Tuberculosis Flashcards
Tuberculosis is caused by which bacteria?
Mycobacterium Tuberculosis
The most characteristic phenotypic feature of the Mycobacterium Tuberculosis complex is the:
“Acid-fastness” the ability to withstand decolorization with an acid alcohol mixture after coloration
Where do the mycobacterium primarily reside?
Inside the cell (Intracellular pathogens)
Mycobacterium’s relation to oxygen is _________
Obligate aerobes
Mycobacterium, in the presence of a normal immune response, induce a ________ in the tissues
Granulomatous response
Microbiologically, M. Tuberculosis is a:
Rod-shaped, non-spore-forming, thin aerobic bacterium measuring 0.5 to 3 Micro meters
M. Tuberculosis appear _______ on Gram stain
Neutral
the 3 Mycobacterial pathogens that cause tuberculosis are:
M. Tuberculosis
M. Bovis
M. africanum
Other than the 3 main pathogens of the Mycobacterium complex, other members which rarely cause disease include:
M. Microti
M. pinnipedii
M. caprae
_________ is not part of the TB complex but it has been identified to cause TB in a small number of patients from or with connection to east africa
M. Canettii
____ % of cases of TB are estimated to be HIV infected
10
Person-to-person transmission of TB occurs via:
Inhalation of droplet nuclei (Airborne particles 1-5 Microns in diameter)
A person with infectious pulmonary TB often transmits the disease by
Coughing, sneezing or speaking, as it makes the disease particles airborne quickly
A person with TB coughing may have as many as ______ infectious nuclei per cough
3000
Factors associated with risk for TB transmission via droplet nuclei include:
Presence of active untreated pulmonary or laryngeal TB
Presence of cavitary disease
Presence of sputum with positive NAA test for M. TB complex
Presence of sputum with positive smear for acid-fast bacilli [AFB]
Presence of sputum with positive M.TB culture [Even with negative AFB]
Short time [<9 days] to positive M.TB culture
Procedures that can result in the dispersal of droplet nuclei-associated risk for TB transmission include:
Endotracheal intubation
Bronchoscopy
Nebulizer
Inhalation of M.TB and deposition in the lungs can lead to 4 possible outcomes
- immediate clearance of the organism
- primary disease [Rapid progression to active disease]
- Latent infection [with or without subsequent reactivation disease]
- reactivation disease [following a period of latent infection]
TB affects the lungs in about ___% of cases
80
about ___% of TB cases involve extrapulmonary sites [with or without concomitant lung disease]
30
In relation to the site of TB infection, up to two thirds of HIV infected patients with TB may have:
Both Pulmonary and extrapulmonary, or extrapulmonary alone
The most common extrapulmonary site infected by TB?
Lymph nodes
In relation to age, primary TB was considered to be mainly a disease of _______
Childhood
Symptoms and Signs of TB
Fever
Pleuritic or retrosternal chest pain
Describe TB fever
Gradual onset and low grade but could be as high as 39C and lasts an average of 14 to 21 days. It is resolved in 98% of patients by 10 weeks
___% of patients with TB fever developed pleuritic or retrosternal chest pain
25
half of pleuritic chest pain TB patients had evidence of _________
Pleural effusion
Radiographic findings in primary pulmonary TB
Chest radiograph is often normal Hilar adenopathy in 65% Pleural effusion in 1/3 of patients Pulmonary infiltrates were observed in 27 percent of patients Perihilar and right sided infiltrates Contralateral hilar changes
