What is the underlying pathophysiological mechanism responsible for the development of chronic inflammatory diseases like rheumatoid arthritis?

Posted: June 6th, 2021

# What is the underlying pathophysiological mechanism responsible for the development of chronic inflammatory diseases like rheumatoid arthritis?

Chronic inflammatory diseases are a group of conditions that involve persistent or recurrent inflammation in various parts of the body. Inflammation is the body’s natural response to harmful stimuli, such as infection, injury, or foreign substances. However, when inflammation becomes chronic, it can cause damage to healthy tissues and organs, leading to various symptoms and complications.

Some of the common chronic inflammatory diseases include:

– Rheumatoid arthritis (RA): a condition that affects the joints, causing pain, swelling, stiffness, and deformity.
– Crohn’s disease: a condition that affects the digestive tract, causing abdominal pain, diarrhea, weight loss, and bleeding.
– Ulcerative colitis: a condition that affects the colon and rectum, causing inflammation, ulcers, bleeding, and pus.
– Psoriasis: a condition that affects the skin, causing red, scaly patches that itch and burn.
– Psoriatic arthritis: a condition that affects both the skin and the joints, causing psoriasis symptoms and joint inflammation.
– Lupus: a condition that affects multiple organs and systems, causing fatigue, fever, rash, joint pain, and organ damage.

The underlying pathophysiological mechanism responsible for the development of chronic inflammatory diseases is not fully understood. However, researchers believe that it involves a complex interaction between genetic factors, environmental triggers, and immune system dysregulation.

Genetic factors: Some people may inherit genes that make them more susceptible to developing chronic inflammatory diseases. For example, certain variants of the human leukocyte antigen (HLA) gene are associated with an increased risk of RA, psoriasis, and psoriatic arthritis. Other genes that encode for cytokines (inflammatory molecules), receptors, enzymes, or transcription factors may also influence the development and progression of chronic inflammatory diseases.

Environmental triggers: Some external factors may trigger or worsen chronic inflammation in susceptible individuals. These factors may include infections (such as bacteria, viruses, fungi, or parasites), toxins (such as pollution or industrial chemicals), stress (such as physical or psychological trauma), diet (such as high-fat or high-sugar foods), smoking (which increases oxidative stress and inflammation), or drugs (such as nonsteroidal anti-inflammatory drugs or NSAIDs).

Immune system dysregulation: The immune system is composed of various cells and molecules that work together to protect the body from harmful invaders. However, in chronic inflammatory diseases, the immune system becomes overactive or misdirected, producing excessive or inappropriate inflammation against the body’s own tissues. This can result from several mechanisms, such as:

– Autoimmunity: The immune system fails to recognize self from non-self and attacks healthy cells and tissues as if they were foreign. This is the case in RA, lupus, Crohn’s disease, and ulcerative colitis.
– Hypersensitivity: The immune system reacts excessively or abnormally to harmless substances or stimuli. This is the case in psoriasis and psoriatic arthritis.
– Deficiency: The immune system lacks certain components or functions that are essential for regulating inflammation. This is the case in some rare genetic disorders that cause auto-inflammatory syndromes.

The chronic inflammation caused by these mechanisms can lead to tissue damage, fibrosis (scarring), angiogenesis (new blood vessel formation), neovascularization (abnormal blood vessel formation), and dysplasia (abnormal cell growth). These changes can impair the normal function of the affected organs and systems, resulting in various clinical manifestations and complications.

The treatment of chronic inflammatory diseases aims to reduce inflammation, prevent tissue damage, control symptoms, and improve quality of life. The treatment options may vary depending on the type and severity of the disease, but they generally include:

– Anti-inflammatory drugs: These drugs help to reduce inflammation by inhibiting certain enzymes or pathways involved in the inflammatory process. Examples include NSAIDs (such as ibuprofen or naproxen), corticosteroids (such as prednisone or hydrocortisone), or biologics (such as TNF inhibitors or interleukin inhibitors).
– Immunosuppressive drugs: These drugs help to suppress the immune system’s activity by interfering with its cells or molecules. Examples include methotrexate (which inhibits DNA synthesis), azathioprine (which inhibits purine synthesis), cyclosporine (which inhibits T cell activation), or rituximab (which depletes B cells).
– Symptomatic drugs: These drugs help to relieve specific symptoms associated with chronic inflammatory diseases. Examples include analgesics (such as acetaminophen or opioids), antidiarrheals (such as loperamide or bismuth subsalicylate), antihistamines (such as diphenhydramine or cetirizine), or moisturizers (such as emollients or keratolytics).

The management of chronic inflammatory diseases also involves lifestyle modifications, such as:

– Avoiding or minimizing exposure to environmental triggers, such as infections, toxins, stress, or allergens.
– Following a balanced and nutritious diet, rich in antioxidants, omega-3 fatty acids, and fiber, and low in saturated fats, sugars, and processed foods.
– Quitting smoking and limiting alcohol consumption, as these habits can worsen inflammation and increase the risk of complications.
– Exercising regularly and maintaining a healthy weight, as these practices can improve blood circulation, muscle strength, joint mobility, and mood.
– Seeking psychological support and coping strategies, such as counseling, relaxation techniques, or support groups, as these can help to deal with the emotional and social impact of chronic inflammatory diseases.

Chronic inflammatory diseases are a group of conditions that involve persistent or recurrent inflammation in various parts of the body. They are caused by a complex interaction between genetic factors, environmental triggers, and immune system dysregulation. They can cause various symptoms and complications that affect the quality of life of the patients. The treatment and management of chronic inflammatory diseases aim to reduce inflammation, prevent tissue damage, control symptoms, and improve quality of life.

References:

– Chronic Inflammation – StatPearls – NCBI Bookshelf. (2023). Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK493173/
– Chronic Inflammatory Disease: Types, Symptoms, and Treatment. (2021). Retrieved from https://www.verywellhealth.com/chronic-inflammatory-disease-5184744
– All about inflammation – Harvard Health. (n.d.). Retrieved from https://www.health.harvard.edu/staying-healthy/all-about-inflammation