Spotlight on Visual hallucinations in blindness

In this clinical summary, Dr. Douglas Lanska of the Great Lakes VA Healthcare System at the VA Medical Center in Tomah, Wisconsin, explains the clinical presentation, pathophysiology, diagnostic workup, and management of visual hallucinations in blindness. Bonnet syndrome (sometimes referred to as Charles Bonnet syndrome) is now most commonly considered to refer to visual hallucinations in visually impaired individuals with full alertness, unimpaired cognition, and no psychosis. Although Bonnet syndrome is most commonly identified in patients with bilaterally decreased central visual acuity, similar phenomena also occur in patients with retrochiasmal visual field defects. Bonnet hallucinations are thought to result from a “release” mechanism associated with modality-specific sensory deprivation, ie, “phantom vision” akin to phantom limbs in patients with loss of somatosensory input after an amputation. Although there is no definitive treatment available for Bonnet syndrome, various ophthalmologic interventions, behavioral strategies, and pharmacologic agents have been used to try to reduce or relieve symptoms.

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MedLink Neurology authors are always at work to bring you broad and up-to-date coverage of neurology topics. We are pleased to highlight clinical summaries that have been recently added or updated and to introduce the authors who write these authoritative articles. We hope you enjoy these overviews and appreciate the contributions of our more than 450 authors who keep MedLink Neurology the premier information resource for neurologists.

Spotlight on Hyperornithinemia

Hyperornithinemia is a slowly progressive disease, primarily of the eyes, with visual deterioration starting in late childhood and blindness around the fifth decade of life. It is an autosomal-recessive inborn error of metabolism due to deficiency of the enzyme ornithine aminotransferase. Chorioretinal degeneration and hyperornithinemia are diagnostic for the disease. Except for a few cases that respond to vitamin B6, treatment is strict protein restriction and supplementation of arginine-free amino acid mixture. Successful reduction of ornithine halts the progression of the disease In this clinical summary, Dr. Andreas Schulze of the University of Toronto provides an in-depth review of the clinical presentation, pathophysiology, diagnosis, and treatment options for hyperornithinemia.

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MedLink Neurology authors are always at work to bring you broad and up-to-date coverage of neurology topics. We are pleased to highlight clinical summaries that have been recently added or updated and to introduce the authors who write these authoritative articles. We hope you enjoy these overviews and appreciate the contributions of our more than 450 authors who keep MedLink Neurology the premier information resource for neurologists.

Spotlight on Temporal arteritis

Temporal arteritis is an important cause of ischemic complications in elderly patients, and timely diagnosis can prevent important morbidity, most notably blindness from either anterior ischemic optic neuropathy or central retinal artery occlusion. These patients, left untreated, are also at increased risk for ischemic stroke. Treatment with high-dose corticosteroids is effective in preventing these complications, and initial treatment with intravenous pulse corticosteroids leads to more sustained clinical remission and lower subsequent oral corticosteroid dosage requirement. Other adjunctive immunosuppressant drugs are also currently being used in this setting as steroid-sparing agents.

In this clinical summary, Dr. James Goodwin of the University of Illinois Eye & Ear Infirmary cites work indicating that oral or intravenous cyclophosphamide is a viable option for treatment of steroid-refractive temporal arteritis or as a steroid-sparing agent when symptoms return at prednisone doses greater than 10 mg/day.

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MedLink Neurology authors are always at work to bring you broad and up-to-date coverage of neurology topics. We are pleased to highlight clinical summaries that have been recently added or updated and to introduce the authors who write these authoritative articles. We hope you enjoy these overviews and appreciate the contributions of our more than 450 authors who keep MedLink Neurology the premier information resource for neurologists.