I'm learning about inflammation and infection. I understand the pathophysiology of inflammation when you get an penetrating injury or an infection. I know that it occurs because your body is trying to get rid of the pathogen or invader inside your body. The part that I'm confused about is the pathophysiology of when inflammation happens without an invader. Like for example if you get a burn or a sprain why does the inflammation occur if there is no invader to get rid of? I know it may be a silly question, but I tried looking it up in my book and have not found an answer (the inflammation section is very short. Like 2 pages) and I've also tried googling it and looking it up on YouTube, but have also not been able to find any answers. It just states that you get inflammation with a sprain or a burn and what the symptoms of inflammation are (which I already know all that), but it does not explain to me why. I'm the type of person that needs to know the why of things, even though I may already know the what, because I just learn better and retain the information and it helps me later on to build on it and understand other concepts better. I just need to know so that I can put things together. Thanks in advance.

Tissue injury and inflammation

Inflammation: The Leukocyte Adhesion Cascade

The inflammatory response to skeletal muscle injury: illuminating complexities. - PubMed - NCBI

The immune response to trauma. - PubMed - NCBI

Above are a few reliable sources that have more detailed information about the inflammatory process as it pertains to physical injury.

Think about it this way: your immune system is responsible for total wellness of the body. Therefore, the same system that responds to and mitigates the threat of pathogenic invaders also responds to internal damage resulting from physical injury. If you look at it on a broader scale, while the cause of damage may be different in an infection versus an injury, the result is often the same: the disruption of tissue and cellular damage requiring clean up and repair.

What happens when you get an infection? There is often cellular damage and a need for repair due to an external force (a pathogen). What happens when you've received a physical injury such as a sprain? While there may not be any pathogen, there is still a need for repair to tissues, which occurs via the same process. Even in a process that involves an injury that occurs under (ideally) sterile conditions such as a surgery, the body experiences inflammation at the site of the surgery in order to properly heal.

Inflammation can be a result of infection, but in a healthy person, it is a symptom of the body attempting to heal itself--it's a sign of an active immune system.

Thank you, thank you, thank you! You rock! That makes absolutely total sense. Now I can finally understand. Sometimes it takes me a long time to really get something, but when I get it it's like a ray of light shinning on me, LOL! Now when I have a patient with inflammation I'll be able to understand the pathophysiology behind it. Again thanks a million. God bless!

Tissue injury and inflammation

Inflammation: The Leukocyte Adhesion Cascade

The inflammatory response to skeletal muscle injury: illuminating complexities. - PubMed - NCBI

The immune response to trauma. - PubMed - NCBI

Above are a few reliable sources that have more detailed information about the inflammatory process as it pertains to physical injury.

Think about it this way: your immune system is responsible for total wellness of the body. Therefore, the same system that responds to and mitigates the threat of pathogenic invaders also responds to internal damage resulting from physical injury. If you look at it on a broader scale, while the cause of damage may be different in an infection versus an injury, the result is often the same: the disruption of tissue and cellular damage requiring clean up and repair.

What happens when you get an infection? There is often cellular damage and a need for repair due to an external force (a pathogen). What happens when you've received a physical injury such as a sprain? While there may not be any pathogen, there is still a need for repair to tissues, which occurs via the same process. Even in a process that involves an injury that occurs under (ideally) sterile conditions such as a surgery, the body experiences inflammation at the site of the surgery in order to properly heal.

Inflammation can be a result of infection, but in a healthy person, it is a symptom of the body attempting to heal itself--it's a sign of an active immune system.