Widened mediastinum


 * Associate Editor-In-Chief: Varun Kumar, M.B.B.S.

Overview
A widened mediastinum is a mediastinum which measures greater than 8 cm in width on PA chest X-ray. A widened mediastinum can be indicative of life threatening conditions such as aortic dissection and esophageal rupture.

Complete Differential Diagnosis of the Causes of ...
(By organ system)

Complete Differential Diagnosis of Causes of a Widened Mediastinum
In alphabetical order

Causes include;


 * Acute descending necrotizing mediastinitis


 * Anthrax
 * This is a classic finding associated with inhalational anthrax. A widened mediastinum was found in 7 of the first 10 victims infected by anthrax (Bacillus anthracis) in 2001.
 * Aortic dissection
 * Bronchogenic cyst
 * Churg-Strauss syndrome
 * Dermoid cyst
 * Esophageal achalasia
 * Esophageal cancer
 * Esophageal rupture
 * Goitre
 * Hiatus hernia
 * Hilar lymphadenopathy
 * Lymphoma
 * Mediastinal germ cell tumor
 * Mediastinal tumor
 * Mediastinal mass
 * Mediastinitis
 * Neurilemmoma
 * Non-Hodgkin lymphoma
 * Partial anomalous pulmonary venous connection
 * Pericardial effusion
 * Pneumomediastinum
 * Sarcoidosis
 * Superior vena cava obstruction
 * Supine AP chest x ray can yield a false positive "widened mediastinum".
 * Among patients who have sustained blunt traum, AP chest radiographs are often obtained in the supine position to maintain spinal precautions. This supine position may result in fluid shifts that are in turn associated with a widening of the mediastinum. After the spine had been "cleared", some authors recommend repeating the chest X ray with the patient in the erect position which results in normalization of the mediastinal size in around 40% of patients.
 * Teratoma
 * Thymoma
 * Thyroid cancer
 * Tularemia

Diagnosis
Widening of the mediastinum on the chest X ray may represent a medical emergency and the following diagnoses should be excluded immediately:
 * 1) Aortic dissection
 * 2) Esophageal rupture

In ruling out the presence of traumatic aortic injury in a patient, a widened mediastinum is reported as having a 53% sensitivity, 59% specificity and 83% negative predictive value.

Other less sensitive signs on the chest x ray of aortic injury include the following:
 * 1) Depression of the left main-stem bronchus
 * 2) Deviation of a naso-gastric tube to the right
 * 3) Apical pleural hemoatoma (cap)
 * 4) Disruption of the calcium ring in the aortic knob (broken-halo)

Chest X Ray
Shown below is the development of a new widened mediastinum in a patient with aortic dissection: