Disease Classification and Etiology
Disease Classification
Genetic Diseases
Hereditary diseases are caused by modifications in the genome passed down through generations. Sex-linked inherited diseases occur when the modification is on a sex chromosome, affecting only one sex. Mitochondrial diseases are inherited through modified mitochondrial DNA, always originating from the mother.
Degenerative Diseases
These diseases involve impaired regenerative ability. Sometimes, the body loses its ability to regenerate (e.g., Parkinson’s and Alzheimer’s), while in other cases, regeneration doesn’t stop (e.g., some cancers).
Autoimmune Diseases
In autoimmune diseases, the immune system attacks the body.
Exogenous Diseases
These diseases are caused by external factors.
Traumatic Diseases
Result from accidents. Congenital diseases, while sometimes considered endogenous, can be exogenous, even traumatic, occurring before birth (e.g., shock, maternal illness, pollutants).
Infectious Diseases
Caused by microscopic agents like bacteria, fungi, viruses, protozoa, viroids, and prions. Venereal diseases are infectious diseases transmitted through sex. When the pathogen is macroscopic, the disease is parasitic.
Nutritional Diseases
Stem from inadequate nutrition. Deficiency diseases are due to diets lacking in vitamins.
Iatrogenic Diseases
Caused by medical error or negligence.
Environmental Diseases
Occur in the individual’s environment, with occupational diseases being increasingly important. Toxic diseases are caused by poisons, including pollutants and food poisoning.
Allergic Diseases
Sometimes considered endogenous, these are caused by a disproportionate immune system response.
Postural Diseases
Caused by prolonged bad posture.
Other Classifications
Disease Progression
Acute diseases have a clear start and end, while chronic diseases lack a clear end.
Frequency
Pandemic diseases affect everyone at once. Epidemic diseases affect many people in a specific area. Endemic diseases affect a particular place. Most diseases are sporadic, affecting only a few people.
Affected Systems
Diseases can be classified by the affected system: respiratory, lung, genitourinary, circulatory, gastrointestinal.
Etiology: The Origin and Cause of Disease
Health
Health can be defined as the level of functional or metabolic efficiency of an organism. The WHO defines health as a state of complete physical, mental, and social well-being. This broad concept encompasses many aspects.
Mental Health
Deals with the prevention, treatment, and rehabilitation of psychological disorders, including those related to sexual identity.
Public Health
Encompasses health promotion and public health systems (hospitals, clinics, campaigns, outreach).
Sexual Health
Addresses the physical, mental, emotional, and social development of an individual’s sexuality.
Reproductive Health
Concerns reproductive processes, organs, and systems, including sexual dysfunction and infertility.
Maternal Health
Relates to the mother’s health before, during, and after childbirth.
Family Planning
Involves controlling birth, including contraception, abortion procedures, or abortions.
Environmental Health
Studies the physical, chemical, and biological processes affecting health. Hygiene, nutrition, and physical activity also influence health.
To avoid controversy, we focus on etiology: the factors causing disease.
Disease
A disease is a state and malfunction of a living being. A noxa is a factor that produces disease, which can be intrinsic or extrinsic. Diagnosis is the procedure for determining health or disease. Medical personnel perform a scan to collect clinical signs or symptoms. A clinical sign is an observable, measurable value of an alteration (e.g., pressure, temperature). A symptom is a subjective perception of the patient. When basic explorations are insufficient, instrumental techniques and complementary techniques are used. Laboratory tests are mostly biochemical tests of bodily fluids. Diagnostic imaging techniques (TDI) create images of the body’s interior. Endoscopy involves inserting cameras through natural or artificial openings. A biopsy is the removal of a tissue sample for analysis. Each disease has a clinical picture: a set of related clinical signs and symptoms. Diseases can be endogenous, where the origin is the patient themselves.