Tuberculosis Flashcards
TB
It’s caused by the bacterium ____.
Mycobacterium tuberculosis
TB
What is latent TB?
What is active TB?
Latent TB: Where the person is infected but does not have active disease and is NOT infectious
Active TB: Where the person is symptomatic and may be infectious.
TB
How does it present?
- cough
- haemoptysis
systemic symptoms:
- fevers
- night sweats
- weight loss
TB
What are some common Ddx?
What other more specific features may those conditions have?
- Pneumonia: characterised by fever, productive cough, and signs of consolidation on examination and chest X-ray
- Lung Cancer: a persistent cough, haemoptysis and weight loss are common symptoms, often in a smoker or former smoker
- COPD: characterised by chronic productive cough, dyspnoea and a history of tobacco or other inhalational exposure
- PE: characterised by acute onset dyspnoea, chest pain and haemoptysis
TB
What is first line investigation?
What are some classic findings (but non-specific)?
CXR
Classic findings may include:
Apical infiltrates
Cavitation
Miliary pattern
TB
What other scane might we do if the cxr is inconclusive?
HRCT
TB
If TB is suspected and a cxr has been done, what is the other imperative investigation?
microbiological confirmation
sputum samples for:
- smear microscopy
- culture
- nucleic acid amplification tests (NAAT)
TB
What is NAAT?
nucleic acid amplification tests
TB
Microbiological Investigations
What is the quickest but least sensitive test?
Sputum smear microscopy
TB
Microbiological Investigations
What is the gold standard? (what is the con about this test?)
Culture
take several weeks for results due to the slow-growing nature of Mycobacterium tuberculosis
TB
Microbiological Investigations
NAAT, such as the Xpert MTB/RIF assay, provides a rapid diagnosis and can simultaneously detect ____ resistance.
rifampicin
TB
What 2 tests are used to diagnose latent TB or when active TB is suspected, but other investigations are inconclusive?
Tuberculin Skin Test
Interferon Gamma Release Assays
TB
Drug Sensitivity Testing
Once the TB bacterium is isolated, drug sensitivity testing is crucial to determine the susceptibility pattern of the Mycobacterium and to guide appropriate treatment.
The NICE guideline recommends universal susceptibility testing for ____ and ____ .
rifampicin and isoniazid
TB
Pharmacological Management
For drug-sensitive TB, the initial intensive phase consists of four drugs:
- Isoniazid
- Rifampicin
- Pyrazinamide
- Ethambutol
These are prescribed for two months, followed by a continuation phase of four months with Isoniazid and Rifampicin.
TB
For latent TB infection, NICE recommends a regimen of Rifinah (which is ____ and ____) for 3 months or Isoniazid alone for 6 months.
Rifampicin + Isoniazid
TB
What 2 drugs does Rifinah consist of?
Rifampicin + Isoniazid
TB
Monitoring during treatment includes what kinds of regular tests?
3
- clinical assessments
- sputum cultures
- LFTs
TB
Monitoring during treatment includes regular clinical assessment, sputum cultures, and liver function tests.
Adverse effects are common and can include: (3)
Hepatotoxicity
Peripheral neuropathy
Hypersensitivity reactions.
TB
Public Health Measures
Once a case is confirmed, what are the next steps?
contact tracing
TB
Public Health Measures
What should those with latent TB be offered?
treatment to prevent progression to active disease
TB
What are some factors implicated in the reactivation of latent tuberculosis?
- HIV co-infection
- Immunosuppressant therapy (chemotherapy/monoclonal antibody treatment), including corticosteroids
- Diabetes mellitus
- End-stage chronic kidney disease
- Malnutrition
- Ageing
TB
A patient with confirmed pulmonary tuberculosis is started on the standard four-drug antitubercular therapy.
What should be the duration of the intensive phase of treatment?
2 months
According to the NICE guideline, the intensive phase of antitubercular therapy for pulmonary tuberculosis is 2 months long. The initial or “intensive” phase typically involves a four-drug regimen of isoniazid, rifampicin, pyrazinamide, and ethambutol.
After the intensive phase, the continuation phase follows. This generally lasts 4 months (making a total standard treatment duration of 6 months) and consists of isoniazid and rifampicin. If there is drug resistance, extrapulmonary involvement or other complications, the duration of treatment may be extended.
