Abstract
Ophthalmoplegic migraine (OM) is a rare, enigmatic condition with a long and complicated history (1, 2). The patient, who became the subject of my first published paper (3), initially sparked my interest. OM almost always begins in childhood, with repeated episodes of headaches usually lasting several days, that gradually resolve while a third (rarely fourth or sixth) nerve palsy slowly evolves, leaving the patient with a painless unilateral third that recovers over the course of weeks.
The International Headache Society (IHS) Classification Committee doubted that OM ‘has anything to do with migraine’ because of the long duration of the headache. Some suggested it was a variant of the Tolosa–Hunt syndrome.
Magnetic resonance (MR) scanning has demonstrated a characteristic finding in all reported cases of bona fide OM involving the third nerve. The scans show thickening and contrast enhancement of the nerve root as it exits the midbrain. The abnormality may persist after the third nerve palsy resolves. A case involving only the superior division of the third nerve (4) and two involving the fourth nerve ((5); James A. Sharpe, personal communication) did not show enhancement, possibly due to the small calibre of the nerves. The only report of MR scanning in a patient with sixth nerve OM showed reversible enhancement of the nerve fascicle within the pons (6); this was only published in Abstract form, and we must await the full paper with figures to determine the veracity of the observation.
For the past three decades I have often sought comfort and heightened confidence when one of my opinions was shared by Professor James Lance, whom I regard as among our most astute neurological scholars. Thus, the article on OM in this issue of Cephalalgia by Lance and Zagami, contending that the entity is not migraine and not Tolosa–Hunt syndrome is in accord with, and thus strengthens, my convictions.
But what is OM? Ischaemia seems improbable for a recurrent cranial mononeuropathy. It certainly is not a schwannoma, as proposed by an author (7) who, along with the journal reviewers, seemed unaware of the previously reported MR studies. Lance and Zagami propose that OM is a recurrent demyelinating/inflammatory cranial neuropathy. They may be correct, but this will be impossible to prove without a post mortem study during an acute episode, a highly unlikely occurrence for a benign condition affecting mainly young people.
I am hopeful that the new IHS Classification will shift OM from ‘migraine’ to a ‘cranial neuralgia’ category.