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| {{Infobox_Disease |
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| Name = {{PAGENAME}} |
| | {{Tuberculous meningitis}} |
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| | '''For patient information click [[Tuberculous meningitis (patient information)|here]]''' |
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| DiseasesDB = |
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| ICD10 = {{ICD10|A|17|0|a|15}}, {{ICD10|G|01||g|00}} |
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| ICD9 = {{ICD9|013.0}}, {{ICD9|322.9}} |
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| MedlinePlus = |
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| eMedicineSubj = neuro |
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| eMedicineTopic = 385 |
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| MeshID = D014390 |
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| {{SI}}
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| | {{CMG}} |
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| '''Tuberculous meningitis''' is also called "TB meningitis".
| | {{SK}} TB meningitis; tubercular meningitis |
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| Tuberculous [[meningitis]] is ''[[Mycobacterium tuberculosis]]'' infection of the [[meninges]]. It is the most common form of [[central nervous system|CNS]] [[tuberculosis]].
| | ==[[Tuberculous meningitis overview|Overview]]== |
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| ==Clinical features== | | ==[[Tuberculous meningitis historical perspective|Historical Perspective]]== |
| [[Fever]] and [[headache]] are the cardinal features. [[Confusion]] is a late feature and [[coma]] bears a poor prognosis. [[Meningism]] is absent in a fifth of patients with TB meningitis. Patients may also have focal neurological deficits. | |
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| ==Pathology== | | ==[[Tuberculous meningitis classification|Classification]]== |
| '''[[ Mycobacterium_tuberculosis|Mycobacterium tuberculosis]]''' of the meninges is the cardinal feature and the inflammation is concentrated towards the base of the brain. Infection begins in the lungs and may spread to the meninges by a variety of routes.
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| Blood-borne spread certainly occurs and 25% of patients with [[miliary TB]] have TB meningitis, presumably by crossing the [[blood-brain barrier]]<ref>{{cite journal | title=''Mycobacterium tuberculosis'' invasion and traversal across an invitro human blood-brain barrier as a pathogenic mechanism for central nervous system tuberculosis | author=Jain SK, Paul-Satyaseela M, Lamichhane G, ''et al.'' | journal=J Infect Dis | year=2006 | volume=193 | issue=9 | pages=1287–95 }}</ref>; but a proportion of patients may get TB meningitis from rupture of a cortical focus in the brain (a so-called '''[[Rich focus]]'''); an even smaller proportion get it from rupture of a bony focus in the spine. It is rare and unusual for TB of the spine to cause TB of the [[central nervous system]], but isolated cases have been described.
| | ==[[Tuberculous meningitis pathophysiology|Pathophysiology]]== |
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| ==Diagnosis== | | ==[[Tuberculous meningitis causes|Causes]]== |
| Diagnosis of TB meningitis is made by analysing [[cerebrospinal fluid|CSF]] collected by [[lumbar puncture]]. When collecting CSF for suspected TB meningitis, a minimum of 1[[millilitre|ml]] of fluid should be taken (preferably 5 to 10ml).
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| The CSF usually has a high protein, low glucose and a raised number of lymphocytes. [[Acid-fast bacilli]] are sometimes seen on a CSF smear, but more commonly, ''M. tuberculosis'' is grown in culture. A spiderweb clot in the collected CSF is characteristic of TB meningitis, but is a rare finding.
| | ==[[Tuberculous meningitis differential diagnosis|Differentiating Tuberculous Meningitis from other Diseases]]== |
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| More than half of cases of TB meningitis cannot be confirmed microbiologically, and these patients are treated on the basis of clinical suspicion only. The culture of TB from CSF takes a minimum of two weeks, and therefore the majority of patients with TB meningitis are started on treatment before the diagnosis is confirmed.
| | ==[[Tuberculous meningitis epidemiology and demographics|Epidemiology and Demographics]]== |
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| ===Nucleic acid amplification tests (NAAT)=== | | ==[[Tuberculous meningitis risk factors|Risk Factors]]== |
| This is a heterogeneous group of tests that use [[polymerase chain reaction]] (PCR) to detect mycobacterial nucleic acid. These test vary in which nucleic acid sequence they detect and vary in their accuracy. The two most common commercially available tests are the amplified mycobacterium tuberculosis direct test (MTD, Gen-Probe) and Amplicor. In 2007, a systematic review of NAAT by the NHS Health Technology Assessment Programme concluded that for diagnosing tuberculous meningitis "Individually, the AMTD test appears to perform the best (sensitivity 74% and specificity 98%) [page 87]" <REF NAME="pmid17266837">{{cite journal |author=Dinnes J, Deeks J, Kunst H, Gibson A, Cummins E, Waugh N, Drobniewski F, Lalvani A |title=A systematic review of rapid diagnostic tests for the detection of tuberculosis infection |journal=Health Technol Assess |volume=11 |issue=3 |pages=1-314 |year=2007 |id=PMID 17266837 | url = http://www.hta.nhsweb.nhs.uk/project/1247.asp}}</REF>. In the NHS [[meta-analysis]], they found the pooled prevalence of TB meningitis to be 29% [page 85]; however there was much heterogeneity in the reported sensitivities. Using a [http://medinformatics.uthscsa.edu/calculator/ clinical calculator], these numbers yield a [[positive predictive value]] of 94% and a [[negative predictive value]] of 90%; however the 30% prevalence may be high due to referral bias. Alternate estimates of disease prevalence can be entered into the [http://medinformatics.uthscsa.edu/calculator/ clinical calculator] to refine the predictive values.
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| ===Imaging=== | | ==[[Tuberculous meningitis natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
| Imaging studies such as [[computed tomography|CT]] or [[magnetic resonance imaging|MRI]] may show features strongly suggestive of TB meningitis, but cannot diagnose it.
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| | ==Diagnosis== |
| | [[Tuberculous meningitis history and symptoms|History and Symptoms]] | |
| | [[Tuberculous meningitis physical examination|Physical Examination]] | |
| | [[Tuberculous meningitis laboratory findings|Laboratory Findings]] | |
| | [[Tuberculous meningitis chest x ray|Chest X Ray]] | |
| | [[Tuberculous meningitis CT|CT]] | |
| | [[Tuberculous meningitis MRI|MRI]] | |
| | [[Tuberculous meningitis echocardiography or ultrasound|Echocardiography or Ultrasound]] | |
| | [[Tuberculous meningitis other imaging findings|Other Imaging Findings]] | |
| | [[Tuberculous meningitis other diagnostic studies|Other Diagnostic Studies]] |
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| ==Treatment== | | ==Treatment== |
| ''See: [[tuberculosis treatment]]''
| | [[Tuberculous meningitis medical therapy|Medical Therapy]] | |
| | | [[Tuberculous meningitis surgery|Surgery]] | |
| The treatment of TB meningitis is [[isoniazid]], [[rifampicin]], [[pyrazinamide]] and [[ethambutol]] for two months, followed by isoniazid and rifampicin alone for a further ten months. Steroids are always used in the first six weeks of treatment (and sometimes for longer). A few patients may require [[Immunomodulator|immunomodulatory]] agents such as [[thalidomide]].
| | [[Tuberculous meningitis primary prevention|Primary Prevention]] | |
| | | [[Tuberculous meningitis secondary prevention|Secondary Prevention]] | |
| Treatment must be started as soon as there is a reasonable suspicion of the diagnosis. Treatment must not be delayed while waiting for confirmation of the diagnosis.
| | [[Tuberculous meningitis cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | |
| | [[Tuberculous meningitis future or investigational therapies|Future or Investigational Therapies]] |
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| [[Hydrocephalus]] occurs as a complication in about a third of patients with TB meningitis and will require a ventricular shunt. | | ==Case Studies== |
| | [[Tuberculous meningitis case study one|Case #1]] |
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| ==References== | | ==Related Chapters== |
| <references/>
| | * [[Tuberculosis]] |
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| | [[Category:Tuberculosis]] |
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