ROLE OF TRANSTHORACIC ULTRASOUND IN DIAGNOSIS OF PNEUMONIA IN THE EMERGENCY DEPARTMENT

Abstract

SUMMARY P neumonia is the first cause of mortality related to infectious diseases in Western countries, and a major cause of severe sepsis and septic shock. However the diagnosis of acute pneumonia is often difficult in the emergency setting, as clinical, biological, and imaging sign are not specific (Mayaud, 2011). International guidelines recommend the use of chest x-ray as first line examination, despite its low sensitivity and specificity. Thoracic computed tomography (CT) scan, although considered as the gold standard, is often not performed and involves an important exposure to ionizing radiations, limiting its use to difficult cases (Niederman et al., 2001). An adequate treatment of pneumonia is depending on an early diagnosis, yet the diagnosis is not always clear at presentation, that could result in delayed antibiotics delivery (Hagaman et al., 2009). The aim of this work is to assess role of chest ultrasound in the detection of pneumonia in the emergency department in relation to CXR, discharge diagnosis, and CT chest. The study was carried out on sixty adult patients of both sexes, who were presented to Emergency Department at Abassia Chest Hospital and admitted to inpatient wards till discharge. Transthoracic ultrasound and CXR were done to all patients, CT chest was done for thirty-seven patients as recommended by the consultant in charge of each patient, the results of each compared to each other and to final diagnosis at discharge. In the current study it was found that clinical baseline data, signs and symptoms of pneumonia such as cough, expectoration of purulent sputum, tachypnea, crepitations on auscultation and increase count of total leukocytic count and ESR level were significant in the diagnosis of pneumonia. Considering discharge diagnosis as the reference standard, LUS had higher diagnostic characteristics than CXR in detection of pneumonia which was significant in specificity. As LUS had sensitivity of 98 % and specificity of 83.3%. CXR had sensitivity 90% and specificity 16.6%, In patients with CT chest 32/37 with confirmed pneumonia 31 was detected by LUS, sensitivity compared to CT was 97% (31/32) while CXR sensitivity was 87.5% (28/32) and this was identical to discharge diagnosis in those cases. According to the high concordance between chest ultrasound and chest X-ray in detection of pneumonia, lung ultrasound could replace chest X-ray or being used beside it; as the first-line imaging investigation for its various advantages over chest x-ray. Suggesting that in difficult cases (deep lesion) or in case of negative ultrasound, thoracic CT scan could be performed as suggested by a proposed decision-making