Acquired <finding or disorder)

JIRA ID: IHTSDO-1059

Release used for analysis: 

Approvals 

1. Content Issue Summary 

a. Summary of issue 

There are currently approximately 690 concepts in the Clinical findings and Disease hierarchy that contain the word "acquired" in the FSN.  These are used clinically to differentiate clinical conditions that may be either congenital or acquired later in life.  Most of these concepts are currently primitive.  There are a number of issues related to the presence of these primitive concepts: 

• Many of the existing terms have been modeled using "Acquired X (morphologic abnormality)" concepts, which allows them to be sufficiently defined, but results in creation of additional morphology concepts that only differ in the period of life in which they appear. This is analogous to the "Congenital X" morphologies that are being inactivated through remodeling of the Congenital disease subhierarchy. 
• "Acquired" and "Congenital" are not morphologies, but timeframes.  We currently do not have a way of denoting "All periods of life after birth" like we do for "Congenital".
• The ability to define acquired disorders might also open the door that all disorders that are normally acquired after birth have an OCCURRENCE relationship added, which seems to be “overmodeling”.  The "Acquired deformity" morphology concepts are incomplete and a suboptimal way to address temporality. 
• The application of the proposed modeling pattern would only be applied in situations where there is a specific need to differentiate between congenital and acquired conditions of the same type.

b. Related content projects and requests 

2. Analysis of Issue 

Acquired conditions are those which manifest after birth.  Since this relates to a period of life as opposed to a specific process or structure.  

Three alternatives have been considered:

• Create an intermediate primitive grouper - "Acquired disorder" that would allow subtypes to be fully defined under. These would also classify under the appropriate parent term related to the disorder.
• Create a "period of life" subtype that included all periods except "fetal, congenital, and neonatal(?) (substantial testing of impacts would be needed)
• Create a set of "Acquired X (morphologic abnormalities)" to support definition of acquired disorders.

This demonstrates a need to support disjointness, which will hopefully be supported by the concept model in the near future. There are challenges with using period of life as a way to classify these as age ranges fdiffere among juridictions. There is also the distinction between hereditary and "congenital", which are often conflated in disease naming. Hereditary diseases often manifest later in life. Would these be considered "acquired"? What do we mean when we say "acquired"?

It would be prudent to limit the use of the period of life grouper for only those disease where the FSN specifies "acquired". However, would diseases that manifest later in life but are actually genetic be incorrectly classified under acquired disorder? What is the  advantage of this top level grouper "Acquired disorder"? The challenge is how to represent the acquisition/origin of the trait as opposed to the clinical manifestation of the trait.

3. Additional issues identified  

This slution does not adequately address concepts containing the term "juvenile" as that term is used to represent the clinical manifestation of a disorder at a very broad range of life periods.  There is an inactive concept  282035009 -    Juvenile (qualifier value), which I suspect was inactivated due to the variability in determining which more specific life periods it encompasses.

4. Solution 

A new qualifier value of "Post-natal" will be created to aggregate the periods of life that would be used to define "Acquired" conditions.

All concepts that current explicitly state "acquired" in their FSN would have a new relationship OCCURRENCE = Post-natal period (qualifier value) added to the defining relationship group(s).  This will allow many of the currently primitive concepts to become sufficiently defined resutling in a richer set of inferences.