When Contrast Leaves the Lungs Wet: Recognising Non-cardiogenic Pulmonary Oedema After Contrast CT

Contrast media are widely used in diagnostic and interventional imaging and are generally considered safe.Non-cardiogenic pulmonary oedema after intravenous iodinated contrast can be difficult to recognise, particularly in patients with pre-existing left ventricular dysfunction, in whom it may be mistaken for cardiogenic pulmonary oedema.We report a case of a 73-year-old man with a documented left ventricular ejection fraction (LVEF) of 39% and scarring consistent with a previous myocardial infarction who developed acute pulmonary oedema 30 minutes after receiving Iohexol (Omnipaque) for outpatient CT coronary angiography.The patient's primary complaint was breathlessness, and he denied any chest pain.A chest X-ray taken in the emergency department showed florid pulmonary oedema.He was initially given a glyceryl trinitrate infusion and a single dose of 80 mg of intravenous furosemide, following which he developed hypotension.He subsequently received 250 mL fluid boluses (Plasma-Lyte 148), to a total of 1000 mL of intravenous fluid.Non-invasive ventilation (NIV) was initially used and was later changed to oxygenation via nasal cannula.He improved symptomatically, and his blood pressure recovered; he was successfully weaned off oxygen the next day.His CT coronary angiogram performed before the presentation was reviewed by the Radiology team, which did not demonstrate obstructive coronary disease, and a large-volume pulmonary embolism was also ruled out.Two high-sensitivity troponin results were negative, and his N-terminal pro-B-type natriuretic peptide (NT-proBNP) level, measured the following day, was 687 pg/mL.A consensus was reached that this was an uncommon reaction to the contrast.Non-cardiogenic pulmonary oedema should be considered in any patient who develops acute respiratory distress following contrast administration.Early recognition, exclusion of other cardiac causes, and prompt supportive care can result in rapid recovery.Clinicians and radiologists should be aware of this reaction, because its management, which involves NIV and cautious intravenous fluid replacement, differs from that of cardiogenic pulmonary oedema.