Sepsis is a life-threatening condition that arises when the body's response to infection injures its own tissues and organs.
Common signs and symptoms include fever, increased heart rate, increased breathing rate, and confusion.
There may also be symptoms related to a specific infection, such as a cough with pneumonia, or painful urination with a kidney infection. In the very young, old, and people with a weakened immune system, there may be no symptoms of a specific infection and the body temperature may be low or normal rather than high.
Severe sepsis is sepsis causing poor organ function or insufficient blood flow. Insufficient blood flow may be evident by low blood pressure, high blood lactate, or low urine output. Septic shock is low blood pressure due to sepsis that does not improve after reasonable amounts of intravenous fluids are given.
Sepsis is caused by an immune response triggered by an infection.
The infection is most commonly bacterial, but it can be from fungi, viruses, or parasites.
Common locations for the primary infection include lungs, brain, urinary tract, skin, and abdominal organs. Risk factors include young or old age, a weakened immune system from conditions such as cancer or diabetes, and major trauma or burns.
Diagnosis was based on meeting at least two systemic inflammatory response syndrome (SIRS) criteria due to a presumed infection. In 2016 screening by SIRS was replaced with qSOFA which is two of the following three: increased breathing rate, change in level of consciousness, and low blood pressure.
Blood cultures are recommended preferably before antibiotics are started; however, infection of the blood is not required for the diagnosis. Medical imaging should be done to look for the possible location of infection.
Other potential causes of similar signs and symptoms include anaphylaxis, adrenal insufficiency, low blood volume, heart failure, and pulmonary embolism among others.