Pathology of Pulmonary infections

Question 1

d: pneumonia

Answer 1

Inflammation of one or both lungs due to (but not always) infection

Question 2

describe the pathology of pneumonia

Answer 2

Classical acute inflammatory response Immune system plays part (antibodies lead to opsonisation + phagocytosis of bacteria

Question 3

how is pneumonia classified?

Answer 3

clinical setting
organism
morphology

Question 4

what is often the cause of lobar pneumonia? and how is it acquired in a clinical setting?

Answer 4

Streptococcus pneumoniae (pneumococcus)
community

Question 5

describe the classical acute inflammatory response for pneumonia?

Answer 5

exudation of fibrin rich fluid, neutrophil + macrophage infiltration, resolution

Question 6

describe the role of the immune system in pneumonia

Answer 6

antibodies lead to opsonisation, phagocytosis of bacteria

Question 7

name the complications of pneumonia

Answer 7

fibrous scarring
abscess
bronchiectasis
empyema

Question 8

what factors may cause bronchopneumonia?

Answer 8

COPD
Cardiac Failure
complications in a viral infection
aspiration of gastric contents

Question 9

what organism causes bronchopneumonia? which one is particular common for aspiration?

Answer 9

Strep. Pneumoniae, Haemophilus influenza, Staphylococcus, anaerobes, coliforms

Staph/anaerobes/coliforms

Question 10

d: lung abscess

Answer 10

Localised collection of pus

Tumour-like

Question 11

what are the symptoms of lung abscess and the clinical context?

Answer 11

chronic malaise and fever

aspiration

Question 12

d: bronchiectasis

Answer 12

Abnormal fixed dilatation of the bronchi

Question 13

causes bronchietasis

Answer 13

Usually due to fibrous scarring following infection (pneumonia, tuberculosis, cystic fibrosis)
Also seen with chronic obstruction (tumour)
Dilated airways accumulate infected secretions

Question 14

d: TB

Answer 14

Mycobacterial infection

Question 15

Name the places where TB can occur

Answer 15

lung, gut, kidneys, lymph nodes, skin….

Question 16

what is the classical presentation of pathology of TB?

Answer 16

type IV hypersensitivity

granulomas with caseous necrosis

Question 17

what are the 2 TB causing microorganisms?

Answer 17

M. tuberculosis

M.bovis

Question 18

How do the pathogens cause TB?

Answer 18

to avoid phagocytosis

to stimulate a host T-cell response

Question 19

what does an increased T cell response lead to?

Answer 19

causes granulomatous inflammation, tissue necrosis and scarring
this is hypersensitivity (type IV)

Question 20

Describe the path of a pathogen in Primary TB

Answer 20

inhaled organism phagocytosed and carried to hilar lymph nodes. Immune activation (few weeks) leads to a granulomatous response in nodes (and also in lung) usually with killing of organism.
in a few cases infection is overwhelming and spreads

Question 21

describe how secondary TB occurs

Answer 21

reinfection or reactivation of disease in a person with some immunity
disease tends initially to remain localised, often in apices of lung.
can progress to spread by airways and/or bloodstream

Question 22

describe the tissue changes in primary TB

Answer 22

Small focus (Ghon focus) in periphery of mid zone of lung
Large hilar nodes (granulomatous)

Question 23

describe the tissue changes in secondary TB

Answer 23

Fibrosing and cavitating apical lesion (cancer an important differential diagnosis

Question 24

if a slide is described as military, what does it look like?

Answer 24

millet seeds

Question 25

why does disease reactivate?

Answer 25

Decreased T-cell function
age
coincident disease (HIV)
immunosuppressive therapy (steroids, cancer chemotherapy)
Reinfection at high dose or with more virulent organism

Question 26

what is the immunocompromised host?

Answer 26

patient cant respond normally to an infection as immune system is down

Question 27

name some opportunistic pathogens

Answer 27

virus (cytomegalovirus - CMV)
bacteria (Mycobacterium avium intracellulare)
fungi (aspergillus, candida, pneumocystis)
protozoa (cryptosporidia, toxoplasma)