What causes sepsis?

Sepsis is caused by the body's dysregulated response to an infection, which can begin in the lungs, urinary tract, skin, abdomen or another area. The infection may be caused by bacteria, viruses, fungi or other germs. Sepsis is not simply an infection spreading through the blood; the body's response can injure its own tissues and organs.

The immune system normally detects germs and coordinates inflammation to contain them. In sepsis, that response becomes harmful or poorly controlled. Inflammation and changes in blood flow can affect circulation, breathing, kidney function, brain function and other organs. An infection does not always start with severe symptoms, and sepsis can develop from a local infection such as pneumonia, a urinary tract infection or cellulitis.

The original infection may enter through damaged skin, the respiratory tract, the urinary system, the digestive system or a medical procedure. People with weakened immunity, older adults, infants and those with significant long-term health conditions may need especially prompt assessment when infection symptoms worsen, although sepsis can affect anyone.

If an infection is getting worse or you feel suddenly much more unwell, seek urgent medical assessment. Tell the clinician where the infection may have started, when symptoms changed, and which medicines or treatments you have taken. Do not delay care while trying to identify the exact germ at home. A clinician may assess your vital signs, examine you, and arrange tests to look for infection and organ strain.

Get emergency help immediately for confusion, difficulty breathing, faintness, bluish or unusually pale skin, severe weakness, very little urine, or a rapidly worsening condition. A high or unusually low temperature, shaking chills, fast breathing or a racing heartbeat with an infection also needs urgent medical attention. These signs can indicate that the infection is affecting circulation or organ function.

You could ask: Where might the infection have started? Which symptoms suggest that an organ is being affected? Which tests or treatments are needed now? What changes should prompt emergency help after I leave? If antibiotics or another antimicrobial is prescribed, ask how to take it and what to do if symptoms continue to worsen.