## Clinical Context Bitemporal superior quadrantanopia with a sellar mass compressing the optic chiasm from below is a neurosurgical emergency. The inferior nasal fibres of the optic chiasm (which cross first and represent the superior visual fields) are compressed, causing the characteristic bitemporal superior field loss. ## Why Urgent Neurosurgical Consultation? **Key Point:** Compressive lesions of the optic chiasm risk permanent visual loss and can cause pituitary apoplexy if the mass enlarges acutely. Transsphenoidal decompression is the definitive treatment for sellar masses causing optic chiasm compression. **Clinical Pearl:** The superior visual field loss (rather than inferior) indicates compression from below — typical of pituitary adenomas. This requires urgent surgical decompression to prevent irreversible vision loss and restore pituitary function. **High-Yield:** Any mass compressing the optic chiasm with progressive visual field defect is a surgical emergency. Delay risks permanent blindness. ## Management Algorithm ```mermaid flowchart TD A[Bitemporal superior quadrantanopia + sellar mass]:::outcome --> B{Acute vision loss?}:::decision B -->|Yes or progressive| C[Urgent neurosurgical consultation]:::action B -->|Stable, chronic| D[Elective surgical planning]:::action C --> E[Transsphenoidal decompression]:::action E --> F[Restore visual function & pituitary axis]:::outcome ``` ## Why Other Options Are Wrong - **Corticosteroids alone:** Useful for inflammatory causes (optic neuritis, sarcoidosis) but do not relieve mechanical compression. Delay worsens prognosis. - **VEP testing:** While VEP may show demyelination in optic neuritis, this patient has a structural mass on imaging — diagnosis is already confirmed. VEP delays urgent decompression. - **Topical timolol:** Addresses glaucoma, not the underlying compressive pathology. Irrelevant to chiasmal compression. 
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