Condition.code is a CodeableConcept, which means it can have multiple codings. Multiple codes (both unmodified and modified, as well as at varying levels of granularity) can all be present so long as they're all describing the same Condition at some level of granularity. Clinical systems can choose to capture Meddra terms for their AdverseEvent conditions, though if not captured specifically for research purposes, the most likely case is that the Condition will be captured in something like SNOMED and will then need to be mapped to Meddra.