Diesel Aspiration Induced Chemical Pneumonitis : A Case Report

Chemical pneumonitis is caused by a direct chemical insult due to the entry of a foreign substance, solid or liquid, into the respiratory tract. The clinical and radiologic manifestations are from asymptomatic focal inflammatory reaction with few or no radiologic abnormalities to severe complications. The clinical history is important in diagnosing aspiration pneumonia. The nature of the aspirated material, the quantity of aspirated material and the time course of the event influence the size and distribution of the lung parenchymal abnormalities. The most common predisposing factors for aspiration in adults are alcoholism, stroke, seizures, loss of consciousness and neuromuscular disorders. Chest radiography is readily available and inexpensive as the primary imaging modality and also for monitoring. Sonography may sometimes be useful to detect pleural fluid and underlying lung consolidation. CT is the modality of choice to resolve details. Introduction: 1Chemical pneumonitis is caused by a direct insult to the broncho-alveolar endothelium by the entry of a foreign substance, solid particles or liquid, into the respiratory tract. The clinical and radiologic manifestations may range from asymptomatic focal inflammatory reaction with few or no radiologic abnormalities to severe, sometimes fatal, complications. The clinical history is crucial in diagnosing aspiration pneumonia. The nature of the aspirated material, the quantity of aspirated material, and the time course of the event influence the size and distribution of the lung parenchymal abnormalities. Reports of diesel aspiration followed by chemical pneumonitis and its management have rarely been published. We present a case of severe diesel induced chemical pneumonitis that was successfully treated in our pulmonary care unit (PCU). 2 Predisposing factors: • alcohol intoxication • general anesthesia • unconsciousness/coma • structural abnormality of larynx/pharynx/oesophagus • neuromuscular/swallowing disorders Primary Imaging examination: Chest radiography is readily available and inexpensive. Postero-anterior and lateral views are the commonly used imaging modality to diagnose, evaluate and monitor aspiration pneumonia and its complications. Ultrasound is useful for monitoring pleural effusion with collapsed-consolidated basal segments. Computed tomography (CT) is useful for resolution of details of pulmonary architecture and differentiation of pleural from pulmonary collections. Unlike radiography, CT is capable of differentiating fluid from solid tissue and detection of hyperemia/inflammation by contrast enhancement; thus it is ideal for displaying detailed features of aspiration pneumonia – consolidation, broncho-alveolar exudates, encysted fluid collections, abscesses, pleural effusion or empyema. CT precisely delineates the lobar/segmental location of the lesion. A foreign body in the tracheo-bronchial tree and associated atelectasis/consolidation can be easily defined with a CT scan. Clinical presentation: Patients with chemical pneumonia may present with an abrupt development of symptoms within a few minutes or as a gradual, insidious onset up to 2 hours after the aspiration event.3 It may start with mild dyspnea, rapid breathing, audible wheezing, and cough with pink or frothy sputum. Diesel being relatively heavy and inert easily settles in the basal parts of lung, particularly right middle lobe, on aspiration in upright posture and produces basal consolidation/ exudates. The clinical course in case of diesel aspiration is comparatively slow and indolent. Findings on physical examination may include tachypnea, tachycardia, fever, respiratory rales, wheezing, and occasionally cyanosis. Case Report: A 55 years male worker in an automobile workshop was trying to siphon off diesel from a container by sucking through a tube. There was accidental aspiration into the lung, following which the patient developed breathlessness, cough, nausea and vomiting. On clinical examination there was tachypnea, tachycardia and reduced air entry into the right lung on auscultation. Chest radiograph revealed confluent alveolar opacities in right mid and lower zones silhouetting the cardiac and diaphragmatic outlines, suggestive of predominantly right middle & lower lobe consolidation resulting from chemical pneumonitis. A few patchy opacities were also noted in the left lower zone.