Chapter 3 - Infection & Inflammation Flashcards Preview

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Flashcards in Chapter 3 - Infection & Inflammation Deck (35)
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1
Q

What are the features of acute inflammation?

A

Vascular congestion, edema

Fibrinous exudate, tissue damage & necrosis

Neutrophils

2
Q

What can trigger acute inflammation?

How can it resolve?

A

Trauma, ischemia, toxins, infection…

Can be followed by resolution, fibrosis/scar, abscess formation, or chronic inflammatory change

3
Q

Describe the appearance of granulation tissue

A

Watery or myxoid background with inflammatory cells, sparse fibroblasts, and capillaries with prominent endothelium.

4
Q

Describe the appearance of biopsy site changes

A

Fibroblast proliferation (early scar)

Foreign body-type giant cells, foamy macrophages, fat necrosis

Suture material

5
Q

What are the features of chronic inflammation?

A

Increased vascularity and/or fibrosis

Tissue destruction

Lymphoplasmacytic infiltrate

6
Q

What are some activated forms of macrophages?

A

Epithelioid

Foamy

Giant cell (langerhans - ring nuclei, foreign body-type - scattered nuclei)

7
Q

How do histiocytes normally appear?

A

Bland, fading into the background. Granular cytoplasm (phagocytosed junk).

Stream in a circular pattern.

Can be foamy (almost signet-ring like)

8
Q

What can cause granuloma formation?

A

Mycobacterial and fungal infection

Autoimmune disease

Sarcoidosis

Toxins & irritants

9
Q

How d o granulomas appear?

A

Aggregate of histiocytes with surrounding lymphocytes & plasma cells.

Giant cells are helpful but not essential.

Old granulomas can become hyalinized and acellular.

10
Q

Describe the appearance of the following fungi:

Candida

Aspergillus

Mucor

A

Candida: Round-to-oval yeast forms and pseudohyphae (segmented and nonbranching) at the epithelial surface.

Aspergillus: Long, thin hyphae with 45-degree branching and septation. Can be a solid ball or as single hyphae.

Mucor: Irregular and wide nonseptate hyphae. Almost invisible on H&E.

11
Q

Describe the appearance of the following fungi:

Histoplasma

Cryptococcus

Pneumocystis

A

Histoplasma: Tiny intracellular yeast forms with narrow-based budding, either within acrophages or granulomas

Cryptococcus: Encapsulated yeast forms with narrow-based budding, with high size-variability (but larger than histoplasmosis)

Pneumocystis: Flattened, contact-lens shaped in the alveoli. Invisible on H&E but accompanied by foamy pink exudate.

12
Q

Describe the appearance of:

Helicobacter pylori

Actinomyces

A

H. Pylori: Tiny seagull-shaped bacilli in pit lumens or surfaces of a background of chronic inflammatory infiltrates.

Actinomyces: Puffball bacterial colony; granular grey-purple, sometimes filamentous, with no identifiable structures.

13
Q

Distinguish between the appearances of HSV and CMV.

A

HSV: Infects epithelium (look adjacent to ulcer), which become multinucleated with glassy nuclear inclusions.

CMV: Also infects mesenchymal cells (look in ulcer bed), which are enlarged with large nuclei and dense round inclusion within nucleus with a pale halo.

14
Q

Describe the appearances of giardia, trichomonas, and cryptosporidium.

A

Giardia: Flounder with a long tail; kite-shaped at the luminal surface of villi without much inflammation.

Trichomonas: Like giardia, on pap smears

Cryptosporidium: Tiny round parasites along the brush border in the duodenum.

15
Q
A

Acute inflammation & abscess formation

  1. Neutrophils
  2. Extravasated blood
  3. Prominent capillaries
  4. Fibrin accumulation
16
Q
A

Granulation tissue

Arrow: Condensing/thickening of the stroma around capillaries

17
Q
A

Biopsy site changes

Arrow: Foamy histiocyte ingesting some residual fat
Inset: Hemosiderin in macrophages

18
Q
A

Dermal scar

Note displacement of subcutaneous fat and adnexal structures

19
Q
A

Histiocytes (circle) amongst lymphocytes (arrowhead)

20
Q
A

Granulomas in Crohn’s disease; subtle (arrow) with a collar of lymphocytes

21
Q
A

Granulomas in sarcoidosis. Obvious, well-defined masses of pink histiocytes with giant cells (arrowhead)

22
Q
A

Granuloma in TB. Histiocytes only visible at periphery, as core is necrotic (arrow).

23
Q
A

Hyalinized granuloma

24
Q
A

Candida (PAS)

Arrow: Pseudohyphae & yeasts

25
Q
A

Aspergillus (GMS)

Note branching hyphae

26
Q
A

Mucor (PAS)

Note thick, “hollow” irregular outlines

27
Q
A

Histoplasmosis (GMS)

Tiny yeasts (40x objective)

28
Q
A

Cryptococcus (GMS)

Note larger organisms than histoplasmosis (still 40x) and range of sizes & shapes

29
Q
A

Pneumocystis (GMS)

Lung tissue…

30
Q

Describe the appearance of TB and MAC.

A

TB: Bright wine-red, tiny scattered bacilli on AFB. Must scan entire slide at 40x… consider auramine-rhodamine if AFB is negative.

MAC: Profound proliferation within “foamy” macrophages. Can look like Whipple’s disease, but PAS-negative.

31
Q
A

Mycobacteria (AFB)

32
Q
A

H. Pylori in gastric mucosal pits

33
Q
A

Actinomyces

34
Q
A

Herpesvirus

Arrow: Multiple molded nuclei with peripheral rim of chromatin and glassy inclusion nearly replacing chromatin

35
Q
A

Cytomegalovirus

Arrow: Central reddish-dense nuclear inclusion, surrounded by clear halo and rim of purple chromatin