1. Extremely sharp, severe, or intense; more acute than acute.
Usage: Medical and technical contexts
2. Occurring or developing very suddenly and with great severity, especially of a disease or condition.
Usage: Medical terminology

Examples

• The patient experienced hyperacute pain following the injury.
• Hyperacute rejection of the transplanted organ occurred within hours.
• The hyperacute phase of the infection required immediate intensive care.
• Doctors noted hyperacute inflammation in the affected tissue.
• The hyperacute onset of symptoms alarmed the medical team.
• Treatment must begin during the hyperacute stage for best outcomes.