Pituitary Innovation and Teaching
Dr. Irene Vanek video
Introduction: My name is Dr. Irene Vanek. I am a neuro-ophthalmologist, and I am part of the pituitary team. That means I manage vision, and I work closely with the neurosurgeons involved with pituitary care.
Presurgical assessments: They need the whole team involved, which means the neurosurgical aspect with the neuro-imaging. They need the endocrinologist for the hormonal assessment, because only some tumours are what we call secreting tumours – most of the tumours are not. I, as a neuro-ophthalmologist, deal with those who have decline of the vision. Of course, I see some with perfectly normal vision, and yet they have pituitary tumour, but they all get basic screening in order to know how we should most effectively manage them.
Physiology of vision: The physiology of vision, which involves the pituitary tumour, consists of the visual impulse, or the visual signal, being collected from the retina and goes into the optic nerve, which is the first station. It then goes to the chiasm, and those 2 structures are the most important in evaluating the visual dysfunction in patients with pituitary tumour. The other pathways, or the other stations, in this visual pathway, are very important for vision. But the pituitary tumour usually involves the anterior chiasmatic pathway, which is the optic nerve and the chiasm.
Visual problems that pituitary patients encounter: It really varies from patient to patient – some patients notice nothing at all and they could have accidentally found the pituitary tumour due to other quests, or they may complain of dimming vision (sometimes they may think it is cataracts or other eye causes). Sometimes they actually notice decrease of visual field, usually on the side, and it can be present in one eye or in both eyes. Some patients can notice decrease of colour vision perception, which actually happens with any cause which involves optic nerve function. Some patients may have double vision, and those in particular may be the ones who have a haemorrhage in the pituitary tumour, which we call pituitary apoplexy. That is one of the causes when they come to the hospital and get investigated pretty quickly because they have other symptoms associated with it as well, such as headaches.
Pressure in the eye: If you have a patient who has a secreting tumour, they may have a higher pressure, and they get picked up quite easily because they have all the hormonal changes. The regular pituitary takes much longer to recognize the visual decline, but often they are diagnosed by eye specialists or by ophthalmologists with glaucoma. And what often happens is that the pituitary tumour gets missed. And so I would like to bring to everybody’s attention that certain amount of patients will have glaucoma and yet they have a pituitary tumor. And so when there is a patient with glaucoma, I generally prefer to do imaging to make sure there is nothing in the brain associated with it. I have seen quite a number of patients with a large pituitary tumour who were managed by eye people for glaucoma for years.
Treatments? From the visual point of view, my role is to establish exactly what visual function they have at the time of examination. The time of examination ideally would mean that they come pre-op. So I would do my clinical examination, and I will do visual field. I may do HRT, which is a scanning of the optic nerve head, and I establish to what degree the visual function is comprised because the tumour grows out of the pituitary fossa and has approximately 1cm to travel before it reaches the chiasm. And once it happens, there is a propensity for visual decline. And they may notice visual field changes, usually on the side of the visual field and we call that, when that happens, compressive optic neuropathy. And we generally recommend surgery.
After surgery? It’s been my experience, unless the optic nerve has been really severely compromised prior to surgery, most patients do actually notice improvement of the vision, which is really most gratifying. They can notice the first improvements few days after the surgery, but we won’t really know what is the end result of vision for approximately a year.
FAQ? People who come here are usually frightened, because, for their vision, which is quite understandable. I try to establish exactly where they are at and reassure them that we can do something to improve their vision. In most cases, that is indeed so.
So the aim of the evaluation is to establish, in summary, exactly what visual function they have pre-op, and then see them immediately post-op, and then to follow-up with them in frequent intervals with visual field and clinical evaluations in order to manage any changes that may happen or occur along the way.
Will vision worsen more if tumour recurs? Certain percentages of tumours do recur in variable amounts of time, and more often than not, because we are not able to completely remove the tumour for neurosurgical reasons. The role of a neuro-ophthalmologist is to do frequently enough the examinations and the visual field to catch the change as it is happening. In other words, don’t let the vision drop too much. On the other side of the coin, there is the issue that the optic nerve is damaged, and that means the perfusion, or what we call the blood supply, to the optic nerve, has suffered somewhere along the way, and the optic nerve is much more sensitive to any additional burden, which, say, the new tumour can produce. And hence, one has to be more pro-active than perhaps expected by other specialists. And therefore, frequent check-ups are really on the top of my list.
The reasonably frequent question that I get is “what are the chances of restoring vision or the found optic nerve damage? This is a very important question because I do tell the patient that they have optic nerve damage, one eye, both eyes, or one eye more than the other. And then they ask me what will happen to this after the surgery? There are two sides of the coin to this: anatomy of the optic nerve, which tells me how the optic nerve looks like. That’s the anatomy. So I will tell them, “yes , the optic nerve looks pale, in one eye or in both eyes”. And the other side of the coin is, “how does this pale optic nerve appearance translate into what the vision can do?” So the appearance of the optic nerve is the anatomy. The visual field and the vision, as such, is function. And those two have to be understood in its complexity in order to be able to give the patient a proper answer as to what we expect the vision to be after the surgery. So in other words, just to make it really simple, you can have a pale optic nerve and see nothing or you can have a pale optic nerve and see 20/20. The problem with the pale optic nerve is that after, say, you have a prolonged pituitary tumour that hasn’t been detected in time, the longer it stays there, the more damage it has the chance to produce both to the anatomy and the function. And then if you de-bulk the tumour, and then sometimes in the future, in whatever interval, they get a new tumour, which grows reasonably slowly (as most of them do), then once you have this damage to the optic nerve, this optic nerve is more susceptible to trouble. And therefore, if I see them 6 months or2 years after surgery, and I am noticing any little change – decreased colour vision in particular. So I compare all the parameters of what I had in the previous examination, and I collect new data exactly of those same parameters, and any difference I see, I act upon. And the purpose is to make sure that with this particular damaged optic nerve, which is more susceptible, that they won’t have a rapid decline if we don’t interfere. So the most crucial question in any pituitary tumour management, from the visual point of view, is when to interfere. And that is what my role is.
Page last updated: June 3, 2016