Chiasmal herniation following treatment of pituitary macroadenoma

Neuro-ophthalmic evaluation and management of pituitary disease

Neuro-ophthalmic evaluation is a crucial component of the diagnostic and prognostic assessment of pituitary disease and compressive chiasmopathy, and can inform the timing of vision-restoring tumour resection surgery. The most common disease affecting the pituitary with neuro-ophthalmic implications are pituitary adenomas. Neuro-ophthalmic manifestations include decreased vision, abnormal colour vision and impaired visual field or diplopia. The recognition of these syndromes is critical to achieve early diagnosis and treatment and to improve prognosis. The pattern of vision loss in chiasmal compression is determined by the anatomical relationship between the pituitary lesion and optic chiasm, and potential visual field defects include bitemporal deficits, junctional scotomas, monocular cecocentral defects, and incongruous homonymous hemianopias. Rarer neuro-ophthalmic manifestations of pituitary disease include ophthalmoplegia, nystagmus, and obstructive hydrocephalus. There is growing evidence that demonstrates the strong diagnostic utility of optical coherence tomography (OCT) parameters in detecting the presence of compressive chiasmopathy, as well as the prognostic ability to predict the rate and degree of visual recovery following decompression surgery. Long-term neuro-ophthalmic monitoring is critical for detecting delayed vision loss following resection surgery, which may represent tumour recurrence or secondary complications.

Growth hormone receptor antagonist pegvisomant and its role in the medical therapy of growth hormone excess

Pegvisomant is a growth-hormone (GH) receptor antagonist that prevents the formation of the active heterotrimer of the dimerised GH receptor and the GH molecule necessary for downstream signal transduction. Over the past 20 years, it has become a key therapeutic option for physicians treating syndromes of GH/IGF-1 excess. Sufficient longitudinal follow-up data suggest that it can be deemed both safe and effective. It is the drug with the greatest potential for achieving an amelioration of the biochemical effects of GH excess with a corresponding normalisation of IGF-1 levels; however, insufficient dose titration has lessened real-world therapeutic outcomes. Theoretical concerns about stimulating tumour growth have been resolved as this has not been observed, while derangement of liver enzymes and local skin-related adverse reactions may occur in a minority of the patients. It may be a particularly impactful medication for the treatment of children, young people, and those with inherited disorders of GH excess, where other treatment modalities often fail. Combination therapy of pegvisomant with first- and second-generation somatostatin receptor ligands or with dopamine agonists remains an ongoing area of interest and research. High cost remains a barrier to the use of pegvisomant in many settings.

How I do it: endoscopic endonasal chiasmopexy for optic chiasm prolapse

BACKGROUND

Prolapse of the optic system into an empty sella is an unusual complication of the management of pituitary tumors.

METHOD

We described the technical nuances for an endoscopic endonasal chiasmopexy, the indications for the procedure, and the caveats on the diagnosis of optic chiasm prolapse.

CONCLUSION

The endoscopic endonasal chiasmopexy provides a direct route to lift the optic system. In most cases, the procedure may be achieved extradurally, protecting the chiasm from manipulation and postoperative fibrosis.