| Description |
Summary: • Neurocysticercosis is caused by pork tapeworm Taenia solium; affected patients will either have traveled to or lived in a country where T. solium is endemic • Eggs from worm or worm's muscular proglottid (reproductive part) are released in the worm's feces, which is consumed by (e.g.) a pig > pig gets taeniasis: worm grows inside pig and cysts form in muscle o Human ingests egg (from salad, fruit, water, etc.) and egg may travel to the head instead of intestine > cyst forms in the brain or eye (neurocysticercosis) > Cystic lesion can be inside the ventricle (intraventricular), in subarachnoid space, or parenchyma • Inflammatory response occurs once worm dies; vesicular (cystic) stage > colloidal phase > involution > calcification (shows up on CT), which can be symptomatic or not o Symptomatic: seizure disorder (parenchymal disease) or papilledema (intraventricular or subarachnoid), mass effect due to increased ICP, 6th nerve palsy, diplopia (cyst in extraocular muscle), vitritis/uveitis/asymptomatic (cyst in eye) o i.e., the alive worm is actually better for you than the dead worm • Diagnosis made by seeing cysticerca in blood or CSF; will see pleocytosis and possibly eosinophils • Treatment: albendazole, praziquantel, sometimes steroids o If worm is alive and encysted in the eye, surgical procedure like vitrectomy may be required to remove the worm →must do an eye exam before starting treatment! o Be prepared for inflammatory consequences if you kill the worm • Takeaways for consumers: undercooked pork is not the only concern o When travelling, it is best to follow CDC guidelines and only eat cooked food so you don't ingest the eggs yourself; avoid salads, peel and wash fruit yourself, boil water before drinking |
| Transcript |
So today we're going to be talking about neurocysticercosis in neuro-ophthalmology, and we're going to be focusing on the neuro part because we're interested in the neurophthalmic presentations of the cysticercosis. As you know, the life cycle of this organism is really important to understand how you get it but also number two, who's going to get it. So, we're going to be interested in this condition when people are from or who have travelled to endemic countries that have the tapeworm Taenia solium, which is the pork tapeworm. So, there are other tapeworms but this is the one we're going to be talking about today. And so the life cycle of this thing is the eggs - either the eggs from the organism or the shed muscular proglottid from the segments of the worm - and that worm, the tapeworm, is living inside of the intestines of the person. So, the worm sheds the segments and the eggs in their feces, and then some organism comes and eats that. And this is a terrible drawing of my pig. So this pig is going to eat that poo which contains the egg, and then the pig will get taeniasis, so the worm is going to grow inside this pig and these cysts are going to be in the muscle. And so normally, you're thinking, okay, if I don't eat undercooked pork, I won't get the cyst which is inside the muscle of this pig. And if a human being eats this then it'll go down into their intestine, and by that I mean you're eating the egg which happens to be on your salad, or on a piece of fruit, or just in the water. And if that happens, then sometimes the egg gets confused and the tapeworm doesn't get to go to your intestine; it migrates up into your head, and then you get a cyst which is supposed to be hatching in your intestine but the cyst is now in your brain or in your eye, and that we call neurocysticercosis. So when the cystic lesion is inside your head, it can be inside the ventricle and intraventricular, it can be in the subarachnoid space in the meninges, or it can be in the parenchyma itself. And normally as long as the worm is alive, your immune system isn't going to attack it so it kind of has a symbiotic relationship with you. But as soon as the worm dies, the inflammatory response will occur, and so there are different stages of neurocysticercosis: the vesicular stage, which is the cystic stage, and then, over time, the worm starts making it into like a colloidal phase and then once it dies, it goes into involution and then becomes calcified. So when we do a CT scan of neurocysticercosis, if we see all the calcified versions of it, that is the involuted form, the calcified form, the worm is dead, and that can either cause a symptom or be asymptomatic. And the most common symptom that we see is seizure disorder from parenchymal disease, but it can come to us as papilledema because they have intraventricular or subarachnoid form, they have the meningeal form, or mass effect any of the number of mechanisms of increased intracranial pressure. So the way that neurocysticercosis comes to me is the cyst that's in the muscle caused diplopia, or the cyst is in your eye and it can cause inflammation vitritis, uveitis, or be asymptomatic, or the cyst could be in your brain and cause increased intracranial pressure and papilledema and sixth nerve palsy, etc. So those are the ways that neurocysticercosis comes to me, and as long as the worm is alive, you're probably not going to notice it. But once it dies, now you got problems because the inflammatory response is going to kick in and that's actually where the problem is going to arise. And so, the diagnosis is made by seeing the cysticerca and the body, and that you can do in the blood or the CSF, you're going to do spinal tap in patients with papilledema, there's going to be a pleocytosis, there might be eosinophils. And then the treatments are of course the anti-worm treatments albendazole, praziquantel, etc. And sometimes we need steroids because once you kill the worm, kind of like a Jarisch-Herxheimer-like reaction might occur and make you worse. In addition, we've got to look in their eye because if we see the worm and it's alive and encysted in the eye, then we really can't be killing that worm, because it'll cause the inflammation in your eye, and so that might require a surgical procedure like a vitrectomy to actually take the worm out. So we need to look in their eye. The most important part for you as a consumer is, it's not just undercooked pork. So, undercooked pork is how you get the worm - that's taeniasis, that's the regular life cycle - and usually the pig is the one that's eating the shed poo egg, but sometimes you are the pig in the lifestyle, and that's how you get neurocysticercosis. So when I travel, I follow the CDC guidelines for avoiding/acquiring these kinds of infections by only eating cooked food. If I'm gonna have a raw thing like a fruit, I peel it myself and wash it in clean water. I don't eat the salads, I only stick to cooked food. And it really doesn't matter about the pork, the pork is for taeniasis. And so you really got to worry about accidentally ingesting poo when you travel. So that is following the CDC guidelines. I also don't drink the water there and I boil everything that I'm going to drink. So you need to know a little bit about neurocysticercosis, both its life cycle and also that the alive worm is actually better for you than the dead worm. And if you're going to kill the worm, you need to be ready to deal with the consequences, the inflammatory consequences, and always do an eye exam before starting treatment. |
