It's a medical emergency.

Meaning

A serious health problem requires immediate attention.

Examples

• John: I think she's having trouble breathing.
• Alice: Oh my goodness! <b>It's a medical emergency</b>! Call 911 immediately!
• John: I'm already on the phone. <b>It's a medical emergency</b>; we need to act fast.
• Alice: I'll try to help her stay calm while we wait.