Table 3.

Etiologies of abducens cranial nerve palsy based on anatomical localization

Anatomical localization	Etiologies
Nuclear	Congenital Demyelination Infarction Hemorrhage Cavernoma Tumors Wernicke–Korsakoff syndrome
Fascicle	Demyelination Infarction Tumors Hemorrhage Trauma
Subarachnoid space	Aneurysmal of the vertebral artery, posterior-inferior cerebellar artery Microvascular ischemia (diabetes, hypertension, dyslipidemia, coronary artery disease, and atherosclerosis) Meningeal inflammation: tubercular meningitis, cryptococcal meningitis, neuroborreliosis, Lyme’s disease, syphilis, CMV meningitis, skull base osteomyelitis Non-localizing signs: Benign intracranial hypertension, meningitis, Cerebral venous sinus thrombosis, intracranial space-occupying lesion Trauma Tumors: Nerve sheath tumor, Schwannoma, meningioma, ependymoma, Clival tumor, skull base tumor, nasopharyngeal tumor, carcinomatous/lymphomatous meningitis, metastasis Inflammatory: Sarcoidosis, IgG4 disease, Wegner’s granulomatosis, necrotizing vasculitis, systemic lupus erythematosus Arnold–Chiari malformation Miller Fisher syndrome Spontaneous intracranial hypotension
Petrous apex	Infection: Otitis media, mastoiditis Nasopharyngeal carcinoma Thrombosis of transverse/sigmoid sinus Trauma Paget’s disease
Cavernous sinus	Aneurysm from the internal carotid artery Carotid-cavernous fistula Cavernous carotid artery dolichoectasia Inflammatory: THS, sarcoidosis, IgG4 disease, Wegner’s granulomatosis Tumors: Nasopharyngeal carcinoma, pituitary macroadenoma, meningioma, lymphoma, meningioma, metastasis Infection: Mucormycosis, aspergillosis, tuberculoma 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, Wernicke–Korsakoff syndrome idiopathic palsies, post-radiation, Miller Fisher syndrome, infectious mononucleosis, pregnancy, trauma