3.1: Week 3 pt 1

Question 1

Define atelectasis

Answer 1

Loss of lung volume in some (or all) of the lung
Increased tissue density (whiter)

Question 2

List & describe the 2 main types of atelectasis

Answer 2

1) Obstructive/resorptive (ex/ mass, mucus plug, foreign body aspiration)
**default, unless otherwise specified
Airway is obstructed and remaining air is absorbed
2) Nonobstructive
Compression
Scarring
loss of surfactant
Exs/ mass in thorax, large pneumothorax, pleural effusion, poor inspiration (< 8 ribs on PA view)

Question 3

List the signs of atelectasis

Answer 3

Increased density
Displaced fissures
Displaced structures- towards
Overinflation - contralateral

Question 4

With atelectasis, there is __________ density of the affected lung

Answer 4

increased

Question 5

1) Why do mobile structures move w atelectasis?
2) What does the trachea look like?

Answer 5

1) Capable of movement due to changes in lung volume
2) Normally midline with slight rightward deviation at aortic knob; especially mobile in response to upper lobe volume loss

Question 6

Where should the heart be normally on CXR?

Answer 6

RHB should project at least a little bit (1cm) to the right of the spine

Question 7

Define compressive atelectasis

Answer 7

AKA passive atelectasis
Loss of volume due to compression by space-occupying process or poor inspiration (less than 8 posterior ribs)

Question 8

What are the typical causes of compressive atelectasis?

Answer 8

Pleural effusion
Pneumothorax
Mass

Question 9

Passive compression of the lung can occur either from what 2 things?

Answer 9

Poor inspiratory effort (and is manifest as increased density at the lung bases (solid white arrow))
or
is secondary to a large pleural effusion or pneumothorax

Question 10

Bronchogenic Carcinoma:
1) What does CXR usually show?
2) What abt CT?

Answer 10

1) Relatively clear demarcation between nodule and surrounding lung tissue
2) Spiculation: Centrally dense, peripheral projections
Very suspicious for malignancy

Question 11

Define obstructive atelectasis

Answer 11

Obstructing lesion blocks new air from entering
Remaining air is absorbed

Question 12

How much time do you have if obstructive atelectasis is complete?

Answer 12

1) 18-24 hours to entire lung collapse (room air)
2) Less than 1 hour on 100% oxygen
-Room air is 78% nitrogen and 21% O2
-Nitrogen is a major component of normal alveolar inflation while O2 is absorbed

Question 13

In general, what does obstructive atelectasis look like?

Answer 13

1) Lobes collapse in “fan-like” shape with base of the fan at the pleural surface and apex anchored at the hilum
2) Unaffected lobes will undergo compensatory hyperinflation

Question 14

1) Why does atelectasis follow when the endotracheal tube (ET) is too low?
2) Is it reversible?

Answer 14

1) If ET tube is too low, tip will enter right lower lobe bronchus; only right lower lobe will be aerated, so atelectasis of entire left lung will shortly follow
2) Once ET tip is withdrawn above carina, atelectasis will clear rapidly

Question 15

Does atelectasis always resolve quickly?

Answer 15

May take hours or days to resolve (after obstruction is cleared)
Slowly resolving atelectasis may show patchy areas until it has completely cleared

Question 16

Define:
1) Visceral pleura
2) Parietal pleura
3) Pleural space

Answer 16

1) Lines the outside of the lung
2) Lines the inside of the thoracic cage
3) 2-5mL pleural fluid
Several hundred mL’s produced and absorbed throughout the day

Question 17

1) Define pleural effusion
2) What is the first step of imaging?
3) What do you do next?

Answer 17

1) Excess fluid in pleural space; various causes
2) CXR: 1st step
3) CT: evaluate degree and underlying disease
U/S: esp. for guided removal of pleural fluid (thoracentesis

Question 18

Give 3 examples of increased formation of fluid [causing pleural effusion] and why they occur

Answer 18

1) CHF
-(increased hydrostatic pressure)
2) Hypoproteinemia
-(decreased colloid osmotic pressure)
3) Hypersensitivity reaction
-(increased capillary permeability)

Question 19

Give 2 examples of decreased absorption of fluid [causing pleural effusion]

Answer 19

1) Lymphangitic blockage (from tumor)
2) Increased venous (hydrostatic) pressure – pushes fluid into the pleural space
-Decreases rate of transport

Question 20

Define and describe transudates

Answer 20

(low protein and LDH)– transported from somewhere else
Form with pressure differentials, like:
-***CHF
-Hypoalbuminemia
-Cirrhosis/ascites

Question 21

Define and describe exudates

Answer 21

(higher protein and LDH)- excreted from within cavity
Form with inflammation, like
1) Empyema, hemothorax, chylothorax (milky white lipid rich commonly from lymph)
2) ***Most common cause of exudative pleural effusion is malignancy

Question 22

Radiographic appearance of pleural effusions depends on?

Answer 22

1) Position – fluid moves with patient position
We’ll assume patient is upright for CXR
2) Amount of fluid
3) Degree of elastic recoil of the lung

Question 23

Describe subpulmonic effusions

Answer 23

Almost all pleural effusions first collect beneath the lung
(because patient is upright)
Will flow freely as patient changes position

Question 24

Describe right-sided effusions

Answer 24

May be more subtle because liver and pleural fluid have similar density
Hemidiaphragm’s highest point may be displaced laterally
Normally should be in the middle

Question 25

Costophrenic blunting: When can it be noted? Why does it occur?

Answer 25

1) Can be noted on frontal or lateral projections 2) Typical of pleural effusions There are other causes too: thickening, scarring; atelectasis

Question 26

Meniscus sign: What is it a sign of? Describe it

Answer 26

Pleural effusion: Pleural fluid appears to rise higher along lateral margin than medially Produces a “meniscus” shape Higher laterally; lower medially

Question 27

Describe opacified hemithorax in pleural effusions

Answer 27

Massive pleural effusion About 2L Entire lung will be “whited” out Mobile structures push away from affected side

Question 28

1) Describe Loculated pleural effusions 2) Does this have therapeutic significance?

Answer 28

1) Remains in same location regardless of patient’s positioning -Due to adhesions (likely from old infection or hemothorax) -Suspect a loculated effusion when it appears to defy gravity 2) Yes, has therapeutic significance Drainage tube placement Will discuss more in ultrasound unit

Question 29

Pleural effusions: 1) Describe Fissural pseudotumors 2) List some features

Answer 29

1) AKA vanishing tumors Distinct collections of pleural fluid between fissures Almost always occurs in presence of CHF 2) “lenticular” shape with pointed ends (looks like a lemon) 75% occur in horizontal fissure Do not flow freely with position changes Disappear when condition is treated And then reappear

Question 30

Hydropneumothorax: 1) What is it? 2) What are some causes? 3) What are some features? 4) Do you need to do anything other than CXR?

Answer 30

1) Presence of both fluid *and* air in pleural space 2) Trauma, surgery, recent thoracocentesis 3) Straight and sharp air-fluid level (instead of meniscoid shape) 4) CT to differentiate from lung abscess

Question 31

Airspace disease: 1) Produces what kind of opacities in the lung? 2) Describe the margins 3) Are the opacities distinct? 4) Give 2 other characteristics

Answer 31

1) Fluffy Cloudlike Hazy 2) Fuzzy Indistinct 3) Opacities tend to be confluent 4) Air bronchograms  Silhouette sign 

Question 32

Pneumonia as evidenced by radiographic study is what?

Answer 32

1) A consolidation in the lung, caused by dense exudate which results from the body’s inflammatory response to infection. 2) This infection is spread most often through the air, and thus most often manifests as airspace disease, residing in the lobar or segmental portions of the lung.

Question 33

Describe segmental pneumonia

Answer 33

Spread by the bronchial tree, often seeding many foci at the same time (therefor often multiple segments involved) (Staph sometimes does this) Segments are not bound by fissures, so the borders have what characteristic?

Question 34

Describe Interstitial Pneumonia

Answer 34

Typically, viral or mycoplasma Exists in the interstitium of the lung—not in the airway May evolve into airway disease after invading alveoli Ex/covid-19, which begins as interstitial disease and evolves into ARDS

Question 35

Describe round pneumonia

Answer 35

Spherical Posterior Usually in the lower lobes Usually in children Usually not a tumor. . . Though it might look like one

Question 36

Aspiration Pneumonia: 1) Why does it occur? 2) Does it clear quickly? 3) What can it lead to?

Answer 36

1) Stroke, TBI, AMS, Drug overdose, GERD, elderly, critical care patients… 2) If water, it will clear rapidly 3) If aspirate becomes infected, it can lead to PNA Often anerobic, RLL May also lead to secondary infection or diffuse edema

Question 37

Pneumonia Resolution: 1) When does it occur? 2) How long does it take? 3) What would you need to get if it doesn't resolve as expected?

Answer 37

1) Will begin in 2-3 days if treated with appropriate antibiotic Most pneumonias resolve from within called vacuolization 2) Will disappear gradually over days to weeks Resolving in patches 3) If not resolved in several weeks, could be underlying mass preventing drainage and would need to get CT scan