I tried this but in the diagnosis (diagnosticos?) table I stored the code value (codigo) instead of the diagnosis value, which I assume is a descriptive version of the code. I then related the diagnosis table to the code table (ICD-10) by the code value instead of the diagnosis value.
In a portal I put two fields, one was the code from the diagnosis table and one was the code from the ICD-10 table. I made the first one a pop-up menu that referred to a value list that referred to the code value and the descriptive value from the code table and indicated to display the "second value" only.
So, when you go into the portal, you click on the diagnosis field which pops up all the values from the descriptions in the code table, and when you choose one, it puts the code into the second field (because of the relationship not the pop-up). Not sure if this is what you were even asking for (plus my Spanish is non-existant) but I thought it might help.