An idiopathic disease is any disease with an unknown cause or mechanism of apparent origin.
For some medical conditions, one or more causes are somewhat understood, but in a certain percentage of people with the condition, the cause may not be readily apparent or characterized. In these cases, the origin of the condition is said to be idiopathic. With some other medical conditions, the root cause for a large percentage of all cases has not been established—for example, focal segmental glomerulosclerosis or ankylosing spondylitis; the majority of these cases are deemed idiopathic.
Derivation
The term 'idiopathic' derives from
Ancient Greek ἴδιος
idios "one's own" and πάθος
pathos "suffering", so
idiopathy means approximately "a disease of its own kind".
Examples
Diseases where the cause is seen as wholly or partly idiopathic include:
-
Idiopathic pulmonary fibrosis
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Idiopathic pulmonary haemosiderosis
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Idiopathic intracranial hypertension
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Idiopathic chronic fatigue
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Granulomatous prostatitis
Medical advances and this term
Advances in
medicine improve the understanding of causes of diseases and the classification of diseases; thus, regarding any particular condition or disease, as more root causes are discovered and as events that seemed spontaneous have their origins revealed, the percentage of cases designated as idiopathic will decrease. Environmental and occupational risk factors are increasingly being associated with diseases classified as
idiopathic. Emerging evidence indicates a complex relationship between intrinsic (
Genetic disorder) and extrinsic (environmental and occupational risk factors) factors in disease physiopathology.
Usage of synonyms
The word
essential is sometimes
with
idiopathic (as in essential hypertension, essential thrombocythemia, and
essential tremor) and the same is true of
primary (as in primary biliary cholangitis, or
primary amenorrhea), with the latter term being used in such cases to contrast with
secondary in the sense of "secondary to i.e., some other condition." Another, less common synonym is
agnogenic (
agno-, "unknown" +
-gen, "cause" +
-ic).
The word cryptogenic ( , "hidden" + -gen, "cause" + -ic) has a word sense that is synonymous with idiopathic
Some birth defect are idiopathic, and sometimes the word congenital is used synonymously with idiopathic; but careful usage prefers to reserve the word congenital for conditions to which the literal sense of the word applies (that is, those whose pathophysiology has existed since the infant period).
Syndrome without a name
The term
syndrome without a name (SWAN) is used "when a child or young adult is believed to have a genetic condition and testing has failed to identify its genetic cause". It is believed that "about half (50%) of children with learning disabilities and approximately 60% of children with congenital disabilities (disabilities which are apparent from birth) do not have a definitive diagnosis to explain the cause of their difficulties".
See also
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Diagnosis of exclusion
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Embolic stroke of undetermined source
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Functional disorder
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Idiosyncratic drug reaction
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Fever of unknown origin
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