You would enter your US medical expenses in the same way that you would enter your Canadian expenses. You would just need to convert the amount to Canadian dollars. You can get the exchange rate from this Bank Of Canada webpage: Exchange Rates
To enter your Medical Expenses in TurboTax Online:
Select Find (or the magnifying glass icon) from the top right of the page.
Enter medical expenses in the Find window.
Select Medical Expenses Profile from the list of results.
Select Go.
Select all checkboxes that apply, then select Continue.