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Flashcards in TB Deck (11):

Describe transmission of TB

Carried in mucus and saliva droplets released when coughing or sneezing
Others inhale droplets (droplet infection) remain suspended for hours in poorly ventilated areas
close contact with infected person increases rick of developing the disease
Tough bacterium can survive as dust from dried droplets making room of patient infected


What is TB?

Contagious disease caused by bacteria
Respiratory or pulmonary TB is the most common
affects lungs and is contagious


What is latent TB

Bacteria remain dormant - no symptoms but if immune system is weak they can become active again


What are the symptoms?

Coughing, shortness of breath, loss of appetite and weight loss



Skin and blood tests -s small amount of tuberculin is injected under skin of forearm, inflamed area cauased by antiboides indicate TB antigens are present. analyse T cells specific to antigens on TB bacterium
Identification of bacteria - sample of Sputum coughed up is taken and cultured to see bacteria present identified through staining
Chest X-Rays - extent of damage and disease in lungs


What is glandular TB?

Moves to bones, lymph nodes and CNS
Follow an initial pulmonary infection
Enlarged glands in neck or arm pits


Describe role of fever

As part of inflammatory response, fever causing substances are released from neutrophils and macrophages affecting hypothalamus and alter set point for core body temp to a higher temp - effects act ti warm up to the new set point
Raised temp enhances immune function and phagocytosis, bacteria and virus reproduce more slowly


Treatment of TB

Course of antibiotics for 6 months
After 2 weeks people feel better so need to continue


Describe primary infection of TB

Macrophages engulf bacteria
A mass of tissue, known as a granuloma form; these tissue masses are anaerobic and have dead bacteria and macrophages in the middle.
After 3-8 weeks the infection is controlled


Describe active TB

occurs when the patient’s immune system can’t contain the disease any more (because of old age, HIV, malnutrition). Bacteria multiply rapidly and destroy lung tissue. The patient now has symptoms including coughing, shortness of breath and weight loss.


Describe how bacteria evade the immune system

Bacteria can survive in macrophages
Resist killing mechanism used
Thick waxy cell wall so they are hard to break down