Mediastinum Flashcards
you see these vertebrae in a bulldog. is this normal or abnormal?
this is normal, certain breeds like bulldogs can have wedge shaped vertebrae which normal for the breed, do not confuse for trauma and use your clinical hx
what is pectus excavatum?
a common incidental finding where there is a deviation of the caudal sternebra
what do you see here, what is this called?
pectus excavatum; a normal incidental finding where the caudal sternebra deviate and can appear abnormal
to confirm a rib fracture, what things can you look for besides the fracture itself?
there will be underlying pulmonary contusions; the fracture injures the lung paremchyma, so you should look for opacities underneath the fracture which may be indicative of hemorrhage
thoracic wall masses are often or what origin?
rib origin, like a chondrosarcoma or osteosarcoma
is this a pulmonary mass or a thoracic wall mass? how can you tell?
a thoracic wall mass, because it looks more convex, like it’s pushing on the lung parenchyma
is this a pulmonary mass or a thoracic wall mass? how do you know?
a pulmonary mass, becausethe angle in which the mass meets the body wall is sharp, it is not a nice convex shape. it does not appear as though the lung is being pushed by a mass from the outside
what are some reasons why you would see the pleural space (normally you can’t see it lol)
if there’s fluid or soft tissue in the pleural space, or if we arent “straight on”, meaning there is an angle when taking the radiograph allowing us to see lines of pleura (I think, it’s unclear)
what are fissure lines?
the interlobular lines between the lung lobes. they are more easily seen if there is pleural thickening
what is this pointing to?
a fissure line, indicating there may be pleural disease like fluid or something in the pleural space
what are the 3 main categories of pleural space disease according to romero lol
pleural effusion, pneumothorax, and diaphragmatic hernia
a dog with dyspnea, tachypnea, and decreased heart and lung sounds. what is this likely?
pleural effusion, can see retraction and rounding of the lung lobes and an increase in opacity, almost looks like a scalloped edge
what view is more sensitive for picking up pleural effusion, DV or VD?
VD, however this is more dangerous for the patient
this is pleural effusion. which one of these is a DV and which is the VD? why?
left is VD because the fluid would accumulate dorsally and leave the heart ventrally, so you can see the cardiac silhouette
right is DV beause the fluid accumulates ventrally, and since the heart is also ventral you can’t see it because of effacement (soft tissue of the heart blends in with the fluid in the lungs)
if the pleural effusion is super severe where there is effacement of all thoracic contents, what should you do?
thoracocentesis to drain and then retake the radiographs. if you do not do this it is very hard to tell masses from the heart, etc
what are the 4 kinds of pneumothorax?
open: free passage of air from environment
closed: air is leaking from lungs, trachea, bronchi, esophagus, or mediastinum
tension: one way valve, air can get in but not out
normotensive: pleural pressure is the same as atmosphere
what are 3 radiographic signs of penumothorax?
- gas in pleural space
- retraction of lung lobes (vasculature also retracts)
- elevation of cardiac silhouette
WOT DIS
pneumothorax, can see dark black area ventral to the heart, retraction of lung lobes and vasculature, and cardiac silhouette is elevated
WOT DIS
pneumothorax
why is tension pneumothorax an emergency, and what will you see on a radiograph?
- with every breath air gets into the pleural but does not get released
- this causes displacement of the lung and a mediastinal shift away from the side with the tension pneumothorax
these are all showing what
tension pneumothorax
what structures are in the cranial, middle, and caudal mediastinum?
cranial: great vessels, esophagus, trachea, lymph nodes, thymus, fat
middle: heart
caudal: esophagus, aorta, vena cava
how thick should the cranial mediastinum normally be?
2x width of vertebral bodies in dogs and 1 in cats. there is also variation with body condition score and with breed
what is one thing to look for on a radiograph if you suspect a mediastinal mass?
deviation of the trachea
what do you see, what is goin on
the trachea is deviated dorsally and there is a lot of opacity in the ventral cranial aspect of the thorax. this ended up being a thyroid carcinoma, but all we could say is that there is a cranial mediastinal mass
what do you see here?
the trachea is deviated to the right side, so there’s a pretty good chance theres a mediastinal mass on the left cranial/middle portion
what are you seeing here? pretend this is from Buddy, a lab who is “well loved” ;)
the mediastinum looks pretty wide, but this is probably just a fat dog
what do you see on both the lateral and the DV/VD idk which it is in this photo
there is a soft tissue opacity ventral tot he trachea, so somewhere in the cranial mediastinum. this is right where the tracheal lymph nodes are, so these may be enlarged. this is confirmed on the DV/VD view where you can see an abnormally wide mediastinum cranially
what do you see here on both views
on the lateral I can see two areas of soft tissue opacity ventrally in the thorax, adjacent to the sternebrae. The sternal lymph nodes are in this area, so perhaps they are enlarged. On the DV/VD view, the cranila mediastinum appears abnormally wide, which is likely due to these sternal lymph nodes being enlarged.
overall what does pneumomediastinum look like on a radiograph?
it provides good contrast in the mediastinal area, so you can see structures that are not normally visible in that region
what 3 things can pneumomediastinum progress to or result in?
pneumothorax
subcutaneous emphysema
pneumoretroperitoneum
what are 6 causes of pnuemomediastinum?
- trauma like HBC
- extension of gas from the neck like secondary to a venipuncture
- tracheal perforation
- esophageal perforation
- extension of gas from retroperitoneum
- gas producing organism
WOT DIS
pneumomediastinum, the trachea and vasculature in the area has way more contrast and is easier to see
WOT DIS
pneumomediastinum, there is increased contrast and the trachea is sharply defined
WOT IS GOING ON HERE
apparently this is pneumomediastinum and pneumoretroperitoneum (basically there is a connection through the diaphram so the gas can extend between these two spaces)
wot
the esophagus is VERY dilated and gas filled
there are two kinds of megaesophagus, what are they and give examples of conditions under each kind
diffuse: myasthenia gravis
segmental: PRAA, esophagitis
what is a tracheal stripe sign and what does it indicate?
where the dorsal tracheal wall appears as a nice white line, indicative of excess gas in the esophagus which is immediately dorsal to the trachea. The gas appears black, making that dorsal tracheal wall appear as a white line. Can be indicative of esophageal dilation or megaesopagus
are hernias usually traumatic or congenital?
congenital
WOT DIS
some sort of diaphragmatic hernia (peritoneal pleural congenital hernia), can see the abdominal contents inside the chest cavity, and the lack of the cardiac silhouette
wot dis
there is no caudal border of the diaphram seen which is sus, and there is an area of increased opacity near the diaphram as well. This is a peritoneal pericardial hernia, making the heart appear big when in fact the pericardial space is filled with guts
what are the 3 types of hiatal hernias?
esophageal, paraesophageal, and mixed
what is an esophageal hiatal hernia?
when an abdominal portion of the esophagus comes into/slides into the chest cavity thru the normal esophageal hiatus in the diaphram
wot dis
there is an area of increased opacity in the caudal area, this is what an esophageal hiatal hernia looks like
what is a paraesophageal hiatal hernia?
when a buldge happens adjacent to the esophagus
behold the hernia diagram to understand
teehee
what is going on here? this is a german shepherd dog
you can see how dilated the esophagus is and the area of increased opacity near the diaphram. This is a gastro-esophageal hiatal hernia, it is a rare thing that can happen in GSDs, where a part of the stomach is inverting itself into the esophagus and moves through the esophageal hiatus
