Chest xray help

i can't spot pneumothoraxes at all.. all i know is if one side is significantly darker than the other (loss of interstitium) then it's more likely for it to be on that side but what if it's darker because the other side has a consolidation.. I just cant spot the plural space line at all

Reply 1

Democracy

Original post by ugliestboieva

Even if the other side has a consolidation, the presence of a contralateral pneumothorax should still be appreciable. It's not that the pneumothorax is dark, it's that it's black with loss of lung markings i.e. signifying the presence of air in the pleural cavity.

It takes practice and some pneumothoraces can be subtle. For medical school exams and OSCEs, normally they should be obvious and you should be able to see the pleural edge as well as the loss of peripheral lung markings - i.e. something like this:

Spoiler

Obviously don't forget to check for other important signs like tracheal deviation, mediastinal shift, etc which classically suggest a tension pneumothorax, especially in MCQs. And as always, think about the history and examination findings you've been given. Tall, thin, young, smoking male +/- Marfan's or another connective tissue disorders in an MCQ is very strongly suggestive of pneumothorax.

It'll come with practice, just keep looking.

(edited 4 years ago)

Reply 2

ugliestboieva

Original post by Democracy

Spoiler

Thanks for your detailed explanation :smile:

It's just weird because some X-rays have more lung markings than others but still can be considered to be normal?

Reply 3

Etomidate

Original post by ugliestboieva

Thanks for your detailed explanation :smile:

It's just weird because some X-rays have more lung markings than others but still can be considered to be normal?

There's a website that just lets you click through hundreds of normal chest x-rays so you can develop an appreciation of normal variation. It's great for honing your pattern recognition especially when you're in the stages where you havent examined many CXRs. I can't recall the name, but if you do some googling I'm sure you could find it.

Edit: Here it is http://www.chestx-ray.com/index.php/education/normal-cxr-module-train-your-eye#!1

(edited 4 years ago)

Reply 4

Omar_Little

Original post by ugliestboieva

Thanks for your detailed explanation :smile:

It's just weird because some X-rays have more lung markings than others but still can be considered to be normal?

One small point to also bear in mind is that when you look at a proper CXR it is usually a higher quality image than examples online so you can quickly zoom in and the markings become more apparent. Even more so if you have a decent sized screen.

Reply 5

seaholme

You can usually see a distinct line where the air ends and the lung begins, even with small ones. Look at the apices. The air displaces the lung and so the lung itself is slightly more defined in that area, creating a subtle border. In big pneumothoraces it’s super obvious. If it’s just dark on both sides at the apex and you can’t see any lung border then it’s probably just the exposure. If you’re using PACS or something, I find inverting the image can often help because when you invert it the lung border often pops out a bit clearer. And in practice, clinical history will always help raise your suspicion or not!

Reply 6

Beska

Loss of lung markings is the one key thing to look for. Can help distinguish a difficult pneumothorax from normal lung, also helps exclude a pneumothorax if something looks like a pneumothorax (but isn't). Lack of lung markings = no lung = pneumothorax (within the bounds of what a normal pneumothorax looks like... obviously an effusion collapse etc etc would also have lack of lung markings)

Reply 7

Ghotay

I have only ever seen one pneumothorax picked up on CXR in clinical practice. Quite an interesting one as the patient wasn't a typical demographic for a spontaneous pneumothorax, examination and obs were normal, they were just a bit breathless.

Every other I've seen has been found on trauma CT. Including one case of bilateral pneumothoraces that were completely invisible on the initial CXR, but perfectly clear on the CT. CXR performed before spine was cleared so just shows how useless lying CXRs are.

Anyway - look at more chest xrays and you get more used to what is normal. That's basically it

Reply 8

Etomidate

Original post by Ghotay

The question is, if we can only see it on CT, do we care about it?

Reply 9

Ghotay

Original post by Etomidate

The question is, if we can only see it on CT, do we care about it?

Hmmm, in this case it was a patient with a medium-impact injury who was initially felt to be ok and might only require overnight observation, but then flail segment was picked up on CXR, then bilat pneumothoraces on CT, which in combination earned then a trip to the trauma centre. I don't know if the pneumothoraces themselves made that much difference, but I guess in the broader context showed the severity of the injury?

Reply 10

Etomidate

Original post by Ghotay

I would imagine the flail segment would have been sufficient to warrant very close observation. The CT only pneumothoracies probably wouldn’t contribute much.