We thank the authors of the letter for their interest in the topic. As mentioned in the original paper, patients with ‘idiopathic pericardial effusions’ are labelled in this way only after exclusion of any specific aetiology according to clinical judgement.1
The aetiology of pericardial diseases is varied, and the risk is to have a very long list of causes,2–5 where clinicians may miss themselves. We strongly support a clinically oriented approach to the aetiology search, where the clinical suspicion guides the choice of the diagnostic evaluations to be performed, according to the pretest probability.
In the reported cases, cardiac tamponade and pericardial thickening are two high risks features that warrant aetiology search, and this approach is consistent with 2015 European Society of Cardiology guidelines.3
We agree that IgG4-related disease should be suspected in the proper patient, presenting with…