Disappearing diplopia - An unusual presentation of Tolosa-Hunt syndrome: A case report

Tolosa-Hunt syndrome (THS) is a rare benign treatable cause of painful ophthalmoplegia with frequent VI, III, IV cranial nerve (CN) involvement. Optic and trigeminal nerve involvement is rare but described. The disease is characterized by severe preceding or concomitant headache and remarkable response to steroids. Although labelled benign residual neurology is not uncommon in THS.We present a case of THS in a middle-aged Sri Lankan male who presented initially with vertical diplopia and normal contrast enhanced CT scan, treated as for idiopathic IV nerve palsy. A month henceforth he developed severe episodic headache with autonomic symptoms, right sided ptosis and progressive visual impairment with improved diplopia, normal fundoscopy, inflammatory and infective markers and autoimmune profile. MRI brain showed enhancing lesion of cavernous sinus extending to orbital apex consistent with THS. He showed dramatic improvement with steroids with complete resolution of neurology at the end of 4 weeks.THS should be considered in a patient presenting with disappearing painful diplopia. Headache may mimic primary headache syndromes and may not precede ophthalmoplegia. Imaging may be initially normal. MRI is mandatory for diagnosis as histology is not always feasible. Steroid responsiveness can be diagnostic if more sinister differentials are ruled out.