Sepsis, septicaemia, sepsis syndrome, and septic
shock: the correct definition and use
Sepsis is an old medical term which comes from the Greek
'sepsin' meaning 'to make putrid'. Although most authors
agree that sepsis refers to the systemic response to infection
caused by any class of microorganisms, 1-3 a single com-
prehensive and correct definition ofthis widely used term is
still lacking. Also, in some medical dictionaries sepsis is
defined incorrectly. For example, Stedman's Medical Dic-
tionary4 defines this term as the presence of various
pus-forming and other pathogenic organisms, or their
toxins, in the blood or tissues. This definition does not
reflect the presence of illness in the host, and thus it is a
more suitable definition ofbacteraemia, viraemia, endotox-
aemia, etc, where the presence of these microorganisms or
their toxins in the bloodstream does not always necessitate
the occurrence ofillness. So, sepsis should be defined as the
systemic inflammatory response to infection caused by any
class ofmicroorganisms with the invasion ofthese microor-
ganisms or their toxins in the bloodstream causing illness.
This illness is clinically manifested by fever or hypother-
mia, tachycardia, and tachypnea, and it may be associated
with various degrees ofinjury to one or more major organs.
Thus, sepsis may be graded as mild, moderate, or severe,
according to the severity ofthe associated organ or organs,
injury and failure. When sepsis causes shock, this situation
is defined as septic shock, and there is a consensus
regarding this definition.
Some authors have recently begun to use the terms
'sepsis syndrome', and 'systemic inflammatory response
syndrome' to describe the presence of severe sepsis or
septic shock.356 I believe that the introduction of these
terms is unnecessary since the term sepsis with its degrees
(mild, moderate, and severe), and septic shock, as defined
above are comprehensive and more correct and clear.
The term 'septicaemia' is frequently used in the medical
literature and still appears in most medical journals,7I9 and
in recent editions of medical textbooks,' and of medical
dictionaries.4 Septicaemia is defined as a systematic disease
causedby the spread ofmicroorganisms and their toxins via
the circulating blood.4 However, the term sepsis, as defined
above, describes more clearly this situation, thus the term
is unnecessary. Furthermore, the suffix
* Sepsis: the systemic inflammatory response to infection
caused by any class ofmicroorganisms with the invasion of
these microorganisms or their toxins in the bloodstream
* Septicaemia: a systemic disease caused by the spread of
microorganisms and their toxins via the circulating blood
* Sepsis syndrome: the association ofsepsis with altered organ
perfusion and/or altered organ function
* Septic shock: a severe form ofsepsis causing inadequate
tissue perfusion and shock
'aemia' means blood, andwhen it is connected with another
word it means that something is present in the circulating
blood,4 eg, bacteraemia when bacteria are present in the
bloodstream. Thus, the term 'septicaemia' means that
sepsis is present in the circulating blood. However, as
sepsis refers to the systemic response to infection caused by
any class of microorganisms or their toxins, and not a
particle which can circulate in the bloodstream, the term
'septicaemia' is meaningless, confusing, and unsuitable.
Thus, I suggest that the term 'septicaemia' is no longer
used in the medical literature.
In summary, the appropriate terms to use to describe an
infection by any microorganism when the microorganism
or its toxin is present in the bloodstream are bacteraemia,
invasion of these microorganisms or their toxins into the
bloodstream causes illness, this may be defined as mild,
moderate, or severe sepsis, or septic shock, whichever is
Department of Internal Medicine B,
Bnai Zion Medical Center, and
Technion Faculty of Medicine,
Israel Institute of Technology,
1 Kasper DL, Zaleznik DF. Gas gangrene and other clostridial infections. In:
Isselbacher KJ, Braunwald E, Wilson JD, Martin JB, Fauci AS, Kasper DL,
eds. Harrison's principles of internal medicine, 13th edn. Vol 1. New York:
McGraw-Hill, 1994; pp 636-40.
2 Vincent JL, Bihari D. Sepsis, severe sepsis or sepsis syndrome: need for
clarification. Intensive Care Med 1991; 18: 255-7.
3 Bone RC. Why new definitions ofsepsis and organ failure are needed. AmJ
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Williams & Wilkins, 1995; p 1598.
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terminology ... or more confusion? Crit Care Med 1991; 19: 996-8.
6 Casey LC, Balk RA, Bone RC. Plasma cytokine and endotoxin levels
correlate with survival in patients with the sepsis syndrome. Ann Intern Med
1993; 119: 771-8.
7 Leclerc F, Delepoulle F, Diependaele JF, et al. Severity scores in menin-
gococcal septicaemia and severe infectious purpura with shock. Intensive
Care Med 1995; 21: 264-5.
8 Berger C, Uehlinger J, Ghelfi D, et al. Comparison ofC-reactive protein and
white blood cell count with differential in neonates at risk for septicaemia.
Eur J Pediatr 1995; 154: 138-44.
9 Rantale A, Vaahtorantalehtonen H. Hematogenous endophthalmitis in
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