Tuberculosis Flashcards
How is incident rate calculated?
Number of cases decided by the population
What is the organism responsible for TB?
Mycobacteria
What species of Mycobacteria is responsible for human disease?
Mycobacterium tuberculosis M.bovis Mycobacterium avid-intracellulare M. kansasii M. malmoense M. xenopii Mycobacterium leprae
Which mycobacteria species are more likely to effect immunocompromised patients?
MOTT - Mycobacterium avium-intracellulare M. kansasii M. malmoense M. xenopii
What are the characteristics of mycobacteria?
Non-motile bacillus
Very slow growing
Aerobic
Very thick cell wall
AAFB
Resistant to acids, alkalis and detergents
Resistant to neutrophil and macrophage destruction
What happens to mycobacteria outdoors?
It is eliminated by UV radiation and infinite dilution
What is histologically characteristic of TB?
Caseous necrosis
What is the consequence of activated macrophages in the pathology of TB?
Tissue destruction
What are the three results of primary infection?
Progressive disease
Contained/latent
Cleared/cured
In how many cases is the primary infection cleared?
In 85% of cases
How does mycobacteria spread inside the body?
Via the lymphatics to the draining hilar lymph nodes and spreads to all the organs of the body
What can happen when the primary infection progresses?
Primary focus continues to enlarge Hilar lymph nodes compress bronchi Lobar collapse Lymph discharge into bronchus Widespread small granulomata Tuberculous bronchopneumonia Tuberculous pleural effusion
What are some post primary infection diseases?
Pulmonary disease Lymph nodes, usually cervical Bone and joint diseases Genito-urinary diseases Males; infertility - vas deferens Females; infertility - uterus, Fallopian tubes Pericardium; constrictive pericarditis Abdomen; ascites, ileal TB → obstruction Adrenal → Addison’s disease Skin; lupus vulgaris
What are the signs and symptoms of TB?
Can be none Cough - sputum Haemoptysis Pleuritic pain Breathlessness Systematically unwell
Who are more likely to have TB?
Immunosuppressed Malnutrition Alcoholics Previous gastric surgery Malignancy Diabetes melitus Adolescence Elderly Recent immigrants from high prevalence country Homeless
