Briefly outline the difficulties encountered in the clinical and laboratory diagnosis of sepsis in the critical care unit.
a) Fever and other SIRS criteria have low specificity
b) No specific clinical signs of sepsis apart from specific syndromes such as endocarditis
c) Elderly, immunocompromised and malnourished patients-do not manifest typical signs of sepsis
d) Both infective and non infective causes of SIRS may coexist in the same patient and therefore presence of inflammation not always a reliable sign.
e) Deep seated collections difficult to diagnose
a) Leukocytosis not specific as it is a marker of stress rather than infection
b) Reliable diagnosis established by presence of organisms only in blood or in sterile tissues; but tissues may be difficult to obtain
c) Administration of antibiotics frequently before diagnostic tests limits utility of cultures
d) Cultures might sometimes take time for positive results to come back
e) Tests such as PCR might not be universally available
f) Serology tests frequently non specific
g) Biomarkers such as procalcitonin and CRP and IL-6 do not have a high sensivity and specificity.
h) Lack of consensus on criteria regarding what constitutes ventilator associated pneumonia, line sepsis etc.
My own attempt to rewrite the answer to this question is non-superior to the college answer. It is surprisingly difficult to find any article which complains about how difficult it is to make the diagnosis of sepsis.
Claessens, Yann-Erick, and Jean-François Dhainaut. "Diagnosis and treatment of severe sepsis." Critical Care 11.Suppl 5 (2007): S2.
Lynn, Lawrence A. "The diagnosis of sepsis revisited-a challenge for young medical scientists in the 21st century." Patient safety in surgery 8 (2014): 1.
Vandijck, D. M., J. M. Decruyenaere, and S. I. Blot. "The value of sepsis definitions in daily ICU-practice." Acta Clinica Belgica 61.5 (2006): 220-226.