Not necessarily extenuating circumstances, as these are things that are unexpected/out of your control. However I can understand how caring for a relative could also be unexpected, so if this is the case you need to make this clear in how you describe it.
If it wasn’t unexpected but it still disrupted your studies (eg you couldn’t attend school/college/university) this should be something you highlight as a major commitment that conflicted with your studies though. It might be worthwhile flagging how many hours per week you were actively caring for the relative and also explain the time period it happened as well.