Can I extend my tourist visa exemption in Thailand for medical reasons?

The hospital can arrange an extension - for a fee

You can get a 30 day extension for 1900baht on your 60 day visa exempt entry in Bangkok at the IT Square Laksi Plaza immigration office. If you haven't taken it, go do it, you can apply for a 30 day extension when you have 45 days or less left on your current stamp and you don't lose any time applying early.

IF you already took that 30 day extension and want to get an extension based on medical reasons, you'd need documentation from the hospital stating you cannot travel for xxx days.

You'd go to the immigration office and get an extension based on medical necessity for 1900baht. They can be issued for up to 90 days but the documents from the hospital has to request how long they say you can't travel until