chest ct-scan for the diagnosis of community-acquired pneumonia

Conditions: Community-acquired Pneumonia; Dyspnea

Summary: primary objective : to estimate impact of ct-scan on diagnostic for emergency department (ed) patients with suspected community-acquired pneumonia (cap). secondary objective: to estimate impact of ct-scan on treatment (antimicrobial therapy) and site of care for ed patients with suspected cap.

rational: community-acquired pneumonia (cap) is a frequent infectious disorder in patients visiting the ed. cap is responsible for high morbidity and associated-mortality is increasing in western countries. cap corresponds to invasion of the lung by pathogens. diagnosis depends on clinical and x-ray assessment. however, these signs and symptoms are poorly specific and are often lacking. as prognosis depends on precocious and fitted antimicrobial treatment, making cap diagnosis in a short time span (4-8 hours) is mandatory. preliminary studies suggest that chest ct-scan could over-performed x-ray for diagnosis of cap. consensus conferences suggest the use of ct-scan in patients with uncertain diagnosis and unusual presentation and outcome. because ct-scan is currently easily available, its use in a first intent is questionable for ed patients with suspected cap. primary objective: to estimate impact of ct-scan on diagnostic for ed patients with suspected cap. secondary objective: to estimate impact of ct-scan on treatment (antimicrobial therapy) and site of care for ed patients with suspected cap. prospective multicenter study to measure chest ct-scan impact. 350 patients visiting the ed of 4 inner tertiary teaching hospitals in paris, france, with suspected cap. management: patients will be managed according to current guidelines, including conventional chest x-ray. evaluation criteria. attending ed physicians will implement pre- and post-test proforma for diagnosis (cap) level of certainty, treatment (antimicrobial agents), site of care, before and after chest ct-scan. comparison of ed physician's answers before/after ct-scan. patients will be followed until day 28. an adjudication committee (1 pneumologist, 1 infectiologist, 1 radiologist)will review patients' data for gold standard diagnosis. statistical considerations: the investigators hypothesize that chest ct-scan wil modify diagnosis certainty in 20%. this implies that 300 participants should be enrolled to allow assessment of changes in 15 % et 25 %. undue changes will be calculated a posteriori when diagnosis gold standard will be established by adjudication committee. anticipated results: chest ct-scan should improve diagnosis certainty, treatment and site-of-care in patients visiting the ed with suspected cap. if this is observed in at least 20%, the investigators will measure impact of chest ct-scan in a prospective randomized interventional study.

Eligibility criteria:
inclusion criteria: * patient above 18 years of age * patient with a presumptive diagnosis of cap according to attending ed physician * patient experiencing at least one systemic sign (t°\>38°c or \ 90/min, rr\>20/min) * patient experiencing one respiratory sign (cough, lateral chest pain, localized crackles, dyspnea) that recently appeared * patient with a prior medical examination, the results have been or will be communicated * patient gave written informed consent or in cases of emergency parent/ support person who gave written informed consent if he/she is present on the day of inclusion exclusion criteria: * pregnancy * patient with shock * patient with respiratory distress and immune suppression * patient with other criteria for immediate icu referral to icu * patient with living conditions making it impossible to follow 28 days * patient not affiliated with a social security system

Keywords: community-acquired pneumonia diagnosis emergency medicine chest ct-scan