date ranges, up to, through a specific date [duplicate]
Solution 1:
In practice, they mean the same thing.
If you want to be very (very) precise, the first sentence could be construed to mean that the doctor ceased caring for the patient at some point on the 19th, while the second sentence means that the doctor cared for the patient for the entire day of the 19th. This distinction, while technically valid, is being unrealistically fussy. If the exact time of day the care ended were considered important, the first sentence would be used, but with the exact time of care termination noted.