The untreatable pain out of nothing
You are seeing a 43 year old male.
“Two weeks ago I woke up because of very strong pain in the left shoulder and the left upper arm. For one week I took every pain killer I had around – but nothing really helped! Then the pain got less and finally stopped. But now I cannot pick up for example my keys with thumb and index finger!”
In a quick clinical examination you notice weakness for pinch grip, but no sensory deficit.
On the pics you see his left median nerve on the upper arm – which looks like this for some centimeters. The last picture is side comparison. What is your diagnosis?
Please note: Images enlarge when clicking on them.
Parsonage Turner with AIN syndrome
Struthers' ligament compression
I think we have a pro here… 😊👍🏻
Dear Aleksandar! Compression because of a Struthers' ligament would take place at the distal humerus – you are completely right about this. However, there are several points that speak against this diagnosis in this case:
1. The patient tells us about sudden onset of strong pain, that also remitted spontaneously – in case of compression we would rather expect a chronic course.
2. Clinical examination shows an isolated weakness in pinch grip without a sensory deficit (which points to affection of the anterior interosseus nerve) – if the whole nerve is compressed we would rather expect the patient to develop the clincal picture of a proximal lesion of the median nerve, also including a sensory deficit.
3. Ultrasound: we admit, we only posted a picture not a video – but there was no sign of compression, no supracondylar spur and no ligament that could be visualized. Further, in case of compression we would only expect a short swelling of the nerve proximal (sometimes also distal) to the site of compression, not extending over some centimeters.
Putting a. history, b. clincial examination and c. ultrasound findings together allows establishing the diagnosis of Anterior interosseus syndrome (as one possible phenotype of neuralgic amyotrophy/Parsonage Turner Syndrome)