Table 2.

Etiologies of fourth cranial nerve palsy based on anatomical localization

Anatomical localization	Etiologies
Nuclear	Trauma Infarction Hemorrhage Cavernoma Demyelination Tumors
Fascicle	Trauma Infarction Hemorrhage Cavernoma Demyelination Tumors
Subarachnoid space	Aneurysmal of the superior cerebellar artery Trauma Microvascular ischemia (diabetes, hypertension, dyslipidemia, coronary artery disease, atherosclerosis) Meningeal inflammation: tubercular meningitis, cryptococcal meningitis, neuroborreliosis Hypertrophic meningitis: Sarcoidosis, IgG4 disease, Wegner’s granulomatosis Hydrocephalous Benign intracranial hypertension Tumors: Nerve sheath tumor, Schwannoma, meningioma, ependymoma, carcinomatous/lymphomatous meningitis, metastasis Iatrogenic trauma during neurosurgical procedures Miller Fisher syndrome
Cavernous sinus	Inflammatory: THS, sarcoidosis, IgG4 disease, Wegner’s granulomatosis Tumors: pituitary macroadenoma, meningioma, lymphoma, metastasis Infection: Mucormycosis, aspergillosis, tuberculoma Aneurysm from the internal carotid artery, carotid-cavernous fistula Pituitary apoplexy
Orbit	Infection: Aspergillosis, mucormycosis, pyogenic orbital cellulitis, tuberculosis of orbit Tumors Inflammatory, granulomatous: Sarcoidosis, IgG4 disease Orbital trauma
Localization unknown	Migraine, congenital, postviral palsy, idiopathic palsies, postradiation, Miller Fisher syndrome