Intended for healthcare professionals

Clinical Review

Sepsis: definition, epidemiology, and diagnosis

BMJ 2007; 335 doi: (Published 25 October 2007) Cite this as: BMJ 2007;335:879
  1. Andrew Lever, professor of infectious diseases and honorary consultant physician1,
  2. Iain Mackenzie, consultant in intensive care medicine and anaesthesia2
  1. 1Department of Medicine, University of Cambridge, Cambridge
  2. 2John Farman Intensive Care Unit, Box 17, Addenbrooke's Hospital, Cambridge CB2 2QQ
  1. Correspondence to: I Mackenzie iain{at}
  • Accepted 14 September 2007

On 29 March 2005 a 41 year old journalist died of sepsis six days after a minor surgical procedure; she had consulted eight doctors over the intervening Easter bank holiday weekend. Whereas the national press focused on the political question relating to the provision of out of hours medical services in the United Kingdom, the coroner pointed out that “non-recognition of the seriousness of her condition contributed [to her death].” With an estimated annual mortality of between 30 and 50 deaths per 100 000 population,1 2 this condition ranks in the top 10 causes of death,3 affects all ages, and occurs in the community, in long term care facilities, and among patients admitted to hospital under the care of any, and every, medical specialty.

Summary points

  • Sepsis encompasses a spectrum of illness that ranges from minor signs and symptoms through to organ dysfunction and shock

  • Sepsis ranks in the top 10 causes of death

  • The pathophysiology of sepsis arises largely from the response of the host's innate immune system, under the influence of genetic factors

  • The signs and symptoms of sepsis are influenced by the virulence of the pathogen, the portal of entry, the susceptibility and response of the host, and the temporal evolution of the condition

  • Sepsis is a clinical diagnosis; microbiological investigations are commonly negative

  • Powerful molecular biological techniques are likely to make a substantial contribution to the diagnosis of sepsis in the next five to 10 years

What is sepsis?

Systemic illness caused by microbial invasion of normally sterile parts of the body is referred to as “sepsis.” This is a term that specifically serves to differentiate an illness of microbial origin from an identical clinical syndrome that can arise in several non-microbial conditions, of which pancreatitis is the archetype. The similarity in clinical picture is explained by the pathophysiological role …

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