The goalkeeper was stretchered off and taken to hospital after landing awkwardly on his left elbow as Neal Maupay opened the scoring for the Seagulls in the third minute.
talkSPORT understands Lloris, who appeared in total agony, needed morphine to numb the pain.
“The news after game wasn’t good,” Pochettino told talkSPORT.
“Through the website we’ll update and explained what happened. But of course, it’s not good news. I think he has suffered a big issue.”
The injury came after Lloris made yet another howler, dropping the ball on his goal-line and allowing Maupay to nod into the empty net.
Brighton youngster Aaron Connolly then piled more misery on Pochettino by scoring on his first Premier League start either side of half-time.
Following the 7-2 defeat to Bayern Munich at home in the Champions League on Wednesday, the trip to the Amex continued a week from hell for Spurs.
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