TB Flashcards
Bacteria that causes TB
Mycobacterium tuberculosis
Which type of TB is infectious?
pulmonary
Describe the natural history of TB
1) TB spread by coughing
2) 1y infection
3) immune clearance
4) establishment of latent infection
5) reactivation of TB causing disease
6) Back to 1
what is the incubation period of TB?
3-9 months, unusual after 2 years
when are granulomas formed- what stage of infection?
in the adaptive immune phase of containment
5 symptoms of TB
cough (2-3 weeks or longer) fevers unexplained weight loss drenching night sweats lymphadenopathy
3 key features to look out for on a hx
hx of prior TB infection
known or possible TB exposure
current/past residence or travel to an endemic country
what does miliary TB indicate?
haematogenous spread
what is the cheapest test for TB?
staining for acid and alcohol fast bacilli (AAFB)
2 types of microscopy used to diagnose TB
Light
fluorescence
What is the sensitivity of sputum cultures for TB?
80%
What is the specificity of sputum cultures for TB?
98%
why is culture necessary in TB diagnosis?
vital for drug susceptibility testing and species identification
What rapid test can be used for TB diagnosis?
nucleic acid amplification tests
what test for diagnosis of TB can be used in HIV patients?
urine antigen test- detects mycobacterial cell wall glycolipid lipoarabinomannan (urine LAM)
Treatment of TB
2 months RIPE- Rifampicin Isoniazid Pyrazinamide Ethambutol
followed by 4 months of isoniazid and rifampicin
Why are people with HIV so susceptible to TB? (5)
- HIV promotes reactivation of latent TB
- HIV impairs containment of TB
- Accelerates TB pathology
- TB promotes immune activation which enables HIV to infect more CD4 cells
- HIV impairs granuloma formation
10 aspects of the NHS TB strategy for 2015-2020
- improving access to services and ensuring early diagnosis
- providing universal access to high quality diagnostics
- improving treatment and care services
- ensuring comprehensive contact tracing
- improving BCG vaccination uptake
- reducing drug-resistant TB
- tackling TB in under-served populations
- systematically implementing new entrant latent TB screening
- strengthening surveillance monitoring and;
- ensuring an appropriate workforce to deliver TB control.
what was the first anti-Tb drug?
streptomycin
what is directly observed treatment?
initiated for those who are unable to adhere to tx. professional case worker, person trained to be a DOT observer, or a trusted family member or friend will watch the patient take their TB treatment.
key stage of TB mx for public health?
contact tracing
how many sputum samples should you send for analysis?
3
