Acute Inflammation | Immunology

Summary

This lecture delves into acute inflammation, a rapid immune response to injury or infection. It outlines the nonspecific nature of inflammation, its purpose to neutralize irritants and initiate repair, and its various causes, including microbes and physical trauma. The lecture highlights the clinical features of inflammation, both local and systemic, and explains the two-phase process involving vascular and cellular responses. It concludes with the possible outcomes: complete resolution, replacement with fibrotic tissue, or progression to chronic inflammation.

Takeaways

• 🔍 Acute inflammation is a rapid, short-term response of the immune system to injury or infection.
• 🛡️ The primary purpose of acute inflammation is to neutralize the injurious agent, prevent its spread, and initiate the healing process.
• 🌡️ Causes of inflammation include microbes, physical trauma, radiation, temperature extremes, chemicals, ischemia, foreign substances, and immune system overreactions.
• 🏥 Clinical features of acute inflammation are categorized into local (redness, heat, swelling, pain, loss of function) and systemic (fever, increased heart rate, increased white blood cells, etc.).
• 🩺 The suffix '-itis' in medical terminology indicates inflammation of a specific body part, such as 'colitis' for colon inflammation.
• 🔬 The process of acute inflammation involves two main phases: the vascular phase (vasodilation and increased permeability) and the cellular phase (white blood cell activity).
• 🚨 Histamine, prostaglandins, and cytokines are key chemical mediators that initiate and sustain the inflammatory response.
• 🔄 Neutrophils play a crucial role in the early stages of acute inflammation by migrating to the site of injury, phagocytosing bacteria, and dead cells.
• 🔄 Macrophages become active in the later stages, aiding in the removal of debris and contributing to the resolution of inflammation.
• 🌟 Possible outcomes of acute inflammation include complete resolution, replacement with fibrotic tissue (fibrosis), or the development of chronic inflammation.

Q & A

What is acute inflammation?

Acute inflammation is a rapid, nonspecific response of the innate immune system that occurs in vascular tissues and is characterized by a short time frame, coming on quickly and then resolving.

What is the purpose of acute inflammation?

The purpose of acute inflammation is to neutralize the injurious agent, potentially remove or seal it off from the rest of the body, and initiate the wound healing process.

What are the common causes of acute inflammation?

Common causes include microbes such as bacteria, viruses, and fungi; physical trauma; radiation; burns; chemicals; ischemia; foreign substances; and immune system overreactions like hypersensitivity disorders.

What are the local clinical features of acute inflammation?

The local clinical features include redness, heat, swelling, pain, and loss of function, which are typically localized to the area of injury or infection.

What are the systemic clinical features of acute inflammation?

Systemic clinical features include fever, an acute phase protein release from the liver, leukocytosis (increase in white blood cells), increased heart rate, increased blood pressure, increased respiratory rate, and symptoms like anorexia and malaise.

What does the term 'itis' indicate in medical terminology?

In medical terminology, the suffix 'itis' indicates inflammation. For example, colitis is inflammation of the colon, appendicitis is inflammation of the appendix, and dermatitis is inflammation of the skin.

What are the two main phases of the inflammatory process?

The two main phases of the inflammatory process are the vascular phase, involving vasodilation and increased vascular permeability, and the cellular phase, involving the migration of white blood cells to the site of injury.

How do neutrophils play a role in acute inflammation?

Neutrophils are the most abundant white blood cells in acute inflammation. They become phagocytic, eating up damaged cells and bacteria, and are crucial for the removal of the injurious agent.

What are the three possible outcomes of acute inflammation?

The three possible outcomes of acute inflammation are complete resolution, where the injurious agent is removed and the tissue is repaired; replacement, where damaged tissue is replaced by connective tissue like collagen, leading to fibrosis; and chronic inflammation, which occurs if the agent is not removed or if there is an ongoing immune response.

How does the body initiate the healing process during acute inflammation?

The body initiates the healing process during acute inflammation by activating fibroblasts, which are connective tissue cells that lay down collagen to repair and seal off the area of injury.