Name:
Carpal Tunnel Syndrome: Richard S. Bedlack, MD, PhD, MS discusses the clinical examination for carpal tunnel syndrome.
Description:
Carpal Tunnel Syndrome: Richard S. Bedlack, MD, PhD, MS discusses the clinical examination for carpal tunnel syndrome.
Thumbnail URL:
https://cadmoremediastorage.blob.core.windows.net/a5ab0614-d0f2-4980-9a87-656e6ba1acee/thumbnails/a5ab0614-d0f2-4980-9a87-656e6ba1acee.jpg?sv=2019-02-02&sr=c&sig=vH8MxjKXWb0HeszX65dNoiLmV9%2Bap3NMwoUmmQ8iJmo%3D&st=2024-12-22T05%3A51%3A29Z&se=2024-12-22T09%3A56%3A29Z&sp=r
Duration:
T00H05M20S
Embed URL:
https://stream.cadmore.media/player/a5ab0614-d0f2-4980-9a87-656e6ba1acee
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/a5ab0614-d0f2-4980-9a87-656e6ba1acee/6830504.mp3?sv=2019-02-02&sr=c&sig=UuoSAED6B5LueyikFoLE9yKY7GLQymADYd9DOukL3F4%3D&st=2024-12-22T05%3A51%3A29Z&se=2024-12-22T07%3A56%3A29Z&sp=r
Upload Date:
2022-02-28T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
>> I'm Jann Ingmire with JAMAevidence. Today we'll hear from Dr. Richard Bedlack about Carpal Tunnel Syndrome, a topic discussion Chapter 10 of the Rational Clinical Examination. Welcome to the podcast Dr. Bedlack and please, introduce yourself to our listeners. >> Well, thanks for having me Jan. My name's Dr. Richard Bedlack. I'm a neurologist and a specialist in Neuromuscular Medicine at Duke University, and the Durham VA Medical Center in Durham, North Carolina. >> Well, thank you for joining us.
What causes carpal tunnel syndrome, and what are some of the more common signs and symptoms? >> So, Jan, within the wrist there's a small space, which is deep to something called the transverse carpal ligament and between the rigid carpal bones, this is called the carpal tunnel. And through it passes the median nerve and some flexor tendons. Carpal tunnel syndrome occurs when the median nerve gets compressed in this small space. And common symptoms of carpal tunnel syndrome include wrist pain, which sometimes radiates proximally up the forearm, as well as intermittent hand numbness, especially in the thumb, index, and middle fingers.
The most common sign is sensory loss over the median nerve dermatome, which involves the thumb, the forefinger, and the middle finger. In more severe cases, there can be weakness of the median innervated abductor pollicis brevis and opponens muscles as well. >> What is the prevalence of carpal tunnel syndrome in the general population? >> Jan, it turns out to be pretty common. So, 1/2 of 1% of the population reports that they were diagnosed with carpal tunnel syndrome, but it's probably even more common than that.
If you do population-based studies, the condition seems to exist in about 3% of Americans. >> How is carpal tunnel syndrome typically diagnosed? >> Jan, we can usually diagnose it by history and exam, electrodiagnostic testing, which means nerve conduction studies, can be used to confirm a diagnosis in confusing cases, or when conservative measures have failed, and surgery's being considered. >> During the physical examination, how can clinicians elicit symptoms and signs of carpal tunnel syndrome to aid in diagnosis?
And which findings favor the electrodiagnosis of carpal tunnel syndrome, and which findings seem to argue against it? >> That's an excellent question. So, Jan it turns out there's three parts of the history and exam for clinicians to remember. First, they can ask their patients to use something which is called the Katz hand diagram. This is a drawing of the palmar and dorsal hand surfaces and on this diagram, patients should color in the location of their pain and numbness.
Symptoms involving the fingertips and/or the thumb side of the hand are highly supportive of carpal tunnel syndrome with a likelihood ratio of 2.4. Symptoms involving only the ring and middle fingers and the ulnar side of the hand argue strongly against carpal tunnel syndrome with a likelihood ratio of 0.2. Second, clinicians can test the sensation of their patient's hands to see if there's median dermatomal sensory loss.
This can be accomplished by pressing a clean, sharp pin against the palmar surface of the index and the ipsilateral little fingers. Diminished pinprick sensation in the index finger compared to the little finger, which is called the hypoalgesia, is strongly supportive of carpal tunnel syndrome, with a likelihood ratio of 3.1. Finally, clinicians can test their patient's thumb abduction strength. To do this, they should have the patient raise their thumb perpendicular to the palm, so that it's directly over the middle of the palm.
The clinician will then attempt to press the thumb back down into the center of the patient's palm. This maneuver isolates the abductor pollicis brevis, which is innervated by the median nerve. Weakness in this muscle is supportive of carpal tunnel syndrome, with a likelihood ratio of 1.8. And normal strength in this muscle makes carpal tunnel less likely with a likelihood ratio of 0.5. >> Is there anything else you would like to tell our listeners about the clinical examination for carpal tunnel syndrome?
>> Jan, I'd just like to say that given how common carpal tunnel syndrome appears to be, I think it's important for clinicians to be aware of it and to remember the three key parts of the history and clinical exam that are helpful in making a diagnosis. Now there are many other questions and exam maneuvers that are sometimes employed. For example, Phalen's test and looking out for a Tinel sign, but these don't appear to be nearly as useful. For confusing cases or those that don't respond to conservative therapy, nerve conductions can be useful for confirming the diagnosis.
>> Well, thank you very much Dr. Bedlack for this helpful synopsis of diagnosing carpal tunnel syndrome. Additional information about this topic is available in Chapter 10 of the Rational Clinical Examination. This is Jan Ingmire talking with Dr. Richard Bedlack about Carpal Tunnel Syndrome for JAMAevidence.
