Myoclonus

Now, myoclonus. Two types of myoclonus. If I had my hands like this and I had a needle in the extensor compartment of the arm and I hold it like this so it must be firing, because I’m extending my hands at the wrist. I would see continuous firing and then a transient drop, firing, now it’s firing again and transient drop and firing. This is the so-called negative myoclonus. So it can be a drop out and firing, or alternatively firing. So it can be a positive discharge or a negative discharge. It is very difficult to localize although people have tried to kind of retrain a part of the brain. The origin of firing can be brainstem of origin, cortical in origin, the weirdest ones are chord in origin. Myoclonus can originate anywhere. Those are the two principles of a myoclonus. They are associated with certain conditions. A beautiful paper on this in the New England Journal on the differential diagnosis of the progressive myoclonic epilepsy’s. I will summarize it for you. There are five of them. Know the associations with these things. Lafora body disease, and therefore in the Lafora body. You must have seen a picture of it. They like to show the Lafora body, I don’t know why. Neuronal ceroid lipo-fucinesis (?), a disease that I see on a regular basis. I’ve never seen a case of neuronal ceroid lipo-fucinesis and I hope I never do, but I will mention neuronal ceroid lipo-fucinesis if I see a case of myoclonus, especially if I’m taking the orals. If I’m discussing it at a case conference I will mention it, I will think about it perhaps in my clinical practice. Maybe that why I’ll get biopsies of the fat pad right in front of the pec. But in general, I won’t.

Unverricht-Lundborg disease. Here’s the list. In that list is this family of MERF diseases, myoclonic epilepsy and regular end fibers. The significance of MERF and to a certain degree _ as well, is that we have now seen … I’m sure you have seen the laboratories coming from ATHENA, that there has been linkage, at least for some of these phenotypes, with specific mitochondrial genomic abnormalities. Mitochondrial genome. So they are beginning to understand that a little bit more. They might hit you with that. I hope they don’t. But this is a list of five disorders associated typically with positive myoclonus, often cortical but not necessarily so.
Women’s health
I want to get to two other points on this list and the first is palatal myoclonus. Now palatal myoclonus is a weird thing and it is associated with a little anatomic factoid that people like to ask about so I’ll review it for you. Here is the phenomenon. This is some kind of, I don’t know, 76-year-old hypertensive, diabetic, alcoholic, multi-system renal failure guy who underwent a CABG and unfortunately had a cross-clamp time of about 56 hours. Came out and got off – can you believe it? – they had to shock him, he came back, but he was hyper-perfused with a blood pressure in the negative numbers for about 17 hours. You know what I’m getting at, don’t you? The nurse is very upset because he is bucking the vent, he’s bucking the vent rhythmically. “He’s bucking the vent rhythmically. Get the neurologist down here!” So you see this guy. He’s completely comatose, as you would expect. He was hypertensive, I mean he was zero-tensive for a long time and you know why he’s bucking the vent? Why we come to this conclusion? Because the vent tube is bucking around rather rhythmically no less. It wasn’t bucking, it was rhythmic bucking and it can have astonishingly fast frequencies or low frequencies and if you stand by the bedside without even doing an exam – I didn’t even take out my syringes – I suspected coma. So I’m sitting there and listening to this and there is this strange ack, ack, ack, clicking sound. What the hell is this? Well, it turns out that the palate can just go into a status myoclonica or something. It just starts going like this. And the rhythm can be highly variable. Low rhythm or fast rhythm. It is associated with a structural lesion, believe it or not. The major pathology associated with palatal myoclonus is hypertrophy of the inferialis. Ridiculous question so I put it in just for fun.

Just to end the case, there’s this weird syndrome of painful legs and moving toes and is just what it is called. What the presentation is, is typically in someone who has had a failed back or some kind of radiculopathy this is what happens. This is the foot, this is the little toe and, in the cases that I’ve seen, so strange – they come in because “I have to see a neurologist because I have a really bad callus on my toe.” Go see a podiatrist, for God’s sake. “No, you don’t understand. In my shoe my little toe is clicking away like this.” A little movement disorder. Painful legs, moving toes. I end with that because it is so ridiculous. It sort of captures the experience of this whole Boards preparation thing.

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