inflammations

Inflammation is a protective biological response of living tissue to harmful stimuli, including infection, tissue injury, and irritants. It involves the vascular and immune systems and serves to eliminate the initial cause of cell injury, clear damaged cells, and promote tissue repair.

The process typically begins with local vascular changes and the release of mediators such as histamine, prostaglandins, bradykinin, and cytokines from resident cells. This leads to vasodilation and increased vascular permeability, allowing fluid, proteins, and leukocytes to move into the affected tissue. Neutrophils are usually the first circulating cells to arrive, followed by monocytes that differentiate into macrophages. These cells phagocytose microbes and debris and release further mediators that modulate the response.

Acute inflammation is short-lived (hours to days) and is characterized by redness, heat, swelling, pain, and sometimes loss of function. If the injurious stimulus persists or resolution fails, chronic inflammation may develop, involving macrophages, lymphocytes, and plasma cells, potentially causing tissue injury and fibrosis. Granulomatous inflammation is a special chronic form seen in certain infections and diseases.

Clinical features include local signs and systemic responses such as fever and elevated inflammatory markers. Laboratory tests commonly show raised C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), leukocytosis, or neutrophilia in bacterial infection.

Management focuses on removing or controlling the cause, reducing tissue damage, and promoting repair. Treatments include nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids for broader suppression, and disease-modifying antirheumatic drugs or biologics for autoimmune conditions. Supportive care and management of complications are also important.

Understanding the balance between protective inflammation and pathological inflammation helps in diagnosing and treating a wide range of conditions, from infections to chronic diseases such as rheumatoid arthritis and inflammatory bowel disease.