Pathology of Pneumonia: Part 4: chronic Pneumonia and causative agents

Question 1

chronic pneumonia

in what type of patient is chronic pneumonia often seen, how does the lesion usually manifest and what type of lesion usually occurs

Answer 1

• often seen in immuno-comprised patients
• lesion usually manifests as localised lesion
• lesion is usually granulomatous inflammation

Question 2

what 2 types of pathogens can cause chronic pneumonia and give **1 example of one and 3 examples of the other**

you can say it in the form of (X. species)

Answer 2

1. Bacteria:
   - Mycobacterium tuberculosis (M. tuberculosis)
2. Fungi:
   - Histoplasma capsulatum (H. capsulatum)

• Blastomyces dermatitidis (B. dermatitidis)
• Coccidiodies immitis (C. immitis)

Question 3

outline 3 steps of how histoplasma capsulatum be acquired and cause chronic pneumonia

Answer 3

1. histoplasma capsulatum acquired via apsiration of spores from soil contaminated with bird droppings containing this fungi
2. macrophages try to digest spores but are unable so wait for T-cells and adaptive immune system to help
3. this takes time, so it gives time for the fungi to multiply in the lung and cause pneumonia

Question 4

what type of granuloma is seen in patients with chronic pneumonia caused by histoplasma capsulatum

Answer 4

• histoplasmosis granuloma

Question 5

what causes the concentric rings in the histoplasmosis granulomas and what clinical outcome can this lead to?

Answer 5

• concentric calcification causes this
• concentric calcification also leads to fibrosis

Question 6

where can B. dermatitidis be found

Answer 6

in soil

Question 7

what 3 ways can lesions caused by C. immitis present themselves

Answer 7

• pyogenic (pus filled)
• granulomatous
• mixed

Question 8

outline 2 possible outcomes for chronic pneumonia caused by H.capsulatum:

Answer 8

Good outcome:
- spontaneous resolution outcome

bad outcome:
- fibrosis due to concentric calcification outcome