CSS remove HTML elements that contain only a

I have HTML headings and paragraphs that look like this:

<h2><br></h2>
<p><br></p>

How would I remove these paragraphs and headings using purely CSS? To make it more difficult I want to remove the parent that contains only <br> tags.

For example <p>foo<br></p>would not be removed.

I would prefer to not use JavaScript/jQuery if possible.