Septicemia can be caused by infection that originates from anywhere in the body, primarily in the lungs, urinary tract, bones, abdomen, and central nervous system. Up to 70% of cases of septic shock are caused by gram-negative bacteria, such as Escherichia coli, Klebsiella pneumoniae, Serratia, Enterobacter, and Pseudomonas.

Complications of septicemia include septic shock, respiratory failure requiring ventilator support, circulatory system collapse, renal failure, and death (mortality exceeds 50% if septic shock develops). Other complications include disseminated intravascular coagulation, heart failure, GI ulcers, and abnormal liver function.

The patient with septicemia typically presents with malaise, spiking fevers and chills, and an extremely ill appearance. Vital signs may reveal tachycardia and tachypnea along with decreased blood pressure. The source of infection may be evident (such as an infected wound or cellulitis) or elusive (such as pneumonia, urinary tract infection, meningitis, or peritonitis). The patient’s condition can quickly deteriorate to sepsis, which is categorized into several levels according to the Society of Critical Care Medicine and the American College of Chest Physicians: