「Tuberculosis」の版間の差分
ナビゲーションに移動
検索に移動
Vaccipedia.admin (トーク | 投稿記録) |
Vaccipedia.admin (トーク | 投稿記録) |
||
182行目: | 182行目: | ||
==Treatment&Management== | ==Treatment&Management== | ||
+ | *needs prolonged Tx | ||
+ | *needs multiple drugs | ||
+ | |||
+ | ===1st line target=== | ||
+ | *cell wall synthesis | ||
+ | **H - isoniazid (isoniotinic adid '''h'''ydrozide) | ||
+ | **E - '''e'''thanbutol | ||
+ | *DNA synthesis | ||
+ | **R - '''r'''ifampicin | ||
+ | *? | ||
+ | **Z - pyra'''z'''inamide | ||
==Drug-resistant== | ==Drug-resistant== |
2021年4月15日 (木) 16:15時点における版
目次
History
- Died from or infected by Tb
- John Keats (poet)
- George O'well
- Nelson Mandella
- Hippocrates description
- Phthisis (to waste away, consumption)
- Robert Koch found the bacteria 1882
Epidemiology
est. case est. death all form 10mil 1.4mil HIV-ass 0.9 mil 208,000 MDR-Tb ≈558,000 ≈190,000
- 8 countries account for 2/3 of all worldwide Tb
- India
- China
- Indonesia
- the Phillippines
- Pakistan
- Nigeria
- Bangladesh
- South Africa
Transmission
- transmission-influencing factors
- sputum status of index case
- proximity - distance between each other
- time
- susceptibility of person
- [math]\displaystyle{ R_0 \approx r \times c \times d }[/math]
- [math]\displaystyle{ r }[/math] = transmissibility
- to reduce [math]\displaystyle{ r }[/math]
- ealier detection
- rapid commencing of treatment
- reduce aerolization (surgical masks on patients)
- surgical masks on patients reduce infectivity by 56%
- to reduce [math]\displaystyle{ r }[/math]
- [math]\displaystyle{ c }[/math] = susceptibility of contacts
- to reduce [math]\displaystyle{ c }[/math]
- open windows
- Tb airborne transmission risk: windows closed 97%, negative pressure room (ACH12) 39%, windows and doors fully open 33%
- N95 respirator
- ARTs for HIV patients
- open windows
- to reduce [math]\displaystyle{ c }[/math]
- [math]\displaystyle{ d }[/math] = duration of infectivity
- to reduce [math]\displaystyle{ d }[/math]
- treat patients appropriately
- to reduce [math]\displaystyle{ d }[/math]
- [math]\displaystyle{ r }[/math] = transmissibility
Risk factors
- HIV
- malnutrition
- Tb risk inversely correlates with BMI
- diabetes
- diabetes and Tb are syndemic
- diabetes and Tb pathophysiologically exacerbate each other even under treatment condition in terms of hepatotoxicity
- overcrowding
- people per room vs Tb rate per 100,000 (in Canada)
- 0.4-0.6 vs 18.9
- 1.0-1.2 vs 113
- people per room vs Tb rate per 100,000 (in Canada)
- ....
Natural history
- inhalation of M.tb containing droplets
- macrophages phagocytosis
- granuloma + lymphadenopathy
- Ghon complex - primary infection
- 5% local progression/disseminated Tb
- 95% latent Tb
- 10% of latent Tb reactivates in lifetime - secondary Tb
Latent Tb
- 1/3 of the world's population have latent Tb
- modelling approx. 1.7 bil. people
- 10% of those latent Tb people get reactivation in their lifetime
Symptoms
- cough ± sputum ± hemoptysis > 2weeks
- fever
- malaise
- weight loss
Various presentations
pulmonary
- 80-85% of TB diagnosis are pulmonary
extra-pulmonary
lymphadenitis - hilar/other
- cold abscess
- more common in cervical and hilar
- possibly in axillar, inguinal and abdominal
- hilar adenitis DDx - sarcoidosis, lymphoma, histoplasmosis
pleural
- usually uni-lateral
- effusion high LDH, high protein, high lymphocyte
pericardial
- cardiac tamponade
- sequele - carcified pericardium
intestinal
- can mimic Crohn's disease
- most common in ileocecal
meningitis
- often involves 3rd and 6th cranial nerves
- meningeal irritation signs often unaccompanied
cerebral tuberculoma
- DDx primary CNS lymphoma
Pott's disease (vertebral destruction due to TB)
- kyphosis, gibbus formation
- sometimes extends to psoas muscle abscess;
arthritis
- synovial fluid does not necessarily contains enough TB bacteria; fluid culture may miss diagnosis
- IGRA could be clue
skin
- erythema nodosum
- DDx - TB, cryptococcal, sarcoidosis, UC, oral contraceptive, ≈50% idiopathic
- lupus vulgaris
miliary TB
- massive lymphohematogenous dissemination
- nodules diameter <10mm
- liver
- spleen
- bone marrow
- lungs
- pulmonary miliary TB easily missed by chest X-ray
- meninges
Diagnosis
baseline investigation
blood
- full blood count
- clues for TB - leukopenia, anemia, thrombocytopenia
- liver enzyme, renal function, electrolyte
- for baseline to monitor Tx side effect or to adjust dose
- diabetes
- co-infection
- HIV
- Hep B - HBsAg
- Hep C - HCV-Ab
imaging
- chest X-ray
- other targeted imaging
microbiological
smear/microscopy
- Ziehl-Neelsen of sputum
- positive smear needs cavitation
- children and HIV-positive tend not to cavitate
- specificity 98%
- fluorescent
culture - 4-8weeks
- culture is definitive/reference standard
- Lowenstein-Jensen medium
- liquid medium 3 weeks
PCR TB DNA
- Gene Xpert
- Xpert MTB/RIF
- can detect drug resistant
histopathology
- tissue biopsy
- caseating granuloma
- multinucleated giant cells with nuclei arranged like a horseshoe
- caseating granuloma
urinary LAM antigen detection
- mycobacterial cell wall glycolipid antigen lipoarabinomannan (LAM)
- marker of active TB
- specificity 98%
- sensitivity 40-70%
Manteau text/tuberculin skin test (TST)
- low value for diagnosis
Interferon gamma release assay (IGRA)
- T-SPOT/Quantiferon(QFT)
- cannot distinguish between latent/active/used be treated
Treatment&Management
- needs prolonged Tx
- needs multiple drugs
1st line target
- cell wall synthesis
- H - isoniazid (isoniotinic adid hydrozide)
- E - ethanbutol
- DNA synthesis
- R - rifampicin
- ?
- Z - pyrazinamide