Mediastinal fluid as a predictor for esophageal perforation as the cause of pneumomediastinum

CT esophagogram in the emergency setting: typical findings and suggested workflow

PURPOSE

Esophageal perforation (EP) can be a diagnostic challenge. Computed tomography (CT) and CT esophagography (CTE) are often used to rule out EP in the emergency setting with promising diagnostic performance, but the standard of care remains fluoroscopic esophagography (FE). We assess the diagnostic performance of CT and CTE when interpreted by expert and generalist radiologists and created an imaging workflow guide.

METHODS

Retrospective study of patients presenting with suspected EP. Two expert radiologists independently reviewed blinded CT/CTE studies, recorded CT findings, and assigned an esophageal injury grade. We also collected initial (general radiologist) CT findings and interpretation and FE diagnoses. We assessed inter-reader reliability and diagnostic performance.

RESULTS

EP was diagnosed in 46/139 (33%) encounters. The most common CT/CTE findings in EP were esophageal wall thickening (46/46, 100%), pneumomediastinum (42/46, 91%), and mediastinal stranding (39/46, 85%). CT and CTE sensitivity for detecting EP was 89% and 89% for expert radiologists, respectively, and 79% and 82% for general radiologists, compared with 46% for FE. Inter-reader agreement for detecting EP by CT and CTE was kappa 0.35 and 0.42 (both p < .001) between expert and generalist radiologists. We present radiographic images for key CT/CTE findings and a suggested workflow for the evaluation of possible EP.

CONCLUSION

CT and CTE are more sensitive than FE for EP in the emergency setting. Due to the rarity of EP and current wide variability in imaging interpretation, an imaging workflow and injury grading system based on esophageal and mediastinal CT findings are offered to help guide management.

Pneumomediastinum complicating diabetic ketoacidosis

Pneumomediastinum is an uncommon finding in patients with diabetic ketoacidosis (DKA) and may occur spontaneously or secondary to an effort rupture of the oesophagus. Excluding oesophageal rupture is important, as delaying treatment increases the risk of mortality. We discuss a case of DKA complicated by vomiting, pneumomediastinum, pneumopericardium and air in the epidural space. Instead of fluoroscopic oesophagography, chest CT was used to investigate oesophageal rupture. We present an overview of case reports and retrospective studies illustrating the utility of chest CT in the investigation of oesophageal rupture over fluoroscopic oesophagography.

Utility of fluoroscopic oesophagography in the setting of spontaneous and blunt traumatic pneumomediastinum

AIM

To determine the incidence of positive fluoroscopic oesophagography in patients presenting with spontaneous or blunt traumatic pneumomediastinum.

MATERIALS AND METHODS

Retrospective chart review was performed on patients who underwent fluoroscopic oesophagography for spontaneous or blunt traumatic pneumomediastinum between 2001-2019. Patients were excluded for history of oesophageal surgery, penetrating trauma, oesophageal cancer, or tracheal/oesophageal instrumentation.

RESULTS

Two hundred and fifty-two patients met the inclusion criteria; 170 presented with spontaneous pneumomediastinum and 82 presented with blunt traumatic pneumomediastinum. Fluoroscopic oesophagography was positive in eight patients with spontaneous pneumomediastinum, for a positivity rate of 4.7% (8/170). There was one false-negative case in a patient who presented with spontaneous pneumomediastinum and was found to have a non-full-thickness oesophageal injury on endoscopy. Fluoroscopic oesophagography was negative in all patients with blunt traumatic pneumomediastinum (0/82). The sensitivity and specificity of fluoroscopic oesophagography were 88.9% (8/9) and 100% (243/243), respectively. Oesophageal injury was more common in patients with spontaneous pneumomediastinum and a pleural effusion (5/11, 45.4%) than in patients with spontaneous pneumomediastinum and no pleural effusion (4/159, 2.5%, p<0.001).

CONCLUSION

The present findings do not support routine oesophagography in patients with blunt traumatic pneumomediastinum. Conversely, a positivity rate of 4.7% in patients with spontaneous pneumomediastinum suggests oesophagography may be warranted in this population, particularly if an associated pleural effusion is present.

Neumomediastino en trauma contuso: ¿son siempre necesarios los estudios invasivos para descartar lesión aerodigestiva?

Introducción. La presencia de neumomediastino secundario a un trauma contuso es un hallazgo común, especialmente con el uso rutinario de la tomografía computarizada. Aunque en la mayoría de los casos es secundario a una causa benigna, la posibilidad de una lesión aerodigestiva subyacente ha llevado a que se recomiende el uso rutinario de estudios endoscópicos para descartarla. El propósito de este estudio fue determinar la incidencia de neumomediastino secundario a trauma contuso y de lesiones aerodigestivas asociadas y establecer la utilidad de la tomografía computarizada multidetector en el diagnóstico de las lesiones aerodigestivas. Métodos. Mediante tomografía computarizada multidetector se identificaron los pacientes con diagnóstico de neumomediastino secundario a un trauma contuso en un periodo de 4 años en un Centro de Trauma Nivel I. Resultados. Fueron incluidos en el estudio 41 pacientes con diagnóstico de neumomediastino secundario a un trauma contuso. Se documentaron en total tres lesiones aerodigestivas, dos lesiones traqueales y una esofágica. Dos de estas fueron sospechadas en tomografía computarizada multidetector y confirmadas mediante fibrobroncoscopia y endoscopia digestiva superior, respectivamente, y otra fue diagnosticada en cirugía. Conclusión. El uso rutinario de estudios endoscópicos en los pacientes con neumomediastino secundario a trauma contuso no está indicado cuando los hallazgos clínicos y tomográficos son poco sugestivos de lesión aerodigestiva.

OUP accepted manuscript

Vomiting-induced pneumomediastinum is often caused by oesophageal perforation or alveolar rupture due to increased pressure. A correct diagnosis is important because both diseases have different treatments and severities. We report the case of a 21-year-old man who presented with chest pain and fever after frequent vomiting and had elevated white blood cell counts on blood tests. There was extensive pneumomediastinum, and the lower oesophagus was swollen and thickened on chest computed tomography. An oesophagram was not possible due to severe nausea and vomiting. Accumulation of free air was found along the peripheral bronchi or the pulmonary vascular sheath in the left lower lobe, which was continuous with the mediastinum. Based on the presence of the Macklin effect, we diagnosed a pneumomediastinum with a high possibility of spontaneous pneumomediastinum. The Macklin effect is a finding that can likely distinguish oesophageal perforation from spontaneous pneumomediastinum.