The IHS criteria should be revised

In 1988, the IHS defined the diagnostic criteria of Tolosa-Hunt syndrome (THS) to include episode(s) of unilateral orbital pain for on average of 8 weeks if untreated, with associated paresis of one or more of the third, fourth, and sixth cranial nerves. Cranial nerve paresis may coincide with the onset of pain or follow it within a period of up to 2 weeks and the pain has to be relieved within 72 hours after the initiation of corticosteroid therapy. Other causative lesions have to be excluded by neuroimaging. On the basis of the history and neuroradiological findings of six patients, we show the pitfalls in diagnostic evaluation of THS based on these criteria. We propose a revision of the IHS criteria: Other causative lesions have to be excluded by neuroimaging especially of the region of the cavernous sinus and the orbita, as well as by blood and CSF diagnostics. With modern imaging techniques ii is now possible to visualize the inflammatory tissue in THS. Positive MRI or CT findings compatible with inflammatory tissue neither exclude nor confirm THS and remain suspect, until a malignant tumor or inflammation other than THS is excluded. Clinical and radiological follow-up examinations have to be performed for at least two years, even in patients with negative MRI at onset.