Mediastinum Flashcards Preview

RUSVM DI > Mediastinum > Flashcards

Flashcards in Mediastinum Deck (32):
1

mediastinum

everything between right and left pleural sacs; bounded by mediastinal pleura

extends from thoracic inlet to diaphragm 

fenestrated - disease usually not unilateral 

not a closed cavity - communicated with neck and retroperitoneal space 

2

mediastinal reflections 

cranioventral 

caudoventral 

caval - can't see

3

cranioventral mediastinal reflection 

border between the right cranial lung lobe and the cranial part of the left cranial lobe 

cranially the left lung extends to the right

caudally the right lung extends to the left 

4

what dis?

normal thymus - young dog

"sail sign" 

5

caudoventral mediastinal reflection 

border between the accessory lobe (R Lung) and the left caudal lobe (L Lung)

left aspect of the accessory lobe crosses midline pushing mediastinal pleura to the left

6

Thickness of the caudoventral mediastinal reflection depends on..

the amount of fat present in mediastinum 

7

what mediastinal organs are normally seen 

heart

trachea

caudal vena cava

aorta

thymus

esophagus

8

mediastinal organs that are not normally visible 

cranial vena cava

azygos vein 

lymph nodes

nerves

various smaller aa. and vv.

9

mediastinal abnormalities 

shift (common)

mass (common)

gas (common)

fluid (rare)

10

mediastinal shift 

atelectasis most common cause

displacement of heart is most reliable sign

helps differentiate lung disease from atelectasis

11

T/F lung opacity, no heart shift = atelectasis

False

lung opacity with no heart shift = disease

12

common causes of mediastinal masses

lymph nodes

thymus

esophagus

13

cranioventral mediastinal masses

mediastinal LN

thymus

sternal LN

cyst

14

hilar mediastinal masses

tracheobronchial LN

left atrium 

heart base tumor

15

dorsal mediastinal masses

esophagus

16

mediastinal lymph nodes

cranial mediastinal 

tracheobronchial (x3)

sternal 

17

cranial mediastinal lymph node drains...

thoracic wall, trachea, thyroid 

18

tracheobronchial lymph node drain 

lungs

19

sternal lymph nodes drain 

mammary glands, peritoneum 

peritonela disease may cause sternal lymphadenopathy

20

how can you diagnose the cause of a mediastinal mass

R/Os can be narrowed based on location 

sonography or CT may help 

usually need cytology

21

what dis?

sternal lymphomegaly

22

what could this be

not a LN → to close to the heart

DDx: cysts, thymus, ectopic thyroid; U/S to differentiate

23

what dis?

moderate trachebronchial lymphomegaly 

24

what can be seen on a VD with trachiobronchial lymphomegaly 

bronchi divergence - bow legged appearance

25

confounding effects of pleural fluid 

prevents identification of mediastinal mass

need to take additional steps - drain fluid and reradiiograph, U/S

26

27

T/F mediastinal structures become more conspicuous with pneumomediastinum

True

see things you normally dont see

air in mediastinum provides contrast

28

T/F pneumomediastimun can progress to pneumothorax if distension is severe but pneumothorax will not progress to pneumomediastinum

True

29

whats the best view to diagnose pneumomediastinum

lateral 

30

causes of pneumomediastinum 

retrograde flow along airways from intrapulmonary rupture

hole in trachea - bite wound, jugular vein puncture, transtracheal aspirate, ET tube cuff overinflation 

neck wound 

31

mediastinal structures that become visable with pneumomediastinum

adventitial border of trachea

ascending aorta

left subclavian artery 

brachiocephalic trunk 

32

mediastinal fluid 

not common

hemorrhage - coagulopathy

exudate - FIP, Esophageal rupture