Walsh & Hoyt: Diagnosis of Infranuclear Ophthalmoplegia

In patients with monocular ophthalmoplegia involving more than one ocular motor nerve, or in patients with bilateral ophthalmoplegia, several possibilities must be considered. Myopathies or disorders of the neuromuscular junction may be responsible, rather than the ocular motor nerves. When the etiology is neurologic, the lesion may be anywhere from the brain stem to the orbit. Intrinsic brain stem lesions may produce mixtures of ocular motor nerve pareses on one or both sides combined with supranuclear disorders of gaze. Extrinsic masses adjacent to the brain stem (especially those that grow along the skull base)and lesions in or near the cavernous sinus, such as meningiomas and pituitary adenomas, are particularly prone to produce both unilateral and bilateral ocular motor polyneuropathies. Pathologic processes including ischemia, hemorrhage, inflammation, compression, infiltration, metabolic dysfunction, toxic reactions, trauma, and degeneration may each be responsible. In most cases, the clinical history and a careful examination, when combined with appropriate neuroimaging, systemic, and otolaryngologic studies, are sufficient to identify the site and nature of the disease process.