Right resource/field for symptoms?


#1

Hello,

I am trying to understand which is the most appropriate resource to store symptoms.

On one hand, in the condition resource documentation we find that:

This resource is not typically used to record information about subjective and objective information that might lead to the recording of a Condition resource. Such signs and symptoms are typically captured using the Observation resource; although in some cases a persistent symptom, e.g. fever, headache may be captured as a condition before a definitive diagnosis can be discerned by a clinician.

Thus, the previous paragraph says that symptoms should be recorded in the observation resource. But then, when we go to the observation resource documentation, there is not a single appearance of the word “symptom”, and the observation resource seems more appropriated for things that the doctor can actually measure or see. I guess however that one could say that a doctor can “observe symptoms”, as for example “the doctor sees that the patient complains about a headache”, but I am not sure if that’s too much of a stretch.

On the other hand, we have the field condition.evidence.code, where we could put the codes of symptoms that are evidence of some conditions. However, we need to start storing symptoms before the condition is created, since the doctor will start taking note of the symptoms of the patient, and then some of those will probably become evidence of some conditions, but some other symptoms claimed by the patient might just be ignored for the current diagnosis, but still they must be recorded somewhere. Besides condition.evidence accepts any type of reference, so for sure it is not an exclusive field for symptoms.

Another piece of information is https://www.hl7.org/fhir/resourceguide.html , which appears to recommend recording symptoms in the condition resource. In this case it seems that the recommendation is to store each symptom as a condition, which seems partially contradictory with the paragraph I pasted above.

So coming back to my original question: which is the right place to store symptoms that the patient claims before any kind of diagnosis has been performed? We have condition, condition.evidence and observation, but none of them seems exactly right.

Additionally, I’d like to ask the following: I have worked in many medical projects, but I am a technical person, and therefore I am probably missing some important part of the story here. I would have expected that such a fundamental medical concept as “symptom” would have had a very clear place in FHIR (and also in SNOMED btw). But this doesn’t appear to be the case. Why is that happening?

Thanks a lot for your help


#2

The question about which resource to use for symptoms is a valid one that we (Patient Care work group) have tried to address as a result of GF#8872 and more recently GF#15970. The current guidance in the boundaries now reads:

This resource is not typically used to record information about subjective and objective information that might lead to the recording of a Condition resource. Such signs and symptoms are typically captured using the Observation resource; although in some cases a persistent symptom, e.g. fever, headache may be captured as a condition before a definitive diagnosis can be discerned by a clinician. By contrast, headache may be captured as an Observation when it contributes to the establishment of a meningitis Condition.
Use the Observation resource when a symptom is resolved without long term management, tracking, or when a symptom contributes to the establishment of a condition.
Use Condition when a symptom requires long term management, tracking, or is used as a proxy for a diagnosis or problem that is not yet determined.

I think the guidance in http://build.fhir.org/resourceguide.html needs to be reviewed and clarified. Feel free to log a change request for that (using the “propose a change” link at the bottom of the page).

Symptoms are within scope of Observation. You are welcome to submit another change request to ask that Observation include the same guidance as Condition has regarding symptoms.

As an implementer, I will add that I agree that symptoms may be found in either resource. It ultimately is the decision of the end user to decide when a symptom warrants long term management and is elevated to a problem or condition. I don’t see FHIR changing that reality.