Inflammation and swelling

From a medical standpoint, does swelling always occur with inflammation?

No. See: tumescence. Also, there are a number of non-inflammatory causes of edema, like incompetent venous valves, congestive heart failure, interrupted lymphatic drainage, etc.

Those are examples of swelling without inflammation. I think the OP is looking for whether there can be inflammation without swelling.

Swelling will always occur with inflammation.

The inflammatory process involves fluids and proteins and cells migrating from the vasculature into local tissue. More fluids and cells entering local tissue will inherently cause swelling.

I can’t speak from a medical standpoint. As a long time marathoner, I have had lots of injuries. In fact, I have had many inflammatory conditions not directly related to running itself. With injuries, first I experience the pain. Then the pain moves through the four levels of pain to the point where I can’t even run on the injury. This can happen over days or over a one minute period. The pain is invariably accompanied by inflammation. The swelling develops over a period of hours and remains throughout the course of the recovery. At the end, the pain and inflammation eventually go away, yet the swelling maintains on for some time. In other words, the swelling has a delayed start and delayed finish, but is linked to inflammation.

Clearly, you can have swelling without inflammation too. Maybe this is labeled edema from a medical standpoint. At one time I experienced something called pedal edema where one foot and leg swelled up so bad I could not put my regular shoe on. There was no pain whatever. I believe it was a mineral imbalance. So obviously, you can have swelling without pain or inflammation, but it is rare to have inflammation without swelling or pain.

That’s my experience anyway.

What about Multiple Sclerosis? There is inflammation, but where is the swelling?

In the optic nerve, for one (optic neuritis is how many people get diagnosed in the first place) and in other nerves and white matter tracts.

As Qad said, and really by definition, swelling always occur with inflammation. It is one of the four sine qua non features of inflammation, the other three being redness, pain, and heat. Still, not all inflammatory processes cause the same proportion of each. To use the cited example above, multiple sclerosis doesn’t cause redness or heat. Or does it?

Actually it does (in some sense). How can that be? Simple - just redefine redness, heat, and swelling as manifestations of more fundamental processes affecting the blood vessels in areas of inflammation as described below.

It’s been known for a long time that redness from inflammation is merely a reflection of the blood vessels in the affected area being dilated (i.e. more redness of blood to see). Likewise for heat - in the skin (where such observations were first made), the dilated blood vessels give off heat. With respect to the swelling of inflammation, that’s a consequence of blood vessels in inflamed areas leaking out their fluid into the surrounding tissues (causing swelling of the latter). And the pain of inflammation is from various chemicals released as part of the inflammatory process.

So, if you redefine swelling (or better yet, understand swelling) as inflammation-induced leaky blood vessels, and redness and heat are understood to be manifestations of blood vessel dilation, etc., it’s then true that those symptoms always occur in inflammation.

Yep, I agree with Doc Mercotan and Karl. Textbook definition of inflammation is that swelling, pain, redness and warmth are present, because of the way fluids move to the site.

(Which makes me wonder… could one so strictly interpret the definition so as to consider a penile erection (or a clitoral/vaginal one, for that matter) “inflammation”? I’m not sure, because it’s not caused by the histamine and kinin triggered leakage of blood products…but it’s sure vasodilation (triggered by nitric oxide), and it causes swelling, redness and warmth and, if unrelieved, can be painful!)

The signs of inflammation are swelling, pain, redness, warmth… and also, “loss of function”.

Adding that last part, it is clear that they are not considered inflammation, as the tissue is working the way it should be working.

Ah, we don’t mention the “loss of function” as specific to inflammation in our nursing text. Odd. So inflammation is also, by definition, pathological… interesting… Thanks for the clarification!

I’m going by Robbin and Cotran’s Pathologic Basis of Disease second chapter in the general pathology section (the latest edition). This is the basic pathology textbook (for humand AND veterinary medicine). Signs of inflammation:

Redness, warmth, swelling, pain, and loss of function. The first four were described by the Greeks, the last one is a “late” addition in the 18th or 19th century (after microscopes were invented).

As far as I know, inflammation IS pathological. The examples you give are physiological, since that IS their function (and are not painful).