What the heck is a pulmonary infiltrate?

[CBG23]

My profs and textbooks throw around this term, but none of them bothered to define what one is. I have looked online and in a couple of medical dictionaries, but had no luck except that apparently it's a nebulous radiology term. Anybody have a specific definition?

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[CBG23]

Also, is this the same thing as consolidation?

 

[ArcGurren]

Infiltrate is when your alveolar spaces are filled with some sort of fluid, i.e. transudate, exudate.

Consolidation refers to the lung becoming a hard, firm mass, which is very characteristic of lobar pneumonia. So this can be due to an exudative infiltrate, for example, in lobar pneumonia, where the cell debris and pus is literally filling up the spaces and instead of giving your lungs this squishiness that you see on autopsy it makes it hard and less pliable, and less able to fill up with air.

So consolidation = texture, infiltration = filling up of the lungs. You can have consolidation with or without infiltration.

 

[CuriousGeorge2]

I thought an infiltrate was just a spot on a lung radiograph that could be due to stuff in the alveolus OR the interstititum? Also, I may be wrong but I though consolidation was basically the same thing as an alveolar infiltrate...

 

[ArcGurren]

I thought an infiltrate was just a spot on a lung radiograph that could be due to stuff in the alveolus OR the interstititum? Also, I may be wrong but I though consolidation was basically the same thing as an alveolar infiltrate...

Yeah infiltrate is used mostly in the context of a CXR/radiograph but point is it ultimately means something "filling up" the space or, yes, the alveolar interstitium sorry if that wasn't clear. Consolidation is more of a measure of the texture and hardening of the lungs.

 

[BigRedBeta]

Yeah infiltrate is used mostly in the context of a CXR/radiograph but point is it ultimately means something "filling up" the space or, yes, the alveolar interstitium sorry if that wasn't clear. Consolidation is more of a measure of the texture and hardening of the lungs.

On CXR you cannot distinguish the two. It's a must to remember what produces the roentgenogram - differences in density. Thus, "pulmonary infiltrate" is one of those non-sense jargon terms that lacks a true meaning but everyone who uses it means there's something on the film that shouldn't be there.

Certainly when tied to a clinical history and physical exam you can piece together what's happening more precisely, but to say just on the basis of the film it's a textural process or a fluid accumulation would be entirely inappropriate. Even blatant atelectasis, (obvious with volume loss and lung mass displacement) will frequently dictated by radiologists as an infiltrate - usually with them hedging "lobar pneumonia vs atelectasis, clinical correlation recommended".

A better term would be "opacification" or even just "density", as these are broader, and with less context or effect on implying disease process.

 

[ArcGurren]

On CXR you cannot distinguish the two. It's a must to remember what produces the roentgenogram - differences in density. Thus, "pulmonary infiltrate" is one of those non-sense jargon terms that lacks a true meaning but everyone who uses it means there's something on the film that shouldn't be there.

Certainly when tied to a clinical history and physical exam you can piece together what's happening more precisely, but to say just on the basis of the film it's a textural process or a fluid accumulation would be entirely inappropriate. Even blatant atelectasis, (obvious with volume loss and lung mass displacement) will frequently dictated by radiologists as an infiltrate - usually with them hedging "lobar pneumonia vs atelectasis, clinical correlation recommended".

A better term would be "opacification" or even just "density", as these are broader, and with less context or effect on implying disease process.

Thanks for the clarification! It's often confusing since they do mention in pulmonary path things like "diffuse bilateral infiltrates" or "lobar infiltrates", when it's obviously more complex.