Zero to GP - GP Revision Podcast
The Zero to GP podcast helps you learn and revise the key facts that you need for your GP exams. It is for educational purposes only. The information is not medical advice and should not be used to guide patient management. There may be errors - always check with the appropriate policies, guidelines and colleagues.
Zero to GP - GP Revision Podcast
Carpal Tunnel Syndrome - Essential GP Revision
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Carpal tunnel syndrome for general practice exams.
Video version: https://youtu.be/QTcPtcvHiYE
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Full AKT Revision Course: https://zerotofinals.com/courses/zerotoakt/
Hi, this is Tom, and in this episode I'm going to be going through carpal tunnel syndrome. And as always, the format for these episodes is I'm going to present you with a case, ask you questions, and I want you to come up with your answer during the gap. And then I'll go through an explanation. So let's jump straight into this episode. So our case today is a 46-year-old woman, and she presents to you as her GP with intermittent numbness and a tingling sensation in her right hand. And she says this is much worse at night. Sometimes it wakes up from wakes her up from sleep with these symptoms, and she says she shakes her hand to try and relieve the symptoms. You're suspecting carpal tunnel syndrome, as this episode would suggest.
SPEAKER_00The question first question I have for you is which nerve is affected in this condition?
SPEAKER_01Carpal tunnel syndrome affects the median nerve.
SPEAKER_02The second question is what is the basic pathophysiology?
SPEAKER_01What's causing these problems with the median nerve?
SPEAKER_02It's really a case of looking at the carpal tunnel. And the carpal tunnel is found in the wrist, and the median nerve travels through the carpal tunnel. The carpal tunnel is between the carpal bones underneath, and across the top is this band, this fibrous band that runs across the wrist called the flexor retinaculum. And between the flexor retinaculum and the carpal bones is the carpal tunnel. The medium nerve is getting squashed inside the carpal tunnel. So that carpal tunnel is too tight and it's squashing the median nerve, preventing signals travelling through that nerve. My next question is which areas are affected in the hand with sensory symptoms in carpal tunnel syndrome? The answer is the thumb, the index finger, the middle finger, and the lateral half of the ring finger. The little finger is shouldn't be affected in carpal tunnel syndrome. If the little finger is affected, um think about a different diagnosis. It could be that there's pathology in the ulnar nerve, but um in carpal tunnel syndrome and with median nerve pathology, the little finger's not usually affected.
SPEAKER_01My next question is what are the key risk factors for carpal tunnel syndrome? There's quite a few risk factors for carpal tunnel syndrome.
SPEAKER_02The first one is repetitive strain on the carpal tunnel. It can be caused by inflammation and swelling of the carpal tunnel due to repetitive strain. So if somebody's using that area a lot, that can trigger carpal tunnel. Other key risk factors that would predispose include obesity, being perimenopausal, and being female on itself is a risk factor, but being perimenopause increases the risk further, rheumatoid arthritis, diabetes, acromegaly with excessive growth hormone, and hypothyroidism. So if you've got a patient presenting with carpal tunnel syndrome, particularly bilateral carpal tunnel syndrome, think about could there be an underlying cause here, such as diabetes, acromegaly, or hypothyroidism? And if you're suspecting endocrine pathology, it may be worth testing for the HBO1C for diabetes, thyroid function test for hypothyroidism, and look at other features that may indicate acromegaly. Okay, on to the next question, which is what motor symptoms may the person experience with carpal tunnel syndrome. So we talked about the sensory distribution of the median nerve, but the median nerve also supplies the motor function, meaning the innervation to the muscles of the thena muscles. So carpal tunnel syndrome can cause weakness of the thena muscles, which are the muscles at the base of the thumb, causing that bulge at the base of the thumb. So this can cause weakness with grip and fine motor skills involving the thumb, and it can cause wasting of that bulky thinar um section of the hand of the hand at the base of the thumb. So if there's muscle wasting there, that could be carpal tunnel syndrome. My next question is what special tests can you do with the patient right in front of you to test specifically for carpal tunnel syndrome?
SPEAKER_01The first one is Phelan's test.
SPEAKER_02And what this involves is having the patient put their hands together with their wrists at 90 degrees, with their um with the backs of their hands against each other and the elbows um out at sort of 90 degrees to the hand. And what this does is with the hands, with the wrist flexed at 90 degrees, um, it puts pressure on the carpal tunnel. And so being in this position it with during phalanx test should recreate some of those carpal tunnel uh syndrome symptoms. So the tingling, the numbness in the hand, and if that the if that's the case, that suggests carpal tunnel syndrome. The second special test is Tinnel's test, and this involves tapping the wrist at the carpal tunnel. So tapping over where the carpal tunnel is should also recreate symptoms. It can take 30 seconds or a minute of these tests before the symptoms are recreated. But uh yeah, tapping over the carpal tunnel, recreating the carpal tunnel syndromes of tingling, uh, pins and needles, numbness in the hand, that's a positive Tinels test suggesting carpal tunnel syndrome. My next question is let's say you're unsure about the diagnosis and you want a definitive investigation. Which definitive test can tell you if there's carpal tunnel syndrome? The definitive test is nerve conduction studies, and this involves placing electrodes in the hand and then the other side on the wrist, other side of the carpal tunnel. So you're placing electrodes on one side and a receiver on the other side, and seeing how well the nerve signals travel through the nerve through the carpal tunnel. And if these signals are reduced, that can suggest carpal tunnel syndrome. You don't always need nerve conduction studies to confirm the diagnosis. If there's typical symptoms and the presentation is very suggestive, you don't necessarily need nerve conduction studies to confirm the diagnosis, but it's helpful if there's doubt. The next question is what conservative options would you have if you've got a patient in front of you, you're suspecting carpal tunnel syndrome, it's a typical kind of presentation. What conservative options do you have initially? So the first thing I tend to start with is recommending a wrist splint at nighttime. So this needs to be a rigid wrist splint that holds the wrist completely straight at nighttime. What happens is people tend to sleep with their wrists flexed during the night, which is what exacerbates the carpal tunnel syndrome and recreates the symptoms. By having a wrist splint, holding the wrist straight at night, that can help reduce the inflammation, settle the carpal tunnel syndrome, and resolve the symptoms. So trying this for say six weeks plus may be enough to resolve the carpal tunnel syndrome and they may not need any further treatment. Another option if facilities are available is to do a steroid injection in the carpal tunnel, and there's options of hand exercises to help to improve the medium nerve function and the hand function. The next question is when would you review this patient? After how long would you review this patient who's trying the conservative options? They need a follow-up after a six weeks trial of conservative options, such as the wrist splints at night, and then if the symptoms have not improved, at that point you consider a specialist referral.
SPEAKER_00Final question is what's the definitive management of carpal tunnel syndrome.
SPEAKER_02And this essentially means cutting the carpal tunnel to relieve the pressure inside that space and relieve the pressure on the median nerve, and this should definitively treat the condition. So thanks for watching this episode. I hope it's been helpful in your GP revision. If you're preparing for the AKT exam, check out the Zero to GP AKT revision book. It contains keynotes on all the topics you need for your GP exams and will help with uh clinical practice, although it's not designed to be used as a reference for clinical practice. There's also the zero to GP.com site, which contains a full question bank and a fact trainer tool and flashcards and notes on uh the all the stuff you need for your GP exams, the full AKT curriculum, and I've got an upcoming course on the 13th of September, where it's a day-long course in London. I'll be presenting all the key stuff, all the key topics for your AKT exam to give you a massive boost towards your exam. Head over to zero to finals.com slash courses to find out more and see all the reviews and the feedback and the testimonials about that course. Um, it will massively increase your chances of passing and doing well in the AKT exam. But for now, uh I'll leave you and I'll see you in the next episode.