| Affiliation |
(AGL) Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, Texas; Professor of Ophthalmology, Weill Cornell Medicine, New York City, New York; (AC) Class of 2023, Baylor College of Medicine, Houston, Texas |
| Transcript |
So today we're going to be talking about what you need to know about spinal tumor in a patient who presents as pseudotumor. So normally, pseudotumor cerebri is our alternative word for idiopathic intracranial hypertension, and the important part is the idiopathic, so we need to make sure that we meet the Modified Dandy criteria for idiopathic intracranial hypertension, and one of the problems with this word pseudotumor cerebri, someone could have pseudo tumor, no tumor in their cerebri, but still have spinal tumor causing intracranial hypertension, so that's why we prefer the term idiopathic intracranial hypertension, and that's why the Modified Dandy criteria require some sort of imaging study of the head, preferably MRI with MR Venogram to rule out sinus thrombosis with Gadolinium and lumbar puncture both to measure the opening pressure as elevated and to make sure the CSF content is normal. And so normally when we're doing lumbar puncture in patients with papilledema, we're thinking about meningitis and meningeal disease, but the other thing to measure in addition to pressure and cell count is the protein. And so if we have an elevated CSF protein, that can plug up the arachnoid granulations, which is one mechanism of causing increased intracranial pressure from the spine lesion. Or, the spine lesion itself could be blocking functionally the CSF hemodynamics or blocking the elastic reservoir in the spine, in the the cal sac, leading to increases in ICP. So if we see elevated CSF protein, that is one clue that in addition to an MRI/MRV of the head in this patient who has papilledema, we should be doing an MRI of the spine. And that is completely counterintuitive that you would have to image the spine in someone who has papilledema. And the tip off is the CSF protein. Now of course, in IIH, your symptoms can only be related to increases in intracranial pressure, so that means headache, pulse-synchronous tinnitus, diplopia, transient visual obscurations. So if you have any spine symptoms, that by itself is an imaging indication for the spine. You could have only signs related to increased ICP. And that means we can only have papilledema, Sixth nerve palsy, big blind spot, or some other nerve fiber load defect on the field. But you really can't have any other signs. But if you have spine signs, for sure you have to image the spine. And, the radiographic findings of increased intracranial pressure. And so one of the things you have to be careful of is, the MRI report in both intracranial hypertension that is primary, the idiopathic form, or secondary, such as spinal tumor, both can have all the radiographic signs of increased intracranial pressure, which means fluid in the sheath, flattening of the globe, empty sella, and venous sinus stenosis. Those are radiographic signs of increased intracranial pressure, not necessarily idiopathic intracranial hypertension. And so, we have to do the spinal tap, not only to do the opening pressure, but to make sure it's not meningitis, and also exclude elevated CSF protein. If our CSF protein is elevated, and we have papilledema, you should image the spine with or without the symptoms and signs of spinal disease, because what we're looking for is a spinal tumor. The spinal tumors that mimic pseudotumor cerebri are usually ependymomas and schwannomas, but any tumor or meningeal process in the spine can elevated your CSF protein and block arachnoid granulations and cause increased intracranial pressure and present with papilledema. So you should be thinking about spinal tumor when you have symptoms of spine, signs of spine, or CSF protein elevation. And before you call someone pseudotumor cerebri, make sure it's not real tumor spinalis. |
