Abscess (6)

Question 1

What is an abscess?

Answer 1

A focal collection of pus that may be caused by seeding of pyogenic organisms into a tissue or by secondary infections of necrotic foci.

Question 2

What is the tissue that the wall of an abscess is characteristically composed of?

Answer 2

Granulation tissue, which is not a true membrane and is not itself pyogenic.

Question 3

What is present inside an abscess?

Answer 3

Central, largely necrotic region
layer of preserved neutrophils,
with a surrounding zone of dilated vessels and fibroblast proliferation indicative of attempted repair.

Question 4

What is pus?

Answer 4

It is a thick, yellowish liquid that is formed as part of an inflammatory response typically associated with an infection and is composed of exudate chiefly containing dead white blood cells (as neutrophils), tissue debris, and pathogenic microorganisms (as bacteria).

Question 5

What are the organisms that can cause abscesses?

Answer 5

• Bacterial: Staph aureus, Streptococcus pyogenes
• Non-bacterial: Fungal, viral, parasitic

Question 6

What is one simple test to detect the cause of an abscess?

Answer 6

Gram stain.

Question 7

What is the cause of fever in an abscess?

Answer 7

Fever is produced in response to substances called pyrogens (TNF, IL-1) that act by stimulating prostaglandin synthesis in the vascular and perivascular cells of the hypothalamus.

Question 8

What is cellulitis?

Answer 8

A spreading bacterial infection of the skin that affects the dermis and subcutaneous fat, characterized by redness, warmth, swelling, and pain.

Question 9

When should antibiotics be given in an abscess?

Answer 9

Antibiotics are indicated if the abscess is not localized (e.g. evidence of cellulitis) or the cavity is not left open to drain freely.

Question 10

What are giant cells?

Answer 10

Giant cells are multinucleated cells derived from the fusion of multiple activated macrophages to form granuloma.

Question 11

What is the most common cause of granuloma formation?

Answer 11

• Tuberculosis.
• Causative agent: Mycobacterium T.B.
• Type of stain: Ziehl-Neelsen stain (Acid fast stain).

Question 12

What changes are seen in a lymph node affected with inflammation?

Answer 12

Reactive follicular hyperplasia.

Question 13

What is the difference between abscess and cellulitis?

Answer 13