Emerg Radiol (2007) 14:113–116 DOI 10.1007/s10140-007-0579-z
CASE REPORT
Multi-detector computed tomography demonstrates smoke inhalation injury at early stage Virve Koljonen & Kreu Maisniemi & Kaisa Virtanen & Mika Koivikko
Received: 19 December 2006 / Accepted: 12 January 2007 / Published online: 7 February 2007 # Am Soc Emergency Radiol 2007
Abstract A multitrauma victim was transported to our trauma centre. Smoke inhalation injury was suspected based on trauma history and clinical examination. The first trauma computer tomography (CT) obtained 2.8 h after the injury revealed subtle ground-glass opacifications with mainly peribronchial distribution and patchy peribronchial consolidations centrally in the left lung. A repeated scan showed a more distinctive demarcation of the peribronchial opacities, further substantiating the clinically verified smoke inhalation injury. The golden standard for diagnosing smoke inhalation injury still is fibroptic bronchoscopy examination. This paper shows that lesions typical to smoke inhalation injury appear much earlier than previously reported. Whether assessment of smoke inhalation injury severity using CT could clinically benefit patients is controversial and still requires further research. Multi-detector computed tomography is readily V. Koljonen (*) Department of Plastic Surgery, Helsinki University Hospital, P.O. Box 266, 00029 HUS Helsinki, Finland e-mail:
[email protected] K. Maisniemi Department of Anaesthesia and Intensive Care, Helsinki University Hospital, Helsinki, Finland K. Virtanen Department of Orthopaedics and Traumatology, Helsinki University Hospital, Helsinki, Finland M. Koivikko Helsinki Medical Imaging Center, Department of Radiology, Helsinki University Hospital, Helsinki, Finland
available in trauma centres and to simply neglect its potential as a diagnostic tool in some inhalation injury would be unwise. Keywords Smoke inhalation injury . Diagnosis . Computed tomography A 26-year old man was transported by ambulance to the Emergency Department of the Töölö Hospital, Helsinki University Hospital, Helsinki, Finland, on 2004, at 7:51 A.M.. The victim was the seat-belted driver. His car exploded into flames after crashing the rock cutting in the motorway, and he was trapped inside the vehicle. After the patient was rescued from the burning vehicle, he was found to be unconscious with spontaneous breathing. Nostril hair was burned, inside the mouth, sooting was noted. Respiratory sounds were wheezing, breathing increasingly difficult but oxygenation still adequate. Because of unconsciousness and smoke inhalation injury (SII) suspicion, the patient was intubated and mechanical ventilation was started at the injury site. During the intubation, it was observed that the epiglottal area was normal, and sooting was present in the trachea. In the emergency room, primary survey revealed severe ventilatory and gas exchange disturbances with decreased lung compliance. High peak inspiratory pressure, peep and FiO2 1.0 were needed to maintain oxygenation at acceptable levels. Despite these measures, hypercapnia (pCO2 7.7–8.2) persisted. Large amounts of crystalloids were needed to preserve adequate volume status and tissue perfusion. Clinical examination revealed multiple, superficial lacerations in the face, left distal radius fracture, bilateral ankle fractures with right sided Gustillo II fracture. The patient sustained deep, third degree burns in his right hand, in the anteromedial thigh, in both ankles, the %TBSA was 5.
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Fig. 1 Trauma CT of smoke inhalation injury 2.8 h after injury shows subtle ground-glass opacifications anteriorly and peribronchially
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Fig. 3 Dense infiltrates of the lingula and lower lobe of the left lung atelectasis with only moderate volume reduction and air-filled bronchi at 2.8 h after injury
Fibroptic bronchoscopy showed mucosal edema, irritation and huge amounts of reddish secretion consistent with inhalation injury. After focused abdominal sonography for trauma, which was negative for cavitary hemorrhage, a multi-detector computed tomography (MDCT) was performed. Our routine trauma protocol includes, in addition to head and cervical spine CT, a whole body CT with intravenous contrast agent using a four-section multi-detector CT scanner (LightSpeed QX/i, GE Medical Systems, Milwaukee, WI). For body MDCT, the imaging parameters were as follows: 4×2.5 mm collimation; gantry rotation time 0.8 s; pitch 6; table feed 15 mm; 140 kV; 280/330 mA (chest/abdomen); and approx-
imate total exposure time 30 s. Interpretation of images was done using conventional clinical workstations (Impax DS3000; Agfa-Gevaert N.V., Mortsel, Belgium). The MDCT scan revealed severe traumatic brain injury with a large hematoma in the corpus callosum. Fractures of first and second ribs, a burst fracture in the third lumbar vertebra. Abdominal organs were intact. Further radiological examinations revealed fractures in the left radius and both ankles. This first trauma CT, obtained 2.8 h after the injury, revealed subtle ground-glass opacifications with mainly peribronchial distribution (Fig. 1) and patchy peribronchial
Fig. 2 Trauma CT at 2.8 h after injury reveals patchy and dense peribronchial consolidations centrally in the left lung, in addition to lower lobe of the left lung atelectasis and anterior infiltrates in the right lung
Fig. 4 A repeated CT scan at 13.8 h after injury. In the same lung area as shown in Fig. 1, a complete resolution of the ground-glass opacities of the right lung is noted, as well as progression and demarcation of peribronchial infiltrates
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consolidations centrally in the left lung (Fig. 2), in addition to lower lobe of the left lung atelectasis (Fig. 3). A repeated scan showed a more distinctive demarcation of the peribronchial opacities in addition to pneumothorax and pneumomediastinum (Fig. 4).
Discussion In this paper, we report a case of SII demonstrated by MDCT at early stages after the burn injury. The inhalation injury is a result combination of inhaling toxic smoke components and direct effect of hot airflow to the airways [1]. SII is a significant factor contributing to increased morbidity and mortality of burn victims [2, 3]. Because of the difficulties in the diagnosis of inhalation injury, several methods have been applied including technetium-99m hexamethylpropylene amine oxime lung scan and cytology obtained at bronchoscopy [4, 5]. These methods are not only time consuming and technically difficult to obtain but also suffer from a low sensitivity and specificity. Clark et al. [6] first introduced the use of CT in the diagnosis of inhalation injury in 1982. Quite recently, Reske et al. [7] reported CT findings in human SII. Chest radiography is, on admission, only of limited value on the diagnosis of SII. In our patient’s case, 2 h after the injury in the Emergency Department, no signs of SII were evident in the chest radiograph. Diagnosis of SII still relies on clinical history information, indoor fire, burns in the facial area, sooting in the mouth and detection of carbon monoxide in the blood. The diagnosis is evidenced by fibroptic bronchoscopy examination, which has been the cornerstone for diagnosis since 1975 [8]. The criteria for inhalation injury are airway edema, inflammation, mucosal necrosis and presence of soot and charring in the airways. In this case report, the patient had soot in trachea, and fibroptic bronchoscopy revealed mucosal edema, irritation and huge amounts of reddish secretion consistent with inhalation injury. It is not customary to perform early CT scan for burns victims. In our patient’s case, the CT scan was not performed because of inhalation injury suspicion, rather to verify possible damage to internal organs. CT, which is well established in lung imaging, is more sensitive and specific in detection of subtle ground-glass opacities and consolidations than conventional radiography. Quite recently, Spyropoulou et al. [9] reported in a series of 13 burn patients results of follow-up CT scans for signs of inhalation injury and pulmonary complications. The results of the CT scan correlated with the clinical course and blood gas determinations, and similar findings in the chest radiograph were observed at a later stage. Because of technical breakthroughs, MDCT is not only faster but also has superior spatial, temporal and contrast resolution, less
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motion artefacts and partial volume rendering effects—all of which contribute to the power of this imaging method [10]. Considering that SIIs are severe, life-threatening injuries, the irradiation dose of chest MDCT is negligible. Our findings confirm and validate the results of recent report by Reske et al. [7]. In their report, a CT, obtained 12 h after SII diagnosis, showed bilateral dorsal atelectasis and bilateral ventral infiltrations more prominent adjacent to the greater airways. In the presented case, we observed an identical distribution of atelectasis, peribronchial consolidations and ground-glass opacifications. The theoretical background for this distribution is sound: the inflow of hot air and smoke will predominantly affect the central airways and adjacent lung tissue. In an experimental setting, Park et al. [11] demonstrated in sheep at 6, 12 and 24 h after SII similar lung findings by CT. They found the lung injury detectable at 6 h demonstrated a correlation of imaging findings with the clinical severity. Our results not only validate the presence of such early CT findings in a human but also show that lung findings detectable by CT may occur significantly earlier than previously appreciated. Whether assessment of SII severity using CT could clinically benefit patients is controversial and still requires further research. MDCT is, however, readily available, and it has become a standard tool in modern emergency medicine. In our opinion, to simply neglect its potential as a diagnostic tool in SII would be unwise.
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