Contempt is a criminal offense, so in theory, yes, you could be extradited.

This is how courts in the USA turn civil matters into criminal matters all the time. For instance, non-payment of child support: you can't legally be imprisoned for your debts, but if you fail to pay after the judge orders you to pay then you are in contempt and you are going to jail.

A judge can hold you upto 180 days.

For contempt?

I don't know which jurisdiction you're referring to, but certainly in Illinois state courts it's an unlimited offense. I don't think there are any statutory restraints on it. I've seen people be sentenced to 20 years for refusing to testify as the sole witness to a murder.

The comment was specifically talking about not paying child support. 180 days is the limit in Colorado.