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Chiasmal syndromes
Neuro-Ophthalmology
Key Points
- •Bitemporal hemianopia is the hallmark of chiasmal lesions - it results from damage to the crossing nasal retinal fibers and respects the vertical midline
- •Pituitary adenoma is the most common cause of chiasmal compression - prolactinoma is treated medically (cabergoline first-line), while non-functioning adenomas require transsphenoidal surgery
- •The junctional scotoma (ipsilateral central scotoma + contralateral superotemporal defect) indicates a lesion at the optic nerve-chiasm junction - due to Wilbrand knee fibers looping into the contralateral optic nerve
- •Bow-tie (band) atrophy is the characteristic disc appearance in chiasmal disease - the degree of pre-existing optic atrophy is the strongest predictor of visual recovery after decompression
- •Always check endocrine profile in chiasmal syndromes - prolactin >200 ng/mL suggests prolactinoma (treat medically), while mild elevation <100 ng/mL may be stalk effect (does NOT indicate prolactinoma)
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Keep reading Chiasmal syndromes
17 more sections are included with the Clinical plan.
- Definition
- Epidemiology
- Aetiology and causes
- Pathogenesis
- Classification
- Risk factors and associations