He and his lawyer have been challenging the legal basis for opening up his medical records. They have every right to do this and Limbaugh's lawyer is obligated to zealously represent his client's interests. It's already clear that this particular DA leaks derogatory statements about Limbaugh to the media, statements that can and have further tarnished his reputation -- which potentially affects his livelihood. In view of this, I have no difficulty understanding Roy Black's reluctance to hand them more ammunition if he doesn't have to.
There is a stark difference between pursuing your legitimate legal options and obstructing an investigation.
His constant whine has been that there's nothing IN his medical records to prove 'doctor shopping' - okay: then PROVE THAT by releasing the records to the court. The public doesn't have to know what is in them but if he has nothing to hide and states that they are harmless to his case then he should have no qualms about opening them to the court.
If there's nothing in them then they aren't 'ammunition', are they? He's tarnished his own reputation enough compared to the district attorney's supposed leaks.