Cranial nerve enhancement resulted from RPON would gradually disappear as the symptoms subside after an episode, but spontaneous resolution of nerve enhancement is very unlikely to be seen in neoplastic (e.g. schwannoma), inflammatory and infectious diseases. Contrast-enhanced MRI results can also reveal the location of nerve inflammation for disease diagnosis. Although Tolosa–Hunt syndrome (THS) and RPON share many clinical features, THS can be identified by the presence of granulomatous inflammation in the cavernous sinus, superior orbital fissure, or orbit in MRI scans.Magnetic resonance angiography (MRA) or CT angiography (CTA) can be used to examine cerebral blood vessels and to rule out vascular abnormalities, such as an aneurysm. In cases where intracranial vascular lesions, for example, subarachnoid hemorrhage cannot be completely ruled out after performing MRA or CTA, physicians may consider using traditional digital subtraction angiography (DSA) for more detailed investigation. Laboratory tests
Lumbar punctures and blood tests might be performed on those with RPON to identify other possible causes of cranial neuropathy, including diabetes, inflammatory diseases, infections, tumors, and other systemic diseases that involve either the central nervous system or the peripheral nervous system. The detection of abnormalities in these tests suggests that RPON is highly unlikely to be the culprit in cranial neuropathy, and more diagnostic tests should be done to find out the underlying condition. Treatment
To date, no clinical trials or treatment guidelines for RPON have been published.
Recurrent painful ophthalmoplegic neuropathy (RPON), previously known as ophthalmoplegic migraine (OM), is a rare neurological disorder that is characterized by repeated headache attacks and reversible ipsilateral paresis of one or more ocular cranial nerves (CN). Oculomotor nerve (CNIII) is by far the most common cranial nerve involves in RPON, while abducens nerve (CNVI) and trochlear nerve (CNIV) involvements are also reported. Globally, RPON was estimated to have an annual incidence rate of 0.7 per million as of 1990, no further epidemiological studies have been conducted. It occurs more often in children and females.Although the etiology of RPON is unknown owing to the rarity of this disease, various potential theories including migrainous and neuropathic mechanisms have been developed. Diagnosis is based on physical examination, magnetic resonance imaging (MRI), and ruling out other possible causes. Despite the fact that there are currently no evidence-based treatment guidelines for RPON, the most commonly used medications are corticosteroids that have been proven effective in alleviating the symptoms. As for people who are unresponsive to steroids, other treatments, such as anti-migraine drugs, botulinum toxin injection and strabismus surgery, may be utilized. For prevention, several medications including calcium channel blockers may be used. However, none have been proved consistently effective. RPON has a good overall prognosis as a result of the self-limiting nature of the condition, but permanent neurological damage may accumulate over repeated episodes. Signs and symptoms
The typical symptoms of RPON are recurrent headaches and ipsilateral paralysis of the extraocular muscles (ophthalmoplegia) that are responsible for controlling eye movements.