For the May 2026 International Edition 82598004 |Secondary hypothyroidism (disorder) has been modelled with a large number of GCI axioms, and as a consequence has acquired a number of new descendants.
My understanding was/is that secondary hypothyroidism is atypical in this regard, having a much more specific meaning - notably hypothyroidism caused by a malfunctioning pituitary gland, failing to produce sufficient thyroid-stimulating hormone (TSH). This situation was approximately how 82598004 was previously modelled, and is, to some extent, reflected in its (still) active synonyms Pituitary hypothyroidism and TSH (thyroid stimulating hormone) deficiency.
Has the clinically-accepted definition and use of secondary hypothyroidism changed?
Thank you for your feedback. The additional du to relationships in the GCI axioms are incorrect. We have removed the GCI axioms, and the changes will be included in the July release. It would be helpful if feedback on content were submitted through the request submission system, as this will help us track the changes.
I believe this represents a specific issue within a larger systemic problem impacting both hypothyroid and hyperthyroid disorder hierarchies.
I tried to point out the problem for hyperthyroidism & thyrotoxicosis a number of years ago using the request system but only a small piece of that request was addressed - the fundamental problem wasn’t. I’ll see if I can find it and link to it later.
Neither “hyperthyroidism” or “hypothyroidism” are inherently a disorder of the the thyroid.
Yet we have many secondary hyperthyroidism and thyrotoxicosis concepts within the “disorder of thyroid gland” that are not disorders of the thyroid gland. examples: “Hyperthyroidism due to struma ovarii”, “iatrogenic thyrotoxicosis” or “thyrotoxicosis factitia”.
The same issue applies to “secondary hypothyroid” - this is not a disorder of the thyroid gland. I believe I’ve also seen this problem in other endocrine disorder hierarchies as well.
I looked at this closely for a proprietary content set I oversaw many years ago. Speaking from memory, I think I solved it there using appropriate endocrine axes to capture a full family of concepts, like low thyroid hormone levels or high levels, in a single hierarchy. I was also able to limit those disorders that are inherently a disorder of the respective gland to the respective gland’s hierarchy. As an off the cuff example (don’t take this literally), all the thyroid function disorders might have fallen into “disorder of thyroid hormone axis” or “disorder of hypothalmic-pituitary-thyroid axis”.
My request was more focused on hyperthyroid vs thyrotoxicosis issue. As with ‘hypothyroidism’, the point remains. These are not inherently a disorder of the thyroid gland.
Doesn’t look like I can follow that link to the US request system but you make the point clearly in your original note.
I confess it’s not something I’d picked up on but I agree it’s relevant - as you say, in some patterns of hyper- and hypothyroidism the thyroid gland itself is blameless, simply doing its job in difficult circumstances.
I note that whilst ICD-10 has a similar arrangement to SNOMED CT’s, ICD-11 has dealt with things by organising both the structural/functional thyroid disorders and the consequences of abnormal thyroid hormone amounts and effectiveness beneath Disorders of the thyroid gland or thyroid hormones system. which to some extent avoids the “all of these imply a disorder of the thyroid gland itself” problem you highlight. In theory a similar disjunctive class could be introduced to SNOMED CT (possibly taking advantage of GCIs that make use of the new ‘has_excess_of’ and ‘has_deficiency_of’ attributes alongside more conventional ‘finding_site’ modelling) but whether it gets added is an SI decision. If the case can be made that the current state of affair is sufficiently ‘wrong’ (rather than just ‘looks wrong’ [see Logical Versus Vernacular]) then arguably something should be done.
Thanks also since your post made me look at 722941003|Secondary hyperthyroidism|. This would appear to have been incorrectly modelled too with a set of GCIs, implying it is “the union of all hyperthyroidisms that are caused by something else” rather than the consequence of a hyperactive pituitary or hypothalamus.
Thanks for submitting the CRS request for the issues raised here.
We will remove those incorrect GCIs from the Secondary Hyperthyroidism as a first step. The issue of incorrect finding site of thyroid gland raised by Steven will require review of all related concepts. The new attributes introduced recently could be utilised to address the issues by a different modeling approach.