Virtual Didactic - EMG Plexopathy presented by Leslie Rydberg, MD-EMG Plexopathy Led by Leslie Rydberg, MD

EMG Plexopathy Led by Leslie Rydberg, MD
Video Transcription
All right, let's go ahead and get started. I want to welcome everybody back to AP Virtual Didactics. My name is Sterling Herring, PGY3 at Vanderbilt.  We've gone through many of the goals already today. Housekeeping-wise, we're going to keep everybody video and audio muted, as always. If you have any questions,  you can click on the participant list. Scroll up near the top. You should be able to see my name, Sterling Herring. If you double-click that,  you can send me a question for our presenter, which I will relay to her at appropriate times, typically at the end of the talk, also as invited throughout the length of the talk.  If you have any questions, suggestions, or concerns about the series itself, please feel free to reach out to Candice. There's her email there on the screen,  or you can track her down on Twitter at the AAP Twitter handle. Again, just to reiterate, this series itself is wrapping up tomorrow, as we are getting feedback from folks  that they are having more and more clinical responsibilities and hopefully programs are ramping up the didactic curricula at home as well.  I'm hearing that that's kind of hit and miss, depending on the location. So that said, all of these videos will continue to be available on the AAP website.  I'll provide that website at the end of this lecture, but all of them will be available at least through the end of this calendar year. So if you've seen some,  but not been able to see all, or if some of your colleagues have been outsourced or redeployed to other departments and have missed out on some didactic opportunities,  we encourage you to invite them to go find these videos and watch them. You don't have to be a member, you don't have to pay anything. These are just a service that AAP is providing  and that our presenters are providing during this, the current outbreak. So that said, without further ado, we're excited to have Dr. Leslie Rydberg back with us  from Shirley Ryan Ability Lab, Northwestern University. Thank you for joining us, Dr. Rydberg. Thank you for having me back.  Happy Thursday, everyone. I'm glad we're wrapping up this series because it sounds like people are getting back to clinical work, which is great.  But of course, everyone needs a chance to learn a little bit more about plexopathy, which is one of my favorite topics. It looks like we have fewer people here today  than when we talked about radiculopathies, but I'm assuming that is more to do with people going back to clinical work and not because people here don't want  to talk about plexopathy.  Everyone wants to talk about plexopathy, always. It's one of the best topics, I think. I think. All right, I'm gonna share my screen here. As you're doing that, I will share  that we are seeing more delayed observation of these lectures now that things are kind of rolling back out in a clinical setting. Oh, that's great.  That's great, so you can come back and watch this one over and over and over again.  All right, so last time, if you caught it, we talked about radiculopathy, and I think the correlate to that is really thinking about the plexus lesion  because the peripheral nervous system is so intertwined that there's really a lot of comparisons between radiculopathy and plexopathy.  So we'll get started with a case to think about. So we have a 23-year-old man who was involved in a motor vehicle accident about four weeks ago.  He has a spinal cord injury, T6 spinal cord injury, and was complicated by a left olecranon fracture and had an ORIF and a left C5 to C7 transverse process fracture.  So he makes it to your rehab unit, and while he's there, he complains of left upper extremity weakness. So to start off with, what is in your differential diagnosis?  Throw a couple things out there in the chat.  All right, so I have one vote for a syrinx or urinary tract infection.  Okay, so from my standpoint, things that I'm thinking about, since this is a lecture about  plexopathy, I'm going to put plexopathy high on my list. So he could have had a nerve injury  related to the initial trauma, right? So plexopathy secondary to the high-speed traction injury.  But also on the differential is a nerve root avulsion secondary to the high-speed traction  injury. Could he have had an ulnar nerve injury that caused some weakness in the ulnar nerve  distribution or an undiagnosed traumatic brain injury? Let's see, a couple more votes here. Syrinx, radiculopathy, plexopathy, cervical myelopathy, or peripheral nerve injury. We've  got a pretty good differential here. So why should we do, or why can we do, electrodiagnostic testing  when we're working at plexopathy? So it can help us localize the lesion, right? So in this case,  I've given you nothing specific about where his arm is weak, so hopefully your physical examination would help you localize that a little bit more clearly. But it can tell us,  how electrodiagnostic testing can help us distinguish between a root-level lesion, a plexus lesion, or a peripheral, focal peripheral mononeuropathy. If we're thinking that it's a  plexus, then electrodiagnostic testing can help get us to a specific region within the plexus.  And then, of course, with electrodiagnostic testing, if we can see how severe a lesion is,  that can help with nerve recovery and counseling. So when we're thinking about the plexus, so this,  as you know, this is our tangle of nerves that provides all the motor and sensory innervation  for the extremity. So the plexus is created from the ventral ramus of the spinal nerves. You can  see that the plexus is here, so the ventral ramus, and it gets the contribution from the  dorsal root and the ventral root. So when we're thinking about electrodiagnostic testing, so we  can have sensory abnormality from a plexopathy, right? So the plexus injury is distal to the  dorsal root ganglion. So we expect that our sensory nerve conduction studies will be abnormal  in the affected region, okay? So this is different from our radiculopathy, which is proximal to the  dorsal root ganglion. So the sensory nerve is a really good place to differentiate between a  radiculopathy or a plexopathy. So the sensory nerve conduction studies should be abnormal in  the affected region. So the motor pattern of injury, so if you have an axonal injury, you may have reduced amplitudes in the...