Cushing's Disease Management

Introduction to Treatment

For patients with Cushing's disease presenting with diplopia, selective adenomectomy via transsphenoidal surgery is the first-line treatment to address the underlying cause, followed by appropriate management of diplopia based on the specific mechanism of visual disturbance 1
Selective transsphenoidal adenomectomy should be performed by surgeons experienced in pituitary surgery to maximize outcomes, with post-operative cortisol level < a certain threshold correlating with long-term remission 1

Consider repeat transsphenoidal surgery if initial surgery fails, and offer radiotherapy if disease is not amenable to curative surgery, with fractionated radiotherapy being effective 1
Stereotactic radiosurgery or gamma knife approaches may be considered for radiotherapy, as an alternative to traditional fractionated radiotherapy 1

Medical therapy, such as certain medications, can be used to reduce cortisol burden while awaiting definitive treatment, and temporary measures like Fresnel or ground-in prism can be used for small to moderate deviations, and occlusion therapy for intractable diplopia 1, 2

For persistent diplopia after Cushing's disease treatment, surgery on restricted eye muscles (primarily recessions) can be performed when deviation has been stable for at least 6 months, with horizontal deviations having better surgical outcomes than vertical deviations 2
Avoid resections in restrictive disease unless necessary for large deviations, and consider surgical recession of affected muscles after disease stability for diplopia due to extraocular muscle restriction 2

A basic evaluation should confirm whether the diplopia is monocular or binocular, assess eye movements in the nine positions of gaze, perform cover/uncover and alternate cover tests, and examine visual acuity and refraction, as recommended by the American Academy of Ophthalmology 2
Key diagnostic tests include:

The American College of Radiology recommends the following imaging modalities:

Condition	Recommended Imaging
Orbital trauma or suspected metallic foreign body	CT Orbits (non-contrast) [3]
Suspected extraocular muscle or soft tissue abnormalities	MRI Orbits with contrast [2, 3]
Suspected brainstem, cavernous sinus, or cranial nerve pathology	MRI Brain with contrast [3]
Suspected aneurysm (especially with pupil-involving 3rd nerve palsy)	CT angiography or MR angiography [2, 3]
Suspected infectious causes	Testing for syphilis and Lyme disease [2]

Lifelong follow-up is essential as recurrence of Cushing's disease can occur up to 15 years after apparent surgical cure, and patients should be informed that the goal is to eliminate diplopia in primary position and downgaze, but it may persist in extreme positions of gaze 1, 2
The prognosis of monocular diplopia depends on the underlying cause, with refractive causes typically having a good prognosis with proper correction, and retinal causes being more challenging to resolve completely, with a moderate level of evidence 2
Binocular diplopia due to microvascular causes often resolves spontaneously within 6 months, and common minor complications include foreign body sensation and subconjunctival hemorrhage, while serious complications, such as globe perforation, endophthalmitis, and anterior segment ischemia, are rare, as reported by the American Academy of Ophthalmology 2