A 51-year-old man suffering from diabetes mellitus with insulin therapy and diabetic nephropathy was referred to our institution for the investigation of abnormal findings on a chest radiograph. He was a current smoker (30 packs/year).
An apical segment right upper lobe cavitary nodule was detected on thoracic computed tomography (CT). We could not detect any large vessels, including the pulmonary veins that penetrated the nodule (Fig. 1).
Although the patient was suspected of having pulmonary tuberculosis, a sputum smear for acid-fast bacilli was negative on three examinations. Therefore, we performed flexible bronchoscopy in a supine position without intravenous sedation.
No endobronchial abnormalities were detected, and curettage was performed twice and transbronchial lung biopsy (TBLB) four times under fluoroscopic guidance. During bronchoscopy, he had no coughing or major bleeding events, and no pneumothorax on a radiography fluoroscopic examination immediately after bronchoscopy. Rapid on-site evaluation of cytology revealed many inflammatory cells and no malignant cells. The total duration of bronchoscopy was about 30 minutes. During bronchoscopy, the patient remained in the supine position.
Immediately after completion of bronchoscopy, his blood pressure decreased to 60/40 mmHg, heart rate decreased to 30 bpm, and oxygen saturation dropped to 70%. A neurological examination revealed a Glasgow Coma Scale (GCS) score of 3/15 points. Hypotension and bradycardia quickly recovered after fluid resuscitation. His level of consciousness improved to GCS 9/15 points; however, left hemiplegia appeared. We suspected an intracranial lesion, and indeed, head CT taken 15 minutes after TBLB showed cerebral air embolism (Fig. 2). Fifteen minutes after head CT, brain magnetic resonance imaging (MRI) on sequences of diffusion-weighted images (DWI) showed hyperintense lesions predominantly located around the air density on CT, which was compatible with air embolism. The patient's level of consciousness improved to GCS 15/15, and the left hemiplegia completely recovered within 1 hour after bronchoscopy. He had no other symptoms. After bronchoscopy, chest radiography revealed that the target lesion had enlarged.
The following day, lower left quadrant pain developed. Abdominal CT revealed pneumatosis intestinalis of the descending colon (Fig. 3). In addition, serum creatine kinase and troponin T levels were elevated. Electrocardiogram demonstrated inverted T waves (Fig. 4). Echocardiography revealed no abnormal cardiac wall motion. We considered air embolism in the inferior mesenteric artery and the right coronary artery. The next day, his abdominal pain and laboratory abnormalities improved with maintenance transfusion and fasting.
A few days later, Mycobacterium tuberculosis was cultured on bronchoscopy specimens. He was therefore administered anti-tuberculosis drugs, and thereafter the nodule shrank.
Chest CT from a previous institution. A cavitary nodule was detected in the right upper lobe.