9 & 11.2 LRTIs & Imaging

Question 1

how are alveolar microbiota part of the defences for respiratory tract?

Answer 1

compete with other organisms to prevent establishment of infection

Question 2

virulence factor of
-chlamydia pneumoniae
-mycoplasma
-influenza
-strep pneumonia/neisseria

Answer 2

-ciliostatic
-shear off cilia
-reduced mucous velocity
-split IgA

Question 3

virulence factor of
-pneumococcus
-mycobacterium/legionella

Answer 3

-capsule inhibits phagocytosis
-resists phagocytosis

Question 4

why is CXR normal in acute bronchitis?

Answer 4

doesn’t affect lung parenchyma, no fluid filling alveoli

Question 5

lobar vs broncho pneumonia on CXR

Answer 5

lobar is complete lobe opacity
broncho is catchy consolidations

Question 6

atypical organisms causing CAP

Answer 6

-mycoplasma (holiday, dry cough, rash)
-legionella
-coxiella burnetti

Question 7

how to decide need to admit for pneumonia?

Answer 7

CURB-65 + observations

Question 8

length of ABx treatment for CAP

Answer 8

5-7 days if mild
7-10 days if severe

Question 9

why are clarithromycin/doxycycline needed for CAP treatment?

Answer 9

start them anyway in case CAP caused by atypical organisms, then stop if not

Question 10

why are second line antipseudomonal beta lactase needed for HAP?

Answer 10

treat pseudomonas risk

Question 11

how many anterior ribs should be visible on PA xray?

Answer 11

8-10

Question 12

compare L and R main bronchus, and the implication

Answer 12

R is shorter, wider, straighter so more likely foreign bodies, especially in children

Question 13

why could hilum appear convex?

Answer 13

filled by masses/lymph nodes

Question 14

lingular lobe

Answer 14

projection of L upper lobe, corresponds to R middle lobe

Question 15

why might R para tracheal stripe be thicker?

Answer 15

lymph nodes, masses

Question 16

aorta pulmonary window is a common site for lymph node enlargement. try or false?

Answer 16

true

Question 17

pneumonia on CXR

Answer 17

-air bronchograms
-fissures thicken

Question 18

lung cancer on CXR

Answer 18

-rounded opacity
-+/- effusion
-+/- lymphadenopathy

Question 19

pulmonary oedema on CXR

Answer 19

-bats wing peihilar shadwoing
-peripheral lines
-pleural effusions

Question 20

COVID on CXR/CT

Answer 20

-multiple peripheral opacities

Question 21

CF on CXR

Answer 21

-bronchiectasis
-thickened bronchial walls: tram track
-airway plugging
-+/- venous catheter

Question 22

PE on CXR

Answer 22

-normal
-peripheral opacity if infarction
-IV septum straighter if R heart strain

Question 23

pneumomediastinum on CXR

Answer 23

-streaky linear lucencies
-gas in neck and axillae
-oesophageal tear

Question 24

pleural plaques on CXR

Answer 24

-calcified

Question 25

mesothelioma on CXR

Answer 25

-lung enacted by ‘rind’ of tissue

Question 26

cough reflex

Answer 26

-irritation of cough receptos
-VCs adduct
-external intercostals and diaphragm contract, air enters lungs
-VCs and epiglottis close, traps air
-intrathoracic pressure increased
-rapid relaxation of internal intercostals and abdominal muscles, VCs abduct sharply for rapid expulsion