The chest x-ray shows

The chest x-ray is technically inadequate, having been performed in the resuscitation area. The image is rotated and under inspired.

The right lung field appears hazy with right perihilar shadow, increased interstitial markings. The heart shadow is enlarged even accounting for the AP view.

Differentials for hazy unilateral lung field are –

• Flash pulmonary edema almost always right sided, due to acute mitral regurgitation secondary to chordae/papillary muscle rupture in the context of myocardial infarction. This is supposed to be due to sudden increase in LA pressure that gets redirected to right pulmonary veins.
• Unilateral aspiration with ARDS.
• Pulmonary contusion in the context of trauma.
• Drowning (asymmetrical distribution)
• Iatrogenic – rapid expansion pulmonary edema post pneumothorax/massive pleural effusion drainage.

The above patient was not involved in trauma, drowning, invasive procedure. There were no clinical features of a chest infection. They had a cardiac event followed by dyspnoea with 12 lead ECG showing acute myocardial infarction. In the clinical context, the likely cause for their presentation was right sided flash pulmonary edema secondary to acute ischemic mitral regurgitation.

Teaching point – think of acute mitral regurgitation in a patient with ischemic chest pain and right sided pulmonary edema which can just involve right upper lobe. This is a cardiovascular & cardiothoracic surgical emergency. Emergency management recommended based on local guidelines.