Medical Image of the Month: Air Bronchogram Sign

Figure 1. Chest radiograph showing bilateral dense airspace disease with air bronchograms. Veno-venous ECMO catheter is visible tracking from the right internal jugular vein to the inferior vena cava.

Figure 2. Chest radiograph on day 5 of ECMO after 4 days of induction chemotherapy demonstrating marked improvement of his airspace disease.

An 18-year-old man without any known past medical history presented with a one-day history of progressive shortness of breath. He reported a sudden onset of symptoms the morning of presentation, and an accompanying sensation of confusion with difficulty concentrating. Initial laboratory evaluation was significant for leukocytosis over 60 K/mm³. Due to his increased work of breathing and worsening lethargy, the patient was intubated and sedated for airway protection and ventilatory support. The patient was admitted to the ICU, and his initial chest radiograph was concerning for acute respiratory distress syndrome. Subsequent hematologic analyses from his admission CBC were consistent with a new diagnosis of acute myelogenous leukemia.

Despite aggressive alveolar recruitment maneuvers and maximum ventilator support, the patient’s oxygen saturation remained poor and his respiratory reserve continued to decline. The decision was made to place the patient on veno-venous extracorporeal membrane oxygenation (ECMO) prior to initiating therapy with doxorubicin and cytarabine (7+3 induction protocol). A dual-lumen ECMO catheter was placed in the right internal jugular vein. His initial chest radiograph demonstrated complete bilateral air bronchograms (Figure 1). The patient was started on chemotherapy while on ECMO and was successfully decannulated after five days on the circuit. His chest radiograph on day 5 of ECMO was significant for marked improvement in bilateral airspace disease (Figure 2).

In patients with hematologic malignancy, an inflammatory response can be generated by either the malignant cells themselves, or more commonly as a reaction to subsequent infection. This inflammation often results in protein-rich fluid infiltrating the alveoli. When this process becomes severe enough to cause hypoxic respiratory failure, it can progress to acute respiratory distress syndrome (ARDS) (1). The chest radiograph demonstrates dense airspace disease which developed in this patient. The fluid-filled alveoli in this extreme example of ARDS created a volume of uniform opacities throughout his lung parenchyma which make the conducting airways stand out clearly (2). Segmental air bronchograms can be seen in localized airspace disease, such as atelectasis or pneumonia, but a full-pulmonary air bronchogram of this clarity can only be seen on a patient undergoing ECMO as there are effectively no functional alveoli to participate in gas exchange.

Eric Brucks, MD and Richard Young, MD

Department of Internal Medicine

Banner University Medical Center

University of Arizona

Tucson, AZ USA

References

1. Papazian L, Calfee CS, Chiumello D, Luyt CE, Meyer NJ, Sekiguchi H, Matthay MA, Meduri GU. Diagnostic workup for ARDS patients. Intensive Care Med. 2016 May;42(5):674-85. [CrossRef] [PubMed]
2. Natt B, Raz Y. Air Bronchogram. N Engl J Med. 2015 Dec 31;373(27):2663. [CrossRef] [PubMed]

Cite as: Brucks E, Young R. Medical image of the month: air bronchogram sign. Southwest J Pulm Crit Care. 2019;19(4):119-20. doi: https://doi.org/10.13175/swjpcc036-19 PDF 

Medical Image of the Week: Pneumothorax with Air Bronchograms

Figure 1. Panel (A) shows mild congestion with prominent bronchovascular markings. Panel (B) shows a large left pneumothorax with total collapse of the left lung marked by extensive airspace opacities and distinct air bronchograms. Panel (C) shows interval placement of a left-sided pigtail catheter with partial resolution of the left pneumothorax. There is persistent collapse of the medial aspect of the left upper lobe. Panel (D) shows complete resolution of the left pneumothorax and left lung atelectasis with continued bilateral airspace disease.

Development of pneumothoraces in critically ill patients is commonly encountered in the critical care unit (ICU). Incidence has been reported between 4-15% of patients. In most instances, pneumothorax in the ICU is considered a medical emergency especially when the patient is mechanically ventilated (1).  Here, we present a 61-year-old man with a past medical history of insulin dependent diabetes and paraplegia from prior spine injury who presented with acute respiratory distress after a pulseless electrical activity cardiac arrest. Cardiopulmonary resuscitation (CPR) was initiated by emergency medical services at home, and continued and the emergency department (ED) for a total of 30 minutes. The patient presented previously to the ED, one week prior, for a mild respiratory illness and tested positive for influenza B. He was sent home on oseltamivir. His family is unsure of compliance with medication but reported he was clinically stable up to the morning of presentation. The patient, as shown in the images, developed a left pneumothorax complicating an "adult respiratory distress syndrome (ARDS)- like" picture probably due to positive pressure ventilation with high positive end expiratory pressure, CPR, or both. The patient underwent immediate chest tube placement and with successful lung re-expansion. Unfortunately, his hemodynamic status/septic shock/multi-organ system failure continued to deteriorate within hours and he expired despite maximal support. Pneumothorax in patients with ARDS has higher morbidity and mortality compared to other critically ill patients due to the high-pressure needed during mechanical ventilation. This places patients at a high risk for the rapid progression to tension pneumothorax and even death. Therefore, in this high-risk population, a pneumothorax requires a high index of suspicion, prompt recognition, and immediate intervention (2).

Huthayfa Ateeli, MBBS and Steve Knoper, MD.

Department of Medicine, Division of Pulmonary, Critical Care, Sleep and Allergy Medicine. University of Arizona, Tucson, AZ USA

References

1. Yarmus L, Feller-Kopman D. Pneumothorax in the critically ill patient. Chest. 2012 Apr;141(4):1098-105. [CrossRef] [PubMed] 
2. Gattinoni L, Bombino M, Pelosi P, Lissoni A, Pesenti A, Fumagalli R, Tagliabue M. Lung structure and function in different stages of severe adult respiratory distress syndrome. JAMA. 1994 Jun 8;271(22):1772-9. [CrossRef] [PubMed] 

Cite as: Ateeli H, Knoper S. Medical image of the week: pneumothorax with air bronchograms. Southwest J Pulm Crit Care. 2016:13(3):129-30. doi: http://dx.doi.org/10.13175/swjpcc066-16 PDF

April 2012 Imaging Case of the Month

Michael B. Gotway, MD

Associate Editor, Imaging

Clinical History: A 31-year-old previously healthy, immunocompetent, non-smoking female developed cough and was initially treated with broad spectrum antibiotics without improvement. Approximately 48 hours later, the patient presented to her physician with progressive shortness of breath and fever to 103°F. A chest radiograph was performed (Figure 1).

Figure 1: Frontal chest radiograph shows extensive bilateral pulmonary opacities predominantly in the lower lobes with preserved lung volumes, normal mediastinal width, and no definite pleural effusion.

The differential diagnostic considerations for the appearance on the chest radiograph include which of the following?

1. Hydrostatic pulmonary edema
2. Acute hypersensitivity pneumonitis
3. Community-acquired pneumonia
4. Opportunistic pulmonary infection
5. All of the above

Reference as: Gotway MB. April 2012 imaging case of the month. Southwest J Pulm Crit Care 2012;4:102-10. (Click here for a PDF version)