Dr. Sanjay Gupta questions Trump's 'routine checkup': 'Those things are done at the White House medical unit'
Sanjay Gupta appears on CNN (screen grab)

CNN correspondent Dr. Sanjay Gupta explained on Monday why President Donald Trump's surprise visit to Walter Reed medical center was anything but "routine."

Trump caused speculation over the weekend when his motorcade set out to Walter Reed without stating a reason. White House Press Secretary Stephanie Grisham later told reporters that Trump was having a "routine checkup" in order to get an early start on his annual physical.

But Gupta didn't seem to buy the explanation from the White House.

"A presidential visit to a hospital is a big thing and it sounds like the staff didn't necessarily know," Gupta said. "They typically all know because it's a pretty big event."

"They say a quick exam and labs, that's what they say he had done," he continued. "Those things are often done at the White House medical unit... They can do quite a bit there, including things like this. So what was it, I guess is the question, that he needed to go to the hospital for specifically? We don't know."

Gupta took issue with Grisham's statement to the press.

"I think any medical professional knows when there is a patient going to the hospital in a surprise way like this, that would be the question," Gupta said. "I'm glad he got it checked out, whatever it is."

Watch the video below from CNN.