When is fluid in the mastoid cells a worrisome finding?

Mastoiditis is a common clinical entity that is technically present in all cases of otitis media; only a minority of cases actually represents the otolaryngologic emergency of acute coalescent mastoiditis. When reviewing an image with a radiologic diagnosis of mastoiditis, looking for key signs such as destruction of bony septa and considering patient presentation can help distinguish mild mastoiditis from acute coalescent mastoiditis.