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Acute Inflammatory Response- Causes, Clinical Significance, Phases, Diagnosis, Treatment and Prevention

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Inflammation is the response of our immunity to harmful external stimuli. Read the article below to learn about inflammation.

Medically reviewed by

Dr. Nagaraj

Published At January 6, 2023
Reviewed AtFebruary 20, 2023


This physiological response to injury is called inflammation. The short-term response is acute inflammation and long-term, and the ongoing response is chronic inflammation. The cellular and molecular changes post-injury reduce impending injury and infections. Any long-term inflammation can lead to chronic inflammatory diseases.

What Is Acute Inflammation?

Acute inflammations begin immediately after injury. This damage can be thermal, mechanical, chemical, radiation or infection. Acute inflammation can present in the form of acute bronchitis, sore throat, wound or trauma, or appendicitis.

It has four characteristic features. They are as follows:

  • Rubor - Redness due to increased blood flow.
  • Calor - Localized increase in temperature or heat.
  • Tumor - Swelling occurs due to increased fluid loss into extracellular spaces.
  • Dolor - Pain which occurs due to stimulation of nerves.
  • Functio Laesa - This causes loss of function.

What Are the Common Causes of Inflammation?

The causes of the inflammation can be classified into two main groups:

  • Exogenous Agents: Consists of microbial agents and non-microbial agents.
  • Microbial Agents: Include pathogen-associated molecular patterns. These consist of microorganisms, and virulent agents, which trigger the inflammatory response.
  • Non-Microbial: Causes include allergens, toxic compounds, irritants, and foreign bodies. These include silica and asbestos.
  • Endogenous Agents: Include signals released by the dead, damaged, malfunctioned, or stressed tissue.

The causes can also be classified as

  • Infectious: Agents include bacteria, viruses, and other microorganisms.
  • Non-Infectious: Agents include physical injuries like frostbite, burns, physical injury, foreign bodies, trauma, ionizing radiation, and chemical compounds.

What Is the Clinical Significance of Acute Inflammation?

  • Cardiovascular Disease: In atherosclerosis, inflammatory mediators play a major role. An increase in the levels of chemokines and cytokines is seen. The first sign of cardiac stress is inflammation.
  • Pancreatitis: Pancreatitis is a genetic disease due to alcohol abuse or pancreatic duct obstruction. This infection activates inflammatory cells like neutrophils and granulocytes. They further secrete inflammatory cytokines.
  • Liver Infection: Inflammation will try to protect the liver from further injury and infection. When this infection exceeds, it will cause liver cell injury, metabolic changes, and ischemia. The infectious agent in such cases is Hepatitis virus, ischemia, alcoholic hepatitis, or drug-induced hepatitis.
  • Kidney Infection: Kidney infections are caused by endothelial cells of renal tubules. These cells secrete cytokines which bring about inflammation.
  • Intestine Infections: Inflammatory bowel disease is caused due to gut microbial flora. They induce cytokines. This is seen in Crohn's disease and ulcerative colitis.

What Are the Phases of Acute Inflammation?

Acute inflammation has two phases; vascular phases, which involve a change in the blood vessels, and cellular phase, which consists of a change in cellular components.

Vascular Phase:

  • Vasodilatation - In this phase, the blood vessels surrounding the injury dilate. This increases the blood flow to the injured area. The cells of the blood vessel are called endothelial cells. These cells initially enlarge, followed by contraction.
  • Exudation of Fluid - The contraction of endothelial cells creates spaces between the cells to increase fluid loss. This loss of fluid in the extracellular space causes swelling.
  • An increase in the tissue fluid increases the migration of inflammatory proteins like complement and immunoglobulins. This increases lymphatic drainage and helps clear pathogens and cellular debris.

Cellular Phase:

The neutrophil is an important cell in inflammatory reactions. The release of chemotaxis follows injury; these are the mediators that help neutrophils attract to the injury site. The neutrophils migrate in the following stages:

  • Margination: The neutrophils line up against the endothelial cells.
  • Rolling: They are in close contact with the endothelial cells and roll along them.
  • Adhesion: They attach to the endothelial cell wall.
  • Emigration: They move through the gaps between the endothelial cells to the affected area. Once the neutrophils are in contact with the pathogen, the pathogen is engulfed to form a phagosome. This process is called phagocytosis. This phagosome is destroyed by an enzyme called lysozyme. This is an oxygen-independent reaction. Another way of phagosome destruction is by free radical formation. This is an oxygen-dependent reaction.

The injury can show the following outcomes:

  • Complete repair and resolution.
  • In cases of increased inflammation, fibrosis and scar formation occurs.
  • If the damage continues, it can lead to chronic inflammation.
  • If bacteria invade the site, it can lead to abscess formation.

How to Diagnose Inflammation?

  • Increased levels of inflammation increase the levels of biomarkers, substances that increase in the body due to inflammation. C-reactive protein levels can be assessed.
  • The erythrocyte sedimentation rate test measures the inflammation, the rate at which red blood cells immerse in the blood tube. Increased inflammation can increase the thickness of blood.

How to Treat Inflammation?

Inflammation does not require any specific treatment. Following measures can be followed to control inflammation.

  • Adequate rest is needed.
  • Cold fomentation with the use of ice packs can provide symptomatic relief.
  • Good care of the wound to prevent infection.
  • We can consume a diet consisting of food with anti-inflammatory properties. Diet rich in fish, fish oil, green leafy vegetables, olive oil, broccoli, avocados, green tea, mushrooms, and tomatoes.
  • Bacterial or fungal infections can require the prescription of antibiotics or antifungals.
  • Nonsteroidal anti-inflammatory drugs can help reduce pain, swelling, and fever. These drugs inhibit inflammatory enzymes. Ibuprofen, Naproxen, and Aspirin are a few such drugs available over the counter. Consult the physician before the long-term use of such medications.
  • Pain relief can be obtained with the use of over-the-counter Paracetamol or Tylenol.
  • Corticosteroids are a group of steroid drugs that help in the treatment of arthritis, dermatitis, hepatitis, asthma, and certain allergic reactions.
  • Topical analgesics are used for acute pain. Topical creams containing Ibuprofen or Diclofenac can help relieve topical inflammatory symptoms.

How to Prevent Inflammation?

  • Maintenance of healthy weight and regular exercise.
  • Avoid smoking.
  • Limit alcohol intake.
  • Stress management techniques like meditation and yoga.
  • Try to avoid fried and processed food, red meat, sugar-containing drinks, and saturated fats in the diet.


Inflammation is the physiological response of the body to any sort of injury or infection. On the basis of time taken to develop these responses, the inflammation can be classified into acute (shorter duration) or chronic (longer duration). Inflammation is mostly accompanied by redness, swelling, and pain. Inflammation does not require any specific treatment.The symptoms can be easily managed and avoided by adapting a healthy lifestyle.

Frequently Asked Questions


What Is the Acute Inflammatory Response in Traumatic Brain Injury?

As a respose to traumatic brain injury, there is increased release in cytokines, interleukin1beta, interleukin-6 (IL-6), interleukin-10, and tumor necrosis factor after 24 hours of injury. In severe brain injury, the presence of immune response is associated with reduced consciousness and higher risks of death from injury.


What Is the Acute Inflammatory Response During a Trauma?

During trauma, a dysregulated acute inflammatory response is induced that affects several organs and sets in a viciuos cycle of inflammation driven by cytokines, chemikines, and products of damaged, stresses, or dysfunctional tissue. It is also pivotal in clearing invading organisms and offending agents and promoting tissue repair under certain conditions.


Does Acute Inflammatory Response Cause Asthma?

Asthma is caused by an aberrant inflammatory response to non-pathogenic stimuli in the airways leading to  a chronic inflammatory response relevant to the pathogenesis of the disease. This inflammation affectes all compartments of the airways including the upper respiratory tract and nose.


What Do Acute Inflammatory Response Involve?

Acute inflammatory response involves five signs- 
 - Heat.
 - Redness.
 - Swelling.
 - Pain.
 - Loss of function.


What Are the Characteristics of Acute Inflammatory Response?

Characteristics of acute inflammatory response is local edema, redness,swelling,  tenderness, and pain, increased temperature and loss of tissue function which result from local immune, vascular and inflammatory cell responses to infection or injury.


Is there Heart Rate Variability in Acute Inflammatory Response?

Due to the physiological association between inflammatory processes and vagus activity, there is higher heart rate variability (HRV), especially indices of vagally-mediated HRV, to be associated with decreased levels of inflammation through the cholinergic anti-inflammatory pathway.


How Does Acute Inflammatory Response Help to Fight Against Infections?

Whenever there is an infective agent invasion, the acute inflammatory response results in release of chemical mediators that cause blood vessels to produce white blood cells called phagocytes that protect the body against infective agents by eat up the microbes or damaged cells. This increases the blood flow in the affected area.


What Are the Stages or Steps of Acute Inflammatory Response?

The four steps of the inflammatory response 
 - Recognizing  the damaged tissue,
 - Recruitment of inflammatory cells, 
 - Removal of extraneous objects, and
 - Repair the damaged tissue.


What Are the Functions of Acute Inflammatory Response?

The main function of acute inflammatory response is to trigger immune response in an area of the body that requires to fight against pathogens causing infection or to aid in injury healing. 
Three functions or steps inculde: vasodialtion, increased vascular permeability, and migration of leukocytes to the affected area.


How Long Does Acute Inflammatory Response Last For?

Acute inflammatory response lasts for a short duration of time from minutes to hours or days based on the type and extent of injury.


What Do You Mean Acute Inflammatory Response?

Acute inflammatory response is a pattern of immune response to a cell or tissue injury, characterized by immediate accumulation of immune cells at the injury site.


How Does Acute Inflammatory Response Aid in Maintaining Homeostasis?

Acute inflammatory response helps in maintaining the homeostasis by coordinating with host immune system function, including T-cell mediated response to recognise and eliminate cancer cells. They modulate tissue environment at all stages of homeostatic imbalance, for example, promotion and resolution of inflammation, tissue regenatio, and remodelling or fibrosis.


What Are the Goals Included in Acute Inflammatory Response?

The main goals of acute inflammatory response include:
 - Fight against infection or pathogen.
 - Prevent infection.
 - Eliminate tissue damage.
 - Promote healing.
 - Recruiting cells of innate immunity.
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Dr. Nagaraj
Dr. Nagaraj



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