Tuberculosis

Question 1

Stains that don’t work on TB

Answer 1

• Acid Fast
• Alcohol fast

Question 2

Special stain for TB

Answer 2

Ziehl-Neelsen Stain

Question 3

Enumerate routes transmission of TB

Answer 3

• Air borne (inhalation)
• Ingestion
• Skin contact

Question 4

Primary sites of TB on the body

Answer 4

• Lung
• Intestine
• Tonsil
• Skin

Question 5

Describe pathogenesis of Tuberculosis

Answer 5

it’s a Type 4 Hypersensitivity reaction:
* 1st exposure: Mycobacterium enters Macrophage unchecked
* 1 week: bacteria proliferates inside the Macrophages in the blood –> Bacillemia
* some macrophages are degenerated, and antigens are released and Expressed onto APCs (antigen presenting cells) —> Activates T lymphocytes
* 10 days: T helper 1 are activated
* 3 weeks: T helper 1 Migrate to inflammatory site & release Interferone Gamma (INF-Y) —> Activates Macrophages into Epithelioid cells
* Epitheloid cells fuse to form giant langerhans cells
* they release chemicals —> Central caseation
* if reactivated –> rapid mobilisation –> tissue necrosis

Question 6

Cytokine released by activated TH1 cells to activate Macrophages into Epitheloid cells

Answer 6

INFy

Question 7

Substances secreted by Epithelioid cells in TB

Answer 7

• TNF (tissue nicrotic factor)
• MIF (migration inhibitory factor)
• NO
• ROS