Sepsis is a life-threatening medical emergency where the body's response to an infection causes its own tissues and organs to be injured. It can lead to septic shock, organ failure, and death. Early recognition of symptoms like fever, confusion, severe pain, rapid breathing, and pale or mottled skin is critical, and requires immediate medical attention.

• Sepsis is triggered by an infection, most often bacterial but also viral, fungal, or parasitic. 
• Common infection sites that can lead to sepsis include the lungs (pneumonia), kidneys and urinary tract, and the abdomen. 

Symptoms of sepsis - NHS

Spotting the signs of sepsis - The UK Sepsis Trust