Optic neuritis

Multiple sclerosis is an autoimmune, demyelinating CNS disorder causing optic neuritis, myelitis, and brainstem/cerebellar syndromes separated in space and time. Diagnosis uses the McDonald MRI-based criteria; acute relapses are treated with high-dose glucocorticoids, and disease-modifying therapy (interferon beta, glatiramer, or a higher-efficacy agent such as ocrelizumab or natalizumab) is started early to prevent relapse and disability accumulation.

Sudden painless monocular vision loss from occlusion of the posterior ciliary artery by giant cell arteritis infarcts the optic nerve head and threatens the fellow eye within days. Treatment with high-dose glucocorticoids must begin on clinical suspicion, before biopsy confirmation, because established blindness is usually permanent.

Papilledema is bilateral optic disc swelling from raised intracranial pressure, most classically idiopathic intracranial hypertension; imaging to exclude a mass lesion or venous sinus thrombosis must precede lumbar puncture, and acetazolamide is the first-line drug once idiopathic intracranial hypertension is confirmed.

Giant cell arteritis is a granulomatous large- and medium-vessel vasculitis of patients over 50 that threatens irreversible blindness through ischemic optic neuropathy. Diagnosis is clinical and must not delay treatment: start high-dose glucocorticoids immediately on suspicion, intravenous methylprednisolone pulse for visual loss, then confirm with temporal artery biopsy within 1 to 2 weeks and add tocilizumab as glucocorticoid-sparing therapy.

Transverse myelitis is inflammation across one or more contiguous spinal cord segments causing subacute weakness, a sensory level, and bladder or bowel dysfunction; diagnosis requires spinal MRI showing cord enhancement or CSF inflammation with exclusion of compressive and infectious causes, and idiopathic disease is treated with high-dose intravenous methylprednisolone.

Idiopathic intracranial hypertension (formerly pseudotumor cerebri) is raised intracranial pressure of unclear cause, without a mass lesion or hydrocephalus, occurring mainly in obese women of childbearing age and presenting with headache, papilledema, and visual symptoms. Diagnosis requires an elevated lumbar puncture opening pressure with normal CSF and normal or empty-sella imaging; treatment centers on weight loss and acetazolamide to protect vision, with surgery reserved for medically refractory disease.

Central retinal artery occlusion is sudden, painless, profound monocular vision loss from embolic or thrombotic occlusion of the central retinal artery, an ocular stroke equivalent in which irreversible retinal infarction begins around 90 minutes after complete occlusion. Diagnosis is clinical on dilated fundoscopy, and management pairs time-critical reperfusion attempts with an emergency embolic and giant-cell-arteritis workup to protect the fellow eye and prevent a subsequent stroke.

Acute angle-closure glaucoma is a pupillary-block emergency in which sudden closure of the iridocorneal angle blocks aqueous outflow, causing severe eye pain, halos, and rapidly rising intraocular pressure that can blind the eye within hours if not treated. Diagnosis is clinical plus tonometry and gonioscopy; treatment is immediate topical and systemic IOP-lowering therapy followed by laser peripheral iridotomy.

Sarcoidosis is a multisystem granulomatous disease of unknown cause defined by noncaseating granulomas, most commonly involving the lungs and hilar lymph nodes. Most patients are asymptomatic or have a self-limited course staged by chest radiograph; symptomatic organ-threatening disease is treated with systemic glucocorticoids, with methotrexate or another steroid-sparing agent added for glucocorticoid-refractory or glucocorticoid-intolerant disease.

Lyme disease is a tick-borne spirochetal infection caused by Borrelia burgdorferi that progresses from erythema migrans through early disseminated cardiac and neurologic disease to late arthritis, diagnosed clinically when erythema migrans is present and otherwise by two-tiered serology, and treated with staged doxycycline, amoxicillin, or cefuroxime regimens.