |pmid=11051295| doi = 10.1055/s-2000-9394 <!--Retrieved from CrossRef by DOI bot-->}}</ref>
==Complications==
In children there are several potential disabilities which result from damage to the nervous system. These include [[sensorineural]] hearing loss, [[epilepsy]], [[cerebral oedema|diffuse brain swelling]], [[hydrocephalus]], [[cerebral vein thrombosis]], [[Intracranial hemorrhage|intra cerebral bleeding]] and [[cerebral palsy]].<ref> {{cite journal|title=Neurological complications of pneumococcal meningitis|journal=Developmental Medicine and Child Neurology|date=Jan 2004|first=G|last=Vasallo|coauthors=T R Martland|volume=Vol. 46|issue=|pages= pg. 11|id= |url=|format=|accessdate=2007-09-03 }}</ref> Acute neurological complications may lead to adverse consequences. In childhood acute bacterial meningitis deafness is the most common serious complication. [[Sensorineural hearing loss]] often develops during first few days of the illness as a result of [[inner ear]] dysfunction, but permanent deafness is rare and can be prevented by prompt treatment of meningitis.<ref name="pmid9068303">{{cite journal |author=Richardson MP, Reid A, Tarlow MJ, Rudd PT |title=Hearing loss during bacterial meningitis |journal=Arch. Dis. Child. |volume=76 |issue=2 |pages=134–8 |year=1997 |pmid=9068303 |doi=}}</ref>
Those that contract the disease during the [[neonatal]] period and those infected by ''S. pneumoniae'' and gram negative [[bacilli]] are at greater risk of developing neurological, auditory, or [[intellectual impairment]]s or functionally important behaviour or [[learning disorder]]s which can manifest as poor school performance.<ref name="pmid11546680">{{cite journal |author=Grimwood K |title=Legacy of bacterial meningitis in infancy. Many children continue to suffer functionally important deficits |journal=BMJ |volume=323 |issue=7312 |pages=523–4 |year=2001 |pmid=11546680 |doi=}}</ref>
In adults [[central nervous system]] complications include brain infarction, brain swelling, [[hydrocephalus]], intracerebral bleeding; systemic complications are dominated by septic [[shock]], [[adult respiratory distress syndrome]] and [[disseminated intravascular coagulation]].<ref name="pmid8503793">{{cite journal |author=Pfister HW, Feiden W, Einhäupl KM |title=Spectrum of complications during bacterial meningitis in adults. Results of a prospective clinical study |journal=Arch. Neurol. |volume=50 |issue=6 |pages=575–81 |year=1993 |pmid=8503793 |doi=}}</ref> Those who have underlying predisposing conditions e.g. head injury may develop recurrent meningitis.<ref name="pmid17682979">{{cite journal |author=Adriani KS, van de Beek D, Brouwer MC, Spanjaard L, de Gans J |title=Community-acquired recurrent bacterial meningitis in adults |journal=Clin. Infect. Dis. |volume=45 |issue=5 |pages=e46–51 |year=2007 |pmid=17682979 |doi=10.1086/520682}}</ref> [[Case-fatality ratio]] is highest for [[gram-negative]] [[etiology]] and lowest for meningitis caused by [[Haemophilus influenzae|''H. influenzae'']] (also a gram negative bacilli). Fatal outcome in patients over 60 years of age is more likely to be from systemic complications e.g. [[pneumonia]], [[sepsis]], cardio-respiratory failure; however in younger individuals it is usually associated with neurological complications.<ref name="pmid17682979">{{cite journal |author=Adriani KS, van de Beek D, Brouwer MC, Spanjaard L, de Gans J |title=Community-acquired recurrent bacterial meningitis in adults |journal=Clin. Infect. Dis. |volume=45 |issue=5 |pages=e46–51 |year=2007 |pmid=17682979 |doi=10.1086/520682}}</ref> Age more than 60, low [[Glasgow coma scale]] at presentation and [[seizure]] within 24 hours increase the risk of death among community acquired meningitis.<ref name="pmid8416268">{{cite journal |author=Durand ML, Calderwood SB, Weber DJ, ''et al'' |title=Acute bacterial meningitis in adults. A review of 493 episodes |journal=N. Engl. J. Med. |volume=328 |issue=1 |pages=21–8 |year=1993 |pmid=8416268| doi = 10.1056/NEJM199301073280104 <!--Retrieved from CrossRef by DOI bot-->}}</ref>
==Prevention==
===Immunization===
Vaccinations against ''[[Haemophilus influenzae]]'' ([[Hib vaccine|Hib]]) have decreased early childhood meningitis significantly.<ref name="pmid10756001">{{cite journal |author=Peltola H |title=Worldwide Haemophilus influenzae type b disease at the beginning of the 21st century: global analysis of the disease burden 25 years after the use of the polysaccharide vaccine and a decade after the advent of conjugates |journal=Clin. Microbiol. Rev. |volume=13 |issue=2 |pages=302–17 |year=2000 | doi= 10.1128/CMR.13.2.302-317.2000 |pmid=10756001 |accessdate=2007-09-03}}</ref>
Vaccines against type A and C ''[[Neisseria meningitidis]]'', the kind that causes most disease in preschool children and teenagers in the [[United States]], have also been around for a while. Type A is also prevalent in sub-[[Sahara]] Africa and W135 outbreaks have affected those on the [[Hajj]] pilgrimage to [[Mecca]]. Immunisation with the ACW135Y vaccine against four strains is now a visa requirement for taking part in the Hajj.<ref>{{cite web |url=http://www.meningitis.org/disease-info/vaccines/vaccines-for-travel-hajj-pilgrims |title=Vaccines for travel and Hajj pilgrims |date=[[February 1]], [[2007]] |publisher=Meningitis Research Foundation |accessdate=2008-06-25}}</ref>
Vaccines against type B ''Neisseria meningitidis'' are much harder to produce, as its capsule is very weakly [[immunogenic]] masking its antigenic proteins. There is also a risk of autoimmune response, and the porA and porB proteins on Type B resemble neuronal molecules. A vaccine called ''[[MeNZB]]'' for a specific strain of type B Neisseria meningitidis prevalent in [[New Zealand]] has completed trials and is being given to many people in the country under the age of 20 free of charge. There is also a vaccine, MenBVac, for the specific strain of type B meningoccocal disease prevalent in [[Norway]], and another specific vaccine for the strain prevalent in [[Cuba]].{{fact|date=May 2008}} According to reports released in May 2008, [[Novartis]] is in the advanced stages of testing a general meningococcus type B vaccine.<ref>{{cite web | author=BBC News Health | url=http://news.bbc.co.uk/1/hi/health/7400593.stm | title=Meningitis B trials "encouraging" | accessdate=2008-05-15}}</ref>
[[Pneumococcal polysaccharide vaccine]] against ''[[Streptococcus pneumoniae]]'' is recommended for all people 65 years of age or older. [[Pneumococcal conjugate vaccine]] is recommended for all newborns starting at 6 weeks - 2 months, [[American Academy of Pediatrics]] (AAP) recommendations.<ref>{{cite web |url=http://www.cispimmunize.org/IZSchedule_Childhood.pdf |title=Recommended Immunization Schedule for Persons Aged 0–6 Years |author=[[Centers for Disease Control and Prevention|CDC]] Advisory Committee on Immunization Practices, [[American Academy of Pediatrics]], and [[American Academy of Family Physicians]] |year=2008 |accessdate=2008-06-25 |publisher=CDC}}</ref>
[[Mumps]] vaccination has led to a sharp decline in mumps virus associated meningitis, which prior to vaccination occurred in 15% of all cases of mumps.<ref name=LoganMacMahon/>
===Prophylaxis===
In cases of meningococcal meningitis, prophylactic treatment of close relatives with antibiotics (e.g. [[rifampicin]], [[ciprofloxacin]] or [[ceftriaxone]]) may reduce the risk of further cases.<ref>{{cite journal |author=Fraser A, Gafter-Gvili A, Paul M, Leibovici L |title=Antibiotics for preventing meningococcal infections |journal=Cochrane database of systematic reviews (Online) |volume= |issue=4 |pages=CD004785 |year=2006 |pmid=17054214 |doi=10.1002/14651858.CD004785.pub3}}</ref>
==Epidemiology==
[[Image:Meningite.png|right|thumb|Demography of [[meningococcus|meningococcal]] meningitis. Red: meningitis belt, orange: epidemic meningitis, grey: sporadic cases]]
Meningitis can affect anyone in any age group, from the newborn to the elderly.
The "Meningitis Belt" is an area in [[sub-Saharan Africa]] which stretches from [[Senegal]] in the west to [[Ethiopia]] in the east in which large epidemics of meningococcal meningitis occur (this largely coincides with the [[Sahel]] region). It contains an estimated total population of 300 million people. The largest epidemic outbreak was in 1996, when over 250,000 cases occurred and 25,000 people died as a consequence of the disease.
==History==
Meningitis was first described in the 1020s in [[Avicenna]]'s ''[[The Canon of Medicine]]'',<ref>Patricia Skinner (2001), [http://findarticles.com/p/articles/mi_g2603/is_0007/ai_2603000716 Unani-tibbi], ''Encyclopedia of Alternative Medicine''</ref> and again more accurately by [[Ibn Zuhr|Avenzoar]] of [[al-Andalus]] in the 12th century.<ref name=Araguz>Martin-Araguz, A.; Bustamante-Martinez, C.; Fernandez-Armayor, Ajo V.; Moreno-Martinez, J. M. (2002). "Neuroscience in al-Andalus and its influence on medieval scholastic medicine", ''Revista de neurología'' '''34''' (9), p. 877-892.</ref> Symptoms of the disease were also noted in 1805 by the Swiss [[Gabinetto Vieusseux]] (a scientific-literary association) during an outbreak in [[Geneva]], [[Switzerland]]. In 1887, Dr. [[Anton Weichselbaum]] (1845-1920) of [[Vienna]] became the first to isolate the specific germ, meningococcus.<ref>{{WhoNamedIt|synd|3451|Weichselbaum's meningococcus}}</ref>
In the 19th century, meningitis was a scourge of the [[Imperial House of Japan|Japanese imperial family]], playing the largest role in the horrendous pre-maturity mortality rate the family endured. In the mid-1800s, only the [[Emperor Kōmei]] and two of his siblings reached maturity out of fifteen total children surviving birth. Kōmei's son, the [[Emperor Meiji]], was one of two survivors out of Kōmei's six children, including an elder brother of Meiji who would have taken the throne had he lived to maturity. Five of Meiji's 15 children survived, including only his third son, [[Emperor Taishō]], who was [[feeble-minded]], perhaps as a result of having contracted meningitis himself. By Emperor [[Hirohito]]'s generation the family was receiving modern medical attention. As the focal point of tradition in Japan, during the [[Tokugawa Shogunate]] the family was denied modern "Dutch" medical treatment then in use among the upper caste; despite extensive modernization during the [[Meiji Restoration]] the Emperor insisted on [[Traditional Japanese medicine|traditional medical care]] for his children.{{fact|date=January 2008}}
==See also==
* [[Encephalitis]]
* [[Maurice Hilleman]]
==References==
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==External links==
* {{dmoz|/Health/Conditions_and_Diseases/Neurological_Disorders/Meningitis/}}
* [http://www.who.int/mediacentre/factsheets/fs141/en/ WHO: Meningococcal meningitis]
* [http://www.merck.com/mrkshared/mmanual/section14/chapter176/176a.jsp Merck Manual: Central nervous system infections]
* [http://www.immunisation.nhs.uk/ Vaccination information from the NHS, UK]
* [http://www2.ncid.cdc.gov/travel/yb/utils/ybGet.asp?section=dis&obj=menin.htm CDC: Meningococcal disease]
* [http://www.cnn.com/HEALTH/library/DS/00118.html CNN Health Library, Meningitis]
* [http://www.meningitisfoundationofamerica.org Meningitis Foundation of America]
* [http://www.meningitisuk.org Information on Meningitis UK and the charity's search for a vaccine]
* [http://www.meningitis-trust.org Information from the Meningitis Trust]
* [http://www.meningitis-trust.org.nz Information from the Meningitis Trust in New Zealand]
* [http://www.nmaus.org Information from the National Meningitis Association - U.S.]
* [http://www.meningitis.org Symptoms & disease information from Meningitis Research Foundation]
* [http://www.meningitis.org/symptoms/other-languages Meningitis Research Foundation - symptoms information in 22 languages]
{{Diseases of the nervous system}}
[[Category:Diseases involving the fasciae]]
[[Category:Inflammations]]
[[Category:Medical emergencies]]
[[Category:Neurological disorders]]
[[af:Meningitis]]
[[ar:التهاب سحايا]]
[[ca:Meningitis]]
[[cs:Meningitida]]
[[da:Meningitis]]
[[de:Meningitis]]
[[el:Μηνιγγίτιδα]]
[[es:Meningitis]]
[[eo:Meningito]]
[[eu:Meningitis]]
[[fa:مننژیت]]
[[fr:Méningite]]
[[gl:Meninxite]]
[[ko:수막염]]
[[hr:Meningitis]]
[[id:Meningitis]]
[[is:Heilahimnubólga]]
[[it:Meningite]]
[[he:דלקת קרום המוח]]
[[kk:Миқұрт]]
[[la:Meningitis]]
[[lt:Meningitas]]
[[hu:Agyhártyagyulladás]]
[[ms:Meningitis]]
[[nl:Hersenvliesontsteking]]
[[ja:髄膜炎]]
[[no:Hjernehinnebetennelse]]
[[pl:Zapalenie opon mózgowo-rdzeniowych]]
[[pt:Meningite]]
[[ro:Meningită]]
[[qu:Ñutqu p'istuq llika unquy]]
[[ru:Менингит]]
[[sq:Meningjiti]]
[[simple:Meningitis]]
[[sl:Meningitis]]
[[fi:Aivokalvontulehdus]]
[[sv:Hjärnhinneinflammation]]
[[vi:Viêm màng não]]
[[tr:Menenjit]]
[[zh:脑膜炎]]