Pathological process
Pathological process (processus pathologicus) is a regular dynamic combination of changes in tissues and organs arising in response to damage. It is important to understand that it includes not only pathogenic (destructive) but also adaptive (protective) mechanisms.
- Dynamism: the process is constantly developing. If the scale and degree of damage increase, it can turn into a full-blown disease.
- Localization: unlike a disease as a whole, the process is often limited to a specific tissue or organ. At the same time, its pathogenic influence may be less pronounced (for example, localized soft tissue trauma is tolerated better than systemic post-traumatic illness).
- Stereotypy: regardless of the cause, the mechanisms of development include standard (typical) links.
- Connection with the disease: it is the duration and severity of the pathological process that form the individual clinical picture of the disease in a specific patient (features of onset, course, complications, and response to treatment).
Pathological reaction
Pathological reaction is the body's response to a stimulus that has lost its biological purpose. Such a reaction is always inadequate (quantitatively or qualitatively) and is not of an adaptive nature, even if it occurs in response to ordinary, non-pathogenic factors.
Most often, it is the result of disruptions in the general reactivity of the body or the reactive properties of individual tissues.
Classic examples:
- Allergic reactions — distorted psychosomatic responses during the development of phase states in the nervous system.
- Phobias — unmotivated, objectively baseless fear of an object or phenomenon.
- Pathological reflexes — situations where irritation in one area causes a destructive response in another. For example, a gallstone reflexively provokes coronary artery spasm and an attack of angina pectoris.
Pathological state
If a process is dynamics, then a pathological state is stability. This is a prolonged, protracted deviation of structure, biochemistry, or function from the norm. Intensive progression is completely uncharacteristic for it.
It arises as a consequence of past pathogenic influences, diseases, or surgical interventions:
- Deformities of heart valves (as an outcome of past endocarditis).
- States after amputation, nephrectomy, tooth extraction, partial lung or bowel resection.
- Congenital malformations and consequences of developmental anomalies (clubfoot, cleft lip or hard palate).
The main clinical significance of such states is that they become risk factors for new diseases. Edentulism naturally provokes gastritis, living with one lung or kidney threatens the development of respiratory failure or uremia, and heart valve stenosis eventually leads to heart failure.
Etiology and properties of pathogenic factors
The term "etiology" in pathophysiology is used in two senses: as the science of the causes of pathologies and as the designation of the specific cause of a specific disease. The cause itself (pathogenic, emergency, or extreme factor) is what triggers the disease and gives it specific features.
For a factor to become pathogenic, it must possess certain properties:
- Unusual nature: the organism simply has no evolutionarily developed protection against animal venoms, synthetic drugs, electric current, extreme temperatures, or aggressive chemicals (acids, alkalis, heavy metal salts).
- Excess: an excessive amount of normal endogenous substances (catecholamines, free radicals, glucose) or external influences (changes in atmospheric pressure).
- Deficiency: a shortage of exogenous (oxygen, vitamins, trace elements) or endogenous (hormones, enzymes, cytokines) components.
- Disruption of biological rhythms: violation of the sleep-wake and eating schedule leads to dyschronosis, neurotic states, and peptic ulcer disease.
- Conditioned-reflex consolidation: a neutral stimulus (the sight of an animal, the setting) becomes associated with damage and itself begins to trigger an attack (for example, in bronchial asthma). This also includes iatrogenesis — disorders resulting from a careless word by a medical worker.
- Polypathogenicity: a single agent hits multiple targets. For example, an excess of catecholamines simultaneously causes arterial hypertension, thrombosis, cardiac arrhythmia, and hyperglycemia.
Briefly: answers to topical questions
What specific typical pathological processes does pathophysiology study?
In the presented materials, the only directly named typical pathological process is hypoxia.
- Hypoxia (Hypoxia) is a typical pathological process that occurs when oxygen delivery to tissues is impaired or its utilization during biological oxidation is disrupted, leading to a disorder in the energy supply of functions and plastic processes.
A complete list of such processes is not provided; however, it is noted that the mechanism of their development has a number of standard links regardless of the cause, and the total number of typical pathological processes is significantly smaller than the number of nosological forms (diseases).
Give examples of factors possessing the property of polypathogenicity, other than catecholamines.
An example of a factor with pronounced polypathogenicity, aside from catecholamines, is the gram-negative bacterium Burkholderia cepacia.
This free-living microorganism demonstrates polypathogenicity due to its ability to cause pathologies in a wide variety of organisms:
- In humans — causes respiratory infections, urinary tract infections, as well as purulent-inflammatory processes (burn disease, meningitis, peritonitis, "Cepacia syndrome").
- In animals — capable of leading to the development of various diseases.
- In plants — also acts as a pathogen.
To avoid confusing terms, use simple associations. A process is a movie (constant dynamics, struggle between damage and adaptation). A state is a photograph (stable defect, scar, absence of an organ). A reaction is a flash (short, but inadequate response).
Class and exam questions
Can a pathological process proceed without the development of disease?
Yes, it is often localized and less pronounced. For example, gastric erosion is a pathological process, whereas peptic ulcer disease is already a formed nosological form with its own systemic manifestations.
Why is a pathological state dangerous for the patient if it is stable?
It does not progress on its own, but serves as a powerful risk factor. For example, valve stenosis following endocarditis creates a constant overload that eventually leads to heart failure.
Why can just looking at an animal trigger an asthma attack without contact with fur?
The mechanism of conditioned-reflex consolidation comes into play. An indifferent stimulus (the sight of an animal) becomes associated in memory with the real allergen and itself acquires pathogenic properties, triggering an attack.
What else to study on this topic
- Mechanisms of formation of typical pathological processes
- The role of reactivity in the development of allergic reactions and phobias
- Iatrogenesis as a variant of conditioned-reflex pathogenic impact
- Polypathogenicity of factors using the example of catecholamine excess
- Dyschronosis and consequences of circadian rhythm disruption
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