Chronic Inflammation - Causes, Symptoms, Diagnosis, and Treatment

Introduction

Chronic inflammation is continuous low-grade inflammation that is present throughout the body. These mediators can be detected in blood tests. These chronic inflammations can cause several systemic diseases.

What Is Chronic Inflammation?

When the body continues producing inflammatory cells even without triggering agents, chronic inflammation is slow and long-lasting inflammation that presents for months or years in the body.

What Are the Causes of Chronic Inflammation?

There are various inflammation triggers around us. These triggers are found in the form of cigarette smoke, air pollutants, water, or food. The following are the common causes of inflammation:

• Resistant Infection: When the previous bacterial, fungal, or viral infections are resistant to the host tissue, these infectious organisms stay in the tissue for long periods.

• Low-level Irritants: Some irritants or foreign materials are resistant to enzymatic degradation. This includes chemicals that are inhaled for prolonged periods, like silica dust.

• Sensitivity: When the body senses unusual triggers, hypersensitivity can cause allergies.

• Autoimmune Diseases: When body immunity recognizes standard body components as a foreign antigen, it attaches to normal body components and causes long-term autoimmune diseases like rheumatoid arthritis.

• Autoinflammatory Diseases: When the cells which control inflammation are defective, the process continues with control.

• Recurrent Acute Inflammation: Sometimes, recurrent episodes of short-term inflammation can lead to chronic inflammation.

• Free Radical Generation: Increased oxidative stress and mitochondrial dysfunction increase the inflammatory response.

What Is the Pathology of Chronic Inflammation?

The features of acute inflammation are seen in chronic inflammation as well. These include:

• Vasodilation - Expansion of blood vessels.

• Increased blood flow and increased permeability.

• Diapedesis - Migration of neutrophils in the infected tissue.

• In chronic inflammation, the neutrophils are replaced by macrophages, plasma cells, and lymphocytes. These inflammatory cells produce cytokines, growth factors, and enzymes leading to tissue damage and repair. These cytokines induce cells in blood vessels which cause chemotaxis and diapedesis.

What Are the Types of Chronic Inflammation?

• Non-specific Proliferative: The inflammatory cells like lymphocytes, macrophages, and plasma cells, along with fibroblasts, connective tissue, epithelial cells, and blood vessels, form granulation tissue. Lung abscess is a type of non-proliferative inflammation.

• Granulomatous Inflammation: A distinct nodular lesion with granulomas formed by macrophages and lymphocytes is a granuloma. The macrophages later form Langhans cells or giant cells like foreign bodies.

What Are the Risk Factors Associated With Chronic Inflammation?

Various risk factors promote inflammation. These factors are as follows:

• Age: Age increases the risk of mitochondrial dysfunction and free radical accumulation. It increases the accumulation of visceral body fat.

• Obesity: Fat tissue secretes adipokines and other inflammatory mediators.

• Diet: Fat and sugar-rich diets increase pro-inflammatory mediators.

• Smoking: Smoking decreases the production of anti-inflammatory mediators.

• Decreased Sex Hormones: Controlled levels of sex hormones help in the maintenance of pro-inflammatory markers.

• Sleep and Stress: Any kind of stress releases cytokines. Sleep deprivation and stress are closely connected and increase the risk of inflammation.

What Are the Symptoms of Chronic Inflammation?

Chronic inflammation is difficult to spot as compared to acute inflammation. Signs of chronic inflammation are as follows:

• Muscle, joints, and body pain.

• Fatigue.

• Insomnia.

• Anxiety and depression.

• Constipation, diarrhea, acid reflux.

• Weight changes.

• Infections.

How to Diagnose Chronic Infections?

We can diagnose chronic inflammation when it presents with other medical conditions:

• High levels of C reactive protein and fibrinogen test indicate inflammation. These levels are elevated in acute inflammation also. Hence, this is not a standard method to determine chronic inflammation.

• Detection of pro-inflammatory cytokines like tumor necrosis factor and interleukin.

How to Manage Chronic Inflammation?

Dietary changes and lifestyle modification help control inflammation.

• Consumption of a diet with a low glycemic index decreases the risk of chronic diseases.

• Decreased intake of saturated and trans fat. Trans fat increases inflammation, whereas omega 3 decreases inflammatory response.

• Fruits and vegetables high in antioxidants, like apples, sprouts, cabbage, broccoli, and cherries, have anti-inflammatory properties.

• Soluble and insoluble fiber is said to decrease inflammatory mediators.

• Nuts, curcumin, and green tea polyphenols are believed to reduce inflammation.

• Micronutrients like magnesium, vitamin D, zinc, and selenium have antioxidant properties.

• Regular exercise lowers pro-inflammatory markers.

• Drugs for chronic inflammation are mentioned below.

• Metformin is a drug used in diabetic patients. It has anti-inflammatory properties.

• Statins reduce bio mediators of inflammation.

• Non-steroidal anti-inflammatory drugs inhibit the enzyme cyclooxygenase, which is responsible for inflammatory response.

• Glucocorticoids are the choice of drug in systemic diseases with chronic inflammation.

What Are the Complications of Chronic Inflammation?

Chronic inflammation contributes to the following diseases:

• Cancer: Inflammation can be associated with cancer of the kidney, prostate, colorectal, and lung.

• Atherosclerosis: Atherosclerosis is a pro-inflammatory disease that increases the risk of cardiovascular risks like myocardial infarction and stroke.

• Rheumatoid Arthritis: Smoking and infections can cause local inflammation in bones and joints.

• Diabetes: Macrophages attack pancreatic cells and release inflammatory molecules. This can cause vascular complications like stroke, heart attack, and eye, kidney, and brain complications.

• Asthma: Improper immune response and inflammation decrease airway function.

• Chronic Obstructive Pulmonary Disease: Inhalation of irritants followed by breathing problems.

• Alzheimer's Disease: Decreased memory and cognitive function due to low inflammation in brain cells.

• Inflammatory Bowel Disease: Inflammation of the digestive tract can lead to ulcerative colitis or Crohn's disease.

• Kidney Disorders: Retaining inflammatory molecules in the blood can worsen kidney diseases.

How to Prevent Chronic Inflammation?

Prevention of chronic inflammation can be done by changing the lifestyle and following a healthy diet. Following are the habits which help prevent inflammatory conditions in the body:

• Increase intake of anti-inflammatory food, and avoid refined sugar, high glycemic food, and trans fat. Increase intake of fruits and vegetables like avocados, kale, and salmon, which help to reduce inflammation.

• Decrease the use of antibiotics like non-steroidal anti-inflammatory drugs. This alters the gut microflora. This can trigger inflammation throughout the body.

• Regular exercise can help reduce the adipose tissue load. Adipose tissue can trigger a low-grade inflammatory response. Exercise helps in weight maintenance and reduces cardiovascular risk. It enhances overall body, muscle, and bone strength.

• Adequate sleep helps in controlling growth hormones and sex hormones. Seven to eight hours of sleep is sufficient for the proper function of the human body.

• We can control stress levels with yoga and meditation. Stress can cause depression and heart disease and reduces the body's ability to control and repair inflammatory responses on its own.

Conclusion

All chronic inflammations cannot be managed. Management of chronic disease needs an interdisciplinary approach. Patients should be informed and educated about the importance of diet and lifestyle changes. Along with these changes, some diseases need anti-inflammatory medications as part of the treatment regimen.