Inflammation

Inflammation (Latin - medical inflammatio ) is the sign of activation of the immune system. This should be removed by an immune reaction pathogens or toxins from the tissue cells. The technical terms of inflammation are usually marked with a combination of the Greek term for the institution concerned with the Greek suffix -itis.

Properties

A foreign substance, or antigen tissue damage triggers the stimulus for a defense reaction of the immune system. The inflammatory reaction occurs in the affected organ, in the surrounding connective tissue in the involved blood vessels and adjacent lymph system instead. This leads to the typical signs of inflammation, redness ( rubor Latin ), heating (Latin calor ), swelling (Latin tumor ), pain ( dolor Latin ) and a limited function (Latin functio laesa ). These five signs are not always directly visible or only partially detectable. An inflammation of the stomach for example, eg mainly cause pain after eating and is then only limited symptomatic. You may be accompanied by nausea.

The redness and swelling is done by increasing the permeability of the blood vessels in the course of diapedesis of immune cells, red blood cells and plasma proteins by secretion of mediators interleukin -1 and prostaglandin I2. The immigrant cells and plasma proteins are referred to as infiltration. The pain is made by a release of pain mediators ( prostaglandin E2, prostaglandin I2, bradykinin and other kinins ) and cytokines (tumor necrosis factor ) by the immune cells and is used for immobilization of the relevant body part and the conservation of energy reserves due to lower activity. The temperature increase is mediated by cytokines such as interleukin -6 on the production of prostaglandin E2 and caused by increased metabolic activity.

Often, the reaction consists of a rejection of a part of the diseased tissue by necrosis or apoptosis and subsequent formation of new cells for the repair of tissue damage. Rejection of cells used for skin cells, inter alia, to protect the underlying tissue. Inflammation can locally in a ( small ) circumscribed area occur or affect the entire body. Examples of localized inflammation are, for example, enteritis (inflammation of the intestine), the colitis (inflammation of the colon ), gastritis (inflammation of the stomach ), arthritis ( joint inflammation), myocarditis (heart muscle inflammation), dermatitis (skin inflammation) and otitis ( ear infection ). An exception is the pneumonia ( pneumonia), in which the suffix " -itis " is missing (but is rarely the form of pneumonitis used).

In classical medicine inflammation are often fought by stopping the triggering stimulus. Suppresses to the defense reaction in the context of symptomatic therapy, healing may be delayed, however.

Causes

Each physiological measure excess stimulus can trigger inflammation, in particular this applies to physical stimuli such as mechanical stimuli ( eg pressure, friction, injury or foreign body, such as metabolites such as uric acid crystals), thermal ( eg, heat, cold), radiation (UV, IR, ionizing radiation), chemical irritants ( irritant and harmful substances such as acids, alkalis, toxins, control enzymes, such as in acute pancreatitis), allergens and car allergens ( z. example, in rheumatic or autoimmune diseases) or pathogens (bacteria, viruses, fungi, parasites).

Sequence of local inflammatory reactions

• Local circulatory disorder: This only minutes long phase is also called the "initial ischemia ". This refers to a short-term local blood flow disturbance by the reaction of the vascular connective tissue to adrenaline ( arterial spasm ). Connected to the constricted arterioles are dilated venules.
• This is followed, especially local, hyperemia, which is triggered by the one triggered by the autonomic nervous system Arteriolenspasmus, on the other by a constriction of the venules. The latter is caused by various mediators, such as prostaglandins, kinins. This outflow obstruction in turn leads to platelet aggregation, the sludge phenomenon ( viscous blood), exudation and the other caused by blood stasis consequences.

General non-specific signs of inflammation

In addition to the five direct signs of inflammation at the site of inflammation can be seen an inflammation of a certain severity in the general reactions of the whole organism. These general reactions include:

• Fever: Accelerated metabolism with faster synthesis among others of antibodies
• Malaise
• Leucocytes or decrease (white blood cells)
• CRP increase ( immunologically effective acute-phase protein)
• Accelerated erythrocyte sedimentation (UCS or BSG for sedimentation rate )
• Procalcitonin increase ( hormone precursor)

Molecular Mechanisms

Inflammation associated with characteristic changes at the molecular level. First, it comes through the triggering stimuli to activity changes in certain cellular signaling pathways, which in turn lead to specific changes in the gene expression pattern. One of the most important intracellular regulators of inflammatory reactions, for example, the transcription factor NF -kB, which is activated by bacterial and viral antigens, cytokines and chemical-physical toxicants and gene expression can change rapidly and comprehensively in affected cells. Among the upregulated genes are particularly cytokines and cell adhesion molecules, which ensure a spread of inflammation to other cells and their gain, often in terms of a positive feedback. An example of a well-characterized molecular inflammatory response is the so-called acute-phase response.

Classification

Inflammation can be classified according to the time course of the disease:

• Peracute = sudden onset of very severe inflammation, which leads to death within a few days
• Acute = sudden onset of inflammation
• Subacute = between acute and chronic - no further definition
• Primary chronic = slow, insidious draining inflammation
• Recurrent = recurrent inflammation
• = progressive progressive inflammation ( without improvement )
• Secondary -chronic = from non-healing acute or recurrent inflammation

After expansion:

• Systemic / generalized / metastatic inflammation ( whole body - usually with fever)
• ( limited to a point ) local inflammation

After the liquid:

• Serous inflammation (large amounts of protein-rich fluid)
• Fibrinous inflammation (large amounts of liquid fibrinhaltiger )
• Purulent inflammation