Respi - lung infection

Question 1

defences of lung

Answer 1

• ciliary action by resp epithelium pushing the microbes trapped by mucus
• cough reflex
• immune response: alveolar macrophages

Question 2

infective lung diseases

Answer 2

• bronchitis & bronchiolitis
• pneumonia
• tuberculosis
• bronchiectasis
• lung abscess

Question 3

bronchitis & bronchiolitis

- 2 examples

Answer 3

bronchitis: infection of bronchi
bronchiolitis: bronchioles

virus:

• RSV (resp syncitial virus)
• influenza tracheobronchitis
• measles/chicken pox: may also spread to lungs

Question 4

pneumonia

+ types of pneumonia (7)

Answer 4

infective inflammation and consolidation of lung
airspaces get filled with inflammatory exudate -> becomes solid/airless

types of pneumonia

• pneumonitis
• bronchopneumonia
• lobar pneumonia
• community/hospital acquired pneumonia
• aspiration pneumonia
• atypical pneumonia
• viral pneumonia

Question 5

pneumonitis

Answer 5

inflammatory disease caused by interstitial inflammation - airways not inflammed yet

also caused by other allergens: toxins, drug reactions, irradiation (exposed to radiation)

Question 6

bronchopneumonia
+ x-ray characteristics
+ who it affects commonly

Answer 6

pneumonic consolidation centered on bronchi -> spreads to involve adjacent alveoli
patchy suppurative inflammation
affects lower lobes more cause of gravity
- common in infancy and elderly

Question 7

lobar pneumonia

- bacteria

Answer 7

rapid spread through alveolar spaces and bronchioles affecting the whole lobe
- strep pneumoniae/ klebsiella -> 1st line antibiotics treatment
prompt treatment!

Question 8

community acquired pneumonia

- bacteria

Answer 8

gram POSITIVE bacteria

• strep pneumonia (most common)
• h.influenzae, legionella, mycoplasma, m.tuberculosis
• viral pneumonia

Question 9

hospital acquired pneumonia

Answer 9

gram NEGATIVE bacteria
- klebsiella, e.coli, pseudomonas
increased risk for pts who are ventilated and intubated
- intubation -> colonisation
BAL (bronchoalveolar lavage) sampling of sputum

Question 10

increase risk of tuberculosis

Answer 10

• diabetes
• chronic lung disease
• alcoholism
• HIV infection
• immunocompromised - opportunistic. even organisms w/ low pathogenicity

Question 11

prevalence of TB

Answer 11

poverty
crowding
chronic debilitating disease

Question 12

TB cause

Answer 12

mycobacterium TB (rod)

• inhaled
• waxy cell wall: resistant to destruction by neutrophils
• susceptible to macrophages, but can still proliferate
• ZN stain positive

Question 13

primary TB

+ possible outcomes (3)

Answer 13

no previous exposure
inhaled -> lymph nodes at lung hilum** (enlarges w/ granulomatous inflammation n caseation + undergo necrosis)

commonly exists as latent TB & stays dormant
may progress to miliary TB if it erodes through blood vessel
Resolution

Question 14

secondary TB

+ outcomes of healing

Answer 14

previous exposure and sensitised
affects immunocompetent adults
- lesion at apex of lung** (further inwards)
may cause tissue destruction -> cavitation

healing:
- leaves area of caseous necrotic material surrounded by thick collagenous wall w/ calcification
- may remain latent but spread when pt becomes immunocompromised
- > destruction of lung tissue, erosion into blood vessels & airways
- > bronchopneumonia/ miliary TB

Question 15

complications of TB

Answer 15

• spread into pleural space via bronchi/ lymphatics

- enters the blood: miliary TB -> spread to pulmonary circulation - can even affect multiple organs

Question 16

immunity against TB

Answer 16

Granulomatous inflammation -> Formation of granulomas
CD4+ T cells secrete cytokines and activate macrophages to kill the bacteria -> formation of epithelioid macrophages and multinucleated giant cells
- ADR: hypersensitivity, tissue destruction

Question 17

miliary TB

Answer 17

appearance on X-ray: white tiny spots distributing the entire lung

Question 18

aspiration pneumonia

• cause
• progression

Answer 18

affects unconscious pts/ impaired swallowing
infection by anaerobes/ oropharyngeal bacteria
inhalation of gastric contents

may lead to formation of lung abscesses

Question 19

atypical pneumonia

• bacteria
• clinical and X-ray presentation

Answer 19

infiltration of the alveolar interstitium by chronic inflammatory cells
- mycoplasma, chlamydia, rickettsia

presents w/ pneumonia symptoms
X-ray: absence of consolidation

Question 20

viral pneumonia

Answer 20

influenza: H5N1, SARS, COVID-19

Question 21

HIV infection causing lung disease

- progression

Answer 21

opportunistic infection: PCP (pneumocystis carinii)
difficult to diagnose and control

may develop into cancer (lung cancer, Kaposi sarcoma, non-hodgkin lymphoma)

Question 22

bronchiectasis

+ characteristics

Answer 22

permanent abnormal dilation of main bronchi

• purulent secretions
• chronic inflammation of wall
• loss of normal resp epithelium

may have recurrent infection
may present w/ haemoptysis
infection may spread to surrounding lung

Question 23

bronchiectasis pathogenesis

2 main factors

Answer 23

problem w/ drainage of secretions

• obstruction of airway
• viscous mucus (cystic fibrosis)
• immotile cilia

recurrent and persistent infection

Question 24

bronchiectasis complications

Answer 24

• chronic suppurative inflammation
• lung abscess
• hematogenous spread of infection
• secondary amyloidosis
• cor pulmonale -> RHF

Question 25

lung abscess | - causes (5)

Answer 25

localised area of suppurative necrosis -> form large cavities infection causes: - pulmonary infarction - aspiration of infective material - infection through the airways - bronchial obstruction -> occlusion of airways - bronchiectasis - staph aureus

Question 26

complications of lung abscess (4)

Answer 26

- septic embolism : formed by multiple abscesses - rupture into pleura : empyema (pus), pneumothorax (air) - erosion into pulmonary vessel -> haemorrhage - bacteremia (bacteria entering the bloodstream)

Question 27

respiratory illnesses in children

Answer 27

developmental: - bronchial atresia - bronchogenic cysts - bronchopulmonary sequestration neonatal respiratory distress syndrome (NRDS) affecting lungs: - immotile cilia syndrome - cystic fibrosis

Question 28

bronchial atresia

Answer 28

tube like structure of airways not formed properly

Question 29

bronchogenic cysts

Answer 29

parts of the bronchial that is sealed off from the rest of the airway

Question 30

bronchopulmonary sequestration

Answer 30

portion of lung that does not communicate w/ normal bronchial tree

Question 31

neonatal respiratory distress syndrome (DRTS) - pathogenesis - effects

Answer 31

deficiency of surfactant (produced by type 2 pneumocytes) in the lungs - high surface tension in the alveoli -> cannot be kept open -> alveolar collapse hyaline membranes present effects: - hypoxia - damage to endothelial and alveolar lining cells affects premature babies

Question 32

immotile cilia syndrome

Answer 32

cilia has abnormal structure/ cilia does not move in coordination the foreign body just gets stuck there and wont get swallowed/ removed -> risk of recurrent infections

Question 33

cystic fibrosis | - more common in what race

Answer 33

production of viscous mucus that cannot be cleared from lungs/pancreas/intestines - > mucus remains stagnant - > repeated infections / bronchiectasis - > resp failure affects Caucasians more - autosomal recessive disorder

Question 34

4 stages of inflammatory response in lobar pneumonia

Answer 34

1. Congestion 2. Red hepatisation (presence of RBC, neutrophils) 3. Grey hepatisation (RBC broken down already, left fibrino exudate) 4. Resolution

Question 35

Complications of pneumonia

Answer 35

- spread locally: lung abscess - spread dismally: septicemia - empyema - rupture of purple not fluid into pleural cavity

Question 36

Clinical manifestations of bronchopneumonia

Answer 36

- mucopurulent sputum and cough | - acute high fever

Question 37

Clinical manifestations of pulmonary TB

Answer 37

Haemoptysis (coughing blood) Chest pain X-ray: nodular lesions - hilum / lung

Question 38

TB histological features (4)**

Answer 38

1. CD4+ T lymphocytes 2. Epithelium histeocytes (granuloma) 3. Multinucleated giant cell 4. Central caseating necrosis

Question 39

Clinical features of bronchiectasis

Answer 39

- crackles in breathing w/ high and low pitch breath sounds (esp during expiration) - mucopurulent foul smelling sputum - breathlessness - hemoptysis (coughing blood)/ blood in sputum

Question 40

treatment of TB

Answer 40

1. Damage already done - contact prophylaxis with isoniazid - isolate and monitor 2. Preventing future damage - 2 months of isoniazid, rifampicin, pyrazinamide, ethambutol (RIPE) - follow up with 4 months of isoniazid, rifampicin - Isolate and monitor - observe sputum conversion, weight gain - can go back to community with directly observed therapy until treatment regimen is complete