Lessons of the month: A forgotten classic: Delayed diagnosis of mitral stenosis presenting initially as Ortner's syndrome.

We present a rare case of delayed diagnosis of mitral stenosis, initially presenting with hoarseness in her voice due to left recurrent laryngeal nerve (LRLN) compression. A 60-year-old woman presented to the otorhinolaryngology department following complaints of progressive hoarseness in voice over a 6-month period. There was dysphonia but no additional evidence of a cranial nerve IX or X palsy on examination, with subsequent flexible nasopharyngolaryngoscopy demonstrating left vocal cord palsy. She was referred for a cardiology consult following findings of atrial fibrillation on electrocardiography. Transthoracic echocardiography revealed an enlarged left atrium with evidence of severe mitral stenosis. A diagnosis of Ortner's syndrome was made and the patient underwent mitral valve replacement. Common causes of Ortner's syndrome include mitral stenosis with left atrium compression of the LRLN, but it can occur due to other causes including pulmonary hypertension or aortic aneurysm compression, among others. There are few data at present to conclude that regression of left atrial enlargement and pulmonary arterial hypertension with symptoms are associated with Ortner's syndrome. Therefore, it remains pertinent for clinicians to be aware of clinical features linked to mitral stenosis including its more uncommon presentations, such as in our case, as earlier intervention may improve prognosis. © Royal College of Physicians 2020. All rights reserved.