diseases

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Definition: A disease is a particular abnormal condition (anomaly - anomalies ), a disorder of a structure or function , that affects part or all of an organism .

The study of diseases forms the pathology.
The classification of diseases forms the nosology.
The study of the causes of diseases forms the etiology.
The study of the mechanisms of diseases forms the physiopathology.

A disease differs from a syndrome , which is a collection of signs or symptoms that occur together. However, for historical reasons, many diseases that have been clearly identified continue to be referred to as "syndromes".

Conversely, numerous conditions of unknown etiology are referred as "diseases", whithout clearly defined causes.

Causes

The study of the causes of diseases forms the etiology.

Diseases may be caused by external factors such as pathogens, or it may be caused by internal dysfunctions, such as autoimmune diseases. The study of the causes of diseases is etiology.

Etiological classification of diseases

 genetic diseases, grouping chromosomal diseases and genic diseases
 infectious diseases caused by infections / infection and infectious agents
 dysimmune diseases caused by dysimmunity
 environmental diseases caused by environment , toxics , drugs
 nutritional diseases caused by nutritional anomalies
 degenerative diseases caused by senescence and ageing / aging
 tumoral diseases ( tumors )

Mechanisms of diseases - Physiopathology

Physiopathological classification

 developmental anomalies (malformations )
 metabolic diseases
 inflammatory diseases
 degenerative diseases / senescence
 tumoral diseases ( tumors )

Phenomenology

These manifestation of diseaes are phenomenons (Greek: φαινόμενον, phainómenon, from the verb phainein, to show, shine, appear, to be manifest or manifest itself, plural phenomena). Phenomena are often, but not always, understood as "things that appear" or "experiences" for a sentient being, or in principle may be so.

For a clinician, a disease is associated with specific symptoms and signs.

For a pathologist, a disease causes morphological anomalies that can be seen with naked eyes ( macroscopical anomalies ) or seen at the microscopical level ( microscopical anomalies ).

Diseases in humpath.com

 Diseases
 Disease localizations

 Group of diseases

• Group of diseases according to etiology
• Group of diseases according to localization
• Group of diseases according to age
• Group of diseases according to the lesional pattern
• Group of diseases according to the physiopathological pathway
• Group of diseases according to the molecular pathway
• Group of diseases according to the clinical semiology

Localization

 systemic diseases
 localized diseases (diseases of a structure)

• diseases of systems
• diseases of organs
• diseases of tissues (tissular pathology )
• diseases of cells (cellular pathology )
• diseases of cellular organelles (cellular pathology )
• diseases of molecules (molecular pathology )

See also

 communicable diseases ( infectious diseases )
 non-communicable diseases (non-communicable diseases )

Links

 diseasedir.org.uk

References

 Wright A, Charlesworth B, Rudan I, Carothers A, Campbell H. A polygenic basis for late-onset disease. Trends Genet. 2003 Feb;19(2):97-106. PMID: 12547519

 Reich DE, Lander ES. On the allelic spectrum of human disease. Trends Genet. 2001 Sep;17(9):502-10. PMID: 11525833