When you have scotoma develop in one eye only and the patient has a pituitary adenoma, takes plaquenil, (hydroxychloroquine) and has ischemic microvascular disease, can you tell which one most likely caused the scotoma?

Ischemia. : Monocular ischemia most likely causes shots a in one eye. Plaquenil (hydroxychloroquine) and pituitary adenoma causes symmetrical bilateral schotoma.

Depends on VF defect: Plaquinil and ischmic optic nerve disease may produce similar visual field defects, however, examination should be able to differentiate the two. Pituitary field defects are quite different. A differentiation should be able to be ascertained.

Exam will help: Only with an exam can one pin down the etiology of the scotomama . The appearance of the optic nerve will help determine the cause. More than likely though it is not caused by the pituitary adenoida.