M103 T4 L12 Flashcards
(52 cards)
How is TB spread?
by airborne droplets
when it is inhaled, it is deposited in terminal airspaces
How does a patient develop an active primary TB infection?
when the TB bacteria transported to the regional lymph node start to multiply inside the macrophage endosome
How does a patient develop an latent TB infection?
when the TB bacteria transported to the regional lymph node lie dormant inside the macrophage endosome
If a patient with a latent TB infection is immunocompetent, what is the chance of the bacteria reactivating?
15%
If a patient with a latent TB infection is immunocompetent, what is the chance of the bacteria reactivating within the first five years of the primary infection?
half of the people that are going to reactivate it will activated within the first five years.
Is TB bacteria aerobic or not?
aerobic
How often do TB bacteria divide?
16 - 20 hours
slowly
Does TB bacteria have a cell wall and a cell membrane?
has a cell wall
doesn’t have a PPLPD cell membrane
Does TB bacteria respond to Gram stains and why?
no bc it doesn’t have a PPLPD cell membrane
How is TB bacteria stained?
with acid - it is an acid fast bacilli
it retains stains after treatment with acids
What type of necrosis is affiliated with TB?
caseation
Where are acid fast bacilli found in TB bacteria when looking down a microscope?
in granulomas
Where are acid fast bacilli found in TB bacteria when looking down a microscope?
in granulomas
Who are particularly at risk of transmitting TB to others?
people who are the close contacts of infectious cases (smear +)
people who have contact with high risk groups
people who are immunedeficient
people who have high risk lifestyle factors
What are two types of high risk groups for TB?
High incidence country
Frequent travel to high incidence areas
What conditions would compromise the immunocompetency of pneumonia patients?
HIV Steroids Chemotherapy and biologics Nutritional deficiency (lack of vit D) Diabetes End stage renal failure
people who have high risk lifestyle factors
Drug/alcohol misuse
Homelessness/hostels/overcrowding
Prison inmates
Genetic susceptibility (twin studies of gene polymorphisms)
Which vitamin is tested for in pneumonia?
vitamin D
How is active TB diagnosed?
the infected area is identified
the organism is isolated
info regarding susceptibility to antibacterials is obtained
How is latent TB diagnosed?
the immune response to TB proteins or TB-specific antigens is identified
What was the most common type of latent screening test?
The tuberculin skin test (Mantoux)
What are disadvs of the tuberculin skin test?
requires a nurse to see the patient on two occasions, one
ideally requires blood tests
the tuberculin can cross react with other mycobacteria antigens
if the patient is really ill or is immunosuppressed, the patient won’t mount a response
What is one limitation of the Interferon Gamma Release Assays?
cannot tell us is whether there’s active disease
What is the most common type of latent screening test?
Interferon Gamma Release Assays
